寡照对设施黄瓜叶片光合参数及光响应曲线的影响

Effects of Sparse Sunlight on Photosynthetic Parameters and Light Response Curves of Cucumber

以"南杂二号"黄瓜为试材,利用遮光网对黄瓜幼苗连续寡照1、3、5h,均处理3、6、9、12d,研究了寡照条件下黄瓜叶片的光合特性;并利用非直角双曲线模型、指数模型、直角双曲线模型和直角双曲线修正模型4种模型模拟光响应曲线,选择最优的模型来模拟光合参数,以期为设施黄瓜种植光照优化控制提供科学依据。结果表明:直角双曲线修正模型最佳,其次为指数模型,非直角双曲线模型,直角双曲线模型,并利用最优的直角双曲线修正模型的模拟值计算出光合参数;寡照下净光合速率、最大光合速率、光饱和点、表观量子效率、气孔导度均降低,蒸腾速率先升高后降低,光补偿点、气孔限制值升高,水分利用率先减少后增加,连续寡照1、3、5h净光合速率较对照分别降低了23.56%、45.40%、62.60%。

‘Nanza No.2＇cucumber was used as test material,the photosynthetic characteristics of cucumber leaves under sparse sunlight conditions were studied by using shading nets for 3 days,6 days,9 days and 12 days of successive widows of cucumber seedlings for 1 hour,3 hours,and 5 hours.Using the non-rectangular hyperbola model,the exponential model,the rectangular hyperbola model and the rectangular hyperbola correction model to simulate the light response curve,the optimal model was selected to simulate the photosynthetic parameters.The purpose was providing the scientific basis for optimizing the control of planting cucumber lighting.The results showed that the rectangular hyperbola correction model was the best,followed by the exponential model,the nonrectangular hyperbola model,the rectangular hyperbola model.The photosynthetic parameters were calculated by the simulated values of rectangular hyperbola correction model.The net photosynthetic rate,maximum photosynthetic rate,light saturation point,apparent quantum efficiency,and stomatal conductance under sparce sunlight were all decreased.The transpiration rate increased first and then decreased.The light compensation point and stomatal limit values increased,and the water use efficiency decreased first and then increased.The net photosynthetic rate at 1 hour,3 hours,5 hours decreased by 23.56%,45.40%,and 62.60%,respectively,compared with the control.