張金林,李惠茹,郭姝媛,王鎖民,施華中,韓慶慶,包愛(ài)科,馬清

(1.草地農(nóng)業(yè)生態(tài)系統(tǒng)國(guó)家重點(diǎn)實(shí)驗(yàn)室,蘭州大學(xué)草地農(nóng)業(yè)科技學(xué)院，甘肅 蘭州 730020;2.美國(guó)德克薩斯理工大學(xué)化學(xué)與生物化學(xué)系,德克薩斯 拉伯克 TX79409,美國(guó))

?

高等植物適應(yīng)鹽逆境研究進(jìn)展

張金林1*,李惠茹1,郭姝媛1,王鎖民1,施華中2,韓慶慶1,包愛(ài)科1,馬清1

(1.草地農(nóng)業(yè)生態(tài)系統(tǒng)國(guó)家重點(diǎn)實(shí)驗(yàn)室,蘭州大學(xué)草地農(nóng)業(yè)科技學(xué)院，甘肅 蘭州 730020;2.美國(guó)德克薩斯理工大學(xué)化學(xué)與生物化學(xué)系,德克薩斯 拉伯克 TX79409,美國(guó))

土壤鹽堿化已經(jīng)成為制約農(nóng)作物生長(zhǎng)及產(chǎn)量的重要因子之一，尋求將鹽堿化對(duì)植物的危害降低到最小程度的策略勢(shì)在必行。關(guān)于植物對(duì)鹽逆境適應(yīng)能力的研究已成為全球關(guān)注的熱點(diǎn), 如何提高植物的耐鹽能力也已成為研究的重中之重。深入探究高等植物適應(yīng)鹽逆境的機(jī)制，有助于提高植物耐鹽性，增加作物產(chǎn)量和保護(hù)生態(tài)環(huán)境。本文就高等植物適應(yīng)鹽逆境的重點(diǎn)研究進(jìn)展，綜述了鹽脅迫對(duì)植物的危害；植物耐鹽的生理機(jī)制，包括滲透調(diào)節(jié)、營(yíng)養(yǎng)元素平衡和增強(qiáng)抗氧化脅迫等；植物耐鹽相關(guān)基因研究進(jìn)展，包括離子轉(zhuǎn)運(yùn)蛋白基因、滲透調(diào)節(jié)相關(guān)基因、信號(hào)傳導(dǎo)相關(guān)基因和細(xì)胞抗氧化相關(guān)基因等；提高植物耐鹽性的途徑。最后針對(duì)今后植物適應(yīng)鹽逆境方面的研究方向進(jìn)行了展望。

高等植物；鹽脅迫；耐鹽性；耐鹽基因

地球表面70%的面積被海洋覆蓋，海水中Na+濃度大約在500 mmol/L以上，而K+濃度僅為9 mmol/L[1]；地殼當(dāng)中鈉元素含量為2.8%，而鉀元素為2.6%[2]。因此，地球被稱(chēng)為“咸行星”[1]。在中世紀(jì)，鹽(氯化鈉，NaCl)被稱(chēng)為“白色金子”，因?yàn)樗呛忘S金一樣昂貴的商品[3]。鹽堿土在陸地生態(tài)系統(tǒng)上分布廣泛，全世界鹽漬土面積約l0億hm2[4]。在全球的干旱和半干旱地區(qū)，約有50%的灌溉土地受到鹽堿化的影響，區(qū)域內(nèi)的非灌溉土地同樣會(huì)發(fā)生鹽堿化[4]。中國(guó)土地鹽漬化大約占到全球鹽漬土面積的1/10[5]，從濱海到內(nèi)陸，從低地到高原都分布著不同類(lèi)型的鹽漬化土地[6]。在長(zhǎng)期的自然進(jìn)化過(guò)程中，海洋植物保留了對(duì)高濃度鹽分的耐受性，然而，大多數(shù)陸生高等植物在進(jìn)化過(guò)程中喪失了這種耐受性而采取了一種甜土植物的生活方式[7]。土壤中可溶性鹽分過(guò)多，會(huì)對(duì)植物造成傷害[4,8]。因此，土壤鹽堿化已經(jīng)成為影響農(nóng)作物生長(zhǎng)及產(chǎn)量的重要因子之一，關(guān)于植物對(duì)鹽逆境適應(yīng)能力的研究已成為全球關(guān)注的熱點(diǎn)。如何提高植物的耐鹽能力已成為研究的重中之重。高等植物對(duì)鹽逆境的適應(yīng)是一個(gè)綜合的生物調(diào)節(jié)過(guò)程，需要各種生理生化過(guò)程的協(xié)同作用，而非某種單一的過(guò)程就能夠使植物成功地抵御鹽逆境。本文綜述了鹽脅迫對(duì)植物的危害，植物適應(yīng)鹽逆境的方式，提高植物耐鹽性的途徑和植物耐鹽的相關(guān)基因研究進(jìn)展，最后針對(duì)植物適應(yīng)鹽逆境方面的研究進(jìn)行了展望。

1 鹽逆境對(duì)植物的危害

鹽逆境對(duì)植物造成的直接危害首先表現(xiàn)為滲透脅迫，并且持續(xù)存在；緊接著表現(xiàn)為離子失調(diào)引起的毒害和營(yíng)養(yǎng)元素的虧缺；最后引起的氧化脅迫導(dǎo)致膜透性的改變、生理生化代謝的紊亂和有毒物質(zhì)的積累，進(jìn)而引起植物生長(zhǎng)發(fā)育和形態(tài)建成的改變(圖1)[1,7-10]。

圖1 鹽脅迫對(duì)植物的危害以及植物耐鹽的主要生理機(jī)制[9]

1.1滲透脅迫

首先，在鹽脅迫下，植物種子的萌發(fā)會(huì)受到影響，一般分為滲透效應(yīng)和離子效應(yīng)。滲透效應(yīng)引起溶液滲透勢(shì)降低而使種子吸水受阻，從而影響種子萌發(fā)；離子效應(yīng)通過(guò)鹽離子(Na+、Cl-、SO42-等)直接毒害而抑制種子萌發(fā)[11]。在對(duì)一年生植物種子耐鹽機(jī)制進(jìn)行研究時(shí)，發(fā)現(xiàn)高鹽濃度會(huì)對(duì)種子產(chǎn)生滲透抑制，只有脅迫減輕時(shí)才能消除這種抑制作用[12]。李昀等[13]通過(guò)對(duì)堿茅(Puccinelliadistans)、黑麥草(Loliumperenne)、野大麥(Hordeumbrevisubulatum)、鹽爪爪(Kalidiumcapsicum)、堿蓬(Suaedaglauca)五種牧草研究發(fā)現(xiàn)，鹽濃度升高，種子的發(fā)芽率會(huì)降低。其次，對(duì)于整株植物而言，若土壤中的鹽分過(guò)多，則會(huì)導(dǎo)致土壤中的水勢(shì)下降，植物細(xì)胞的水勢(shì)相對(duì)過(guò)高，導(dǎo)致植物吸水困難，嚴(yán)重的還會(huì)引起植物失水，引起生理干旱[7]。

1.2離子失調(diào)

土壤中的鹽分多以離子形式存在，雖然高等植物對(duì)土壤中的離子具有選擇吸收作用，但是在吸水的同時(shí)，也必定會(huì)吸收大量的鹽離子[1,7-10]。K+在細(xì)胞內(nèi)可作為60多種酶的活化劑，能促進(jìn)蛋白質(zhì)的合成，促進(jìn)糖類(lèi)的合成與運(yùn)輸；K+也是構(gòu)成細(xì)胞滲透勢(shì)的重要成分[14]。而在根內(nèi)K+可以從薄壁細(xì)胞轉(zhuǎn)運(yùn)至導(dǎo)管，從而降低導(dǎo)管中的水勢(shì)，使水分能從根系表面轉(zhuǎn)運(yùn)到木質(zhì)部中去[15]。K+對(duì)氣孔開(kāi)放有直接作用，有研究表明，K+可以維持細(xì)胞的滲透平衡，在氣孔的關(guān)閉中起作用，還可以作為許多酶的輔助因子行使生理功效[16]。土壤中K+的濃度范圍在0.2～10.0 mmol/L之間，而K+和Na+的水合半徑相似，因此高濃度的Na+會(huì)阻礙植物對(duì)K+的吸收，造成K+匱缺，從而抑制了以上提到的依賴(lài)于K+的生理生化反應(yīng)的正常進(jìn)行[4,7]。同時(shí)，大量Na+、Cl-進(jìn)入細(xì)胞可以破壞Ca2+平衡，細(xì)胞質(zhì)中游離Ca2+急劇增加，使Ca2+介導(dǎo)的鈣調(diào)蛋白(calmodulin,CaM)調(diào)節(jié)系統(tǒng)和磷酸肌醇調(diào)節(jié)系統(tǒng)失調(diào)，細(xì)胞代謝紊亂甚至傷害死亡[17]。此外，土壤中高濃度的鹽分還會(huì)抑制植物對(duì)NO3-和NH4+的吸收，而對(duì)NO3-吸收的抑制作用更大[18]。

1.3氧化脅迫

細(xì)胞膜是植物細(xì)胞重要的保護(hù)屏障，對(duì)物質(zhì)運(yùn)輸、能量傳遞、信號(hào)轉(zhuǎn)導(dǎo)有重要作用。細(xì)胞膜本身具有選擇透過(guò)性，因而可以調(diào)節(jié)細(xì)胞內(nèi)的離子平衡，同時(shí)滿(mǎn)足植物生理活動(dòng)的需要。然而，鹽脅迫導(dǎo)致的氧化脅迫會(huì)使膜的透性發(fā)生改變，一方面對(duì)離子的選擇性、流速、運(yùn)輸?shù)犬a(chǎn)生影響；另一方面，也造成了磷和有機(jī)物質(zhì)的外滲，從而使得細(xì)胞的生命活動(dòng)受到影響[7]。丙二醛(malondialdehyde,MDA)含量的高低和細(xì)胞質(zhì)膜的透性變化是反映膜脂過(guò)氧化作用強(qiáng)弱和質(zhì)膜破壞程度的重要指標(biāo)，其含量可說(shuō)明植物遭受逆境傷害的程度[19]。活性氧的增加還會(huì)破壞細(xì)胞中具有膜結(jié)構(gòu)細(xì)胞器的結(jié)構(gòu)，如引起線(xiàn)粒體DNA的突變，造成細(xì)胞衰老，導(dǎo)致內(nèi)質(zhì)網(wǎng)部分膨脹、線(xiàn)粒體數(shù)目減少而體積膨脹、液泡膜破碎、胞質(zhì)降解等。

1.4光合作用受挫

鹽逆境會(huì)使得植物的光合速率下降，葉綠素是表征光合利用率的最重要的指標(biāo)之一。隨著鹽濃度升高，葉綠素a、b和類(lèi)胡蘿卜素含量均顯著降低，表明高鹽脅迫抑制或破壞了光系統(tǒng)Ⅱ的部分功能，光合作用的能量及電子傳遞受到抑制[20]。同時(shí)，鹽分過(guò)多可使磷酸烯醇式丙酮酸羧化酶(phosphoenolpyruvate carboxylase,PEPC)與1,5-二磷酸核酮糖羧化酶(ribulose-1,5-bisphosphate,Rubisco)活性降低，引起脅迫初期光合作用明顯下降[21]。

1.5有毒物質(zhì)的積累

鹽脅迫下，由于植物細(xì)胞結(jié)構(gòu)的損傷、活性氧的積累、生理代謝的破壞，植株體內(nèi)蛋白質(zhì)的合成速率降低，水解加速，造成植株體內(nèi)氨基酸積累，會(huì)產(chǎn)生許多的有毒物質(zhì)，如大量氮代謝的中間產(chǎn)物，包括NH3和某些游離氨基酸(異亮氨酸、鳥(niǎo)氨酸和精氨酸)轉(zhuǎn)化成有一定毒性的腐胺(如丁二胺、戊二胺等)，而腐胺又可被氧化成NH3和H2O2，當(dāng)它們達(dá)到一定濃度時(shí)，細(xì)胞會(huì)中毒死亡[22]。這些物質(zhì)的積累，會(huì)抑制植物內(nèi)相關(guān)物質(zhì)的合成，使得植物生長(zhǎng)受抑。

2 植物耐鹽的生理機(jī)制

植物受到鹽害脅迫時(shí)，會(huì)采取兩種方式來(lái)減輕鹽脅迫造成的危害：躲避鹽離子的傷害和增強(qiáng)對(duì)鹽脅迫的耐受性[6]。植物避鹽的方式主要分為4種：泌鹽、稀鹽、積鹽和拒鹽。泌鹽(salt excretion)是指植物在吸收鹽分后，不在體內(nèi)存儲(chǔ)，而是通過(guò)體內(nèi)的鹽腺等器官或機(jī)制排出體外，再通過(guò)雨水沖刷等方式脫鹽，從而維持植物體內(nèi)的離子穩(wěn)態(tài)。泌鹽被認(rèn)為是一個(gè)有助于鹽生植物抗鹽的重要機(jī)制[5,23-24]。稀鹽(salt-dilution)是指植物通過(guò)吸收大量的水分、使細(xì)胞加速生長(zhǎng)(增加薄壁細(xì)胞組織，使細(xì)胞質(zhì)膨脹，增大細(xì)胞壁伸展度等)、改變形態(tài)等方法，稀釋體內(nèi)鹽分，降低鹽濃度[7,23]。積鹽(salt-accumulation)是指植物體內(nèi)的原生質(zhì)特化后，將根部吸收的鹽分區(qū)隔化至液泡，同時(shí)，抑制鹽分從液泡內(nèi)溢出，即將鹽分儲(chǔ)存在液泡內(nèi)，作為廉價(jià)的滲透調(diào)節(jié)劑[7,23]。拒鹽(salt-exclusion)是指植物本身排斥鹽離子進(jìn)入細(xì)胞，依靠其對(duì)鹽的不透性，阻止鹽分進(jìn)入植物體；另一方面，植物根部通過(guò)阻止Na+向木質(zhì)部的裝載和加大對(duì)Na+外排來(lái)減少植株對(duì)Na+積累。絕大多數(shù)栽培植物都屬于拒鹽能力弱的甜土植物，拒鹽能力強(qiáng)的鹽生植物有蘆葦、堿茅[7,23,25]。除了通過(guò)以上4種方式來(lái)躲避鹽離子的傷害，所有高等植物都可以通過(guò)以下幾個(gè)方面的生理調(diào)節(jié)過(guò)程來(lái)增強(qiáng)對(duì)鹽脅迫的耐受性，即滲透調(diào)節(jié)、營(yíng)養(yǎng)元素平衡和增強(qiáng)抗氧化脅迫(圖1)。

2.1滲透調(diào)節(jié)

在鹽逆境脅迫下，高等植物通常會(huì)采用兩種滲透調(diào)節(jié)方式，一是在植物體內(nèi)合成有機(jī)調(diào)節(jié)物質(zhì)；二是積累更多的無(wú)機(jī)離子。

通常有機(jī)溶質(zhì)大體可分為3類(lèi)：1) 游離氨基酸(如脯氨酸)，具有很大的水溶性，其疏水端可和蛋白質(zhì)結(jié)合，親水端可與水分子結(jié)合，蛋白質(zhì)可借助脯氨酸束縛更多的水，從而防止?jié)B透脅迫條件下蛋白質(zhì)的脫水變性；它可以維持細(xì)胞內(nèi)外滲透平衡，防止水分散失[26]。2)甜菜堿，作為一種無(wú)毒的滲透調(diào)節(jié)劑和酶的保護(hù)劑，它的積累使植物細(xì)胞在鹽脅迫下保持膜的完整性，在滲透脅迫下仍能保持正常的功能。許多高等植物，尤其是藜科和禾本科植物，在受到水/鹽脅迫時(shí)積累大量甜菜堿[27]。甜菜堿對(duì)類(lèi)囊體膜也有穩(wěn)定作用，并顯著提高光系統(tǒng)Ⅱ光合放氧的穩(wěn)定性；甜菜堿能保護(hù)抗氧化酶系統(tǒng)[超氧化物歧化酶(superoxide dismutase,SOD)、抗壞血酸過(guò)氧化物酶(ascorbate peroxidase,APX)、過(guò)氧化氫酶(catalase,CAT)等]的活性[28]；甜菜堿還可以穩(wěn)定生物大分子的結(jié)構(gòu)與功能，解除高濃度鹽對(duì)酶的毒害作用，防止脫水誘導(dǎo)的蛋白質(zhì)熱動(dòng)力學(xué)干擾[29]。3)可溶性糖和多元醇，也可以作為滲透調(diào)節(jié)物質(zhì)，調(diào)節(jié)植物細(xì)胞的滲透勢(shì)，從而增強(qiáng)植物的耐鹽機(jī)制[30]。

無(wú)機(jī)離子(K+,Na+和Cl-)作為滲透調(diào)節(jié)劑具有很多優(yōu)點(diǎn)，也日益受到重視。首先，由于離子的大量存在，無(wú)需消耗物質(zhì)和能量來(lái)大量合成，所以較為廉價(jià)；第二，無(wú)機(jī)離子的調(diào)節(jié)作用可以在短時(shí)間內(nèi)迅速完成；第三，它們的作用也顯著高效[31]。無(wú)機(jī)離子在整株植物滲透調(diào)節(jié)中的作用可以很簡(jiǎn)易地通過(guò)直接測(cè)量莖或根的滲透壓而容易的驗(yàn)證，并且可以與它們?cè)诮M織液中的濃度進(jìn)行比較。無(wú)機(jī)離子主要是 K+、Na+、Cl-，無(wú)論是在鹽生植物還是在非鹽生雙子葉植物中，這3種離子提供了80%至95%的細(xì)胞液滲透壓[31]。K+是循環(huán)豐富的離子，同時(shí)K+是植物生長(zhǎng)的必需元素，在維持細(xì)胞的基本功能中扮演了重要角色，并且在保持低水平的蛋白酶和核酸內(nèi)切酶活性以及防止植物在鹽脅迫下細(xì)胞損傷和死亡中的作用也是不言而喻的[32]。有研究表明，堿茅與更敏感的長(zhǎng)穗偃麥草(Elytrigiaelongata)相比，在嚴(yán)重的高鹽或缺氧條件下，長(zhǎng)穗偃麥草將更嚴(yán)重地丟失K+，從而證明了K+保留在根中對(duì)高鹽缺氧土地耐受性的作用[33]。而對(duì)積鹽型鹽生植物而言，對(duì)Na+的吸收遠(yuǎn)遠(yuǎn)大于K+的吸收[34]。絕大部分被植物細(xì)胞吸收的Na+并非存在于細(xì)胞質(zhì)中，而是區(qū)隔化在液泡中作為廉價(jià)的滲透調(diào)節(jié)物質(zhì)來(lái)維持正常細(xì)胞膨壓，從而增強(qiáng)植物抵御鹽逆境的能力[35-37]。研究表明，在介質(zhì)當(dāng)中添加適量的NaCl可以增強(qiáng)荒漠植物霸王(Zygophyllumxanthoxylum)的抗旱性，從而促進(jìn)其生長(zhǎng)[38-39]；進(jìn)一步分析表明，干旱脅迫下霸王葉中Na+濃度顯著增加了64%，Na+對(duì)葉滲透勢(shì)的貢獻(xiàn)由8%增至13%；50 mmol/L NaCl處理使干旱脅迫下霸王葉中Na+顯著增加了2.3倍，Na+對(duì)葉滲透勢(shì)的貢獻(xiàn)增至28%，從而提高了植株的滲透調(diào)節(jié)能力[38]。

2.2營(yíng)養(yǎng)元素平衡

在正常生理狀態(tài)下，植物細(xì)胞內(nèi)的離子保持均衡狀態(tài)，而在鹽脅迫下，細(xì)胞質(zhì)中過(guò)多的離子尤其是Na+對(duì)植物細(xì)胞的代謝活動(dòng)會(huì)有傷害。大多數(shù)植物在鹽脅迫下，組織內(nèi)的K+含量會(huì)降低[4]。王鎖民等[40]在對(duì)植物Na+、K+的選擇性吸收及運(yùn)輸?shù)难芯炕A(chǔ)上，首次提出植物根系對(duì)土壤中Na+、K+的選擇性吸收(selective absorption,SA)能力以及植株不同部位對(duì)Na+、K+選擇性運(yùn)輸(selective transport,ST)能力的計(jì)算公式。研究表明，小花堿茅(Puccinelliatenuiflora)可以在高Na+環(huán)境下生存，且其體內(nèi)維持很低的Na+濃度，主要依靠其對(duì)K+/Na+強(qiáng)大的選擇性吸收能力和限制Na+的吸收[25]。這一結(jié)果在對(duì)鹽敏感和耐鹽品種的長(zhǎng)穗偃麥草的比較研究中得到了進(jìn)一步證實(shí)，即耐鹽品種的SA和ST值均顯著大于鹽敏感品種[41]。海濱堿蓬(Suaedamaritima)體內(nèi)的K+含量變化是隨NaCl濃度的升高而呈升高趨勢(shì)，這樣既可以保持一定的K+營(yíng)養(yǎng)，還可以保持相對(duì)穩(wěn)定的K+/Na+，這對(duì)植物本身生長(zhǎng)有利[42]。在鹽脅迫的條件下，提供某些微量元素，可有效地提高植物的含水量，促進(jìn)植物的光合作用，有利于植物生長(zhǎng)。研究表明，在含有Na+的土壤中添加硅時(shí)，植株的含水量提高了7.3%，同時(shí)，植物的光合效率、CO2同化效率等也得到了顯著地提高；在黃瓜(Cucumissativus)[43]、大麥(Hordeumvulgare)[44]、水稻(Oryzasativa)[45-46]、紫花苜蓿(Medicagosativa)[47]、小麥[48]和草地早熟禾(Poapratensis)[49]等植物研究中也得到了同樣的結(jié)果。

2.3增強(qiáng)抗氧化脅迫

在正常的生理?xiàng)l件下，植物體內(nèi)的活性氧自由基和自身的抗氧化系統(tǒng)對(duì)活性氧的清除是動(dòng)態(tài)平衡的，可以保持體內(nèi)正常的代謝過(guò)程。在干旱、鹽漬等脅迫下，膜脂過(guò)氧化作用加劇，植物體內(nèi)活性氧含量上升，隨之超氧化物歧化酶、過(guò)氧化物酶(peroxidase,POD)、過(guò)氧化氫酶和抗壞血酸(ascorbic acid,ASA)等保護(hù)酶的活性也相應(yīng)增加，從而防止膜脂的過(guò)氧化作用，以此來(lái)增強(qiáng)植物對(duì)逆境的耐受性[50]。管博等[51]在鹽地堿蓬(Suaedasalsa)的研究發(fā)現(xiàn)，隨著鹽脅迫的增強(qiáng)，SOD作為防御活性氧自由基(reactive oxygen species,ROS)的第一道防線(xiàn)，其活性顯著增加，CAT活性變化趨勢(shì)與SOD相似。此發(fā)現(xiàn)在對(duì)梭梭(Haloxylonammodendron)[52]和溝葉結(jié)縷草(Zoysiamatrella)[53]的研究中也得到證實(shí)。有研究表明，高鹽和干旱處理下，西藏野生大麥(Hordeumvulgarevar.trifurcatum)體內(nèi)的ROS水平會(huì)顯著升高來(lái)抵御傷害[54]。然而在重度鹽脅迫下，植物體內(nèi)的這些活性氧去除劑的結(jié)構(gòu)發(fā)生破壞，植物清除活性氧的防御能力下降，使膜脂的過(guò)氧化作用加劇，破壞細(xì)胞膜的透性[4,7,55]。

3 高等植物耐鹽相關(guān)基因研究進(jìn)展

隨著分子生物學(xué)的發(fā)展，人們能夠在基因組成、表達(dá)調(diào)控及信號(hào)轉(zhuǎn)導(dǎo)等分子水平上認(rèn)識(shí)植物的耐鹽機(jī)理；并且已經(jīng)通過(guò)對(duì)植物耐鹽相關(guān)基因的研究，來(lái)進(jìn)一步提高植物的耐鹽性。目前，高等植物耐鹽相關(guān)基因的研究主要集中在離子轉(zhuǎn)運(yùn)蛋白基因、滲透調(diào)節(jié)相關(guān)基因、信號(hào)傳導(dǎo)相關(guān)基因、細(xì)胞抗氧化相關(guān)基因等。

3.1離子轉(zhuǎn)運(yùn)蛋白基因

3.1.1質(zhì)膜上離子轉(zhuǎn)運(yùn)蛋白基因 有研究表明，環(huán)核苷酸調(diào)控通道(cyclic-nucleotide-gated channel,CNGCs)和非選擇性陽(yáng)離子通道/電壓非依賴(lài)型通道(non-selective cation channel/voltage-independent channel,NSCCs/VICs)是不同類(lèi)型的通道蛋白，在一些植物中CNGCs涉及Ca2+的信號(hào)轉(zhuǎn)導(dǎo)，而NSCCs/VICs涉及Na+的攝入[56]。而NSCCs/VICs[57]是根部Na+進(jìn)入細(xì)胞膜的通道蛋白，當(dāng)NSCCs通道被抑制時(shí)，就可緩解細(xì)胞的鹽脅迫(圖2)。Tyerman和Skerrett[58]在研究小麥根部的NSCCs通道時(shí)發(fā)現(xiàn)，涌入的Na+主要分布于根部的各個(gè)區(qū)室及表皮的原生質(zhì)內(nèi)。低親和性陽(yáng)離子轉(zhuǎn)運(yùn)體(low-affinity cation transporter,LCT1)是從小麥中發(fā)現(xiàn)的一類(lèi)能夠介導(dǎo)低親和性陽(yáng)離子吸收的蛋白[59]。研究表明，小麥中的LCT1不僅可以維持Rb+與Na+的濃度的平衡，吸收少量的Ca2+，也可維持Na+/K+的濃度[60]；但由于受到土壤中Ca2+濃度的影響，LCT1并不是Na+流入的主要通道[4,61]。

高親和K+轉(zhuǎn)運(yùn)載體(high-affinity K+transporter,HKT)是一種與植物耐鹽性密切相關(guān)的Na+或Na+-K+轉(zhuǎn)運(yùn)蛋白，能將植物木質(zhì)部中過(guò)多的Na+卸載到其周?chē)”诩?xì)胞中，降低地上部Na+含量，并維持體內(nèi)K+穩(wěn)態(tài)平衡[4,62](圖2)。根據(jù)在異源表達(dá)系統(tǒng)中對(duì)Na+和K+運(yùn)輸?shù)牟煌琀KT蛋白可被分成兩種[63]：HKT1作用于外部K+缺乏時(shí)，主要用于特異性Na+的運(yùn)輸和介導(dǎo)Na+的吸收[64]；HKT2則是有K+-Na+協(xié)同轉(zhuǎn)運(yùn)蛋白及其同系物的功能[4]。Ren等[65]繪制了一個(gè)水稻SKC1基因的QTL圖譜，并發(fā)現(xiàn)SKC1基因編碼一種HKT型K+/Na+通道蛋白，在植物鹽脅迫下調(diào)節(jié)K+/Na+離子平衡，維持細(xì)胞內(nèi)外的滲透壓，從而提高植物耐鹽能力，后來(lái)證明SKC1為水稻HKT1;5基因。Laurie等[66]研究表明HKT2基因的低表達(dá)可以抑制Na+的進(jìn)入，從而降低組織內(nèi)Na+的濃度。作為高親和性Na+轉(zhuǎn)運(yùn)的轉(zhuǎn)運(yùn)體，HKT轉(zhuǎn)運(yùn)蛋白在草類(lèi)以及其他植物中可能都在控制整體植株中Na+的轉(zhuǎn)運(yùn)起重要作用[2]。Kader等[67]在研究水稻時(shí)發(fā)現(xiàn)，轉(zhuǎn)運(yùn)蛋白基因OsHKT1、OsHKT2和OsVHA在鹽脅迫下誘導(dǎo)表達(dá)，可以通過(guò)調(diào)節(jié)Na+與K+的比例而降低Na+的濃度。研究表明，SsHKT1在鹽地堿蓬的離子平衡和耐鹽方面有重要作用[68]。

眾多研究表明，高親和K+轉(zhuǎn)運(yùn)載體(high-affinity K+transporter,HAK)基因?qū)a+的吸收也有重要作用[69]。鹽對(duì)HvHAK1積累影響的分析結(jié)果表明，在轉(zhuǎn)錄水平上，一個(gè)強(qiáng)而短暫NaCl脅迫觸發(fā)HvHAK1的上調(diào)，說(shuō)明HvHAK1是一個(gè)高鹽應(yīng)答的快速反應(yīng)基因。還有研究表明，在鹽逆境脅迫下，HvHAK1 mRNA的積累和對(duì)K+攝取的控制是高度相關(guān)的[70]，對(duì)Na+吸收的控制則對(duì)維持細(xì)胞內(nèi)的pH重要[71]。研究表明，PhaHAK5、PhaHAK2-n、PhaHAK2-e、PhaHAK2-u等基因均可調(diào)節(jié)鹽生植物中Na+的濃度[72]。

圖2 植物細(xì)胞Na+運(yùn)輸機(jī)制及響應(yīng)鹽逆境的重要調(diào)控網(wǎng)絡(luò)(在Deinlein等[62]基礎(chǔ)上修訂)

擬南芥K+轉(zhuǎn)運(yùn)體(ArabidopsisK+transporter,AKT1)類(lèi)的通道蛋白是在植物中廣泛表達(dá)的一類(lèi)內(nèi)整流K+通道。作為一條對(duì)NH4+不敏感的K+吸收途徑,AKT1的主要功能是與對(duì)NH4+敏感的K+吸收途徑并行存在,使植物能夠適應(yīng)多樣的外界環(huán)境。研究表明，小麥中K+缺乏時(shí)，TaAKT1通道會(huì)增強(qiáng)對(duì)Na+的吸收。眾多研究顯示，OsAKT1的表達(dá)并不影響植物中K+的濃度，但是Na+的積累卻依靠此基因的表達(dá)[73]。KUP基因家族對(duì)細(xì)胞內(nèi)K+濃度的調(diào)節(jié)有多種類(lèi)型[74]，它們的表達(dá)可以表現(xiàn)出對(duì)K+的高吸收性，但是在擬南芥(Arabidopsisthaliana)中，NaCl的加入會(huì)抑制K+的吸收[75]。Wang等[34]研究表明，積鹽型鹽生植物海濱堿蓬存在兩條低親和性Na+吸收途徑，即在低濃度NaCl(25 mmol/L)條件下主要由HKT介導(dǎo)Na+的吸收，在高濃度NaCl(150 mmol/L)條件下主要由AKT1介導(dǎo)Na+的吸收。Zhang等[76]進(jìn)一步研究發(fā)現(xiàn)兩條途徑的外界Na+濃度介于95～100 mmol/L NaCl之間。

鹽敏感(salt overly sensitive，SOS)基因是從一類(lèi)超鹽敏感突變體中發(fā)現(xiàn)的，遺傳分析表明，這些突變體可分為5種，即sos1、sos2、sos3、sos4和sos5[77-78]。目前篩選出的一些SOS基因家族編碼重要的植物離子載體蛋白、信號(hào)轉(zhuǎn)導(dǎo)蛋白等，它們的存在對(duì)提高植物的耐鹽性有重要作用。質(zhì)膜Na+/H+逆向轉(zhuǎn)運(yùn)蛋白就是由SOS1編碼的，該蛋白的主要功能就是將Na+排到細(xì)胞外部，從而減少細(xì)胞內(nèi)Na+的積累[62,79-80](圖2)。Guo等[81]研究表明，SOS1在小花堿茅拒Na+當(dāng)中發(fā)揮著重要作用。Ma等[82]對(duì)霸王ZxSOS1的研究表明，ZxSOS1參與調(diào)控霸王體內(nèi)Na+、K+轉(zhuǎn)運(yùn)和空間分配，進(jìn)而影響植株生長(zhǎng)。Feki等[83]將硬質(zhì)小麥(Triticumdurum)TdSOS1轉(zhuǎn)入擬南芥顯著提高了轉(zhuǎn)基因植物的耐鹽性。Nie等[84]通過(guò)將大豆(Glycinemax)GmsSOS1基因轉(zhuǎn)到缺失SOS1的擬南芥中，證明了其互補(bǔ)性，即驗(yàn)證了SOS1的功能。SOS2和SOS3都是編碼信號(hào)轉(zhuǎn)導(dǎo)途徑中的蛋白，在信號(hào)轉(zhuǎn)導(dǎo)過(guò)程中，彼此有著千絲萬(wàn)縷的聯(lián)系。同時(shí)，有研究表明二者功能的行使與Ca2+有密切的關(guān)系[85]。目前研究的SOS信號(hào)通路就是：高濃度的Na+引起細(xì)胞內(nèi)Ca2+濃度上升，Ca2+與SOS3結(jié)合，結(jié)合Ca2+后的SOS3與SOS2直接互作而激活了SOS2，之后通過(guò)SOS3氨基末端的?；?amino terminus myristoylation)使SOS3-SOS2復(fù)合體會(huì)鉚釘?shù)郊?xì)胞質(zhì)薄膜上，該復(fù)合體中被激活的SOS2磷酸化質(zhì)膜上的SOS1，從而提高SOS1對(duì)Na+的轉(zhuǎn)運(yùn)活性而促進(jìn)高濃度Na+的外排[7]。但在擬南芥和水稻之間SOS信號(hào)通路似乎具有保守型，在水稻中，功能性同系物SOS1，SOS2，SOS3也構(gòu)成一個(gè)重要的耐鹽的信號(hào)通路[86]。SOS5則在細(xì)胞壁形成、細(xì)胞伸展、植物繁殖等過(guò)程中起重要作用[77]。這一系列研究表明，在鹽脅迫下SOS基因家族對(duì)植物的耐鹽性有重要作用。

3.1.2液泡膜上離子轉(zhuǎn)運(yùn)蛋白基因 成熟植物細(xì)胞的液泡為Na+儲(chǔ)存提供弄了一個(gè)很大的空間。將Na+區(qū)域化在液泡中是減少細(xì)胞溶質(zhì)之中Na+的有效方式，從而減少胞液中Na+的毒害作用。鈉和氯離子在細(xì)胞溶質(zhì)中的濃度是由穿過(guò)質(zhì)膜和液泡膜的凈通量決定的。液泡膜蛋白中，Na+/H+逆向轉(zhuǎn)運(yùn)蛋白(Na+/H+transporters,NHX)參與運(yùn)輸Na+，該轉(zhuǎn)運(yùn)蛋白是由液泡膜H+-ATP酶和H+-焦磷酸酶的作用所形成的質(zhì)子梯度來(lái)驅(qū)動(dòng)的(圖2)[34,62]。NHX基因被證明可以將細(xì)胞質(zhì)中的Na+區(qū)域化在液泡中。第一個(gè)從擬南芥克隆出的NHX型轉(zhuǎn)運(yùn)體基因被命名為AtNHX1[87]，它屬于AtNHX1-6亞科六成員之一。這組轉(zhuǎn)運(yùn)體運(yùn)用質(zhì)子驅(qū)動(dòng)力來(lái)運(yùn)輸Na+和K+[88-89]。除了在耐鹽性中的作用，NHX轉(zhuǎn)運(yùn)體還涉及許多其他細(xì)胞過(guò)程，包括細(xì)胞內(nèi)pH值調(diào)節(jié)[90]，囊泡運(yùn)輸和蛋白定位[91]。從發(fā)現(xiàn)擬南芥中NHX轉(zhuǎn)運(yùn)體后，已在許多其他植物中發(fā)現(xiàn)了此類(lèi)型的轉(zhuǎn)運(yùn)體，包括水稻OsNHX1[92]、細(xì)葉海濱藜(Atriplexgmelini)AgNHX1[93]、大麥HvNHX1[94]、棉花(Gossypiumspp.)GhNHX1[95]、玉米ZmNHX[96]、小麥TaNHX1[97]和TaNHX2[98]、苜蓿MsNHX1[99]、大豆(Glycinemax)GmNHX1[100]、長(zhǎng)穗偃麥草(Elytrigiaelongata)AeNHX1[101]、珍珠狼尾草(Pennisetumglaucum)PgNHX1[102]、灰綠藜(Chenopodiumglaucum)CgNHX1[103]、胡楊(Populuseuphratica)PeNHX1-6[104]、鹽穗木(Halostachyscaspica)HcNHX1[105]、霸王ZxNHX1[37]、海蓬子(Salicorniabigelovii)SbNHX1[106]和花花柴(Kareliniacaspia)KcNHX1和KcNHX2[107]等。 Wu等[37]發(fā)現(xiàn)在鹽或干旱條件下，霸王ZxNHX的上調(diào)與Na+的積累呈正相關(guān)關(guān)系。進(jìn)一步研究表明，霸王ZxNHX在控制Na+、K+的吸收，長(zhǎng)距離運(yùn)輸和整株內(nèi)離子穩(wěn)態(tài)方面具有重要作用[108]。自從報(bào)道AtNHX基因超表達(dá)可以使擬南芥具有耐鹽性后[87]，AtNHX或其他NHX基因在植物中超表達(dá)以使之具有抗逆性的成功例子也越來(lái)越多。例如將擬南芥AtNHX1分別導(dǎo)入玉米[109]、小麥[110]、棉花[111]和花生(Arachishypogaea)[112]，將細(xì)葉海濱藜AgNHX1導(dǎo)入水稻[93]，將棉花GhNHX1導(dǎo)入煙草[95]，將短芒大麥草(Hordeumbrevisubulatum)HbNHX1導(dǎo)入煙草[98]，將狼尾草(Pennisetumalopecuroides)PgNHX1導(dǎo)入芥菜(Brassicajuncea)[113]和水稻[102]，將長(zhǎng)穗冰草(Agropyronelongatum)AeNHX1導(dǎo)入擬南芥和高羊茅(Festucaelata)[101]，將擬南芥AtNHX5導(dǎo)入蘭豬耳(Toreniafournieri)[114]，將獐茅(Aeluropussinensis)AlNHX導(dǎo)入煙草[115]，將小麥TaNHX1導(dǎo)入紫花苜蓿[116]，將北美海蓬子(SalicorniaBigelovii)SbNHX1導(dǎo)入麻瘋樹(shù)(Jatrophacurcas)[117]，將綠豆(Vignaradiata)VrNHX1導(dǎo)入擬南芥[118]，均顯著提高了轉(zhuǎn)基因植物的耐鹽性。

NHX轉(zhuǎn)運(yùn)體通過(guò)跨液泡膜H+梯度驅(qū)動(dòng)來(lái)轉(zhuǎn)運(yùn)Na+至液泡，因此通過(guò)H+-ATP酶和H+-焦磷酸酶的超表達(dá)增加H+驅(qū)動(dòng)力，從而有可能提高抗鹽性。然而，由于其多亞基的特征，液泡H-ATP酶并不是超表達(dá)的理想候選者，因?yàn)椴淮罂赡軐⑺械膩喕谙嗨频乃竭^(guò)量表達(dá)而去創(chuàng)建一個(gè)功能性的超表達(dá)轉(zhuǎn)基因植物。液泡膜H+-焦磷酸酶(vacuolar pyrophosphatase,VP)是用于此目的的一個(gè)更好的選擇，因?yàn)樗且粋€(gè)單一的多肽蛋白[119-120]，并且，它產(chǎn)生H+梯度的能力可與H-ATP酶相媲美(圖2)[62,121]。H-焦磷酸酶基因也首先在擬南芥中被克隆出來(lái)，命名為AVP1[119]。VP基因也已從其他許多高等植物中克隆得到，如鹽芥TsVP[121]和鹽地堿蓬SsVP等[122]。擬南芥AVP1的過(guò)量表達(dá)賦予轉(zhuǎn)基因植物耐旱和耐鹽性，在許多植物中得到了證實(shí)，如擬南芥[120,123]、番茄[124]、紫花苜蓿[125]、匍匐翦股穎(Agrostisstolonifera)[126]、大麥[127]、甘蔗(Saccharumofficinarum)[128]。同時(shí)，其他VP基因?qū)胫参锖?，植物抗逆性也得到了提高，例如將鹽地堿蓬SsVP1轉(zhuǎn)入擬南芥[122]，將鹽芥(Thellungiellahalophila)TsVP轉(zhuǎn)入煙草[129]、棉花[130]和玉米[130]，將鹽爪爪KfVP1轉(zhuǎn)入擬南芥[131]，將小麥TaVP1轉(zhuǎn)入煙草[132]，將小麥TaVP基因轉(zhuǎn)入煙草[133]。

近年來(lái)，一些學(xué)者將NHX和VP兩種轉(zhuǎn)運(yùn)蛋白基因構(gòu)建雙價(jià)表達(dá)載體同時(shí)超表達(dá)進(jìn)行了轉(zhuǎn)基因研究，如在水稻中超表達(dá)鹽地堿蓬SsNHX1和擬南芥AVP1[134]，水稻OsNHX1和OsVP1[135]；在擬南芥中超表達(dá)小麥TaNHX1和TaTVP1[136]；在西紅柿中超表達(dá)狼尾草PgNHX1和擬南芥AVP1[137]；在煙草中超表達(dá)小麥TaNHX1和TaTVP1[138]以及在百脈根(Lotuscorniculatus)中超表達(dá)霸王ZxNHX和ZxVP1-1[139]。

3.2滲透調(diào)節(jié)相關(guān)基因

滲透脅迫是植物鹽脅迫的主要方面，滲透調(diào)節(jié)相關(guān)基因在植物耐鹽性中的作用也進(jìn)行了較多研究。多元醇、脯氨酸、海藻糖、甜菜堿等均是植物耐鹽的重要滲透調(diào)節(jié)物質(zhì)，因而合成這些滲透調(diào)節(jié)物質(zhì)的一些關(guān)鍵基因在耐鹽中起到重要作用。如mtlD基因和gutD基因，它們分別編碼合成甘露醇和山梨醇的酶。超表達(dá)mtlD基因增加了甘露醇在毛白楊(Populustomentosa)體內(nèi)的積累從而增強(qiáng)了其耐鹽性[140]；轉(zhuǎn)gutD基因可使轉(zhuǎn)基因植株產(chǎn)生山梨醇，轉(zhuǎn)基因玉米可耐受1.17% NaCl的濃度[141]；在水稻中超表達(dá)mtlD和gutD基因提高了其耐鹽性[142]。Kishor等[143]對(duì)P5CS基因進(jìn)行研究，獲得P5CS轉(zhuǎn)基因煙草，其中脯氨酸的含量明顯提高，與對(duì)照相比，耐鹽性有提高。晚期胚胎發(fā)生富集蛋白(late embriogenesis abundant protein,LEA)是Dure等[144]首次在棉花種子發(fā)育晚期胚胎中發(fā)現(xiàn)的一類(lèi)蛋白。Xu 等[145]將LEA基因轉(zhuǎn)入水稻懸浮細(xì)胞中，得到的轉(zhuǎn)基因植株經(jīng)過(guò)繁殖，在第二代中表現(xiàn)出耐鹽的能力。張寧等[146]從菠菜(Spinaciaoleracea)葉片中分離了甜菜堿醛脫氫酶(betaine-aldehyde dehydrogenase,BADH)基因，并將該基因與其他植物的BADH序列作了同源性分析，同時(shí)，證實(shí)了菠菜BADH基因的轉(zhuǎn)錄與表達(dá)受干旱和鹽脅迫的誘導(dǎo)。Jia等[147]將山菠菜(Atriplexhortensis)的BADH基因轉(zhuǎn)入煙草，提高了煙草的耐鹽性。在水稻中過(guò)量表達(dá)缺失D結(jié)構(gòu)域的組成型活性突變形式OsbZIP46CA1可以顯著增強(qiáng)耐旱性和抵抗?jié)B透脅迫的能力,并可顯著上調(diào)已知的逆境應(yīng)答基因(包括ABF或AREB類(lèi)成員的下游基因)的表達(dá)[148]。

3.3信號(hào)傳導(dǎo)相關(guān)基因

在鹽脅迫下，植物可以關(guān)閉或開(kāi)啟某些基因的表達(dá)，從而維持自身的營(yíng)養(yǎng)平衡。與植物耐鹽性相關(guān)的信號(hào)轉(zhuǎn)導(dǎo)途徑包括：SOS途徑(見(jiàn)3.1.1)、脫落酸(abscisic acid,ABA)信號(hào)和蛋白激酶途徑。

ABA應(yīng)答基因可分為ABA依賴(lài)型和ABA非依賴(lài)型。目前，已發(fā)現(xiàn)多種轉(zhuǎn)錄因子與鹽脅迫有關(guān)，這些基因的表達(dá)分為4條途徑：兩條依賴(lài)ABA途徑，兩條不依賴(lài)ABA途徑[149]。十字花科植物鹽芥是擬南芥的近親，它耐鹽，耐低溫和氧化脅迫，鹽芥基因組相對(duì)較小，因此成為研究植物耐受逆境分子機(jī)理的理想材料[150]。在鹽芥中研究發(fā)現(xiàn)，所有涉及ABA生物合成途徑的基因家族在鹽脅迫下基因數(shù)目增加，這種增加會(huì)調(diào)節(jié)復(fù)雜的ABA生物合成過(guò)程[45,151]。

蛋白激酶在調(diào)節(jié)植物對(duì)非生物脅迫的響應(yīng)中發(fā)揮了重要作用。蛋白激酶是信號(hào)轉(zhuǎn)導(dǎo)的重要元件，信號(hào)轉(zhuǎn)導(dǎo)中絲裂原活化蛋白激酶(mitogen-activated protein kinase,MAPK)途徑是重要途徑之一。目前已分離到多種能被逆境誘導(dǎo)的MAPK基因：擬南芥AtMEKK1、AtMEK1/AtMEK2、ATMPK3、AtMPK4、ANP1、AtMKK2以及煙草NPK1、AtMPK3和AtMPK6等[152-153]。III型亞家族SnRK2蛋白(SnRK2.6/2.3/2.2)是擬南芥脫落酸信號(hào)轉(zhuǎn)導(dǎo)過(guò)程中關(guān)鍵的正調(diào)控因子。這些激酶受脫落酸或滲透脅迫激活后,可磷酸化與脅迫相關(guān)的轉(zhuǎn)錄因子和離子通道,最終使植物免受高鹽的危害[154]。有研究表明，野大麥的CIPK蛋白(CBL-interacting protein kinase,CIPK)HbCIPK2對(duì)鹽和滲透脅迫耐受性起正調(diào)節(jié)作用，HbCIPK2有助于阻止根中K+的丟失和Na+的積累，以便維持K+/Na+的動(dòng)態(tài)平衡和細(xì)胞免于死亡[155]。有研究結(jié)果表明,PLDα1(磷脂酶)D衍生的磷脂酸(phosphatidic acid,PA)與微管結(jié)合蛋白(microtubule-associated protein,MAP)MAP65-1結(jié)合后，可調(diào)控微管的穩(wěn)定及對(duì)鹽脅迫的耐受性。MAP65-1是PA的一個(gè)靶蛋白,該研究揭示了在環(huán)境脅迫引起的信號(hào)轉(zhuǎn)導(dǎo)過(guò)程中膜脂與細(xì)胞骨架之間的功能性聯(lián)系[156]。這一研究結(jié)果提出了植物中磷脂酸通過(guò)調(diào)控微管結(jié)合蛋白活性參與鹽脅迫反應(yīng)的新機(jī)制。

3.4細(xì)胞抗氧化相關(guān)基因

膜脂的過(guò)氧化導(dǎo)致細(xì)胞膜透性的增加是鹽脅迫的主要危害之一。細(xì)胞膜本身具有選擇透過(guò)性，表面具有多種離子運(yùn)輸與傳遞的蛋白，內(nèi)部有多種抗氧化機(jī)制，因而可以抵制膜內(nèi)不飽和脂肪酸的過(guò)氧化作用。目前發(fā)現(xiàn)，SOD、POD、GSH等是細(xì)胞內(nèi)主要的抗氧化物質(zhì)。它們本身可抑制氧自由基的產(chǎn)生，清除體內(nèi)的活性氧。眾多研究表明，植物體內(nèi)某些基因的存在，對(duì)植物的抗氧化有重要作用。如：NtGST/GPX基因編碼的酶既有谷胱苷肽-S-轉(zhuǎn)移酶活性，又有谷光苷肽過(guò)氧化物酶活性，將該基因在煙草中過(guò)量表達(dá)，可以增強(qiáng)植物的耐鹽性和耐寒性[157]。Kovtun等[158]將一種MAPKKK基因——ANP1基因轉(zhuǎn)入煙草中發(fā)現(xiàn)，它可通過(guò)MAPK級(jí)聯(lián)反應(yīng)激活谷胱苷肽-S-轉(zhuǎn)移酶基因(GST6)的表達(dá)，從而使植株表現(xiàn)出耐鹽性。S-腺苷甲硫氨酸脫羧酶(S-adenosylmethionine decarboxylase,SAMDC)是多胺合成中的一個(gè)關(guān)鍵酶，SAMDC基因在煙草中過(guò)量表達(dá)可以增強(qiáng)植物對(duì)鹽和其他非生物脅迫的抗性。維生素C是植物體必需的維生素之一,在光合電子傳遞、活性氧清除、氧化還原平衡調(diào)控、細(xì)胞分裂與生長(zhǎng)、衰老與凋亡等生理過(guò)程中具有重要作用。在對(duì)擬南芥的研究中表明，擬南芥AtERF98是維生素C合成的關(guān)鍵轉(zhuǎn)錄調(diào)控因子，鹽可以誘導(dǎo)AtERF98表達(dá)，而AtERF98突變顯著抑制鹽誘導(dǎo)的維生素C合成，并降低清除活性氧的能力，表現(xiàn)為鹽敏感。這些結(jié)果表明，ERF類(lèi)轉(zhuǎn)錄因子可通過(guò)調(diào)控抗氧化物質(zhì)的合成來(lái)調(diào)節(jié)植物對(duì)鹽脅迫的應(yīng)答反應(yīng)[159]。

4 提高植物耐鹽性的途徑

提高植物耐鹽性的途徑有很多，其中包括抗鹽鍛煉，加入生長(zhǎng)調(diào)節(jié)劑和培育耐鹽新品種等。

4.1抗鹽鍛煉

植物耐鹽能力常隨生長(zhǎng)發(fā)育時(shí)期的不同而異，且對(duì)鹽分的抵抗力有一個(gè)適應(yīng)鍛煉過(guò)程。種子在一定濃度的鹽溶液中吸水膨脹，然后再播種萌發(fā)，可提高作物生育期的耐鹽能力。因此，在對(duì)植物進(jìn)行抗鹽鍛煉時(shí)，可逐漸升高Na+濃度，從而提高植物的耐鹽能力。用CaCl2浸種的玉米在鹽脅迫下的葉綠素含量、細(xì)胞膜透性和根系活力的變化程度均小于水浸種，脯氨酸含量、干物質(zhì)重高于水浸種，水勢(shì)低于水浸種，提高了三葉期玉米的耐鹽能力[160]。在低濃度鈉鹽處理下，夏枯草(Prunellavulgaris)種子的發(fā)芽率、發(fā)芽勢(shì)、活力指數(shù)、根長(zhǎng)、苗高以及鮮重都得到了顯著提高[161]。

4.2加入生長(zhǎng)調(diào)節(jié)劑

在很多情況下,植物對(duì)逆境脅迫的響應(yīng)是通過(guò)改變內(nèi)源激素的水平來(lái)實(shí)現(xiàn)的。如植物處于非生物逆境脅迫條件下會(huì)產(chǎn)生大量的ABA和乙烯(ethylene,Eth)等。生長(zhǎng)素不僅調(diào)控植物的生長(zhǎng)發(fā)育,也廣泛參與逆境脅迫反應(yīng)[162]。植物使用不同的策略來(lái)應(yīng)對(duì)高鹽土壤，植物可以調(diào)整自身的根系結(jié)構(gòu)和根生長(zhǎng)的方向來(lái)避免局部鹽濃度過(guò)高的情況[163]。有一種模式就是通過(guò)鹽度影響了植物激素在根系的分布，從而影響根生長(zhǎng)。除了植物生長(zhǎng)素(indole-3-acetic acid,IAA)，細(xì)胞分裂素(cytokinin,CTK)，乙烯和脫落酸也有相應(yīng)的作用。植物生長(zhǎng)素的運(yùn)用可以通過(guò)促進(jìn)側(cè)根形成從而緩解滲透脅迫并不受ABA的影響，這表明這兩種激素的行為獨(dú)立地確定側(cè)根原基的命運(yùn)[164]。用植物激素處理植株，是常用的提高植物耐鹽性的途徑之一。例如，在含0.15% Na2SO4土壤中的小麥生長(zhǎng)不良，但在播前用IAA浸種，可以抵消Na2SO4抑制小麥根系生長(zhǎng)的作用，使小麥生長(zhǎng)良好[165]。ABA是一種逆境激素，能誘導(dǎo)氣孔關(guān)閉，減少蒸騰作用、減少鹽的吸收，提高作物的耐鹽能力，它普遍存在于高等植物中，在植物對(duì)逆境的適應(yīng)中有著重要的作用[166]。此外，NO在植物耐受逆境中的作用尤其引人注意。如NO能顯著緩解鹽對(duì)鹽地堿蓬種子萌發(fā)的抑制,外源NO供體硝普鈉(sodium nitroprusside,SNP)能通過(guò)促進(jìn)種子吸水以緩解鹽的滲透脅迫來(lái)緩解鹽脅迫下鹽地堿蓬種子萌發(fā)[167]。并且SNP還可以緩解鹽脅迫對(duì)蒺藜苜蓿(Medicagotruncatula)種子萌發(fā)的抑制作用[168]。

4.3培育耐鹽品種

隨著植物分子生物學(xué)研究的深入、植物基因工程的發(fā)展、育種學(xué)的進(jìn)步，培育耐鹽的植物品種已經(jīng)從普通的生理生化等表面的研究深入到了分子領(lǐng)域?，F(xiàn)今，人們可以通過(guò)改造植物內(nèi)部的基因、構(gòu)建耐鹽基因的載體和遺傳轉(zhuǎn)化等方法進(jìn)一步改良植株。如上文所述，利用高等植物耐鹽相關(guān)基因培育耐鹽作物品種將會(huì)成為未來(lái)研究的主要方向。此外有研究表明，植物的多倍體化同樣可以使植物具有耐鹽性，同時(shí)增強(qiáng)植物鉀的積累[169]。

5 展望

近年來(lái)對(duì)于作物的耐鹽性研究發(fā)展迅速，但在很大程度上仍然停留在通過(guò)鑒定和利用擬南芥中已知的相應(yīng)基因來(lái)進(jìn)行耐鹽性調(diào)控的水平。對(duì)水稻[64,170]和小麥[171-172]的研究已經(jīng)指出了一條闡明作物特別是禾谷類(lèi)作物耐鹽機(jī)制的研究方向，但對(duì)作物的系統(tǒng)性研究仍然需要使用正向和反向遺傳工具以及植物生理學(xué)、生物化學(xué)和分子生物學(xué)等手段。用正向遺傳篩選作物鹽敏感突變體從而確定作物中重要的耐鹽基因仍然沒(méi)有廣泛開(kāi)展，這種方法將有助于找到新基因或特定的作物耐鹽機(jī)制?？梢韵嘈?，擬南芥中未確定的某些機(jī)制，可能存在于作物中，特別是具有不同體系結(jié)構(gòu)和組織構(gòu)架的單子葉植物組織中。

由3種類(lèi)型的Na+轉(zhuǎn)運(yùn)體調(diào)控的3種細(xì)胞水平耐鹽機(jī)制(控制Na+吸收，增強(qiáng)Na+外排，提高Na+區(qū)域化)可以共同協(xié)調(diào)來(lái)提高植物的抗鹽能力。然而，雖然在細(xì)胞水平上這3種Na+轉(zhuǎn)運(yùn)機(jī)制易于理解，但在整體植物中這些轉(zhuǎn)運(yùn)體在特定位置上的協(xié)調(diào)作用機(jī)制仍然沒(méi)有完全搞清楚。因此，還需要在生理和分子水平上進(jìn)一步研究來(lái)確定這些轉(zhuǎn)運(yùn)體的組織和細(xì)胞定位以闡明其在抗鹽中的相互協(xié)調(diào)功能。除此之外，這些轉(zhuǎn)運(yùn)體在其他生物過(guò)程中的作用也有待于進(jìn)一步研究。顯而易見(jiàn)的是，這些轉(zhuǎn)運(yùn)體不僅僅對(duì)植物耐鹽性很重要，而且還涉及其他的細(xì)胞生理學(xué)過(guò)程，這在擬南芥中已經(jīng)得到證實(shí)；然而，除了耐鹽性以外，這些轉(zhuǎn)運(yùn)體在作物中的其他作用還不是很清楚。對(duì)這些方面研究將會(huì)有助于我們估計(jì)過(guò)量表達(dá)這些轉(zhuǎn)運(yùn)體來(lái)增強(qiáng)植物耐鹽性后所產(chǎn)生的潛在副作用。

鹽生植物為闡明高等植物耐鹽機(jī)制的研究提供了天然資源。利用親緣關(guān)系密切的鹽生植物和甜土植物以及比較基因組學(xué)研究方法將有助于闡明鹽生植物耐鹽性的遺傳基礎(chǔ)。Wu等[150]的研究證明了這一結(jié)論，即利用比較基因組學(xué)方法來(lái)確定鹽芥基因組和擬南芥基因組之間的差異以及其與鹽脅迫反應(yīng)和抗鹽的關(guān)系，最終鑒定其耐鹽的分子機(jī)制。雖然比較基因組學(xué)的研究需要完整的基因組序列，但可以預(yù)見(jiàn)的是，隨著測(cè)序技術(shù)的迅速發(fā)展和相關(guān)成本的減少，可供利用的基因組序列將會(huì)更加豐富。這種方法也可以用于鑒定自然變異種群中耐鹽變種中的耐鹽基因的變化，這會(huì)在分子育種方面為作物的耐鹽性遺傳改良提供有價(jià)值的信息。此外，轉(zhuǎn)錄組學(xué)、蛋白質(zhì)組學(xué)和表觀(guān)遺傳學(xué)等手段將加速鹽生植物耐鹽機(jī)制的研究和耐鹽基因的大量挖掘。

[1] Flowers T J.Improving crop salt tolerance.Journal of Experimental Botany, 2004, 55:307-319.

[2] Kronzucker H J, Coskun D, Schulze L M,etal.Sodium as nutrient and toxicant.Plant and Soil, 2013, 369:1-23.

[3] Janz D, Polle A.Harnessing salt for woody biomass production.Tree Physiology, 2012, 32:1-3.

[4] Zhang J L, Flowers T J, Wang S M.Mechanisms of sodium uptake by roots of higher plants.Plant and Soil, 2010, 326:45-60.

[5] Zhao K F, Li F Z, Fan S J,etal.Halophytes in China.Chinese Bulletin of Botany, 1999, 16(3):201-207.

[6] Zhao K F.Plants adapt to salt adversity.Bulletin of Biology, 2002, 37(6):7-10.

[7] Zhang J L, Shi H Z.Physiological and molecular mechanisms of plant salt tolerance.Photosynthesis Research, 2013, 115:1-22.

[8] Munns R, Tester M.Mechanisms of salinity tolerance.Annual Review of Plant Biology, 2008, 59:651-681.

[9] Zhu J K.Plant salt tolerance.Trends in Plant Science, 2001, 6:66-71.

[10] Kronzucker H J, Britto D T.Sodium transport in plants:a critical review.New Phytologist, 2011, 189:54-81.

[11] Gorai M, El A W, Yang X,etal.Toward understanding the ecological role of mucilage in seed germination of a desert shrubHenophytondeserti:interactive effects of temperature, salinity and osmotic stress.Plant and Soil, 2014, 374:727-738.

[12] Wei Y, Dong M, Huang Z Y,etal.Factors influencingseed germination ofSalsolaaffinis(Chenopodiaceae), a dominant annual halophyte inhabiting the deserts of Xinjiang.Flora of China, 2008, 203:134-140.

[13] Li Y, Shen Y Y, Yan S G.Comparative studies of effect of NaCl stress on the seed germination of 5 forage species.Pratacultural Science, 1997, 14(2):50-53.

[14] Liang Y C.Effects of silicon on enzyme activity and sodium, potassium and calcium concentration in barley under salt stress.Plant and Soil, 1999, 209:217-224.

[15] Trono D, Flagella Z, Laus M N,etal.The uncoupling protein and the potassium channel are activated by hyperosmotic stress in mitochondria from durum wheat seedlings.Plant Cell and Environment, 2004, 27:437-448.

[16] Becker D, Hoth S, Ache P,etal.Regulation of the ABA-sensitiveArabidopsispotassium channel gene GORK in response to water stress.Febs Letters, 2003, 554:119-126.

[17] Ottow E A, Brinker M, Teichmann T,etal.Populuseuphraticadisplays apoplastic sodium accumulation, osmotic adjustment by decreases in calcium and soluble carbohydrates, and develops leaf succulence under salt stress.Plant Physiology, 2005, 139:1762-1772.

[18] Song J, Ding X D, Feng G,etal.Nutritional and osmotic roles of nitrate in a euhalophyte and a xerophyte in saline conditions.New Phytologist, 2006, 171:357-366.

[19] Liu J, Cai H, Liu Y,etal.A study on physiological characteristics and cmparison of salt resistance of twoMedicagosativaat the seeding stage.Acta Prataculturae Sinica, 2013, 22(2):250-256.

[20] Jarunee J, Kenjiusui, Hiroshi M.Differences in physiological responses to NaCl between salt-tolerantSesbaniarostrataBrem.and Obem.And non-tolerantPhaseolusvulgarisL.Weed Biology and Management, 2003, 3:21-27.

[21] Makela P, Karkkainen J, Somersalo S.Effect of glycinebetaine on chloroplast ultrastructure, chlorophyll and protein content, and RuBPCO activities in tomato grown under drought or salinity.Biologia Plantarum, 2000, 43:471-475.

[22] Leshem Y, Melamed B N, Cagnac O,etal.Suppression ofArabidopsisvesicle-SNARE expression inhibited fusion of H2O2containing vesicles with tonoplast and increased salt tolerance.Proceedings of the National Academy of Sciences of the United States of America, 2006, 103:18008-18013.

[23] Flowers T J, Colmer T D.Salinity tolerance in halophytes.New Phytologist, 2008, 179:945-963.

[24] Shabala S, Bose J, Hedrich R.Salt bladders:do they matter.Trends in Plant Science, 2014, 19(11):687-691.

[25] Wang C M, Zhang J L, Liu X S,etal.Puccinelliatenuifloramaintains a low Na+level under salinity by limiting unidirectional Na+influx resulting in a high selectivity for K+over Na+.Plant, Cell and Environment, 2009, 32:486-496.

[26] Ueda A, Yamamoto-Yamane Y, Takabe T.Salt stress enhances proline utilization in the apical region of barley roots.Biochemical and Biophysical Research Communications, 2007, 355:61-66.

[27] Wang C Q, Zhao J Q, Chen M,etal.Identification of betacyanin and effects of environmental factors on its accumulation in halophyteSuaedasalsa.Journal of Plant Physiology and Molecular Biology, 2006, 32(2):195-201.

[28] Md A H, Mst N A B, Yoshimasa N,etal.Proline and glycinebetaine enhance antioxidant defense and methylglyoxal detoxification systems and reduce NaCl-induced damage in cultured tobacco cells.Journal of Plant Physiology, 2008, 165:813-824.

[29] Incharoensakd A, Takabe T, A kazawa T.Effect of bteaine on enzyme activity and subunit internation of ribulose-1,5 -bisphosphate carboxylase/oxygenas fromAphnothecehalophytica.Plant Physiology, 1986, 81:1044-1049.

[30] Dubey R S, Singh A K.Salinity induces accumulation of soluble sugars and alters the activity of sugar metabolising enzymes in rice plants.Biologia Plantarum, 1999, 42:233-239.

[31] Shabala S, Shabala L.Ion transport and osmotic adjustment in plants and bacteria.Biomolecular Concepts, 2011, 2:407-419.

[32] Demidchik V, Cuin T A, Svistunenko D,etal.Arabidopsisroot K+-efflux conductance activated by hydroxyl radicals:single-channel properties, genetic basis and involvement in stress-induced cell death.Journal of Cell Science, 2010, 123:1468-1479.

[33] Teaklea N L, Bazihizina N, Shabala S,etal.Differential tolerance to combined salinity and O2deficiency in the halophytic grassesPuccinelliaciliataandThinopyrumponticum:The importance of K+retention in roots.Environmental and Experimental Botany, 2013, 87:69-78.

[34] Wang S M, Zhang J L, Flowers T J.Low-affinity Na+uptake in the halophyteSuaedamaritima.Plant Physiology, 2007, 145(2):559-571.

[35] Cuin T A, Bose J, Stefano G,etal.Assessing the role of root plasma membrane and tonoplast Na+/H+exchangers in salinity tolerance in wheat:in planta quantification methods.Plant, Cell and Environment, 2009, 34:947-961.

[36] Schmidt U G, Endler A, Schelbert S,etal.Novel tonoplast transporters identified using a proteomic approach with vacuoles isolated from cauliflower buds.Plant Physiology, 2007, 145:216-229.

[37] Wu G Q, Xi J J, Wang Q,etal.TheZxNHXgene encoding tonoplast Na+/H+antiporter from the xerophyteZygophyllumxanthoxylumplays important roles in response to salt and drought.Journal of Plant Physiology, 2011, 168:758-767.

[38] Ma Q, Yue L J, Zhang J L,etal.Sodium chloride improves photosynthesis and water status in the succulent xerophyteZygophyllumxanthoxylum.Tree Physiology, 2012, 32(1):4-13.

[39] Yue L J, Li S X, Ma Q,etal.NaCl stimulates growth and alleviates water stress in the xerophyteZygophyllumxanthoxylum.Journal of Arid Environments, 2012, 87:153-160.

[40] Wang S M, Zhu X Y, Shu X X.Studies on the characteristics of ion absorption anddistribution inPuccinelliatenuiflora.Acta Prataculturae Sinica, 1994, 3(1):39-43.

[41] Guo Q, Meng L, Mao P C,etal.Salt tolerance in two tall wheatgrass species is associated with selective capacity for K+over Na+.Acta Physiologiae Plantarum, 2014, 37:1708.

[42] Zhang J L, Flowers T J, Wang S M.Differentiation of low-affinity Na+uptake pathways and kinetics of the effects of K+on Na+uptake in the halophyteSuaedamaritime.Plant and Soil, 2013, 368(1-2):629-640.

[43] Zhu Z J, Wei G Q, Li J,etal.Silicon alleviates salt stress and increases antioxidant enzymes activity in leaves of salt-stressed cucumber (CucumissativusL.).Plant Science, 2004, 167:527-533.

[44] Liang Y C, Zhang W H, Chen Q,etal.Effects of silicon on H+-ATPase and H+-PPase activity, fatty acid composition and fluidity of tonoplast vesicles from roots of salt-stressed barley (HordeumvulgareL.).Environmental and Experimental Botany, 2005, 53:29-37.

[45] Gong H J, Randall D P, Flowers T J.Silicon deposition in the root reduces sodium uptake in rice (OryzasativaL.) seedlings by reducing bypass flow.Plant Cell and Environment, 2006, 29:1970-1979.

[46] Ma J F, Yamaji N, Mitani N,etal.An efflux transporter of silicon in rice.Nature, 2007, 448:209-212.

[47] Wang X S, Han J G.Effects of NaCl and silicon on ion distribution in the roots, shoots and leaves of two alfalfa cultivars with different salt tolerance.Soil Science and Plant Nutrition, 2007, 53:278-285.

[48] Tuna A L, Kaya C, Higgs D,etal.Silicon improves salinity tolerance in wheat plants.Environmental and Experimental Botany, 2008, 62:10-16.

[49] Chai Q, Shao X, Zhang J.Silicon effects onPoapratensisresponses to salinity.HortScience, 2010, 45:1876-1881.

[50] Bose J, Rodrigo-Moreno A, Shabala S.ROS homeostasis in halophytes in the context of salinity stress tolerance.Journal of Experimental Botany, 2014, 65(5):1241-1257.

[51] Guan B, Yv J B, Lu Z H,etal.Effects of water-salt stresses on seeding growth and activities of antioxidative enzyme ofSuaedasalsain coastal wetlands of the yellow river delta.Environmental Science, 2011, 32(8):2422-2429.

[52] Lu Y, Lei J Q, Zeng F J,etal.Effects of salt treatments on the growth and ecophysiological characteristies.Acta Prataculturae Sinica, 2014, 23(3):152-159.

[53] Xue X D, Dong X Y, Duan Y X,etal.A comparison of salt resistance of three kinds ofZoysiaat different salt concentrations.Acta Prataculturae Sinica, 2013, 22(6):315-320.

[54] Ahmed I M, Nadira U A, Bibi N,etal.Secondary metabolism and antioxidants are involved in the tolerance to drought and salinity, separately and combined, in Tibetan wild barley.Environmental and Experimental Botany, 2015, 111:1-12.

[55] Gao H J, Yang H Y, Bai J P,etal.Ultrastructural and physiological responses of potato (SolanumtuberosumL.) plantlets to gradient saline stress.Frontiers in Plant Science, 2014, 5:787.

[56] Talke I N, Blaudez D, Maathuis F J M,etal.CNGCs:prime targets of plant cyclic nucleotide signalling.Trends in Plant Science, 2003, 8:286-293.

[57] Amtmann A, Sanders D.Mechanism of Na+uptake by plant cells.Advances in Botanical Research, 1999, 29:75-112.

[58] Tyerman S D, Skerrett I M.Root ion channels and salinity.Scientia Horticulturae, 1999, 78:175-235.

[59] Zhang H F, Wang S M.Advances in study of Na+uptake and transport in higher plants and Na+homeostasis in the cell.Chinese Bulletin of Botany, 2007, 24(5):561-571.

[60] Amtmann A, Fischer M, Marsh E L,etal.The wheat cDNA LCT1 generates hypersensitivity to sodium in a salt-sensitive yeast strain.Plant Physiology, 2001, 126:1061-1071.

[61] Kronzucker H J, Szczerba M W, Schulze L M,etal.Non-reciprocal interactions between K+and Na+ions in barley (HordeumvulgareL.).Journal of Experimental Botany, 2008, 59:2793-2801.

[62] Deinlein U, Stephan A B, Horie T,etal.Plant salt-tolerance mechanisms.Trends in Plant Science, 2014, 19(6):371-379.

[63] Zamani B M, Ebrahimie E, Niazi A.In silico analysis of high affinity potassium transporter (HKT) isoforms in different plants.Aquatic Biosystems, 2014, 10:9.

[64] Wang Q, Guan C, Wang P,etal.AtHKT1;1 andAtHAK5 mediate low-affinity Na+uptake inArabidopsisthalianaunder mild salt stress.Plant Growth Regulation, 2015, 75(3):615-623.

[65] Ren Z H, Gao J P, Li L G,etal.A rice quantitative trait locus for salt tolerance encodes a sodium transporter.Nature Genetics, 2005, 37:1141-1146.

[66] Laurie S, Feeney K A, Maathuis F J M,etal.A role forHKT1 in sodium uptake by wheat roots.Plant Journal, 2002, 32:139-149.

[67] Kader M A, Seidel T, Golldack D,etal.Expressions ofOsHKT1,OsHKT2, andOsVHAare differentially regulated under NaCl stress in salt-sensitive and salt-tolerant rice (OryzasativaL.) cultivars.Journal of Experimental Botany, 2006, 57(15):4257-4268.

[68] Shao Q, Zhao C, Han N,etal.Cloning and expression pattern ofSsHKT1 encoding a putative cation transporter from halophyteSuaedasalsa.DNA sequence, 2008, 19(2):106-114.

[69] Senn M E, Rubio F, Banuelos M A,etal.Comparative functional features of plant potassiumHvHAK1 andHvHAK2 transporters.Journal of Biological Chemistry, 2001, 30:44563-44569.

[70] Fulgenzi F R, Peralta M L, Mangano S,etal.The ionic environment controls the contribution of the barleyHvHAK1 transporter to potassium acquisition.Plant Physiology, 2008, 147:252-262.

[71] Carden D E, Walker D J, Flowers T J,etal.Single-cell measurements of the contributions of cytosolic Na+and K+to salt tolerance.Plant Physiology, 2003, 131:676-683.

[72] Takahashi R, Nishio T, Ichizen N,etal.Cloning and functional analysis of the K+transporter PhaHAK2 from salt-sensitive and salt-tolerant reed plants.Biotechnol Letters, 2007, 29:501-506.

[73] Golldack D, Quigley F, Michalowski C B,etal.Salinity stress-tolerant and -sensitive rice (OryzasativaL.) regulate AKT1-type potassium channel transcripts differently.Plant Molecular Biology, 2003, 51:71-81.

[74] Kim E J, Kwak J M, Uozumi N,etal.AtKUP1:AnArabidopsisgene encoding high-affinity potassium transport activity.Plant Cell, 1998, 10:51-62.

[75] Fu H H, Luan S.AtKUP1:a dual-affinity K+transporter fromArabidopsis.Plant Cell, 1998, 10:63-73.

[76] Zhang J L.Low-Affinity Na+Uptake and Accumulation in the Halophyte Suaeda maritina[D].Lanzhou： Lanzhou University, 2008.

[77] Shi H, Kim Y, Guo Y,etal.TheArabidopsisSOS5 locus encodes a putative cell surface adhesion protein and is required for normal cell expansion.Plant Cell, 2003, 15(1):19-32.

[78] Shi H Z, Quintero F J, Pardo J M,etal.The putative plasma membrane Na+/H+antiporterSOS1 controls long-distance Na+transport in plants.Plant Cell, 2002, 14:465-477.

[79] Wu G Q, Wang P, Ma Q,etal.Selective transport capacity for K+over Na+is linked to the expression levels ofPtSOS1 in halophytePuccinelliatenuiflora.Functional Plant Biology, 2012, 39:1047-1057.

[80] Liu M, Wang T Z, Zhang W H.Sodium extrusion associated with enhanced expression ofSOS1 underlies different salt tolerance betweenMedicagofalcataandMedicagotruncatulaseedlings.Environmental and Experimental Botany, 2015, 110:46-55.

[81] Guo Q, Wang P, Ma Q,etal.Selective transport capacity for K+over Na+is linked to the expression levels ofPtSOS1 in halophytePuccinelliatenuiflora.Functional Plant Biology, 2012, 39:1047-1057.

[82] Ma Q, Li Y X, Yuan H J,etal.ZxSOS1 is essential for long-distance transport and spatial distribution of Na+and K+in the xerophyteZygophyllumxanthoxylum.Plant and Soil, 2014, 374:661-676.

[83] Feki K, Quintero F J, Khoudi H,etal.A constitutively active form of a durum wheat Na+/H+antiporterSOS1 confers high salt tolerance to transgenicArabidopsis.Plant Cell Reports, 2014, 33(2):277-288.

[84] Nie W X, Xu L, Yu B J.A putative soybeanGmsSOS1 confers enhanced salt tolerance to transgenicArabidopsissos1-1 mutant.Protoplasma, 2015, 252(1):127-134.

[85] Ishitani M, Liu J, Halfter U,etal.SOS3 function in plant salt tolerance requires N-myristoylation and calcium binding.Plant Cell, 2000, 12(9):1667-1678.

[86] Martinez-Atienza J, Jiang X, Garciadeblas B,etal.Conservation of the salt overly sensitive pathway in rice.Plant Physiology, 2007, 143:1001-1012.

[87] Gaxiola R A, Rao R, Sherman A,etal.TheArabidopsisthalianaproton transporters, AtNHX1 and AVP1, can function in cation detoxification in yeast.Proceedings of the National Academy of Sciences of the United States of America, 1999, 96:1480-1485.

[88] Apse M P, Aharon G S, Snedden W A,etal.Salt tolerance confermi by over expression of a vacuolar NaCMC antiport inArabidopsis.Science, 1999, 285(12):1256-1258.

[89] Venema K, Quintero F J, Pardo J M,etal.TheArabidopsisNa+/H+exchanger catalyzes low affinity Na+and K+transport in reconstituted vesicles.Journal of Biological Chemistry, 2002, 277:2413-2418.

[90] Yamaguchi T, Fukuda-Tanaka S, Inagaki Y,etal.Genes encoding the vacuolar Na+/H+exchanger and flower coloration.Plant Cell Physiology, 2001, 142:451-461.

[91] Sottosanto J B, Gelli A, Blumwald E.DNA array analyses ofArabidopsisthalianalacking a vacuolar Na+/H+antiporter:impact of AtNHX1 on gene expression.Plant Journal, 2004, 40:752-771.

[92] Fukuda A, Nakamura A, Tanaka Y.Molecular cloning and expression of the Na+/H+exchanger gene inOryzasativa.BBA-Gene Structure and Expression, 1999, 1446:149-155.

[93] Ohta M, Hayashi Y, Nakashima A,etal.Introduction of a Na+/H+antiporter gene fromAtriplexgmeliniconfers salt tolerance to rice.FEBS Letters, 2002, 532:279-282.

[94] Fukuda A, Chiba K, Maeda M,etal.Effect of salt and osmotic stresses on the expression of genes for the vacuolar H+-pyrophosphatase, H+-ATPase subunitA, and Na+/H+antiporter from barley.Journal of Experimental Botany, 2004, 55:585-594.

[95] Wu C A, Yang G D, Meng Q W,etal.The cottonGhNHX1 gene encoding a novel putative tonoplast Na+/H+antiporter plays an important role in salt stress.Plant Cell Physiology, 2004, 45:600-607.

[96] Zorb C, Noll A, Karl S,etal.Molecular characterization of Na+/H+antiporters (ZmNHX) of maize (ZeamaysL.) and their expression under salt stress.Journal of Plant Physiology, 2005, 162:55-66.

[97] Brini F, Gaxiola R A, Berkowitz G A,etal.Cloning and characterization of a wheat vacuolar cation/proton antiporter and pyrophosphatase proton pump.Plant Physiology and Biochemistry, 2005, 43:347-354.

[98] Yu J N, Huang J, Wang Z M,etal.An Na+/H+antiporter gene from wheat plays an important role in stress tolerance.Journal of Biosciences, 2007, 32:1153-1161.

[99] Yang Q C, Wu M S, Wang P Q,etal.Cloning and expression analysis of a vacuolar Na+/H+antiporter gene from alfalfa.DNA sequece, 2005, 16:352-357.

[100] Li W Y, Wong F L, Tsai S N,etal.Tonoplast-locatedGmCLC1 andGmNHX1 from soybean enhance NaCl tolerance in transgenic bright yellow (BY)-2cells.Plant, Cell and Environment, 2006, 29:1122-1137.

[101] Qiao W H, Zhao X Y, Li W,etal.Overexpression ofAeNHX1, a root-specific vacuolar Na+/H+antiporter fromAgropyronelongatum, confers salt tolerance toArabidopsisandFestucaplants.Plant Cell Reports, 2007, 26:1663-1672.

[102] Verma D, Singla-Pareek S L, Rajagopal D,etal.Functional validation of a novel isoform of Na+/H+antiporter fromPennisetumglaucumfor enhancing salinity tolerance in rice.Journal of Biosciences, 2007, 32:621-628.

[103] Li J Y, He X W, Xu L,etal.Molecular and functional comparisons of the vacuolar Na+/H+exchangers originated from glycophytic and halophytic species.Journal of Zhejiang University Science, 2008, 9:132-140.

[104] Ye C Y, Zhang H C, Chen J H,etal.Molecular characterization of putative vacuolar NHX-type Na+/H+exchanger genes from the salt-resistant treePopuluseuphratica.Physiologia Plantarum, 2009, 137:166-174.

[105] Guan B, Hu Y, Zeng Y,etal.Molecular characterization and functional analysis of a vacuolar Na+/H+antiporter gene (HcNHX1) fromHalostachyscaspica.Molecular Biology Reports, 2010, 38:1889-1899.

[106] Jha A, Joshi M, Yadav N,etal.Cloning and characterization of theSalicorniabrachiataNa+/H+antiporter geneSbNHX1 and its expression by abiotic stress.Molecular Biology Reports, 2011, 38:1965-1973.

[107] Liu L, Zeng Y, Pan X,etal.Isolation, molecular characterization, and functional analysis of the vacuolar Na+/ H+antiporter genes from the halophyteKareliniacaspica.Molecular Biology Reports, 2012, 39:7193-7202.

[108] Yuan H J, Ma Q, Wu G Q,etal.ZxNHXcontrols Na+and K+homeostasis at the whole-plant level inZygophyllumxanthoxylumthrough feedbackregulation of the expression of genes involved in their transport.Annals of Botany, 2015, 115(3):495-507.

[109] Yin X Y, Yang A F, Zhang K W,etal.Production and analysis of transgenic maize with improved salt tolerance by the introduction ofAtNHX1 gene.Acta Botanica Sinica, 2004, 46:854-861.

[110] Xue Z Y, Zhi D Y, Xue G,etal.Enhanced salt tolerance of transgenic wheat (TritivumaestivumL.) expressing a vacuolar Na+/H+antiporter gene with improved grain yields in saline soils in the field and a reduced level of leaf Na+.Plant Science, 2004, 167:849-859.

[111] He C, Yan J, Shen G,etal.Expression of anArabidopsisvacuolar sodium/proton antiporter gene in cotton improves photosynthetic performance under salt conditions and increases fiber yield in the field.Plant Cell Physiology, 2005, 46:1848-1854.

[112] Banjara M, Zhu L, Shen G,etal.Expression of anArabidopsissodium/proton antiporter gene (AtNHX1) in peanut to improve salt tolerance.Plant Biotechnology Reports, 2012, 6:59-67.

[113] Rajagopal D, Agarwal P, Tyagi W,etal.PennisetumglaucumNa+/H+antiporter confers high level of salinity tolerance in transgenicBrassicaJuncea.Molecular Breeding, 2007, 19:137-151.

[114] Shi L Y, Li H Q, Pan X P,etal.Improvement ofToreniafournierisalinity tolerance by expression ofArabidopsisAtNHX5.Functional Plant Biology, 2008, 35:185-192.

[115] Zhang G H, Su Q, An L J,etal.Characterization and expression of a vacuolar Na+/H+antiporter gene from the monocot halophyteAeluropuslittoralis.Plant Physiology and Biochemistry, 2008, 46:117-126.

[116] Zhang Y M, Liu Z H, Wen Z Y,etal.The vacuolar Na+-H+antiport geneTaNHX2 confers salt tolerance on transgenic alfalfa (Medicagosativa).Functional Plant Biology, 2012, 39:708-716.

[117] Joshi M, Jha A, Mishra A,etal.Developing transgenic Jatropha using theSbNHX1 gene from an extreme halophyte for cultivation in saline wasteland.PLoS One, 2013, 8(8):e71136.

[118] Mishra S, Alavilli H, Lee B H,etal.Cloning and functional characterization of a vacuolar Na+/H+antiporter gene from mungbean (VrNHX1) and its ectopic expression enhanced salt tolerance inArabidopsisthaliana.PLoS One, 2014, 9(10):e106678.

[119] Sarafian V, Kim Y, Poole R J,etal.Molecular cloning and sequence of cDNA encoding the pyrophosphate-energized vacuolar membrance proton pump ofArabidopsisthaliana.Proceedings of the National Academy of Sciences of the United States of America, 1992, 89:1775-1779.

[120] Gaxiola R A, Palmgren M G, Schumacher K.Plant proton pumps.FEBS Letters, 2007, 581:2204-2214.

[121] Gao F, Gao Q, Duan X G,etal.Cloning of an H+-PPase gene fromThellungiellahalophilaand its heterologous expression to improve tobacco salt tolerance.Journal of Experimental Botany, 2006, 57:3259-3270.

[122] Guo S L, Yin H B, Zhang X,etal.Molecular cloning and characterization of a vacuolar H+-pyrophosphatase gene, SsVP, from the halophyteSuaedasalsaand its overexpression increases salt and drought tolerance ofArabidopsis.Plant Molecular Biology, 2006, 60:41-50.

[123] Li J, Yang H, Peer W A,etal.ArabidopsisH+-PPaseAVP1 regulates auxin-mediated organ development.Science, 2005, 310:121-125.

[124] Park S, Li J, Pittman J K,etal.Up-regulation of a H+- pyrophosphatase (H+-PPase) as a strategy to engineer drought-resistant crop plants.Proceedings of the National Academy of Sciences of the United States of America, 2005, 102:18830-18835.

[125] Bao A K, Wang S M, Wu G Q,etal.Overexpression of theArabidopsisH+-PPase enhanced resistance to salt and drought stress in transgenic alfalfa (MedicagosativaL.).Plant Science, 2009, 176:232-240.

[126] Li Z G, Baldwin M, Hu Q,etal.Heterologous expression ofArabidopsisH+-pyrophosphatase enhances salt tolerance in transgenic creeping bentgrass (AgrostisstoloniferaL.).Plant Cell Environment, 2010, 33:272-289.

[127] Schilling R K, Marschner P, Shavrukov Y,etal.Expression of theArabidopsisvacuolar H+-pyrophosphatase gene (AVP1) improves the shoot biomass of transgenic barley and increases grain yield in a saline field.Plant Biotechnology Journal, 2014, 12(3):378-386.

[128] Kumar T, Uzma, Khan M R,etal.Genetic improvement of sugarcane for drought and salinity stress tolerance usingArabidopsisvacuolarpyrophosphatase (AVP1) gene.Molecular Biotechnology, 2014, 56(3):199-209.

[129] Lv S L, Lian L J, Tao P L,etal.Overexpression ofThellungiellahalophilaH+-PPase (TsVP) in cotton enhances drought stress resistance of plants.Planta, 2009, 229:899-910.

[130] Pei L, Wang J, Li K,etal.Overexpression ofThellungiellahalophilaH+-pyrophosphatase gene improves low phosphate tolerance in maize.PLOS One, 2012, 7(8):e43501.

[131] Yao M, Zeng Y, Liu L,etal.Overexpression of the halophyteKalidiumfoliatumH+-pyrophosphatase gene confers salt and drought tolerance inArabidopsisthaliana.Molecular Biology Reports, 2012, 39:7989-7996.

[132] Khoudi H, Maatar Y, Gouiaa S,etal.Transgenic tobacco plants expressing ectopically wheat H+-pyrophosphatase (H+-PPase) geneTaVP1 show enhanced accumulation and tolerance to cadmium.Journal of Plant Physiology, 2012, 169:98-103.

[133] Li X, Guo C, Gu J,etal.Overexpression of VP, a vacuolar H+-pyrophosphatase gene in wheat (TriticumaestivumL.), improves tobacco plant growth under Pi and N deprivation, high salinity, and drought.The Journal of Experimental Botany, 2014, 65(2):683-696.

[134] Zhao F Y, Zhang X J, Li P H,etal.Co-expression of theSuaedasalsaSsNHX1 andArabidopsisAVP1 confer greater salt tolerance to transgenic rice than the singleSsNHX1.Molecular Breeding, 2006, 17:341-353.

[135] Liu S P, Zheng L Q, Xue Y H,etal.Overexpression ofOsVP1 andOsNHX1 increases tolerance to drought and salinity in rice.Journal of Integrative Plant Biology, 2010, 53:444-452.

[136] Brini F, Hanin M, Mezghani I,etal.Overexpression of wheat Na+/H+antiporterTNHX1 and H+- pyrophosphataseTVP1 improve salt- and drought-stress tolerance inArabidopsisthalianaplants.Journal of Experimental Botany, 2007, 58:301-308.

[137] Bhaskaran S, Savithramma D L.Co-expression ofPennisetumglaucumvacuolar Na+/H+antiporter andArabidopsisH+- pyrophosphatase enhances salt tolerance in transgenic tomato.Journal of Experimental Botany, 2011, 62:5561-5570.

[138] Gouiaa S, Khoudi H, Leidi E O,etal.Expression of wheat Na+/H+antiporterTNHXS1 and H+- pyrophosphataseTVP1 genes in tobacco from a bicistronictranscriptional unit improves salt tolerance.Plant Molecular Biology, 2012, 79:137-155.

[139] Bao A K, Wang Y W, Xi J J,etal.Co-expression of xerophyteZygophyllumxanthoxylumZxNHXandZxVP1-1 enhances salt and drought tolerance in transgenicLotuscorniculatusby increasing cations accumulation.Functional Plant Biology, 2014, 41:203-214.

[140] Hu L, Lu H, Liu Q L,etal.Overexpression ofmtlDgene in transgenicPopulustomentosaimproves salt tolerance through accumulation of mannitol.Tree Physiology, 2005, 25:1273-1281.

[141] Liu Y, Wang G Y, Liu J J,etal.Transfer ofE.coligutDgene into maize and regeneration of salt-tolerant transgenic plants.Science in China Series C-Life Science, 1999, 42(1):90-95.

[142] Wang H Z, Huang D N, Lu R F,etal.Salt tolerance of transgenic rice (OryzasativaL.) withmtlDgene andgutDgene.Chinese Science Bulletin, 2000, 45:1685-1690.

[143] Kishor P B K, Hong Z, Mian G H.Over expression of △’-pyrroline-5-carboxylate synthetase increases proline production and confers osmotolerance in transgenic plants.Plant Physiology, 1995, 108:1387-1394.

[144] Dure L, Greenway S C, Galau G A.Developmental biochemistry of cottonseed embryogenesis and germination-changing messenger ribonucleic-acid populations as shown byinvitroandinvivoprotein-synthesis.Biochemistry, 1981, 20(14):4162-4168.

[145] Xu D, Duan X, Wang B,etal.Expression of a late embryogenesis abundant protein geneHVA1, from barley confers tolerance to water deficit and salt stress in transgenic rice.Plant Physiology, 1996, 110:249-257.

[146] Zhang N, Wang D, Si H J.Isolation and induced expression of betaine aldehyde dehydrogenase genefrom spinach.Journal of Agricultural Biotechnology, 2004, 12(5):612-613.

[147] Jia G X, Zhu Z Q, Chang F Q,etal.Transformation of tomato with theBADHgene fromAtripleximproves salt tolerance.Plant Cell Reports, 2002, 21(2):141-146.

[148] Tang N, Zhang H, Li X H,etal.Constitutive activation of transcription factor OsbZIP46 improves drought tolerance in rice.Plant Physiology, 2012, 158:1755-1768.

[149] Shinozaki K, Yamaguchi-Shinozaki K.Gene expression and signal transduction in water stress response.Plant Physiology, 1997, 115:327-334.

[150] Wu H J, Zhang Z H, Wang J Y,etal.Insights into salt tolerance from the genome ofThellungiellasalsuginea.Proceedings of the National Academy of Sciences, 2012, 109(30):12219-12224.

[151] Taji T, Seki M, Satou M,etal.Comparative genomics in salt tolerance betweenArabidopsisand a Rabidopsis-related halophyte salt cress usingArabidopsismicroarray.Plant Physiology, 2004, 135:1697-1709.

[152] Sheen J.Signal transduction in maize andArabidopsismesophyll protoplasts.Plant Physiology, 2001, 127:1466-1475.

[153] Moon H, Lee B, Choi G,etal.NDP kinase 2 interacts with two oxidative stress-activated MAPKs to regulate cellular reduxstate and enhances multiple stress tolerance in transgenic plants.Proceedings of the National Academy of Sciences, 2003, 100(1):358-363.

[154] Xie T, Ren R, Zhang Y Y,etal.Molecular mechanism for inhibition of a critical component in theArabidopsisthalianaabscisic acid signal transduction pathways, SnRK2.6, by protein phosphataseABI1.Journal of Biological Chemistry, 2012, 287:794-802.

[155] Li R F, Zhang J W, Wu G Y,etal.HbCIPK2, a novel CBL-interacting protein kinase from halophyteHordeumbrevisubulatum, confers salt and osmotic stress tolerance.Plant, Cell and Environment, 2012, 35:1582-1600.

[156] Zhang Q, Lin F, Mao T,etal.Phosphatidic acid regulates microtubule organization by interacting with MAP65-1 in response to salt stress inArabidopsis.Plant Cell, 2012, 24:4555-4576.

[157] Roxas V P, Lodhi S A, Garrett D K,etal.Stress tolerance in transgenic tobacco seedlings that overexpress glutathione S-transferase/glutathione peroxidase.Plant & Cell Physiology, 2000, 41(11):1229-1234.

[158] Kovtun Y, Chiu W L, Tena G,etal.Functional analysis of oxidative stress-activated mitogen-activated protein kinase cascade in plants.Proceedings of the National Academy of Sciences of the United States of America, 2000, 97:2940-2945.

[159] Zhang Z, Wang J, Zhang R X,etal.The ethylene response factor AtERF98 enhances tolerance to salt through the transcriptional activation of ascorbic acid synthesis inArabidopsis.The Plant Journal, 2012, 71:273-287.

[160] Ge Y, Gao P, Xia J Z,etal.The effects of calcium chloride on improving te salt resistance ofZeamaysL.Journal of Northeast Agicultural University, 2004, 35(3):281-284.

[161] Zhang L X, Chang Q S, Hou X G,etal.Effects of sodium salt stress on seed germination ofPrunellavulgaris.Acta Prataculturae Sinica, 2015, 24(3):177-186.

[162] Qian Q, Qu L J, Yuan M,etal.Research advances on plant science in China in 2012.Chinese Bulletin of Botany, 2013, 48:231-287.

[163] Galvan-Ampudia C S, Testerink C.Salt stress signals shape the plant root.Current Opinion in Plant Biology, 2011, 14:296-302.

[164] Brady S M, Sarkar S F, Bonetta D,etal.The abscisic acid insensitive 3(ABI3) gene is modulated by farnesylation and is involved in auxin signaling and lateral root development inArabidopsis.Plant Journal, 2003, 34:67-75.

[165] An J P, Chen K S.The relations between the injury of plasma membrane and the increase of aba content in wheat leaves.Journal of Lanzhou University (Natural Science), 1994, 3:127-131.

[166] Iraudat J, Parcy F, Gosti F.Current advances in abseisic acid action and signaling.Plant Molecular Biology, 1994, 26:1557-1577.

[167] Yuan F, Yang J C, Chen M,etal.Effect of no donor sodium nitroprusside (SNP) on seed germination ofSuaedasalsaL.under NaCl Stress.Plant Physiology Journa, 2010, 46(1):24-28.

[168] Liu W Y, Yang H W, Wei X H,etal.Effects of exogenous nitric oxide on seed germination, physiological characteristics and active oxygen metabolism ofMedicagotruncatula.Acta Prataculturae Sinica, 2015, 24(2):85-95.

[169] Chao D Y, Dilkes B, Luo H,etal.Polyploids exhibit higher potassium uptake and salinity tolerance inArabidopsis.Science, 2013, 341:658-659.

[170] Horie T, Costa A, Kim T H,etal.RiceOsHKT2;1 transporter mediates large Na+influx component into K+-starved roots for growth.EMBO Journal, 2007, 26(12):3013-3014.

[171] James R A, Blake C, Byrt C S,etal.Major genes for Na+exclusion,Nax1 andNax2 (wheatHKT1;4 andHKT1;5), decrease Na+accumulation in bread wheat leaves under saline and waterlogged conditions.Journal of Experimental Botany, 2011, 62:2939-2947.

[172] Byrt C S, Platten J D, Spielmeyer W,etal.HKT1; 5-like cation transporter linked to Na+exclusion loci in wheat,Nax2 andKna1.Plant Physiology, 2007, 143:1918-1928.

參考文獻(xiàn)：

[5] 趙可夫, 李法曾, 樊守金, 等.中國(guó)的鹽生植物.植物學(xué)通報(bào), 1999, 16(3):201-207.

[6] 趙可夫.植物對(duì)鹽漬逆境的適應(yīng).生物學(xué)通報(bào), 2002, 37(6):7-10.

[13] 李昀, 沈禹穎, 閻順國(guó).NaCl脅迫下5種牧草種子萌發(fā)的比較研究.草業(yè)科學(xué), 1997, 14(2):50-53.

[19] 劉晶, 才華, 劉瑩, 等.兩種紫花苜蓿苗期耐鹽生理特性的初步研究及其耐鹽性比較.草業(yè)學(xué)報(bào), 2013, 22(2):250-256.

[40] 王鎖民, 朱興運(yùn), 舒孝喜.堿茅離子吸收與分配特性研究.草業(yè)學(xué)報(bào), 1994, 3(1):39-43.

[51] 管博, 于君寶, 陸兆華, 等.黃河三角洲濱海濕地水鹽脅迫對(duì)鹽地堿蓬幼苗生長(zhǎng)和抗氧化酶活性的影響.環(huán)境科學(xué), 2011, 32(8):2422-2429.

[52] 魯艷, 雷加強(qiáng), 曾凡江, 等.NaCl處理對(duì)梭梭生長(zhǎng)及生理生態(tài)特征的影響.草業(yè)學(xué)報(bào), 2014, 23(3):152-159.

[53] 薛秀棟, 董曉穎, 段艷欣, 等.不同鹽濃度下3種結(jié)縷草的耐鹽性比較研究.草業(yè)學(xué)報(bào), 2013, 22(6):315-320.

[59] 張宏飛, 王鎖民.高等植物Na+吸收、轉(zhuǎn)運(yùn)及細(xì)胞內(nèi)Na+穩(wěn)態(tài)平衡研究進(jìn)展.植物學(xué)通報(bào), 2007, 24(5):561-571.

[76] 張金林.鹽生植物海濱堿蓬Na+吸收和積累的研究[D].蘭州： 蘭州大學(xué), 2008.

[146] 張寧, 王蒂, 司懷軍.菠菜甜菜堿醛脫氫酶基因的分離和誘導(dǎo)表達(dá).農(nóng)業(yè)生物技術(shù)學(xué)報(bào), 2004, 12(5):612-613.

[160] 葛瑛, 高鵬, 夏激宗, 等.氯化鈣在提高玉米抗鹽性方面的作用.東北農(nóng)業(yè)大學(xué)學(xué)報(bào), 2004, 35(3):281-284.

[161] 張利霞, 常青山, 侯小改, 等.不同鈉鹽脅迫對(duì)夏枯草種子萌發(fā)特性的影響.草業(yè)學(xué)報(bào), 2015, 24(3):177-186.

[162] 錢(qián)前, 瞿禮嘉, 袁明, 等.2012年中國(guó)植物科學(xué)若干領(lǐng)域重要研究進(jìn)展.植物學(xué)報(bào), 2013, 48:231-287.

[165] 安建平, 陳靠山.滲透脅迫下小麥的膜損傷與ABA增高的關(guān)系.蘭州大學(xué)學(xué)報(bào), 1994, (3):127-131.

[167] 袁芳, 楊劍超, 陳敏, 等.NaCl 脅迫下外源NO供體硝普鈉(SNP)對(duì)鹽地堿蓬種子萌發(fā)的影響.植物生理學(xué)通訊, 2010, 46(1):24-28.

[168] 劉文瑜, 楊宏偉, 魏小紅, 等.外源NO調(diào)控鹽脅迫下蒺藜苜蓿種子萌發(fā)生理特性及抗氧化酶的研究.草業(yè)學(xué)報(bào), 2015, 24(2):85-95.

Research advances in higher plant adaptation to salt stress

ZHANG Jin-Lin1*, LI Hui-Ru1, GUO Shu-Yuan1, WANG Suo-Min1, SHI Hua-Zhong2, HAN Qing-Qing1, BAO Ai-Ke1, MA Qing1

1.StateKeyLaboratoryofGrasslandAgro-ecosystems,CollegeofPastoralAgricultureScienceandTechnology,LanzhouUniversity,Lanzhou730020,China; 2.DepartmentofChemistryandBiochemistry,TexasTechUniversity,LubbockTX79409,USA

Soil salinity is a serious worldwide problem causing reduction in crop growth and agricultural output potential.Consequently, finding new ways to minimize the adverse effects of soil salinization on agriculture is globally important.Understanding the adaptation mechanisms of higher plants to salt stress is critical for enhancing salt tolerance and yields of crop plants as well as protecting ecological environments.In this paper, we reviewed the key progresses in salt stress adaptation of higher plants, including the effects of salt stress in plants; physiological mechanism of plant salt tolerance (osmotic adjustment, nutrient balance and the antioxidant system); the diversity of genes relevant to salt tolerance (ion transporting protein genes, osmotic regulation-related genes, signal transduction-related genes and cellular antioxidant-related genes and so on); and the approaches for crop improvement in salt tolerance.Prospects for developing crop plants tolerant to salinity are also discussed.

higher plants; salt stress; salt tolerance; salt tolerant genes

10.11686/cyxb2015233

http://cyxb.lzu.edu.cn

2015-05-07；改回日期：2015-07-14

國(guó)家自然科學(xué)基金項(xiàng)目(31222053,31170431和31172256),教育部“長(zhǎng)江學(xué)者和創(chuàng)新團(tuán)隊(duì)發(fā)展計(jì)劃”(IRT13019)和中央高?；究蒲袠I(yè)務(wù)費(fèi)項(xiàng)目(lzujbky-2014-m01和lzujbky-2015-194)資助。

張金林(1975-)，男，甘肅涇川人,教授,博士生導(dǎo)師，博士。

*通信作者Corresponding author.E-mail:jlzhang@lzu.edu.cn

張金林, 李惠茹, 郭姝媛, 王鎖民, 施華中, 韓慶慶, 包愛(ài)科, 馬清.高等植物適應(yīng)鹽逆境研究進(jìn)展.草業(yè)學(xué)報(bào), 2015, 24(12):220-236.

ZHANG Jin-Lin, LI Hui-Ru, GUO Shu-Yuan, WANG Suo-Min, SHI Hua-Zhong, HAN Qing-Qing, BAO Ai-Ke, MA Qing.Research advances in higher plant adaptation to salt stress.Acta Prataculturae Sinica, 2015, 24(12):220-236.