Effect of Different Density and Triming on Photosynthetic Characteristics and Yield of Greenhouse Color Pepper in Irrigated Desert Soil of Hexi Corridor

In order to investigate different density (W1:5.00×10⁴ plant·hm^-2,W2:4.04×10⁴ plant·hm^-2;W3:3.33×10⁴ plant·hm^-2) and pruning (F1:Double rod;F2:three bar;F3:four bar) effects on growth and yield of color pepper in Hexi corridor,photosynthetic characteristics during fruit period and yield of color pepper were studied using split plot experiment design in this paper.The results showed that net photosynthetic rate,transpiration rate,stomata conductance and intercellular CO₂ of color pepper leaf was 25.9 μmolCO₂·m^-2·s^-1,5.7 mmol·m^-2·s^-1,295 mmolH₂O·m^-2·s^-1 and 246 ul·L^-1 respectively.The highest yield of 11.2 kg·m^-2 was obtained with 4.04×104 plant·hm^-2 (W2) and three pole pruning (F2).Color pepper yield also had extremely significant level with W2F2 density combined with pruning.The leaf photosynthetic rate changed in the order of W2F2,W3F2,W1F2,W3F1,W2F1,W1F1,W3F3,W2F3 and W1F3 respectively,while the yield from more to less in proper order of W2F2,W1F2 ,W3F2,W1F1,W1F3 ,W2F1,W3F3,W3F1,W2F3 respectively.F_v/F_m and F_v/F_o of color pepper leaf had a similar change trend.The ratio of F_v/F_m and F_v/F_o from large to small in proper order was W2F2,W3F2,W1F2,W3F1,W2F1,W1F1,W3F3,W2F3 and W1F3 respectively.The actual photochemical efficiency (ΦPSⅡ),coefficient of photochemical quenching(qP) and photochemical quenching coefficient(qN) were highest and light inhibition was the lowest with treatment W2F2.Photochemical quantum yield (F'_v/F'_m) value was highest with greatest inhibition with treatment W1F3.