温室与露地条件下西瓜光合作用的日变化比较

研究了兰州地区日光温室早春茬西瓜品种‘宝冠’和‘新金兰’及露地‘宝冠’、‘新金兰’和‘西农8号’伸蔓期的光合特性.结果表明:‘宝冠’、‘新金兰’2个西瓜品种在温室和露地条件下净光合速率日变化呈单峰型变化趋势,未见"光合午休"现象;‘西农8号’露地栽培条件下光合速率日变化呈单峰型变化趋势,峰值为14.6μmol.m-2.s-1;露地条件下,3个西瓜品种的气孔导度、胞间CO2浓度与净光合速率显著相关;在温室条件下,‘新金兰’的净光合速率(Pn)明显高于‘宝冠’(Pn新金兰=9.86μmol.m-2.s-1Pn宝冠=8.73μmol.m-2.s-1);温室与露地的光量子通量密度是造成西瓜光合能力差异的主要原因.

Comparison on photosynthetic diurnal change of watermelon in greenhouse and open field

The photosynthetic characteristics of watermelon(cvs.Baoguan,Xingjinlan,Xinong No.8) was studied under both in greenhouse and open field in Lanzhou.The results showed that the diurnal change of photosynthetic rate in Baoguan and Xinjinlan had one peak,and there was no midday depression both in greenhouse and open field.Xinong No.8 presented one peak curve in field conditions(Pn max=14.6 μmol·m-2·s-1).Ci,Gs and Pn showed a significant positive correlation in field conditions.Photosynthesis in Xinjinlan was higher sharply than Baoguan in greenhouse(Pn 新金兰=9.86 μmol·m-2·s-1>Pn 宝冠=8.73 μmol·m-2·s-1).It is suggested that PFD is the main factor that cause the difference of photosynthetic characteristics in watermelon between greenhouse-grown and open field.