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作 者 ：刘瑞显;郭文琦;陈兵林;周治国

期 刊 ：应用生态学报 2008年 19卷 07期 页码：1475-1482

关键词：棉花；

摘 要 ：于2005—2006年在南京农业大学卫岗试验站进行盆栽试验，研究花铃期土壤干旱及复水后棉花光合与蒸腾特性及水分利用率对氮素的响应.结果表明：与正常灌水处理（CK）相比，干旱处理棉花随土壤相对含水量（SRWC）的减少，其净光合速率（P_n）和蒸腾速率（T_r）迅速降低；在干旱处理前期，由于棉花T_r下降幅度高于P_n，水分利用率（WUE）表现为上升趋势，而后随SRWC和P_n的降低，WUE呈逐渐下降趋势.土壤干旱改变了P_n和T_r的日变化趋势，干旱处理棉花P_n和T_r从8:00到16:00一直呈下降趋势，而CK则呈单峰曲线，P_n和T_r峰值分别出现在10:00—11:00和12:00；干旱处理和CK的WUE日变化均呈先降后升的趋势，谷值出现在12:00.干旱条件下棉花的P_n和T_r随氮素水平的提高而降低，而WUE则表现为相反趋势；复水后，干旱处理棉花P_n、T_r及WUE日变化趋势与CK一致，但其值低于CK，该趋势在施氮肥条件下表现尤为明显.可见，棉花花铃期土壤干旱条件下增施氮肥虽然有利于WUE的提高，但却降低了棉花的光合性能.

Abstract:With pot culture, the physiological responses of cotton plant to fertilizer nitr
ogen at flowering and boll-forming stages were studied under soil drought and after re-watering. The results showed that under soil drought, the net photosynthetic rate (P_n) and transpiration rate (T_r) declined rapidly with de
creasing soil relative water content (SRWC). At the early stage of soil drou
ght, owing to the declining degree of T_r was greater than that of P_n
, the WUE had an increasing trend; but after then, the WUE decreased with declining SRWC and P_n. Soil drought altered the diurnal patters of P_n and T_r, i.e., decreased continuously from 8:00 to 16:00, while in CK, their peak values appeared at 10:00-11:00 and 12:00, respectively. The diurnal patterns of WUE in drought treatment and CK were the same, i.e., decreased first and increased then, with the bottom appeared at 12:00. Under soil drought, the P_n and T_r decreased with increasing fertilizer nitrogen level, while WUE was in adverse. After re-watering, the diurnal patterns of P_n, T_r and WUE were similar to CK, but their values were smaller than CK, especially under nitrogen application. It was suggested that under soil drought, nitrogen fertilization could be helpful to the increase of water use efficiency, but decreased the photosynthesis of cotton plant at its flowering and boll-forming stages.

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