膜下滴灌对新疆高产棉花光合特性日变化的影响

Effect of Different Norms of Under-Mulch-Drip Irrigation on Diurnal Changes of Photosynthesis and Chlorophyll Fluorescence Parameter of High-Yielding Cotton in Xinjiang

在新疆气候生态条件下 ,研究了膜下不同滴灌量对棉花叶片光合速率及叶绿素荧光参数日变化的影响。结果表明 ,不同滴水量处理后 ,限量滴灌 (按新疆目前生产中 375m3 ·ha-1滴水定额的 2 /3)表现为棉田土壤水分亏缺 ,叶片光合速率在一天内的变化表现为上午 9:0 0～ 11:0 0比适量滴灌棉花叶片光合速率低 ,中午 12 :0 0～ 14 :0 0出现严重的光合午休现象 ,下午光合速率恢复。叶绿素荧光参数的变化表现为 ,中午强光、高温引起限量滴灌棉花叶片的可变荧光Fv、PSⅡ原初光能转换效率Fv/Fm ,较适量滴灌棉花降低且幅度大 ;不同品种间表现为新陆早 8号较新陆早 6号的PSⅡ原初光能转换效率下降幅度大 ,表明新陆早 6号具有较好的耐旱性 ;

Under mulch drip irrigation is an advanced irrigation technique which combines the plastic film covered cultivation with drip irrigation. The influence of different norms of under mulch drip irrigation on diurnal changes of photosynthetic rates and chlorophyll fluorescence parameters was studied to explore the physiologi cal mechanism of water saving and high yielding under mulch drip irrigation cotton in Xinjiang. Results indicted that limited drip irrigation (which supplies 2/3 of water of the norm of 375 m 3·ha -1 which is widely employed in cotton cultivation in Xinjiang) caused water deficiency in cotton field, and the photosynthetic rate is reduced at 9:00 11:00 and significant midday depression is appeared, then increased again. By means of chlorophyll fluorescence determination method, the absorption, transferring and transformation of solar radiation by cotton leaf were investigated. Under drip irrigation, water deficiency reduced leaf Fv and PSII primary light transferring efficiency, and the reduction was greater in Xinluzao8 than that in Xinluzao6. It is suggested that Xinluzao6 has a great tolerance to drought, and Fv/Fm ratio can be employed as a drought resistance index in cotton.