花铃期遮荫对棉花叶片生理特性的影响

【目的】研究棉花花铃期遮荫弱光对棉花叶片生理特性的影响。【方法】选择耐荫性不同的2个棉花(Gossypium hirsutum L.)品种中棉所 49 号和新陆中36 号为材料,于2016至2017年在乌鲁木齐市安宁区镇(87°28′E, 45°56′N)新疆农业科学院综合试验场进行不同程度遮荫大田试验。【结果】遮荫弱光造成棉花主茎功能叶SPAD值、净光合速率(P_n)、蒸腾速率(T_r) 和气孔导度(G_s)迅速降低,胞间CO₂浓度(C_i)上升,棉铃对位叶可溶性糖和氨基酸含量上升。中棉所 49 号的相关指标变化幅度较新陆中36号小。不同生态型品种对遮荫弱光环境的适应性亦不同。【结论】遮荫弱光环境下棉花叶片光合性能下降,光合产物累积能力及输出能力受阻,导致棉铃对位叶可溶性糖和氨基酸含量降低,棉花单株铃数、铃重、籽棉产量亦随遮荫程度加深而显著减少(P<0.05)

Effects of Shading on the Physiological Characteristics of Cotton Leaves during Cotton Flower and Boll Formation Periods

【Objective】 To study the effects of shading and weak llight on the physiological characteristics of cotton leaves during flower and boll formation period. 【Method】Two varieties of cotton (Zhongmiansuo 49 and Xinluzhong 36) with different shade tolerance were selected. The varieties were tested in the comprehensive experimental site of Xinjiang Academy of Agricultural Sciences from 2016 to 2017 in Anning District (N43°58′ and E87°30′), Urumqi City. 【Result】 Under shading and weak light, the chlorophyll SPAD, net photosynthetic rate (Pn), transpiration rate (Tr) and stomatal conductance (Gs) of the functional leaf on the main stems reduced, but the intercellular CO₂ concentration (Ci) increased. The contents of soluble sugar and soluble amino acid in the subtending leaf of cotton boll increased. The variation ranges of related indices of Zhongmiansuo 49 were less than those of Xinluzhong 36, which showed that the adaptability of different ecotypes to shading and weak light environment was also different. Stress caused by low temperature and poor light occurred frequently, which affected cotton leaves enzyme activity, and reduced photosynthetic capacity, then inhibited the plant photosynthesis and decreased the carbohydrates supplementary capacity in the subtending leaf of cotton boll. 【Conclusion】Under shading and weak light environment, the photosynthetic performance of cotton leaves decreased, and the accumulation ability and output ability of photosynthetic products were blocked, which eventually resulted in the decrease of soluble sugar and amino acid content in cotton boll subtending leaves, the number of bolls per plant and boll weight. The yield of seed cotton also decreased significantly with the deepening of shading (P < 0.05)