西南高海拔区域苹果光合作用与光和CO_2响应模型的筛选

【目的】为了阐明我国西南高海拔区域苹果光合作用对光强度和CO_2浓度变化的响应机制,为后续深入开展该区域苹果光合特性研究提供参考,筛选适合该区域苹果光合-光响应和光合-CO_2响应的模型。【方法】以‘黔选2号’‘黔选3号’‘嘎拉’‘蜜脆’‘红星’5个品种苹果叶片为试材,进行光合-光响应和光合-CO_2响应的测定,并利用直角双曲线模型、非直角双曲线模型、指数方程模型和直角双曲线修正模型进行光合-光响应曲线的拟合,运用直角双曲线模型、Michaelis-Menten模型(M-M模型)、直角双曲线修正模型进行光合-CO_2响应曲线拟合。【结果】光合-光响应中,气孔导度的变化影响蒸腾速率的变化,5个品种苹果叶片的光合速率均对强光有较好的适应性,在其他影响因子相同的情况下,CO_2浓度可能是生产中的实际限制因子。光合-CO_2响应中,5个品种苹果叶片气孔导度与蒸腾速率表现为同步变化,但气孔导度的变化并未影响胞间CO_2浓度的值,胞间CO_2浓度的值呈线性增加。在CO_2浓度满足光合作用底物消耗的情况下,光合有效辐射是苹果叶片发挥光合能力的主要限制因子。【结论】在拟合不同品种苹果叶片光合-光响应曲线和光合-CO_2响应曲线的模型中,直角双曲线修正模型拟合效果均表现最好。

Screening of response models of photosynthesis in Malus domestica on light and CO2 at high-altitude areas of southwest China

【Objective】In order to expound response mechanisms of photosynthesis in Malus domestica on changes of light intensity and CO2 concentration at high-altitude areas of southwest China,and to provide some references for researching photosynthetic characteristics in M.domestica at the areas,some response models of photosynthesis-light and photosynthesis-CO2 were screened,suitable for M.domestica at the areas.【Method】using leaves of five cultivars as materials,photosynthesis-light and photosynthesis-CO2 were measured,and a variety of models were used to fit corresponding response curves.The five cultivars were‘Qianxuan No.2’‘Qianxuan No.3’‘Gala’‘Honey Crisp’and‘Starking Delicious’,respectively.The photosynthesis-light response curve was fitted by using retangular hyperbolic model,non retangular hyperbolic model,exponential equation model,and modified retangular hyperbolic model.The photosynthesis CO2 response curve was fitted by using retangular hyperbolic model,michaelis-menten model,and modified retangular hyperbolic model.【Result】In photosynthesis-light response,change of stomatal conductance can affect change of transpiration rate,and photosynthetic rates of the five cultivars are well adapted to strong light.In the case of the same other influencing factors,CO2 concentration can be actual limiting factor in production.In photosynthesis-CO2 response,leaf stomatal conductances of five cultivars show synchronously changes with transpiration rates,but change of stomatal conductance has no effects on value of intercellular CO2 concentration,and value of intercellular CO2 concentration is increased linearly.In the case of CO2 concentration meeting substrate consumption of photosynthesis,photosynthetically active radiation is main limiting factor of leaf making good use of photosynthesis ability.【Conclusion】In the models fitting photosynthesis-light response and photosynthesis-CO2 response curves of different cultivars of M.domestica leaves,fitting effect of modified retangular hyperbolic model is the best.