【作者】 金雅琴；

【导师】 丁雨龙；

【作者基本信息】 南京林业大学 ， 植物学， 2012， 博士

【摘要】 乌桕是我国重要的木本油料树种，也是我国常见的乡土树种之一。开展乌桕栽培与种源试验，筛选抗逆性强的种源，对促进乌桕的品种改良，实现造林良种化、集约化与科学化，促进困难立地资源的开发与利用具有重要意义。本文通过引种试验与实验分析，研究了乌桕实生苗培育技术，摸清了1年生实生苗的生长发育规律，探讨了海水胁迫及干旱逆境下6个不同种源[湖南新宁（XN1）、浙江杭州（HZ2）、河南商城（SC4）、安徽贵池（GCH1）、安徽黄山（HS1）、江苏高淳（GC2）]幼苗生长及各种生理指标的变化及差异性，主要研究结果如下：（1）不同种源乌桕种子性状存在显著变异。依据种子外形和百粒重（带蜡）可以划分成大粒型、中粒型和小粒型种子。与纬度密切相关的年均温度与≥10℃积温是影响乌桕种子性状的主要环境因子。（2）乌桕1年生幼苗高生长与径生长均呈明显的“S型”生长节律，用Logistic方程能够较好地拟合其生长过程。幼苗生长期可划分为4个阶段：出苗期（04-20以前）、生长初期（04-21～6-l5）、生长盛期（06-l6～08-15）和生长后期（08-16～l0-30）。生长盛期是1年中苗木生长的关键期，应加强水肥管理。（3）海水浸淹对乌桕幼苗生长将产生一定的影响。随着海水处理浓度的加大，各种源均呈现出生长变缓，叶面积缩小，生物量下降；随着胁迫时间的延长，MDA、脯氨酸呈现不同程度的增加，而可溶性糖含量不同种源间有较大差异。幼苗Pn也随之下降，并与Gs、Ci和Tr的变化趋势基本一致，但叶绿素变化不明显。SOD呈现一致性升高，尤其后期上升趋势明显，而POD则呈现先升后降的变化。（4）海水浸淹下组织中Na⁺含量明显增加，但伴随着Na⁺增加，K⁺趋于减少，而Mg²⁺和Ca²⁺含量并未随之下降。幼苗根部对Na⁺有较强的富集和截流作用。应用主成分分析和隶属函数法对不同种源乌桕的耐海水性进行了综合评价，6种源的基本耐性顺序为：XN1>HZ2>SC4>GCH1>HS1>GC2。（5）轻度（NaCl质量分数0.2%）盐胁迫对叶绿体影响较小，叶绿体基本能维持其结构和膜的完整性；而重度（NaCl质量分数≥0.6%）盐碱胁迫下，叶绿体膜趋于溶解，结构受损，与细胞壁之间的距离变大，类囊体腔增大，片层紊乱，结构模糊，排列不齐，基粒片层垛叠数目减少，高度降低；淀粉粒数量减少，体积变小甚至消失，嗜锇颗粒数量增多。盐胁迫对幼苗线粒体的影响较小。（6）干旱胁迫下，乌桕植株外部形态表现为叶片下垂、下部枯黄，甚至萎蔫；RWC逐渐下降，而叶绿素变化不显著，类胡萝卜素增加，Pn与Gs总体上下降，SOD和POD活性上升， MDA增加，脯氨酸积累，但细胞膜结构与功能保存尚完好。综合评价表明，HS2、SC4种源综合评价指数最大，其抗旱性略强。更多还原

【Abstract】 Sapium sebiferum （L.） Roxb. is a kind of important woody oleiferous tree inChina, and distributed widely in subtropical region. The investigation on seedlingcultivation, provenance trial and screen of the strong adversity resisting provenancewill improve the afforestation intensively and scientifically with high quality for thistree. It is significant for exploitation of difficult land resources as well.On the basis of introducing and provenance trial, the cultivation techniquesofseedling were expounded. The growth and development rhythm were discussed.Some variations between six different provenances, Hunan Xinning （XN1）,ZhejiangHangzhou （HZ2）, Henan Shangcheng （SC4）, Anhui Guichi （GCH1）, AnhuiHuangshan （HS1）, Jiangsu Gaochun （GC2）, in growth and physiological indexesunder seawater and drought stress were analyzed. The results were as follows:⑴There were obvious variance between different provenances.The seeds couldbe divided into three types by the figure and weight with wax of100seeds: big grain,small grain and middle grain. The accumulated temperature over0℃, which wasrelated to latitude, was main environment factor affect seeds characters of S.sebiferum.⑵The annul growth rhythm of height and caliper on one-year seedling wasfitted for S-curve and could be simulated with Logistic equation. At the same timethe growing period of both height and caliper was divided into4stages according toits growth rate: emergence phase （before Apr20）, initiation phase （Apr2l to Jun15）,prosperous phase （Jun16to Aug15） and later phase （Aug16to Dec30）.The seedlingsshould be managed meticulously during the prosperity period as it was the keyperiod of biomass growth.⑶The seawater inundating wouldexert influence on seedlings to some extent.With the increasing of the concentration of seawater, seedling growth became weak,leaf area reduced, biomass went down, both MDA and proline content showed someincrease with the treating time prolonging, but there were big difference aboutsolvable sugar content among provenances. The net photosynthetic rate （Pn）diminished, and the diminished extent of Pnwas related with stress intensity, thestomatal conductance （Gs）,intercellular CO2concentration （Ci）, transpiration rate （Tr）were so, but the change of chlorophyll content was not evident. SOD raised, especially at late period, and the change tendency of POD were ascended first anddecreased later.⑷The content of Na⁺ascended in evidence with the increasing of seawaterconcentration, but K⁺was not so. The content of Mg²⁺and Ca²⁺decreased along withit. The root of seedlings had strong function of enrichment and interception to Na⁺.By means of principal component analysis and subjection function the basicalsequence of endurance to seawater was XN1>HZ2>SC4>GCH1>HS1>GC2.⑸The salt stress of low content （0.2%） has little effect on chloroplast, and itcould keep the integrality of structure and membrane basically. Under the serioussalt stress （over0.6%） chloroplast tended to dissolving, the structure was damaged.The distance between chloroplast and cell wall became big, thylakoid spacemagnified, chloroplast grana tended to disorder and decreased in number, structuregrew illegibility, arrangement were irregular in formation. On the other hand, thevariance of amyloidal was decreased, the volume contracted or even extinguished,the number of osmiophilic cell increased. The salt stress had the less influence onmitochondria.⑹Under draught stressthe seedlings showed these characteristic as bladesdrooped, the below part became yellow or even withered. With the droughtintensifying the RWC went down gradually, but the variety of chlorophyll contentwas inconspicuous. The carotenoid tended to increasing. In the same time, both Pnand Gsdeclined, and the activities of both SOD and POD strengthened, MDA contentraised, the proline in leaves accumulated, even that structure and function of cellmembrane was in good order. Comprehensive evaluation showed that thecomprehensive evaluation indexes of both HS2and SC4were the biggest, so theyhave relatively strong tolerant to drought stress.更多还原