连续弱光处理对黄瓜生育及光合速率的影响

采用40、60、80和110 μmol·m-2·s-1 4个不同弱光水平对黄瓜进行连续人工气候箱试验.结果表明,连续弱光处理下黄瓜的株高和叶面积增加,5周后达到相对稳定,弱光处理1周黄瓜叶片叶绿素含量增加,此后保持相对稳定,处理间差异不显著;连续弱光处理影响黄瓜的根系活力,随处理光强降低,黄瓜根系活力下降迅速,与110 μmol·m-2·s-1弱光处理相比,60 μmol·m-2·s-1弱光处理的根系活力下降62.2%,40 μmol·m-2·s-1的根系活力仅为其1/8;连续弱光处理下,黄瓜功能叶片的净光合速率随生育期的变化而有所上升,而随着光照强度减弱,其净光合速率逐步降低,呈现同步变化.连续弱光处理导致黄瓜严重化瓜.

Effects of Sustained Low Intensity Light Treatment on Growth Development and Photosynthetic Rate of Cucumber

Cucumber in Growth Experimental Box was treated with sustained low intensity light of 110, 80, 60 and 40 molm~(-2)s~(-1).The results indicated that plant height and leaves area of cucumber increased slowly, both plant height and leaves area reached its maximum in experimental box after five weeks under sustained low intensity light treatment.The chlorophyll content of cucumber leaves increased in first week after low intensity light treatment and kept stable after that,and there was no significant difference between the treatments. Cucumber root activity was negatively affected by low intensity light treatment.Compared with the treatment of 110 molm~(-2)s~(-1), root activity declined by 62.2% under 60 molm~(-2)s~(-1), and root activity of 40 molm~(-2)s~(-1) declined to 1/8 of that under 110 molm~(-2)s~(-1). Net photosynthesis rate (Pn) of cucumber functional leaves increased with plant developmental stage, and Pn of cucumber declined with light intensity (PAR) under sustained low intensity light treatment synchronously. Sustained low intensity light treatment led to severe abortion of cucumber younger fruits.