氮素对棉株上部果枝铃￣叶系统生长及生理特性的影响

以鲁棉研28号为试验材料,不施氮肥为对照,在大田条件下研究低氮(120 kg·hm-2)、中氮(240 kg·hm-2)、高氮(480 kg·hm-2)处理对棉株上部果枝"铃￣叶系统"的形态和生理生化效应。结果表明:1)中氮和高氮显著增加棉花上部果枝的长度、叶面积,高氮显著降低上部果枝近远端直径比;2)与对照相比,中氮上部果枝铃对位叶的叶绿素含量、可溶性蛋白含量显著增加,上部果枝棉子的可溶性蛋白含量也显著提高;3)中氮棉花果枝内外围铃重最大,结铃后期显著大于对照。氮肥提高棉花上部果枝的纤维品质,以中氮内外围棉铃的纤维品质最优。表明施适量氮肥能增强棉花上部果枝的"源￣库"协调性。

Effects of Nitrogen Fertilization on the Growth and Physiological Characteristics of the "Boll-Leaf System" in the Upper Fruit Branches of Cotton (Gossypium hirsutum L.)

The objective of our study was to investigate the effects of N-fertilization rate on the morphological and physiological characteristics of the "boll-leaf system" in the upper fruit branches of cotton. To achieve this, we conducted a two-year experiment with Lumianyan 28 as a material. There were four levels of nitrogen fertilization: control treatment (N0, 0 kg·hm^－2), low nitrogen (N1, 120 kg·hm^－2), moderate nitrogen (N2, 240 kg·hm^－2) and high nitrogen (N3, 480 kg·hm^－2). The main results were as follows: 1) nitrogen fertilization improved the branch length and leaf area, and decreased the diameter ratio of near and far branches. The differences between the control treatment and the moderate and high treatments were significant. 2) Chlorophyll and soluble protein contents in the upper fruit branches' leaves and seeds were increased by nitrogen fertilization. The chlorophyll and soluble protein contents in the upper fruit branches' leaves in the moderate treatment were significantly higher than in the control. The soluble protein content in the upper fruit branches' seeds in the moderate treatment was significantly higher than in the control. 3) With increasing nitrogen fertilizer, the boll weight of the upper fruit branches first increased and then decreased. The boll weight in the moderate treatment was higher than in the other treatments. At the late bolling stage, the differences between the moderate and control treatments became significant. The fiber quality was increased by N application, and the moderate treatment had the best quality in the upper fruit branches. The morphological characteristics, physiological levels and fiber qualities were significantly affected by the N rate. "Source-sink" coordination in the upper fruit branches could be enhanced by the proper amount of N. In this study, moderate nitrogen(240 kg·hm^－2) coordinated the growth of the "boll-leaf system" of the upper fruit branches the best.