模拟贝壳砂水分变化对旱柳光合特性的影响
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引用本文:高 源,夏江宝,赵自国,孔庆仙,谷广义,张 亮.模拟贝壳砂水分变化对旱柳光合特性的影响[J].西北植物学报,2013,33(12):2467~2473
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作者单位
高 源1,夏江宝2*,赵自国2,孔庆仙1,谷广义1,张 亮1 (1 滨州学院 城市与环境系,山东滨州 256603
2 滨州学院 山东省黄河三角洲生态环境重点实验室,山东滨州 256603) 
基金项目:国家自然科学基金项目(31100468);滨州学院国家级大学生创新创业训练计划项目(201210449131);山东省高校科研发展计划项目(J13LC03);滨州学院博士基金项目(2008Y10)
中文摘要:为探讨贝壳堤岛旱柳叶片光合特性的水分响应规律,以2 a生旱柳苗木为材料,模拟设置贝壳砂生境系列水分梯度,测定分析不同土壤水分条件下旱柳叶片的主要光合生理参数。结果表明:(1)直角双曲线修正模型可较好模拟旱柳叶片净光合速率的光响应过程,维持旱柳较高光合作用的土壤相对含水量(RWC)为50.1%~94.4%,适宜光强为800~1 600 μmol·m-2·s-1,水分对光强利用的补偿效应显著。(2)随土壤水分的降低,旱柳叶片净光合速率、光饱和点、表观量子效率及最大净光合速率均表现为先升高后降低;干旱和渍水胁迫条件下,旱柳叶片的光补偿点升高,光饱和点降低,光照生态幅变窄,光能利用效率降低,水分胁迫抑制光能效应明显。(3)随土壤水分的降低,旱柳叶片瞬时和潜在水分利用效率均表现为先升高后降低,分别在RWC为45.7%、40.6%时达到最大值,适度干旱胁迫可显著提高旱柳叶片的水分利用效率。(4)干旱和渍水胁迫均显著降低旱柳叶片的叶绿素含量和叶片水势,随土壤水分降低两者均表现为先升高后降低,叶绿素含量和叶片水势分别在RWC为58.9%、50.1%达到最高值。研究发现,贝壳砂生境旱柳叶片光合生理参数对土壤水分表现出一定的阈值响应,维持旱柳较高光合能力和水分利用效率的适宜土壤水分相对含量为50.1%~77.7%,表现为耐水湿不耐干旱的水分特性。
中文关键词:光合作用  水分利用效率  土壤水分  贝壳砂  旱柳
 
Effect of Simulated Soil Water Change on Photosynthetic Characteristics of Salix matsudana in Shell Sand Habitat
Abstract:We aimed to investigate water response by assessing physiological photosynthetic parameters of Salix matsudana growing on the Shell Ridge Islands,and to determine their moisture adaptability in a sandy habitat formed from seashells.We measured net photosynthetic rate,light response,chlorophyll content,leaf water potential and other parameters of S.matsudana grown in soils with different moisture contents,simulating the natural moisture gradient of the shell sand habitat.We found that:(1)A rectangular hyperbolic correction model best simulates the light response of S.matsudana leaves (R2>0.96).High photosynthetic capacity is maintained at 50.1%~94.4% soil relative water content (RWC) under optimal light intensities ranging from 800~1 600 μmol·m-2·s-1.(2)Photosynthetic light response of S.matsudana leaves show a certain threshold response to soil moisture content.Net photosynthetic rate,light saturation point,apparent quantum yield (AQY) and the maximum net photosynthetic rate all demonstrate optimal capacity at medium soil moisture content.Soil moisture content can significantly affect the light use efficiency and the light ecological amplitude of the plant.Under drought or waterlogged stress conditions,the light compensation point of S.matsudana increases,while its light saturation point decreases,light ecological amplitude narrows and light use efficiency decreases.(3)Instantaneous water use efficiency and potential water use efficiency of S.matsudana leaves reach their maximum values when RWC is 45.7% and 40.6%,respectively.Thus,we conclude that moderate drought stress can significantly increase water use efficiency of S.matsudana growing in a shell sand habitat.(4)Both drought and waterlog stress can significantly lower chlorophyll content and leaf water potential.The chlorophyll content and leaf water potential reach their maximum values when RWC is 58.9% and 50.1%,respectively.Our study shows that net photosynthetic rate,photosynthetic light response parameters,water use efficiency,chlorophyll content and leaf water potential of S.matsudana living in a shell sand habitat have distinct threshold responses correlated with soil moisture.In conclusion,S.matsudana is found to be a species with wide water ecological amplitude,which is resistant to high soil moisture content and susceptible to drought.
keywords:photosynthesis  water use efficiency  soil moisture  shell sand  Salix matsudana Koidz
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