棉(Gossypium hirsutum L.)株生理年龄对棉铃生物量和氮素累积的影响

Effect of Plant Physiological Age on Biomass and Nitrogen Accumulation in Cotton Boll

【目的】探明棉株生理年龄对棉铃生物量和氮素累积的影响及其与棉铃品质的关系。【方法】2005年在江苏徐州(117°11′E,34°15′N)、2007年在河南安阳(114°13′E,36°04′N)设置分期播种(4月25日和5月25日)试验,使棉株不同果枝部位棉铃发育处于相同的温度和不同的棉株生理年龄条件下,研究其生物量和氮素累积的特征及其与棉籽、棉纤维品质的关系。【结果】不同生理年龄条件下,铃壳、棉籽、纤维及单铃最终总生物量和氮素的累积量差异较小,但棉铃各部分生物量和氮素的累积动态存在显著差异:棉株生理年龄较小时(下部果枝),棉铃发育前期生物量和氮素快速累积起始时间较早、速率较高、持续时间较短,而在棉株生理年龄较大时(中部果枝)棉铃生物量和氮素快速累积起始时间较晚、持续时间较长,整个累积过程较为平缓;棉株中部果枝铃纤维比强度显著高于下部果枝铃,而其它主要棉纤维及棉籽品质指标均差异不显著。【结论】棉株生理年龄的变化不改变棉铃最终生物量和氮素累积量,但显著改变棉铃各器官生物量和氮素的累积特征。纤维比强度是对棉株生理年龄或棉铃生物量累积特征最为敏感的指标,棉株中部果枝铃纤维生物量和氮素的平缓累积可能是其纤维比强度较下部铃高的主要原因。

【Objective】 To study the effect of plant physiological age on biomass and nitrogen accumulation in cotton bolls and their relationship with boll quality. 【Method】 The experiments were carried out in Xuzhou （117°11′E, 34°15′N） and Anyang （114°13′E, 36°04′N） with two cotton cultivars Kemian 1 and NuCOTN as materials. The biomass and nitrogen accumulation of cotton bolls were studied with different fruiting positions under the same temperature conditions by setting different sowing dates （25th April and 25th May）. 【Result】 Under younger plant physiological age conditions （bolls developed on lower positional fruiting-branches）, the start time, the rate and the duration of the rapid biomass and nitrogen accumulation period was earlier, higher and longer than that under higher plant physiological age conditions （bolls developed on middle positional fruiting-branches）, respectively, while the total biomass and nitrogen accumulation of the bolls with different plant physiological conditions were not different. Consequently, except that the fiber strength developed in the middle positions was higher than that in lower positions, other fiber qualities （fiber length and micronaire） and cotton seed qualities （the gross protein content and gross oil content） were not different. 【Conclusion】 These results suggested that the variation of plant physiological age seemed not to change the total biomass and nitrogen accumulation in cotton bolls, but may change the process of them. Fiber strength might be the most sensitive fiber character to the variation of plant physiological age. And higher fiber strength in the middle positions than that in lower positionsmight be mainly due to its more tempered biomass and nitrogen accumulation progress.