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题名	极端干旱区胡杨叶片水力性状研究
作者	潘莹萍
学位类别	硕士
答辩日期	2015
授予单位	中国科学院大学
授予地点	北京
导师	陈亚鹏
关键词	叶片水力导度，压力-容积曲线参数，叶片水力脆弱曲线参数，叶片解剖，水分利用效率，地下水埋深
学位专业	理学硕士
中文摘要	叶片作为植物水分传输系统的终端，是植物水分传输系统重要组成部分，并且叶片水力阻力占植物整体阻力的30%。叶片水力性状是反映植物叶片水力传导方面的性状，叶片内部水分有效传输是植物维持其功能的必要前提，叶片水力性状与植物抗旱性有密切关系。因此，在极端干旱区开展胡杨叶片水力性状研究可以对干旱区植物水分关系研究领域中植物水力性状研究提供补充。本文选取塔里木河下游荒漠河岸林建群种胡杨为研究对象，通过对不同地下水埋深梯度下（3.2m，4.2m，6.3m，7.5m）胡杨叶片水力性状指标：叶片水力导度、叶片水力脆弱曲线指标、叶片压力-容积曲线指标、叶片解剖结构指标等测定，分析不同地下水埋深下叶片水力性状特征及其差异性，探讨地下水埋深对叶片水力性状的影响，筛选对地下水埋深变化敏感的抗旱指标；同时测定叶片δ13C值，研究叶片水力性状与植物水分利用效率的关系，主要得出以下结论： 1. 胡杨叶片最大水力导度（Kleaf-max）对地下水埋深变化敏感，随着地下水埋深增加，Kleaf-max呈现上升趋势。研究表明：在干旱胁迫下Kleaf-max变化主要受细胞渗透作用调节；膨压损失时的叶片水势（Ψtlp）与饱和渗透势（πft）在地下水埋深较深处显著降低，并且一些水力参数之间存在相关关系。胡杨叶片水力脆弱曲线呈线性变化，水力脆弱性指标与抗旱性指标间不存在相关关系。不同地下水埋深下胡杨叶片水力安全范围出现了分化，表现为水分条件较好处水力安全范围更大。 2. 荒漠河岸林建群种胡杨叶片解剖结构具有典型的荒漠植物特征，在不同地下水埋深下胡杨叶片解剖结构指标存在差异。研究发现随着地下水埋深增加，叶片厚度（LT）、叶片栅栏组织厚度（PT）、叶片表皮厚度（ET）、叶片主脉导管直径（MVD）有上升趋势；叶片水分散失通道—气孔，其解剖结构指标：气孔保卫细胞长度（SL）、宽度（SW）、气孔面积（SA）在地下水埋深最深处最小，而气孔密度（SD）随地下水埋深的增加而上升。叶片水分传输通道—叶脉，其密度（VD）随着地下水埋深的增加而增加，同时VD与气孔解剖指标具有显著的相关关系，说明胡杨叶片水分传输与水分散失具有匹配关系。 3. 胡杨叶片δ13C值随着地下水埋深的增加有上升趋势，表明随着干旱胁迫的增强，胡杨水分利用效率提高；同时，研究发现δ13C与叶片最大水力导度（Kleaf-max）具有正相关关系；δ13C与叶片解剖指标（LT、PT、ET、MVD、SD、VD）存在正相关关系；而与气孔尺寸指标（SW、SL、SA）存在负相关关系。
英文摘要	Leaf is considered as a critical hydraulic bottleneck in hydraulic plumbing system of plant, and the hydraulic conductance accounts for 30% of the whole-plant resistance. Leaf hydraulic traits (leaf hydraulic conductance, parameters of leaf anantomical, leaf hydraulic vulnerabilities e.g.) reflect the water transport of leaf. Efficient water transport inside leaves is a major determinant of plant function, especially in drought-stressed plants. This research made a supplement to the study of hydraulic traits in arid plant. We selected Populus euphratica, a desert riparian forest vegetation, at the lower reaches of Tarim River as the research material. The hydraulic traits (leaf hydraulic conductance, leaf hydraulic vulnerabilities, parameters of leaf pressure-volume, leaf anatomical parameters) were measured; differences of the parameters among different groundwater depths were compared; and the effects of the groundwater depth on leaf hydraulic traits were analyzed. Meanwhile, the δ13C values of P. euphratica leaves were measured aiming to study the relationship between leaf hydraulic traits and water use efficiency. The main results are as follows: 1. We found that Kleaf-max of P. euphratica showed an increasing trend as the groundwater depth increased, while osmotic potential at full turgor (πft) and turgor loss point (Ψtlp) decreased, suggesting that tolerance to drought increased as the groundwater depth increased. There are some correlations among key leaf parameters calculated from P-V curves, but no clear relationship was found between P-V curve parameters and leaf hydraulic vulnerabilities. Leaf hydraulic safety margins showed negtive and postive varivations under different groundwater depths, wider margins occurred in good water conditions. 2. The results of leaf anatomical structure of P. euphratica, a constructive species in desert riparian forest, indicated that it had the typical characteristics of desert plants. In leaf anatomical parameters, differences were found in leaf anatomical structure parameters among different groundwater depth. The study showed that with the increase of groundwater depth, leaf thickness (LT), palisade tissue thickness (PT), leaf epidermal thickness (ET), leaf main-vein vessel diameter (MVD), stomata density (SD) and vein density (VD) increased; while leaf stomata anatomical structure parameters: stomatal guard cell length (SL), width (SW), stomatal area (SA) decreased. Significant correlations were found between vein density and stomatal anatomical parameters, suggesting that a positive relationship was formed between water transfer and water loss within P. euphratica leaves. 3. The δ13C values in P. euphratica leaves increased with the increasing in groundwater depth, indicating that water use efficiency increased with the enhanced drought stress.We also found a positive correlation between δ13C values and maximum hydraulic conductance; δ13C values and leaf anatomical parameters (LT, PT, ET, MVD, SD, VD) are positively correlated, while negative correlations were found between the stomata pore size parameters (SW, SL, SA) and δ13C values. No correlations were found among water use efficiency and water vulnerabilities.
语种	中文
学科主题	自然地理学
内容类型	学位论文
源URL	[http://ir.xjlas.org/handle/365004/14975]
专题	新疆生态与地理研究所_研究系统_荒漠环境研究室
作者单位	中科院新疆生态与地理研究所
推荐引用方式 GB/T 7714	潘莹萍. 极端干旱区胡杨叶片水力性状研究[D]. 北京. 中国科学院大学. 2015.

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