压砂地“玉金香”甜瓜的光合作用日变化研究

A Study of Photosynthetic Diurnal Variation of Melon "Yujinxiang" on Gravel-mulched Field

选用宁夏压砂地主栽甜瓜品种"玉金香"为试材,测定其坐果期和成熟期植株的净光合速率(Pn)及其影响因子空气温度和叶片温度、光合有效辐射(PAR)、蒸腾速率(E)、气孔导度(Cond)、胞间CO2浓度(Ci)、水分利用率(WUE)的日变化规律。结果表明:"玉金香"甜瓜在不同的生长发育时期光合速率日变化趋势并不相同,坐果期为双峰型曲线,呈现光合"午睡"现象,成熟期则为单峰型曲线,气孔抑制可能为不同时期光合作用不同的主要因素。

Using melon of ＆quot;Yujinxiang＆quot;, the main melon cultivar on grave-mulched field in Ningxia, as the material to deter-mine the diurnal variation of the net photosynthetic rate and the other influential factors such as air temperature, blade tem-perature, photosynthetic active radiation （PAR）, transpiration rate （E）, stomatal conductance （Cond）, intercellular CO2 concen-tration （Ci） and water use efficiency （WUE） in the periods of fruit-set and maturity. The results showed that in the two growing period, the photosynthetic diurnal variation tendency were different, the diurnal variation of photosynthetic rate in the fruit-set period had double peak curves and midday depression; while in maturity period it presented one peak curve. The stomatal limitation may be the main factor which influences the photosynthesis.