中国农业气象

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水分胁迫下黄瓜叶片光响应过程的模拟

张曼义,杨再强,侯梦媛   

  1. 1.南京信息工程大学灾害预报预警与评估协同创新中心,南京 210044;2.南京信息工程大学江苏省农业气象重点实验室,南京210044
  • 收稿日期:2017-02-23 出版日期:2017-10-20 发布日期:2017-10-10
  • 作者简介:张曼义(1994-),女,硕士生,主要研究方向为设施农业气象。E-mail:915192963@qq.com
  • 基金资助:
    国家自然科学基金面上项目(41775104);国家公益性行业(气象)科研专项(GYHY201506001-6)

Simulation of Light Response of Photosynthesis of Cucumis sativus L. Leaves under Water Stress

ZHANG Man-yi, YANG Zai-qiang, HOU Meng-yuan   

  1. 1. Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science & Technology, Nanjing 210044, China; 2. Jiangsu Key Laboratory of Agricultural meteorology, Nanjing University of Information Science & Technology, Nanjing 210044
  • Received:2017-02-23 Online:2017-10-20 Published:2017-10-10

摘要: 以黄瓜品种“博新525”(Boxin525)为试材,设置4个土壤水分处理,即正常灌溉CK(土壤相对湿度为70%~80%)、轻度胁迫T1(土壤相对湿度为60%~70%)、中度胁迫T2(土壤相对湿度为50%~60%)、重度胁迫T3(土壤相对湿度为35%~45%),利用LI-6400便携式光合仪测定不同水分处理下黄瓜叶片的光响应曲线,采用直角双曲线、非直角双曲线、指数和叶子飘等4种光响应模型对黄瓜叶片光响应过程进行模拟,运用统计方法进行模拟效果评价,以探讨水分胁迫对黄瓜叶片光响应过程的影响。结果表明:(1)水分胁迫导致黄瓜叶片净光合速率(Pn)下降,当光合有效辐射PAR(photosynthetically active radiation)为800μmol·m-2·s-1时,T1、T2和T3处理叶片Pn分别比CK下降17.92%、26.49%和50.00%。实测与模拟的光响应曲线对水分胁迫的响应趋势一致,随着胁迫程度增加,Pn-PAR曲线变化幅度减小。(2)水分胁迫显著影响黄瓜叶片的光响应曲线参数。4种模型模拟的叶片初始量子效率均随胁迫加重呈先升高后降低的变化趋势;叶片暗呼吸速率以T2处理最高;4种模型计算的T1、T2和T3处理叶片光饱和点平均值较CK分别下降24.28%、31.99%和38.33%,叶片最大净光合速率平均值分别降低23.88%、33.19%和55.78%。(3)CK处理的黄瓜叶片光响应曲线模拟值偏离程度及光响应曲线参数的平均相对误差均最低,水分胁迫降低了黄瓜叶片光响应曲线的模拟效果。(4)4种模型模拟效果以叶子飘模型最佳,其后依次为指数模型、非直角双曲线模型、直角双曲线模型。研究认为水分胁迫显著影响黄瓜叶片的光响应过程,降低黄瓜叶片的光合能力。

关键词: 黄瓜, 光合作用, 水分胁迫, 光响应模型, 光响应参数

Abstract: For Cucumis sativus L. (cv. Boxin525), four different soil moisture levels were designed, which were normal irrigation (CK, soil relative humidity was 70%-80%), light water stress (T1, soil relative humidity was 60%-70%), moderate water stress (T2, soil relative humidity was 50%-60%) and severe water stress (T3, soil relative humidity was 35%-45%), respectively. Light response curves of cucumber leaves were measured under each treatment using LI-6400 portable photosynthesis system. Four different models (i.e. rectangular hyperbola, non-rectangular hyperbola, exponential and Ye Z P model) were applied to simulate light response curves of cucumber leaves, and the simulation effects were evaluated by statistics methods. Based on the experimental data and simulation results, the effect of water stress on light response curves of cucumber was discussed. The results indicated that water stress caused decline of net photosynthetic rate (Pn), at a PAR (photosynthetically active radiation) level of 800μmol·m-2·s-1, Pn decreased by 17.92%, 26.49% and 50.00% under T1, T2 and T3 treatments, respectively, compared with CK. The simulated light response curves showed a similar trend with the measured ones in response to water stress, and the variation amplitude of Pn-PAR curve decreased as water stress aggravated. Water stress affected light response curve parameters of cucumber leaves significantly. The initial quantum efficiency of cucumber leaves derived from the four mentioned models all increased at first and dropped afterwards with the aggravation of water stress, and the dark respiration rate was the highest under T2 treatment. Compared to CK, the average light saturation point calculated by four models decreased by 24.28%, 31.99% and 38.33%, respectively, under T1, T2 and T3, and the average maximum net photosynthetic rate declined by 23.88%, 33.19% and 55.78%, respectively, under T1, T2 and T3. The deviation degree of simulated light response curve and mean relative error of light response parameters achieved the lowest under CK, and the simulation effects of light response curve were weakened by water stress. The Ye Z P model performed best in simulation of the light response curve, next was the exponential model, the non-rectangular model, and the rectangular hyperbola model was the least effective one. The study indicated water stress significantly influenced light response of photosynthesis of cucumber leaves, and reduced photosynthetic capacity of leaves.

Key words: Cucumber, Photosynthesis, Water stress, Light response model, Light response parameters