覃章輝　陳快　熊莉軍　鄧志軍

摘要：作為用于防治喀斯特地區(qū)石漠化的植物物種，在其種子萌發(fā)階段就必須具有較強(qiáng)的適應(yīng)干旱和富鈣土壤的能力。本文研究了喀斯特地區(qū)鄉(xiāng)土植物全緣火棘種子萌發(fā)過程中對(duì)干旱和鈣離子的耐受能力，用不同水勢(shì)的PEG6000溶液和不同濃度的CaCl2溶液分別模擬干旱和富鈣土壤環(huán)境。結(jié)果表明，全緣火棘種子萌發(fā)對(duì)干旱和鈣均具有很強(qiáng)的耐受能力，其耐旱能力強(qiáng)于很多其他喀斯特地區(qū)鄉(xiāng)土植物的種子，甚至強(qiáng)于一些荒漠植物的種子;其對(duì)鈣離子的耐受能力也明顯強(qiáng)于與其在形態(tài)和生態(tài)特性上非常相似的同屬植物火棘的種子。這或許反映了其對(duì)喀斯特地區(qū)頻發(fā)干旱并富鈣土壤環(huán)境的適應(yīng)，同時(shí)也意味著其具有防治喀斯特地區(qū)石漠化的巨大潛力。

關(guān)鍵詞：喀斯特地貌;石漠化;干旱;水勢(shì);萌發(fā)率

中圖分類號(hào)：S753文獻(xiàn)標(biāo)識(shí)碼：A文章編號(hào)：1004-3020（2019）04-0001-04Effects of PEG and Calcium on the Germination

of Pyracantha atalantioides SeedsQin Zhanghui（1）Chen Kuai（1）Xiong Lijun（2）Deng Zhijun（1）

（1.Seed Biology Laboratory， College of Forestry and Horticulture， Hubei Minzu UniversityEnshi445000;

2. Meteorological Bureau of Enshi Tujia & Miao Autonomous PrefectureEnshi445000）

Abstract： As a plant species used to prevent and control rocky desertification in karst area， it is necessary to adapt to drought and calcium-rich soil at the stage of seed germination. The tolerance to drought and calcium ions during seed germination of native plants in karst area was studied in this study. The drought and calcium-rich soil environments were simulated by PEG6000 solution with different water potential and different concentration of CaCl2 solution. The results showed that the germination of Pyracantha atalantioides seeds had strong tolerance to drought and calcium， and its drought tolerance was stronger than that of many other native plants in karst area， and even stronger than that of some desert plants. Its tolerance to calcium ions was also stronger than that of the seeds of the same genus plant， P. fortuneana， which was similar to P. atalantioides in morphology and ecological characteristics. These may reflect an adaptation of P. atalantioides to drought and calcium-rich soil environment in karst area， and may also means that P. atalantioides has a great potential to be used to prevent and control rocky desertification in karst area.

Key words：karst landform; rocky desertification; drought stress; water potential; germination

中國(guó)西南地區(qū)發(fā)育有大面積的典型喀斯特地貌[1]。喀斯特地貌是石灰?guī)r受流水的溶蝕作用并伴隨外界機(jī)械作用形成的[2]，其發(fā)育的土壤具有土層淺薄且不連續(xù)，持、滯水能力弱等特點(diǎn)[3]。其中，間歇性干旱頻發(fā)和富鈣是喀斯特地區(qū)土壤的兩個(gè)最重要特征[4]。在這些特殊生境中發(fā)育的喀斯特植物群落也與非喀斯特環(huán)境上的地帶性植物群落存在明顯差異[5]，其生態(tài)系統(tǒng)脆弱，石漠化嚴(yán)重[6]。有研究表明，隨著石漠化強(qiáng)度的增加，土壤中的游離鈣離子含量呈遞增趨勢(shì)[7]。因此，篩選出耐旱并能耐受較高濃度鈣離子的植物對(duì)于喀斯特地區(qū)的石漠化防治當(dāng)具有重要意義。

湖北林業(yè)科技第48卷第4期覃章輝，等：PEG和鈣離子處理對(duì)全緣火棘種子萌發(fā)的影響種子萌發(fā)是絕大多數(shù)種子植物生活史中最先表達(dá)的性狀，影響植物各種萌發(fā)后性狀的表型、遺傳表達(dá)和自然選擇[8]，進(jìn)而影響植物的生態(tài)適應(yīng)性，甚至決定一個(gè)種群在特定地區(qū)能否長(zhǎng)久存在[9]。故，篩選耐旱并能耐受較高濃度鈣離子植物的第一步是檢測(cè)候選植物種子萌發(fā)過程對(duì)干旱和較高濃度鈣離子的耐受能力。目前，關(guān)于喀斯特地區(qū)植物種子在萌發(fā)過程中對(duì)富鈣且頻發(fā)間歇性干旱土壤的響應(yīng)方面的研究尚鮮見報(bào)道。