Difference in photosynthesis of different position leaves of greenhouse cucumber in autumn and winter.

摘要

Diurnal photosynthetic changes of upper, middle and lower leaves of cucumber were measured in different dates in the middle and late of autumn and winter. The results indicated that the middle leaves had a relative high photosynthetic rate, the upper leaves took the second place and the lower leaves were the least. With the pass of time, the photosynthesis of cucumber reduced quickly in general, and the upper leaves decreased in greatest extent, the middle leaves and the lower leaves took the second and the third place respectively. The reason why cucumber photosynthesis was low in medium-late stage was that stomatal limitation and senescence of cucumber, and it is necessary to enhance the management of ventilation, lessen the time of ventilation and shorten the size of intake.