土壤水分胁迫对荻光合生理特性的影响

本研究对荻（Miscanthus sacchariflorus）的实生苗进行了4种土壤水分胁迫对照（保持田间最大持水量的80%，下同）、轻度水分胁迫（65%）、中度水分胁迫（45%）和重度水分胁迫（30%）]的盆栽试验，以研究不同程度土壤水分胁迫对荻光合生理特性的影响。在胁迫过程中，随着水分胁迫程度的增加，荻的叶片相对含水量（RWC）、比叶重（SLW）、叶绿素（Chl）含量、最大净光合速率(Pmax)、表观量子效率(AQE)、暗呼吸速率(Rd)、蒸腾速率(Tr)、胞间CO2浓度(Ci)、气孔导度(Gs)、光饱和点(LSP)和光补偿点(LCP)呈下降趋势，各胁迫处理与对照差异显著(P＜0.05)；气孔限制值(Ls)呈上升趋势，各处理间差异显著(P＜0.05)；水分利用效率(WUE)先上升后下降，各处理间差异显著(P＜0.05)。荻叶片的气体交换参数与生理指标对水分胁迫的适应能力较差，可塑性较低。

Effects of soil water stress on photosynthetic characteristics of Misconstrues sacchariflorus

Effects of different soil water stress degrees on physiological characteristics of Misconstrues sacchariflorus were studied by four treatments: CK (keep the maximum capacity of 80%, the same below), light water stress (65%), moderate water stress (45%), and severe water stress (30%). Results showed that the leaf relative water content (RWC), specific leaf weight (SLW) and chlorophyll (Chl) content, maximum net photosynthetic rate (Pmax), apparent quantum efficiency (AQE), dark respiration rate (Rd), transpiration rate (Tr), intercellular CO2 concentration (Ci), stomatal conductance (Gs), light saturation point (LSP) and light compensation point (LCP) decreased with the increasing of the degree of water stress (P＜0.05). However, stomatal limitation (Ls) showed a rising trend(P＜0.05), while water use efficiency (WUE) increased firstly and then decreased(P＜0.05). Leaf gas exchange parameters and physiological indicators of M.sacchariflorus showed poor adaptive capacity to water stress with low plasticity.