中文摘要：

在新疆的气候生态条件下，选用北疆2个棉花（Gossypium hirsutum）丰栽品种‘新陆早13号’和‘新陆早33号，为供试材料，设置限根（RR）与对照（CK）处理，每个处理设置4个水氮水平：水氮亏缺（W0m0）、水分号缺（W0Nl）、氮素亏缺（w0N0）与水氮适量（wlNl），组成再裂区试验方案。采用管栽方法，通过人工改变根系垂直生长深度和水氮供应，在棉花产量形成期测定根系及叶片抗氧化保护酶系活性、生物培累积及分配等，探讨根域限制及水氮供应对棉花根系生长及叶片衰老的影响机理。结果表明：根域限制条件下，棉花根系牛物量、根系与叶片超氧化物歧化酶（SOD）、过氧化物酶（POD）与过氧化氢酶（CAT）活性、棉株总生物量、根冠比均低于对照，而地上部生物量与籽棉产量显著高于对照。水氮供应能有效地调节根系及叶片的生长，不同水氮处理问棉花根系与叶片抗氧化保护酶系活性、叶绿索含量、地上部生物晕及籽棉产量均表现为W1N1〉W0N1〉W1N0〉w0N0，根冠比与根系生物量的表现与之相反。根域限制与水氮供应表现出互作优势，根域限制下适量水氮供应处理的地上部生物量与籽棉产量均明显高于其他处理，根冠比较低。因此，在棉花根系生长受限的条件下，优化生育期间水氮供应，可以增强根系及叶片的抗氧化保护酶系活性、增加光合产物向地上部的分配比例、增加产量，是进一步挖掘膜下滴灌棉花增产潜力的有效途径。

英文摘要：

Aim Our objective was to evaluate the influence of the water and nitrogen treatments on parameters of root and leaf senescence in cotton plants grown under root restriction and with under-mulch drip irrigation. Methods Our experimental materials were upland cotton cultivars ＇Xinluzao 13＇ and ＇Xinluzao 33＇, which are the main cultivars grown in the study region of northern Xinjiang, northwestern China. Treatments consisted of root restriction （RR）, unrestricted root system （CK, control） and four levels of water and nitrogen supply： water and nitrogen deficiency （W0N0）, water deficiency （W0N1）, nitrogen deficiency （W1N0） and moderate supply of water and nitrogen （W1N1）. The treatments were applied in a split-split plot design. Cotton plants were cultivated in soil columns to control the vertical depth of root growth and to regulate application of water and nitrogen. We measured the activity of antioxidant enzymes in the root and leaf and the accumulation and distribution of biomass at the yield-determining stages （from flowering to the full boll opening stage）. Important findings The root biomass, activity of antioxidant enzymes （superoxide dismutase, guaiacol peroxi- dase and catalase） in the root and leaf, total plant biomass and the root/shoot ratio under root restriction decreased compared with the control. In contrast, aboveground biomass and cotton yield under root restriction were considerably higher than with the control. The supply of water and nitrogen effectively regulated root and leaf growth. With regard to their effects on antioxidant enzyme activity in the root and leaf, SPAD chlorophyll content, above- ground biomass and cotton yield, the water and nitrogen treatments were ranked as W1N1 〉 WoN1 〉 W1N0 〉 W0N0. In contrast and with regard to the shoot/root ratio and root biomass, the treatments were ranked as WoN0 〉 W1N0 〉 W0N1 〉 W1N1. Consequently, interaction between root restriction and the applied water and nitrogenregime had a marked effect on