薛曉敏，韓雪平，聶佩顯，董 放，王金政

苯嗪草酮疏果劑對(duì)蘋(píng)果邊果營(yíng)養(yǎng)與激素含量的影響

薛曉敏，韓雪平，聶佩顯，董 放，王金政

（山東省果樹(shù)研究所，泰安 271000）

為明確苯嗪草酮疏果劑對(duì)蘋(píng)果邊果的疏除作用，以9年生天紅2號(hào)/SH38/八棱海棠為試材，在最大邊果直徑6 mm左右時(shí)噴300 mg/kg苯嗪草酮2次，清水為對(duì)照，生理落果后調(diào)查坐果率及坐果比例；噴藥后7、9、11、17、29 d采集處理和對(duì)照邊果，測(cè)定氮磷鉀礦質(zhì)營(yíng)養(yǎng)，淀粉、葡萄糖、果糖、蔗糖和山梨醇碳水化合物，可溶性蛋白質(zhì)含量以及玉米素（Z）、赤霉素（GA3）、生長(zhǎng)素（IAA）和脫落酸（ABA）激素含量。結(jié)果顯示，苯嗪草酮處理后，花序坐果率和花朵坐果率較對(duì)照降低17.95%和27.63%，坐單果比例顯著提高，坐三果及三果以上的比例顯著降低（＜0.01）；處理總體上提高了邊果無(wú)機(jī)營(yíng)養(yǎng)含量，顯著降低了可溶性蛋白質(zhì)含量（＜0.05）；淀粉含量較對(duì)照提高了5.57%～37.20%，但不同程度地降低了蔗糖、葡糖糖、果糖及山梨醇含量，從而使可溶性碳水化合物含量較對(duì)照降低了9.55%～52.60%；處理后脫落酸含量顯著升高（＜0.05），（Z+GA3+IAA）/ABA比值顯著降低。說(shuō)明苯嗪草酮在蘋(píng)果上具有較好的疏除邊果作用，其疏除作用與可溶性蛋白質(zhì)含量降低，可溶性碳水化合物供應(yīng)不足，以及ABA含量升高及生長(zhǎng)型激素/抑制型激素比值降低有關(guān)。

激素；營(yíng)養(yǎng)；苯嗪草酮；坐果率；蘋(píng)果

0 引 言

蘋(píng)果疏花疏果是調(diào)整樹(shù)體負(fù)荷、提高果實(shí)品質(zhì)、減輕大小年結(jié)果的必要技術(shù)，包括人工疏花疏果、化學(xué)疏花疏果和機(jī)械疏花疏果。人工疏花疏果主要在中國(guó)應(yīng)用，美國(guó)、德國(guó)的商業(yè)化果園開(kāi)始試驗(yàn)示范機(jī)械疏花疏果，化學(xué)疏花疏果則是歐美發(fā)達(dá)國(guó)家普遍采取的蘋(píng)果生產(chǎn)花果調(diào)控技術(shù)[1-4]。疏果相對(duì)于疏花來(lái)說(shuō)，安全系數(shù)高，更受果農(nóng)青睞。研究表明，萘乙酸、西維因、6-BA、ACC、乙烯利等在一定濃度范圍內(nèi)均有疏除幼果、平衡負(fù)載量作用[5-8]，對(duì)其疏除機(jī)理也有相關(guān)報(bào)道，如西維因阻礙營(yíng)養(yǎng)物質(zhì)運(yùn)輸養(yǎng)分、萘乙酸干擾激素代謝、乙烯利促進(jìn)乙烯生成等造成幼果脫落[9-10]。苯嗪草酮是一種光合系統(tǒng)Ⅱ（PSⅡ）抑制劑，主要用作除草劑。2014年安道麥公司發(fā)布苯嗪草酮可作為一種低毒、安全的果樹(shù)疏果劑，主要應(yīng)用在蘋(píng)果和梨上，不少學(xué)者開(kāi)展了相關(guān)研究[11-12]。本課題組從光合和熒光角度研究了苯嗪草酮對(duì)蘋(píng)果葉片抑制作用的影響[13]，但是，對(duì)于苯嗪草酮如何影響幼果的生理代謝國(guó)內(nèi)外均未見(jiàn)相關(guān)報(bào)道。

本文以矮砧蘋(píng)果樹(shù)為試材，研究了在最大邊果直徑6 mm左右時(shí)噴施苯嗪草酮對(duì)蘋(píng)果的疏果效應(yīng)及對(duì)邊果營(yíng)養(yǎng)和激素含量的影響，從碳水化合物及激素調(diào)控角度初步揭示了苯嗪草酮的疏果機(jī)制，為生產(chǎn)提供了參考依據(jù)。

1 材料與方法

1.1 試驗(yàn)材料

試驗(yàn)在山東省果樹(shù)研究所天平湖基地（北緯36°12′55.36″，東經(jīng)117°01′09.87″，海拔168 m）進(jìn)行。試材為9年生天紅2號(hào)/SH38/八棱海棠（‘天紅2號(hào)’為紅富士芽變品種），株行距0.75 m×4.0 m，采用高紡錘樹(shù)形、行間生草、樹(shù)盤(pán)覆蓋、肥水一體化技術(shù)，管理水平中等偏上。試驗(yàn)地有機(jī)質(zhì)質(zhì)量分?jǐn)?shù)0.79%，速效氮86.11 mg/kg，速效磷73.71 mg/kg，速效鉀116.32 mg/kg。

1.2 處理方法

選取長(zhǎng)勢(shì)基本一致健康的蘋(píng)果樹(shù)30株，設(shè)噴藥和對(duì)照2個(gè)處理，各處理15株樹(shù)，5株樹(shù)為1個(gè)小區(qū)，3次重復(fù)，處理和對(duì)照之間保留2株樹(shù)作為保護(hù)株。每株樹(shù)隨機(jī)選3個(gè)主枝，統(tǒng)計(jì)花序數(shù)和花朵數(shù)，掛牌標(biāo)記。

2018年4月21日進(jìn)行了苯嗪草酮試驗(yàn)濃度篩選試驗(yàn)，設(shè)置100、200、300、400、500 mg/kg 5個(gè)濃度處理，清水為對(duì)照。選用背負(fù)式電動(dòng)噴霧器對(duì)全樹(shù)進(jìn)行噴布，噴至幼果濕潤(rùn)輕微滴水為止。生理落果后調(diào)查有掛牌的主枝坐果情況，統(tǒng)計(jì)花序坐果率和花朵坐果率，花序坐果率（%）=坐果花序數(shù)/總花序數(shù)×100%，花朵坐果率（%）=坐果數(shù)/總花朵數(shù)×100%。

2019年4月19日在最大邊果直徑6 mm左右時(shí)噴300 mg/kg苯嗪草酮，4月22日噴第二次；對(duì)照噴清水。噴施方法同2018年，生理落果后調(diào)查坐果率和坐果比例，單果率（%）=坐單果花序數(shù)/總花序數(shù)×100%，雙果率（%）=坐雙果花序數(shù)/總花序數(shù)×100%，三果及以上（%）=100?（單果率+雙果率）。

1.3 取樣與測(cè)定

分別在第一次噴藥處理后7、9、11、17及29 d從處理及對(duì)照試驗(yàn)樹(shù)上取邊果，前3次每個(gè)小區(qū)（5株樹(shù)）共采果90個(gè)左右，后2次每個(gè)小區(qū)（5株樹(shù)）共采果60個(gè)左右，均為3個(gè)重復(fù)，去除果柄及萼片后，用鋁箔紙包好，放入液氮罐中速凍，帶回實(shí)驗(yàn)室放至?80 ℃冰箱保存，用于測(cè)定氮磷鉀、碳水化合物、蛋白質(zhì)及激素。

1.3.1 礦質(zhì)營(yíng)養(yǎng)測(cè)定

全氮測(cè)定用半微量蒸餾法，全磷測(cè)定用鉬銻抗吸光光度法，全鉀測(cè)定用火焰光度計(jì)法，具體測(cè)定步驟參考崔建宇等[14]方法。所有指標(biāo)均重復(fù)3次。

1.3.2 碳水化合物含量測(cè)定

單糖和低聚糖提取參考Kang 等[15]方法，葡萄糖、果糖、山梨醇用水提取，稱取約0.2 g樣品，加入1 mL水，勻漿，過(guò)夜浸提。蔗糖用乙腈提取，稱取約0.2 g樣品，加入1 mL 80%乙腈，勻漿，50 ℃水浴30 min，8 000離心10 min，取上清液，針頭式過(guò)濾器過(guò)濾后待測(cè)。用Waters 1525高效液相色譜儀測(cè)定，示差檢測(cè)器為Shodex RI-201H。葡萄糖、果糖、山梨醇用Carbomix Ca-NP 8%色譜柱（300 mm×7.8 mm，10m），柱溫80oC，流動(dòng)相為水，流速0.4 mL/min，進(jìn)樣體積10L；蔗糖用Sepax HP-Amino氨基柱（4.6 mm×250 mm，5m），柱溫40 ℃，流動(dòng)相乙腈∶水=80∶20，流速0.4 mL/min，進(jìn)樣體積10L。根據(jù)葡萄糖、果糖、山梨醇、蔗糖標(biāo)準(zhǔn)曲線和樣品峰面積計(jì)算含量。

將提取可溶性糖的殘余物用高氯酸水解成葡萄糖，蒽酮比色法測(cè)定葡萄糖含量，測(cè)定波長(zhǎng)為620 nm，由葡萄糖標(biāo)準(zhǔn)曲線計(jì)算淀粉含量。

1.3.3 可溶性蛋白質(zhì)含量測(cè)定

可溶性蛋白含量測(cè)定采用考馬斯亮藍(lán)染色法[16]。

1.3.4 激素含量測(cè)定

激素提取方法參考Yan 等[17]，稱取約0.2 g樣品，加入1 mL預(yù)冷的20%甲醇，4 ℃浸提過(guò)夜；8 000離心10 min，取上清液，殘?jiān)?.5 mL 20%甲醇水溶液浸提2 h，離心后取上清液，合并2次上清，40 ℃減壓蒸發(fā)至不含有機(jī)相，加入2 mL石油醚60～90 ℃萃取脫色3次，移去石油醚；向下層水相中加入2 mL乙酸乙酯萃取，轉(zhuǎn)移上層有機(jī)相至新的EP管，重復(fù)萃取3次，合并3次有機(jī)相，氮吹吹干，加入0.2 mL流動(dòng)相溶解，混勻，針頭式過(guò)濾器過(guò)濾后待測(cè)。采用RIGOL L3000高效液相色譜儀，Kromasil C18反相色譜柱（250 mm×4.6 mm，5m），波長(zhǎng)為254 nm，柱溫30 ℃，流動(dòng)相流速0.8 mL/min，進(jìn)樣體積10L，走樣時(shí)間35 min。

1.4 數(shù)據(jù)分析

所有數(shù)據(jù)均采用SPSS軟件進(jìn)行差異顯著性比較，應(yīng)用GraphPad Prism 5 軟件繪圖。

2 結(jié)果與分析

2.1 苯嗪草酮適宜濃度篩選

不同濃度苯嗪草酮處理對(duì)坐果率的調(diào)查結(jié)果如圖1所示。可以看出，與清水對(duì)照相比，100～500 mg/kg的苯嗪草酮處理降低了花序坐果率和花朵坐果率，其中對(duì)照與200～500 mg/kg處理間的花序坐果率存在顯著性差異（＜0.05），而對(duì)照與所有苯嗪草酮處理的花果坐果率均存在顯著性差異（＜0.05）。200～400 mg/kg 3個(gè)濃度之間差異性不顯著，以300 mg/kg的花序坐果率和花朵坐果率最低，分別為72.39%和23.52%，故選300 mg/kg作為后續(xù)試驗(yàn)的噴施濃度。

注：不同小寫(xiě)字母表示不同濃度處理0.05水平差異性顯著。

Note: Different small letter indicates significant difference at 0.05 level between different concentrations.

圖1 不同濃度苯嗪草酮處理對(duì)坐果率的影響

Fig.1 Effect of metamitron with different concentrations on fruit setting rate

2.2 苯嗪草酮處理對(duì)坐果率和坐果比例的影響

由圖2a可見(jiàn)，與對(duì)照相比，幼果期苯嗪草酮處理顯著降低了坐果率（＜0.01），其中花序坐果率降低17.95%，花朵坐果率降低27.63%。同時(shí)，苯嗪草酮處理顯著提高了花序坐單果比例（＜0.01），處理單果率為44.80%，為對(duì)照的5.28倍，且保留的單果均為中心果，說(shuō)明苯嗪草酮僅對(duì)邊果起作用，對(duì)中心果無(wú)影響；處理顯著降低了花序坐三果及以上的比例（＜0.01），處理為對(duì)照的47.91%；坐雙果比例也有所增加，但未達(dá)到顯著水平（圖2b）。說(shuō)明苯嗪草酮在富士蘋(píng)果上有較好的疏果作用，疏除力強(qiáng)，單果率高，分布均勻。

2.3 苯嗪草酮對(duì)無(wú)機(jī)營(yíng)養(yǎng)的影響

由表1可以看出，苯嗪草酮處理后，所有時(shí)期的全氮含量均高于對(duì)照，在噴施后7和9 d二者差異不顯著，可能與處理時(shí)間較短有關(guān)；噴施11 d之后，處理的全氮含量均顯著高于對(duì)照（＜0.05）。苯嗪草酮處理對(duì)全磷和全鉀的影響更為顯著，幾乎所有處理的全磷和全鉀含量均顯著高于對(duì)照（＜0.05），噴后11、29 d處理的全磷含量為對(duì)照的2.05和1.67倍，全鉀含量為對(duì)照的1.93和1.51倍。說(shuō)明苯嗪草酮的疏果作用不是由于氮磷鉀無(wú)機(jī)養(yǎng)分的缺失造成的。

注：**表示處理與對(duì)照間0.01水平差異性顯著，下同。

Note: ** indicates significant difference at 0.01 level between treatment and control, the same below.

圖2 苯嗪草酮處理對(duì)坐果率及坐果比例的影響

Fig.2 Effect of metamitron treatment on fruit setting rate and ratio

表1 苯嗪草酮處理對(duì)氮磷鉀營(yíng)養(yǎng)元素的影響

注：不同小寫(xiě)字母表示處理與對(duì)照間0.05水平差異性顯著。

Note: Different small letter indicates significant difference at 0.05 level between treatment and control.

2.4 苯嗪草酮處理對(duì)有機(jī)營(yíng)養(yǎng)的影響

蘋(píng)果有機(jī)營(yíng)養(yǎng)成分主要是碳水化合物，包括淀粉、葡萄糖、果糖、蔗糖、山梨醇[18]。由圖3a可以看出，盡管蘋(píng)果幼果中淀粉含量較低，但苯嗪草酮處理的淀粉含量多明顯高于對(duì)照，增幅為5.57%～37.20%；圖3b～圖3e為可溶性碳水化合物葡萄糖、果糖、蔗糖及山梨醇含量，可以看出，整體趨勢(shì)為對(duì)照的可溶性碳水化合物含量高于苯嗪草酮處理。為了整體比較處理與對(duì)照可溶性碳水化合物含量，對(duì)葡萄糖、果糖、蔗糖及山梨醇的總含量進(jìn)行了分析，如圖3f所示，可見(jiàn)苯嗪草酮處理的可溶性碳水化合物均顯著低于對(duì)照（＜0.05），降幅為9.55%～52.57%。而可溶性碳水化合物是幼果發(fā)育的直接營(yíng)養(yǎng)物質(zhì)，說(shuō)明苯嗪草酮疏果可能是由于可溶性碳水化合物的供應(yīng)不足造成的。

注：*表示處理與對(duì)照間0.05水平差異性顯著，下同。

Note: * indicates significant difference at 0.05 level between treatment and control, the same below.

圖3 苯嗪草酮處理對(duì)果實(shí)碳水化合物含量的影響

Fig.3 Effect of metamitron treatment on fruit carbohydrate content

2.5 苯嗪草酮處理對(duì)可溶性蛋白質(zhì)含量的影響

如圖4所示，苯嗪草酮處理后蘋(píng)果幼果可溶性蛋白質(zhì)含量明顯降低，差異達(dá)顯著水平（＜0.05）。各個(gè)時(shí)期處理的可溶性蛋白質(zhì)含量分別為對(duì)照的71.42%、72.37%、69.68%、64.20%和86.02%，說(shuō)明苯嗪草酮處理使蘋(píng)果幼果的總體代謝能力減弱，進(jìn)而造成幼果脫落。

2.6 苯嗪草酮處理對(duì)激素的影響

蘋(píng)果幼果脫落受內(nèi)源激素調(diào)控[19-21]。在處理早期（7和9 d），對(duì)照的玉米素含量顯著高于處理（＜0.05）；而在處理后期，對(duì)照的玉米素含量則明顯低于處理（圖5a）。苯嗪草酮處理對(duì)赤霉素也有影響（圖5b）。苯嗪草酮處理顯著提升了幼果生長(zhǎng)素水平（＜0.05），圖5c可見(jiàn)，所有處理的IAA含量均明顯高于對(duì)照，差異性多為顯著水平（＜0.05）。脫落酸是幼果脫落的主導(dǎo)激素種類，苯嗪草酮處理后脫落酸含量普遍升高，各時(shí)期ABA含量均顯著高于對(duì)照（＜0.05），處理為對(duì)照的1.37～3.11倍，說(shuō)明苯嗪草酮提高了幼果的脫落酸含量，從而促進(jìn)了幼果脫落（圖5d）。同時(shí)，對(duì)（Z+GA3+IAA）/ABA的比值（值）進(jìn)行了分析，如圖5e所示，除噴施早期（7d）外，對(duì)照的值均高于處理，其中9、17和29 d 3個(gè)時(shí)期二者間差異達(dá)顯著水平（＜0.05），降幅最大為51.55%，說(shuō)明低值與幼果脫落相關(guān)。

3 討 論

苯嗪草酮作為一種蘋(píng)果疏果劑有近十年的時(shí)間，不少學(xué)者對(duì)不同生態(tài)條件下的不同品種進(jìn)行了噴施時(shí)期、噴施濃度、對(duì)產(chǎn)量品種調(diào)控效應(yīng)等研究[22-24]。Steven等[25]研究認(rèn)為，苯嗪草酮適宜噴施濃度為300 mg/kg，適宜噴施時(shí)期為盛花后23和38 d，與對(duì)照相比，花朵坐果率降低了50.63%，單株產(chǎn)量降低了37.10%，單果質(zhì)量提高了8.54%，分析為苯嗪草酮影響葉綠素?zé)晒馑拢归_(kāi)放的PSⅡ反應(yīng)中心的能量捕捉效率值、PSⅡ光合量子產(chǎn)量及相對(duì)電子傳導(dǎo)率均下降。嘎啦果適宜噴施時(shí)期為中心果直徑6.0～13.5 mm，濃度為1.65 kg/hm2，噴施2次疏果效應(yīng)更好，分析認(rèn)為嘎拉幼果脫落與葉綠素?zé)晒饧耙归g溫度有關(guān)[11,26]。富士適宜噴施時(shí)期為幼果直徑5～10 mm，濃度為350 mg/kg，落果率35.6%～50.9%，且顯著提高了成熟期單果質(zhì)量和商品果比例[8]。本試驗(yàn)中，幼果直徑6 mm左右噴施300 mg/kg苯嗪草酮2次，花朵坐果率24.20%，比對(duì)照降低27.63%，與多數(shù)學(xué)者的疏除效應(yīng)一致。然而，也有學(xué)者認(rèn)為苯嗪草酮適用的幼果直徑較大，可作為一種補(bǔ)救型疏果劑[27-28]。

不少學(xué)者認(rèn)為，礦質(zhì)養(yǎng)分及碳水化合物不足是導(dǎo)致幼果脫落的主要因素之一[29-31]。楊波等[32]研究發(fā)現(xiàn)，扁桃在生理脫落期，正常幼果的N、P、K、B、Zn 5種礦質(zhì)元素的濃度均高于落果，認(rèn)為扁桃幼果脫落與礦質(zhì)元素濃度降低有關(guān)；而本試驗(yàn)結(jié)果則表明，處理的氮磷鉀含量多高于對(duì)照，分析認(rèn)為，疏果劑處理后果實(shí)變小直至萎蔫脫落，氮磷鉀含量在其中相對(duì)“濃縮”，從而高于正常發(fā)育的果實(shí)，這與關(guān)軍鋒等[33]的研究結(jié)果一致。徐昌杰等[31]研究認(rèn)為，柑橘幼果脫落與淀粉含量降低有關(guān)，本試驗(yàn)結(jié)果則顯示，苯嗪草酮處理后幼果的淀粉含量沒(méi)有降低，降低的是可溶性碳水化合物含量，而可溶性碳水化合物含量對(duì)幼果發(fā)育的作用更為直接。

眾多研究表明，不少果樹(shù)幼果脫落與激素含量及激素比例有關(guān)。易落果的柑橘品種具有較高的ABA含量與較低的GA3含量[34]；同樣扁桃幼果脫落與ABA含量升高及GA3和IAA含量降低有關(guān)[35]；蘋(píng)果幼果脫落與ZT、IAA、GA的減少及ABA的增加有關(guān)[36]。本試驗(yàn)中，苯嗪草酮處理后ABA含量顯著升高，與前人的研究相一致；另外果實(shí)脫落往往不是由某一激素單獨(dú)控制的，而是由多種激素協(xié)同作用的結(jié)果，因此本研究對(duì)（Z+GA3+IAA）/ABA進(jìn)行了分析，顯示苯嗪草酮處理后（Z+GA3+IAA）/ABA比值降低，說(shuō)明苯嗪草酮疏果作用與低的（Z+GA3+IAA）生長(zhǎng)素類激素/ABA比值有關(guān)。

4 結(jié) 論

1）在邊果直徑 6 mm時(shí)噴施2次300 mg/kg苯嗪草酮，具有疏除邊果的作用，花序坐果率和花朵坐果率較對(duì)照降低17.95%和27.63%，差異達(dá)極顯著水平（＜0.01）；處理的單果率44.80%，為對(duì)照的5.28倍，差異達(dá)極顯著水平（＜0.01）。

2）苯嗪草酮處理后，淀粉含量不降反升，漲幅為5.57%～37.20%；可溶性碳水化合物總量（葡萄糖、果糖、蔗糖、山梨醇）顯著降低（＜0.05），降幅最大的為52.57%；可溶性蛋白質(zhì)含量顯著降低（＜0.01），降幅最大的為35.80%。

3）激素測(cè)定結(jié)果顯示，苯嗪草酮處理后脫落酸含量顯著升高（＜0.05），處理為對(duì)照的1.37～3.11倍；生長(zhǎng)型與抑制型激素比值[(Z+GA3+IAA)/ABA]降低，降幅最大的為51.55%。

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Effects of fruit thinning agent “metamitron” on nutrition and hormone content of apple lateral fruits

Xue Xiaomin, Han Xueping, Nie Peixian, Dong Fang, Wang Jinzheng

(,271000,)

The work aimed to clarify the effects of metamitron as the fruit thinning agent on the apple fruit setting rate as well as the mineral nutrition, carbohydrates, and hormones of lateral fruitlets, thus providing a reference for applying chemical thinning technology of apples. Thirty 9-year-old apple trees (Tianhong 2/SH38/Malus micromalus) were used as test materials, and 300 mg/kg metamitron solution was sprayed 2 times when the diameter of the biggest lateral fruits were around 6 mm. Spraying water was used as the control. The setting rate of inflorescence and flower were investigated after physiological fruit drop. The mineral nutrition, carbohydrate, soluble protein, and hormone content of lateral fruits were measured after spraying 7, 9, 11, 17, and 29 d. The total nitrogen, phosphorus, and potassium were determined by semi-micro distillation, Mo-Sb-Vc colorimetry, and flame photometer, respectively. Glucose, fructose, sorbitol, sucrose, and hormone contents were determined by HPLC, while the soluble protein content was determined by Coomassie brilliant blue staining. The results showed that the fruit setting rate of inflorescence and flowers decreased by 17.95 and 27.63% compared with the control, respectively. The proportion of inflorescence with single fruit increased by 5.28 times in the treatment, while that of sitting three fruits and more decreased significantly, which was 47.91% of the control. The results of fruit setting rate and fruit setting ratio showed that metamitron could significantly reduce the fruit setting rate, and the single fruit rate was high, with the setting fruits distributed evenly. The total nitrogen content was higher than that of the control at all stages, and the difference between the control and the treatment was significant except 7 and 9 d. The total phosphorus and potassium contents of almost all treatments were significantly higher than those of the control. The total phosphorus contents of 11 and 29 d after spraying was 2.05 and 1.67 times of the control, and the total potassium content was 1.93 and 1.51 times of the control, respectively. The results of mineral nutrition showed that the fruit thinning effect of metamitron was not caused by the deficiency of inorganic nutrients. The content of the soluble protein decreased significantly compared with the control, and the content of each treatment period was 71.42%, 72.37%, 69.68%, 64.20%, and 86.02% of the control, respectively. The starch content of metamitron treatment was significantly higher than that of the control, with an increase of 5.57%-37.20%, yet the content of sucrose, glucose, fructose, and sorbitol decreased with different degrees. Therefore, the soluble carbohydrate content decreased significantly to 9.55%-52.57%. Soluble carbohydrates are the direct nutrients for the development of young fruits, so fruit thinning of metamitron may be caused by insufficient supply of soluble carbohydrates. The abscisic acid content generally increased after the treatment, and the ABA content in each period was 1.37-3.11 times that of the control. The ratio of (Z+GA3+IAA)/ABA decreased significantly, which could cause falling off of young fruits. As a result, metamitron has a good fruit thinning effect on apples, related to the decreased soluble protein content, an insufficient supply of soluble carbohydrate, increased ABA content, and decreased (Z+GA3+IAA)/ABA ratio.

hormone; nutrition; metamitron; fruit setting; apple

2020-09-22

2021-02-07

現(xiàn)代農(nóng)業(yè)蘋(píng)果產(chǎn)業(yè)技術(shù)體系（CARS-27）

薛曉敏，研究方向?yàn)樗z傳育種與栽培。Email：xuexiaomin79@126.com

王金政，研究員，研究方向?yàn)樗z傳育種與栽培。Email：wjz992001@163.com

10.11975/j.issn.1002-6819.2021.07.025

S661.1

A

1002-6819(2021)-07-0206-06

薛曉敏，韓雪平，聶佩顯，等. 苯嗪草酮疏果劑對(duì)蘋(píng)果邊果營(yíng)養(yǎng)與激素含量的影響[J]. 農(nóng)業(yè)工程學(xué)報(bào)，2021，37(7)：206-211. doi：10.11975/j.issn.1002-6819.2021.07.025 http://www.tcsae.org

Xue Xiaomin, Han Xueping, Nie Peixian, et al. Effects of fruit thinning agent “metamitron” on nutrition and hormone content of apple lateral fruits[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2021, 37(7): 206-211. (in Chinese with English abstract) doi：10.11975/j.issn.1002-6819.2021.07.025 http://www.tcsae.org