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| Effects of light and temperature on growth and development of lettuce in stereoscopic cultivation |
| Key Laboratory of Modern Agricultural Equipment and Technology, Ministry of Education and Jiangsu Province, Jiangsu University, Zhenjiang, Jiangsu 212013, China |
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Abstract Using romaine lettuce (lactuca sativa L.) as material， the effects of light and temperature in greenhouse on yield, morphology, chlorophyll content and chlorophyll fluorescence parameters were investigated under the condition of stereoscopic cultivation. The results show that the light radiation intensities in middle layer and in lower layer are 36.4% to 45.6% and 24.8% to 37.3% of that in upper layer，respectively. The light radiation intensity is relatively high in sunny day at 10：00 to 16：00. The temperature is significantly different in the three layers, and the temperatures in the middle and in the lower layers are 84.8% and 73.2% of that in the upper layer，respectively. Fresh weigh, leave number, stem height and leaf area of lettuce of upper layer are all higher than those of middle and lower layers. The analysis on chlorophyll fluorescence parameters shows that with the decreasing of light intensity and temperature in the middle and lower layers, Y(Ⅱ) and ETR are decreased, while Y（NO）and Y（NPQ）are increased. Lettuce yield and photosynthetic capacity are significantly influenced by light and temperature.
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Received: 28 December 2015
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2016, Vol. 37 
