营养液膜栽培生菜光合与蒸腾特性研究

Studies on Photosynthetic and Transpiration Peculiarity of Lettuce in NFT Culture

对营养液 (NFT)栽培条件下散叶生菜光合与蒸腾特性进行了研究。结果表明 ,生长盛期前单位重量叶片叶绿素含量及光合速率均为 :下位叶 >中位叶 >上位叶 ;生长后期中位叶 >上位叶 >下位叶。光合速率日变化呈双峰曲线 ,出现午休现象。两个峰值分别出现在 11:0 0时和15 :0 0时左右 ;13:0 0时有一“低谷”即午休。高温低湿是造成午休现象的主要原因。蒸腾速率与气孔阻力呈负相关 ;

Photosynthetic and transpiration peculiarity of leaf Lettuce in NFT culture was studied. The results showed that both chlorophyll content and photosynthetic rate differed with growing periods, the Lower Leaves> mid ones >upper ones before the flourishing period and mid leaves>upper ones>lower ones in the later period Changes of photosynthetic rate formed a double-peak curve The two peaks appeared at 11:00 and 15:00 respectively, and the trough(“noon break”)at 13:00 The “noon break” phenomenon was cawsed by high temperature and low humidity The transpiration rate was negatively correlative with stomatal resistance, and had certain positive correlation to the photosynthetic rate under most circumstances