关键词: 脉冲光, 生菜, 品质, 光合特性

Abstract: In order to study  the effects of different frequency duty ratio combinations on the photosynthesis of lettuce, this paper took lettuce as test material; screened 3 combined treatments (T1: 2 048 Hz+20%; T2: 512 Hz+40%; T3: 128 Hz+80%) of minimum frequency and duty cycle under the conditions of the same net photosynthetic rate with continuous light; and taking the continuous light as the control(CK) studied the effect of different pulsed light on growth, quality and photosynthetic characteristics of lettuce. The results showed that the overall effect of pulsed light supply mode on lettuce morphology, dry and fresh weights, photosynthetic parameters and chlorophyll fluorescence parameters were not significant, but the content of chlorophyll could be significantly increased by high frequency and low duty ratio pulsed light treatment(T1). Except the content of VC, the quality indexes of lettuce under pulsed light treatment were not worse than those with continuous light, and some indexes such as nitrate nitrogen, soluble total sugar and reducing sugar were even better. As a whole, the quality of lettuce under T1 was the best, indicating under the same net photosynthetic rate as same as continuous light, the feeding mode of pulsed light, would not affect the growth of lettuce, but improve the quality. Under low frequency and high duty ratio pulsed light the lettuce had a better quality, but in actual production suitable light source should be chosen combined with pulsed light energy consumption.

Key words: pulsed light, lettuce, quality, photosynthetic characteristics