不同氮效棉花品种植株农艺性状、氮素积累及光合特性差异

【目的】研究不同氮效品种之间农艺性状,氮素积累及光合特性,为合理施氮提供参考。【方法】以棉花品种新陆早32号(氮高效品种)和新陆早36号(非氮高效品种)为材料,设置240、360 kg/hm²两个氮素水平,寻找差异,优化品种选育,提高氮素效率。【结果】无论在低氮还是高氮条件下,新陆早32号的株高、茎粗和果枝数均高于新陆早36号,分别相差8.34 cm、2.34 mm和1.56台。在氮素积累上,2个品种根的含氮量呈逐渐下降的趋势,但新陆早32号高于新陆早36号;在低氮水平时新陆早32号的茎后期可以积累更多的氮素,与叶片积累相反,而高氮水平时,后期茎的氮素积累相差不大,叶片则一直是新陆早32号含量高,差距保持在3.0 g/kg以上。在光合特性上,新陆早32号的净光合速率、胞间CO₂浓度基本高于新陆早36号,而蒸腾速率则相反。【结论】高氮水平下新陆早32号产量最高,为4 022.82 kg/hm²。不同氮水平下氮效品种均有差异,尤其是在低氮条件下,氮高效品种更能有效的利用氮素,保证产量,并在氮充足条件下提高产量。

The Differences in Plant Agronomic Traits,Nitrogen Accumulation and Photosynthetic Characteristics of Cotton Varieties with Different Nitrogen Efficiency

【Objective】 By studying the differences of agronomic traits, nitrogen accumulation and photosynthetic characteristics among different nitrogen-efficiency varieties, the breeding of varieties was optimized to improve nitrogen efficiency and provide reference for rational nitrogen application.【Method】Using cotton varieties Xinluzao 32 and Xinluzao 36 as experimental materials, two nitrogen levels of 240 and 360 kg/hm² were set up to study the differences of nitrogen efficiency among different cotton varieties.【Results】The results showed that the plant height, stem diameter and number of fruit branches of Xinluzao 32 were higher than those of Xinluzao 36 under both low and high nitrogen conditions, with a difference of 8.34 cm, 2.34 mm and 1.56 sets, respectively.In terms of nitrogen accumulation, the nitrogen content in roots of the two cultivars decreased gradually, but Xinluzao 32's was higher than that of Xinluzao 36. At low nitrogen level, Xinluzao 32 could accumulate more nitrogen in the later stage of stem, contrary to leaf accumulation. At high nitrogen level, the nitrogen accumulation in the later stage of stem was similar, while Xinluzao 32 had high nitrogen content in leaves, and the difference remained above 3.0 g/kg.In terms of photosynthetic characteristics, the net photosynthetic rate and intercellular carbon dioxide concentration of Xinluzao 32 were higher than those of Xinluzao 36, while the transpiration rate was the opposite.【Conclusion】At high nitrogen level, the yield of Xinluzao 32 was the highest, which was 4 022.82 kg/hm². Comprehensive analysis showed that the characteristics of different nitrogen-efficiency varieties were different. Especially under low nitrogen conditions, nitrogen-efficient varieties could utilize nitrogen more effectively, ensure yield and increase yield under sufficient nitrogen conditions.