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 temper...