Under-mulch-drip irrigation is an advanced irrigation technique, which combines plastic-film-covered cultivation with drip irrigation. The influence of different norms of under-mulch-drip irrigation on diurnal changes...Under-mulch-drip irrigation is an advanced irrigation technique, which combines 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 of cotton was studied, in order to understand the physiological mechanisms of water-saving and high-yielding farming in Xinjiang. Results indicated that limited drip irrigation, which supplies 2/3 of 375 m3 ha-1, the widely-used irrigation norm in cotton cultivation in Xinjiang, caused a water deficit in cotton field. Compared with the proper drip irrigation, the leaf photosynthetic rate under limited drip irrigation decreased during 9:00 to 11:00 a. m. , and was significantly suppressed at midday, and then recovered afterwards. Using the chlorophyll fluorescence method, the absorption, transfer and transformation features of solar radiation by cotton leaf were investigated. Under limited drip irrigation, the variable fluorescence (Fv) and primary light transfer efficiency of PSII (Fv/Fm) in cotton leaves were reduced because of the high light intensities and high temperatures at noon, and the decrease in XinluzaoS was greater than that in Xinluzao6. Therefore, it could be concluded that Xinluzao6 has a higher drought-tolerance, and the Fv/Fm ratio could be used as a drought-resistance index for cotton.展开更多
基金supported by the National Natural Science Foundation of China(39960037).
文摘Under-mulch-drip irrigation is an advanced irrigation technique, which combines 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 of cotton was studied, in order to understand the physiological mechanisms of water-saving and high-yielding farming in Xinjiang. Results indicated that limited drip irrigation, which supplies 2/3 of 375 m3 ha-1, the widely-used irrigation norm in cotton cultivation in Xinjiang, caused a water deficit in cotton field. Compared with the proper drip irrigation, the leaf photosynthetic rate under limited drip irrigation decreased during 9:00 to 11:00 a. m. , and was significantly suppressed at midday, and then recovered afterwards. Using the chlorophyll fluorescence method, the absorption, transfer and transformation features of solar radiation by cotton leaf were investigated. Under limited drip irrigation, the variable fluorescence (Fv) and primary light transfer efficiency of PSII (Fv/Fm) in cotton leaves were reduced because of the high light intensities and high temperatures at noon, and the decrease in XinluzaoS was greater than that in Xinluzao6. Therefore, it could be concluded that Xinluzao6 has a higher drought-tolerance, and the Fv/Fm ratio could be used as a drought-resistance index for cotton.
