铃期增温对棉花产量、品质的影响及其生理机制

以泗棉3号棉花品种为材料,于2010和2011年在南京农业大学牌楼试验站设置铃期(7月13日-8月24日)增温试验,模拟全球增温条件下棉花产量、品质的变化趋势及其生理机制.结果表明: 在铃期增温2～3 ℃(日均温31.1～35.2 ℃)条件下,植株总生物量下降约10%,单株皮棉及籽棉产量降低30%～40%.棉纤维品质变化显著，且不同纤维品质指标对增温的响应程度存在较大差异:马克隆值和断裂比强度显著升高,纤维长度下降,而整齐度指数和伸长率无显著变化.棉株光合能力、干物质累积能力和光合产物输出能力显著下降;可溶性氨基酸、可溶性糖、蔗糖含量及碳氮比均显著下降,而淀粉含量显著上升;增温条件下营养器官干物质分配比例增多,生殖器官干物质分配比例相对减少,经济系数随之降低.棉株下部果枝受增温影响较小,中、上及顶部果枝受增温影响较大.表明在增温2～3 ℃条件下,棉株大部分时间处于热胁迫状态,不仅光合能力下降,而且光合产物向“库”端的转运能力下降,最终导致其减产.

Effect of increased temperature in boll period on fiber yield and quality of cotton and its physiological mechanism.

To study the effect of temperature increase in boll period (13-Jul. to 24-Aug.) on cotton yield and fiber quality under the global warming background, a pot experiment with cotton cultivar Simian 3 was carried out in half open top greenhouse in Pailou experiment station (32°02′ N,118°50′ E) of Nanjing Agricultural University in 2010 and 2011. The results indicated that when the temperature was increased by 2-3 ℃ (with an average daily temperature of 31.1 to 35.2 ℃), the biomass declined by 10%, while the cotton yield declined by 30%-40%. The fiber quality also changed significantly with the relative indices responding differently. The micronaire value and fiber strength increased, the fiber length reduced while the fiber uniformity and elongation rate changed little. The plant photosynthesis capability, the biomass accumulation and the ability of carbohydrates transferring to sink organs all deceased. The soluble amino acids, soluble sugar, sucrose and C/N decreased significantly, while the starch content increased significantly. The allocation in vegetative organs was increased while that in reproductive organs was reduced, which in turn declined the economical index. The lower fruit branches were affected little under increased temperature condition while the middle, upper and top branches were affected greatly. The results indicated that, under the 2-3 ℃ warmer condition, the cotton plants experienced the high temperature stress, both the photosynthesis ability and the carbohydrates transportation from source to sink were decreased, leading to the decline of cotton yield.