黄栌幼苗叶片气体交换对干旱胁迫的短期响应  

Short-Term Responses of Leaf Gas Exchange Characteristics to Drought Stress of Cotinus coggygria Seedlings

作　　者：李金航[1] 齐秀慧[1] 徐程扬[1] 王畅[1] 刘海轩[1] 孙鹏[1] 

机构地区：[1]北京林业大学省部共建森林培育与保护教育部重点实验室干旱、半干旱地区森林培育和森林生态系统国家林业局重点实验室,北京100083

出　　处：《林业科学》2015年第1期29-41,共13页Scientia Silvae Sinicae

基　　金：“十二五”国家科技支撑计划项目(2011BAD38B0303)

摘　　要：【目的】本研究探讨不同产地黄栌苗木叶片气体交换特性对土壤水分胁迫的短期响应特点及规律。【方法】采用田间模拟试验,选取北京西山、山东泰山和山西绛县3个产地的1年生黄栌幼苗为供试材料,设置对照（CK,土壤田间持水量的75%~80%）、中度胁迫（MS,土壤田间持水量的55%~65%）和重度胁迫（SS,土壤田间持水量的35%~45%）3个水分梯度,利用LI-6400便携式光合测定系统和SPSS 20.0统计分析软件测定和拟合幼苗成熟叶片的光响应曲线（Pn-PAR）及CO2响应曲线（Pn-Ci）,根据非线性最小二乘法的Levenberg-Marquardt迭代原理计算各光合参数。【结果】1）黄栌幼苗的CO2同化能力随干旱胁迫程度的加剧及胁迫时间的增加显著（P〈0.05）下降,主要原因是持续干旱胁迫环境中幼苗叶片CO2传导及光合电子传递受阻、光能利用率下降。受重度胁迫处理幼苗的CO2气孔导度＋叶肉导度（gsc＋gm）、表观量子产量（AQY）、光饱和点-光补偿点（LSPLCP）、最大电子传递速率（Jmax）和最大电子传递速率/最大羧化速率（Jmax/Vc,max）分别比对照低50.5%,12.0%,21.0%,37.9%和16.9%,干旱胁迫环境中幼苗的gsc,gm,AQY,LSP-LCP,Jmax/Vc,max在胁迫后期比胁迫中期分别低18.7%,81.0%,19.3%,4.6%,5.5%。2）水分亏缺可在一定程度上刺激黄栌幼苗提高弱光利用效率及CO2羧化速率。3）受中度胁迫处理黄栌苗木的CO2气孔限制值（ls）、叶肉扩散限制值（lm）分别比对照高36.9%和25.3%,而受重度胁迫处理幼苗的ls,lm分别比对照高9.7%和103.0%;干旱胁迫环境中黄栌幼苗的平均ls及平均lm在胁迫中期分别比对照高17.7%和46.0%,在胁迫后期则分别比对照高47.0%和71.1%,说明气孔限制和叶肉扩散限制分别是适度干旱胁迫和严重干旱胁迫环境中导致幼苗净光合速率下降的主要原因。4）重度胁迫环境中,山西产地幼苗光饱和时的最大净光合速率（Pn,max�【Objective】This research was carried out to investigate the short-term responses and regular patterns of leaf gas exchange characteristics of Cotinus coggygria seedlings,collected from different locations,to soil water stress.【Method】A field experiment was set and the one-year-old C. coggygria seedlings were collected from three locations：Xishan Mountains in Beijing,Taishan Mountains in Shandong Province and Jiangxian County in Shanxi Province. The seedlings were subjected to three water regimes,including control（ CK,75%- 80% of field water capacity）,moderate stress（ MS,55%- 65% of field water capacity） and severe stress（ SS,35%- 45% of field water capacity）. A LI-6400 portable photosynthesis measurement system was used to determine the light response curves（ Pn- PAR） and CO2 response curves（ Pn- Ci） of the mature leaves,and the statistical analysis software SPSS 20. 0 was applied to fit the curves. Each photosynthetic parameter was calculated according to Levenberg-Marquardt iterative principle of nonlinear least square method.【Result】1） The CO2 assimilation ability of C. coggygria seedlings decreased significantly（ P 0. 05）as drought stress degree increased and drought stress time prolonged. The decrease was mainly ascribed to block of CO2 diffusion and photosynthetic electron transport and decline of light energy utilization efficiency when water deficit occurred.The stomatal conductance to CO2＋ mesophyll diffusion conductance to CO2（ gsc＋ gm）,apparent quantum yield（ AQY）,light saturation point-light compensation point（ LSP-LCP）,maximum electron transport rate（ Jmax） and maximum electron transport rate / maximum carboxylation rate（ Jmax/ Vc,max） of C. coggygria seedlings treated with severe stress were lower than those in control by 50. 5%,12. 0%,21. 0%,37. 9% and 16. 9%,respectively. The gsc,gm,AQY,LSP-LCf P and Jmax/ Vc,maxof C. coggygria seedlings during late stage of drought stress were lower than those during mid-stage of drought stress by 18

关 键 词：黄栌幼苗 干旱胁迫 叶片气体交换 叶肉扩散限制 气孔限制 

分 类 号：S718.43[农业科学—林学]