中文摘要：

【目的】明确果枝部位、温光复合因子和施氮量对棉纤维比强度形成过程的定量关系及两者的补偿效应,探明棉纤维比强度形成的生态基础。【方法】以杂交棉（科棉1号）和常规棉（美棉33B）为材料,于2005年在江苏南京（118°50′E,32°02′N,长江流域下游棉区）和江苏徐州（117°11′E,34°15′N,黄河流域黄淮棉区）设置分期播种（4月25日、5月25日）和施氮量（0、240、480 kg N.hm-2）试验,研究棉株果枝部位、温光复合因子（用纤维加厚发育期的累积辐热积PTP表示）和施氮量对纤维比强度形成的影响。【结果】（1）棉株果枝部位显著影响纤维比强度的形成,并与温光复合因子存在协同效应。棉株中部果枝铃发育期温光条件适宜,其纤维比强度显著大于其它果枝部位铃;随温光条件变差,纤维比强度在果枝部位间的差异不明显。（2）棉纤维比强度随花后天数的增加可分为快速增加和稳定增加两个时期,PTP与纤维比强度快速增加期的日均增长速率（VRG）线性正相关、与快速增加持续期（TRG）线性负相关,与稳定增加期的日均增长速率（VSG）、持续期（TSG）及最终棉纤维比强度（Strobs）呈开口向下的抛物线关系。当PTP达到291 MJ.m-2左右时,纤维比强度Strobs最大（科棉1号、美棉33B分别为34.8、31.9 cN.tex-1）,品种间差异主要源于纤维比强度稳定增加期（中科棉1号和美棉33B的VSG、TSG分别为0.32 cN.tex-1.d-1、21 d和0.18 cN.tex-1.d-1、24 d）。（3）纤维比强度达到最大值所需的PTP随施氮量增加而减小,施氮量可通过棉铃对位叶叶氮浓度（NA）影响纤维比强度的形成,棉花氮素营养对温光复合因子存在补偿效应,当PTP高于104 MJ.m-2时,240 kg N.hm-2下的NA更适宜于比强度的形成;PTP低于此值时,增加施氮量可对温光复合因子进行补偿,以利于高强纤维形成。【结论】棉株果枝部位显著影响纤维?

英文摘要：

【Objective】The effects of fruiting-branch position,temperature-light factor and nitrogen rates on cotton fiber strength were studied.【Method】 Field experiments were carried out in Nanjing（118o50′E,32o02′N,middle lower reaches of Yangtze River Valley） and Xuzhou（117°11′E,34°15′N,Yellow River Valley） with two cotton cultivars（Kemian 1 with average fiber strength 35 cN？tex-1;NuCOTN 33B with average fiber strength 32 cN？tex-1）.Two sowing dates and three nitrogen application levels were applied,thus cotton fiber developing process can be arranged at different fruiting-branch positions and ecological conditions.【Result】 An interaction between fruiting branch and temperature was observed.Cotton bolls in the middle-branch produced stronger fiber than that in lower-and upper-branch when temperature-light factor was optimal.While temperature-light decreased,fruiting-branch effects were not significant.Development of cotton fiber strength could be divided into rapid and steady growth periods.PTP（cumulative photo-thermal product） during cotton fiber secondary wall thickening period（as temperature-light factor） were linear with the rate（VRG） and duration（TRG） of fiber strength rapid growth period,while the rate（VSG） and duration（TSG） of fiber strength steady growth period,the observed cotton fiber strength（FSobs） were quadratic with PTP,respectively.The strongest Strobs（34.8 and 31.9 cN？tex-1 for Kemian 1 and NuCOTN 33B,respectively） was obtained at PTP of 291 MJ？m-2,when VRG was 1.5 cN？tex-1？d-1 and TRG was 16 d,VSG and TSG for Kemian 1 were 0.32 cN？tex-1？d-1 and 21.4 d,while for NuCOTN 33B were 0.18 cN？tex-1？d-1 and 24.0 d,respectively.N fertilization significantly affected formation of cotton fiber strength and had a compensatory effect on PTP.As N increased,PTP for obtaining the highest Strobs decreased.NA under 240 kg N？hm-2 was more suitable for cotton fiber strength when PTP was greater than 104 MJ？m-2;when PTP was less than that