水肥耦合对南疆沙区滴灌红枣光合特性及叶绿素相对含量的影响

为了探索南疆沙区水肥耦合对红枣光合特性及叶绿素相对含量的影响,以大田“8a成龄骏枣树”为供试材料,在滴灌条件下进行水肥二因素三水平完全处理小区试验.结果表明:红枣叶片净光合速率(P_n)与气孔导度(G_s)日变化呈“双峰型”,蒸腾速率(T_r)日变化呈 “单峰型”,细胞间隙CO₂浓度(C_i)和叶片水分利用效率(WUE)日变化呈 “单谷型”;W2F1处理的P_n,T_r,G_s第一次峰值的最大值比常规漫灌(CK)分别提高34.8%, 10.74%,7.14%; W2F3处理C_i和WUE谷值比常规漫灌分别提高29.04%和8.33%,叶绿素相对含量和氮含量均在W3F3处理获得最大值,比常规漫灌分别提高6.00%,9.49%;W3F3处理与W2F1处理差异不具有统计学意义(P>0.05);红枣叶片P_n与T_r,G_s之间密切相关,P_n与叶绿素相对含量及氮含量有一定相关关系,但不密切,叶绿素相对含量与氮含量之间密切相关,与WUE之间相关性较低.根据试验结果,初步认定灌水量820 mm、施肥量450 kg/hm²(W2F1处理)为南疆沙区节水节肥的最佳水肥供应模式.

Effects of water and fertilizer coupling on photosynthetic and chlorophyll contents of jujube under drip irrigation in south Xinjiang sandy area

In order to explore effects of water and fertilizer coupling on photosynthetic characteristics and chlorophyll relative contents of jujube in southern Xinjiang sandy area, the 8-year mature magnificent jujube trees were used as test plant, and water and nitrogen two-factor, three-level Latin square experiments were conducted in a small-sized land under drip-irrigation conditions. The results show that the diurnal variation of net photosynthetic rate(P_n)and stomatal conductance(G_s)of jujube presents two peaks, but the diurnal variation of transpiration rate(T_r)has a single peak. For case W2F1, the variation profiles of intercellular CO₂ concentration(C_i)and leaf water use efficiency(WUE)present a single peak as well, and the maximums of P_n, T_r and G_s increase by 34.8%, 10.74% and 7.14%, respectively, compared with those under ordinary flooding irrigation(CK). For case W2F3, the peak values of C_i and WUE increase by 29.04% and 8.33%, respectively, compared with CK. Note that both chlorophyll relative content and nitrogen content are in the maximum in W3F3 treatment, especially 6.00% and 9.49% higher than in CK, respectively. Unfortunately, W3F3 shows no significant difference from W2F1(P>0.05). P_n is closely related to T_r and G_s, but P_n is just slightly related to chlorophyll relative content and nitrogen content. There is a close correlation between chlorophyll relative content and nitrogen content but a low correlation with WUE. According to the experimental results, a preliminary conclusion can be reached that irrigation 820 mm and fertilizer 450 kg/hm²(W2F1)are the best water-fertilizer supply mode for water and fertilizer saving in southern Xinjiang sandy area.