棉花叶系质量划分及叶层配置的研究

Studies on Classification of the Leaf Systematic Quality and Leaf Area Distribution in Cotton

对棉花品种泗棉3号等采用大田群体与实验室盆栽试验相结合的方法,应用14C同位素标记、剪叶试验及其生理测定等手段,研究在最大LAI相近条件下,叶片的组成、功能和大小分布对成铃和产量的影响。结果表明,棉花叶片的光合产物的运输分配流向及对棉花成铃和产量的作用是不同的,按其对棉铃形成和发育贡献的大小可划分为有效叶、无效叶、高效叶及低效叶,并且明确了在开花结铃期提高有效叶面积率、高效叶面积率,并塑造较小的叶片,均匀的叶层分布的叶层配置可提高群体光合效能,从而确保光合产物向产量器官的输送,提高成铃率,增加总铃数和产量的叶系质量特征。

The lint yield has close relationship with constitute and function of the leaf in the plant of the cotton (Gossypium L.). The objective of this study was to investigate the characteristics of the leaf size, constitute, distribution, photosynthetic function, exported carbohydrates on boll size, boll retention and lint yield under different planting densities, strategy of nitrogen fertilizers, during the 1996-1997 cotton growing seasons at the Yangzhou University Farm, Yangzhou, Jiangsu Province, China. In the 1996, three planting densities (42000, 48000 and 64000 plant·hm^(-2)) and two nitrogen fertilizer(300 and 375 kg·hm^(-2)) were designed to study the relationship between leaf area constitute and boll retention, lint yield under similar maximum LAI. The()^(14)C labeled and part of sympodium leaf cut were used to study the function and the carbohydrate export of different sympodium leaf with three potted cultivars (Simian No.3, Sumian No.5 and CCRI 12). Based on the 1996 results, in 1997 the three different developing type of cotton population were designed with nitrogen fertilizer strategy to study leaf size, LAI distribution on the vertical distribution of sun light intensity in the three cotton populations. The results showed that the role of the sympodium leaf on boll retention, boll size and lint yield was different, the developed leaves after August 15-20 were not much photosynthetic products to the yielding organs, the sympodium leaf with opposite 10 days boll had higher photosynthetic intensity and exported more carbohydrates to the opposite boll. The leaves of the plant can divided into effective and ineffective leaves according to the site of the sympodium leaves on the plant; high efficient leaves and low efficient leaves according to the exist of the opposite boll. The smaller leaf and even LAI distribution made higher sun light intensity in the cotton population and higher lint yield. These conclusions suggest that increasing the ratio of the effective and high efficient leaf area, making smaller leaves and maintaining even leaf area distribution during boll developing stage were key characteristics of the leaf systematic quality for higher boll retention and lint yield.