中文摘要：

【目的】从根系形态变化的角度阐述磷高效基因型棉花对低磷胁迫的响应特征及适应机理,为找出影响棉花磷素吸收的主要因子和通过根系塑性提高养分利用效率的遗传改良提供科学依据。【方法】以磷高效基因型棉花品种新海18号（XH18）、中棉所42号（CCRI-42）、新陆早19号（XLZ19）和磷低效基因型棉花品种新陆早13号（XLZ13）、新陆早17号（XLZ17）为材料,通过特殊土培系统,研究不同磷效率棉花在不同磷水平下（低磷胁迫0、正常供磷150 kg·hm^（-2））根系形态及其与植株磷素吸收的关系。【结果】低磷胁迫显著降低棉花生物量和磷累积量,其中磷高效基因型的生物量和磷吸收量在各施磷水平下分别为低效基因型的1.21—2.08和1.35—1.91倍。施磷可显著增加土壤中Olsen-P含量。低磷胁迫下各基因型棉花品种Olsen-P较适磷条件显著降低,且磷高效基因型棉花降低幅度大于磷低效。在低磷胁迫条件下,磷高效基因型棉花品种在0—25 cm土层中土壤Olsen-P浓度低于磷低效,较磷低效基因型XLZ13和XLZ17分别平均降低了21.1%和30.1%。棉花的总根长、总根表面积、总根体积、平均根系直径在低磷胁迫下显著降低,其中磷高效基因型棉花在各施磷水平下的总根长、总根表面积、总根体积分别为低效基因型的1.54—1.97、1.52—1.92、1.47—1.84倍。低磷胁迫下,磷高效基因型棉花比根长、比根表面积和比根体积均显著大于磷低效基因型棉花品种,分别为低效基因型的1.10—1.25、1.07—1.22、1.01—1.16倍,而平均直径显著低于磷低效基因型,为磷低效基因型的34.2%—70.2%;主成分分析表明,总根长、总根表面积、总根体积、根干质量、中根长、粗根长受基因型差异的影响较为明显,是区分两类磷效率基因型棉花根系形态差异的主要指标。一般线性模型方差分解结果表明,总根长、总根表面积、总?

英文摘要：

【Objective】Efficient genotype cotton plays important roles in promoting low phosphorus（P） stress from the perspective of the root morphology.The purpose of this study is to provide a scientific basis for identifying the main factors that affecting phosphorus absorption of cotton and improving efficiency of nutrient utilization of genetic improvement through root plasticity.【Method】A pot experiment was carried out to test the effects of P supply levels（low P stress 0,Suitable P 150 kg·hm~（-2）） with two P genotype（efficient XH18,CCRI-42,XLZ19;inefficient XLZ13,XLZ17）cottons on root morphology and the relationships between root morphology and P uptake.【Result】 Cotton biomass and P uptake were significantly reduced by low P stress.Efficient genotype cotton biomass and P uptake were 1.21-2.08 and 1.35-1.91 times as much as those of inefficient genotype cotton,respectively.Phosphorus significantly increased Olsen-P content in soil.Olsen-P of P efficient genotype cotton was significantly decreased more than those of two P inefficient cottons compared with phosphorus suitable conditions under low P stress.Olsen-P in the 0-25 cm layer of P efficient genotype cotton was less than P inefficient cotton,compared with XLZ13 and XLZ17 decreased by 21.1% and 30.1% in the low P stress environment.The total root length,total root surface area,total root volume and average root diameter of cotton were significantly reduced under low P stress.The total root length,total root surface area,total root volume of P efficient genotype cotton were 1.54-1.97,1.52-1.92 and 1.47-1.84 times as much as that of those of P inefficient cotton.P efficient genotype cotton＇s specific root length,specific root surface area and specific root volume were significantly higher than those of two P inefficient cottons under low P stress,were 1.10-1.25,1.07-1.22 and 1.01-1.16 times as much as that those of P inefficient genotype cottons.The average root diameter of P efficient genotype cotton was significantly less than P ineff