论文部分内容阅读
光合作用是衡量植物对环境响应的重要指标,通过光响应曲线拟合量化光合特征,可从生理机制方面揭示出植物在不同生长环境下自身的调节与适应机制。本文利用Li-6400便携式光合仪测定了冬小麦在4种不同处理条件下灌浆期旗叶的光响应曲线,采用直角双曲线模型(RHM)、非直角双曲线模型(NRHM)、直角双曲线修正模型(RHMM)、指数模型(EM)和指数改进模型(MEM)对光响应数据进行拟合,分析了不同CO_2浓度和土壤含水量对冬小麦光合特征的影响。结果表明,直角双曲线修正模型对各处理下冬小麦光响应曲线和光响应曲线参数的拟合值都与实测值较为接近,拟合效果最好;随着CO_2浓度升高,各水分处理下冬小麦表观量子效率(α)、光饱和点(LSP)和最大净光合速率(P_(nmax))增大,光补偿点(LCP)和暗呼吸(R_d)降低,即CO_2浓度升高能有效增加冬小麦的光能转化率和光能利用范围,提高冬小麦的光合能力;随着土壤含水量的降低,冬小麦光补偿点(LCP)和暗呼吸速率(R_d)升高,但表观量子效率(α)、光饱和点(LSP)和最大净光合速率(Pnmax)降低,即冬小麦虽然能通过提高初始光合效率抵消一部分干旱胁迫的影响,但干旱胁迫仍会降低冬小麦光合能力;此外,CO_2浓度的增加能抵消部分冬小麦因干旱胁迫引起的光合能力降低。
Photosynthesis is an important index to measure the response of plants to the environment. Fitting photosynthesis characteristics through light response curve fitting can reveal the regulation and adaptation mechanisms of plants under different growth environments in terms of their physiological mechanisms. In this paper, the light response curve of flag leaves of winter wheat under four different treatment conditions was measured by Li-6400 portable photosynthesis apparatus. The right angle hyperbola model (RHM), non-right angle hyperbola model (NRHM) (RHMM), exponential model (EM) and exponential improvement model (MEM) were used to fit the light response data. The effects of different CO 2 concentrations and soil water content on photosynthetic characteristics of winter wheat were analyzed. The results showed that the fitting curves of the light response curve and the light response curve of the orthogonal hyperbolic correction model were close to the measured values and the fitting results were the best. With the increase of CO 2 concentration, The results showed that the quantum efficiency (α), light saturation point (LSP) and maximum net photosynthetic rate (P nmax) increased, and light compensation point (LCP) and dark respiration (R d) decreased. (LCP) and dark respiration rate (R_d) of winter wheat increased with the decrease of soil water content, but the apparent quantum yield (α), light (LSP) and maximum net photosynthetic rate (Pnmax) .While winter wheat could offset the drought stress by increasing the initial photosynthetic efficiency, the photosynthetic capacity of winter wheat was still reduced by drought stress. In addition, the increase of CO 2 concentration could offset part of Winter wheat photosynthetic capacity decreased due to drought stress.