外源6-BA和ABA对不同播种期棉花产量和品质及其棉铃对位叶光合产物的影响

大田播种期(4月25日和5月25日)和植物生长调节剂(6-BA和ABA)试验于2006年在江苏南京(长江流域下游棉区)和河南安阳(黄河流域黄淮棉区)进行，以科棉1号和美棉33B品种为材料，研究外源6-BA和ABA对不同播种期棉铃对位叶光合产物形成与运转的影响及其与产量品质的关系。结果表明: (1) 6-BA显著提高棉铃对位叶蔗糖含量和转化率及淀粉含量，而ABA则主要调节棉铃对位叶内源激素平衡。(2)不同播种期条件下(4月25日和5月25日)，外源6-BA均可使棉花单铃重增加、纤维品质提高，外源ABA在晚播(5月25日，南京试点和安阳试点棉铃发育期MDT_min分别为20.9℃和16.5℃)条件下可使棉花产量(安阳试点)和纤维主要品质指标下降幅度减小；外源6-BA和ABA对棉籽主要品质性状的作用均不显著。(3)晚播条件下外源6-BA和ABA均可提高相对棉花主要品质指标，但两者作用机制不同，外源6-BA主要是提高棉铃对位叶光合产物含量和蔗糖转化率，而ABA则主要是诱导棉株抗逆性。

Effect of 6-BA and ABA Applications on Yield,Quality and Photosynthate Contents in the Subtending Leaf of Cotton with Different Planting Dates

To study the effects of 6-BA and ABA applications on carbohydrate contents and endogenous hormones in subtending leaf, and their relationship to cotton yield and qualities under different planting dates, we conducted a field experiment with two cotton cultivars Kemian 1 and NuCOTN 33B in the Lower Reaches of Yangtze River (Nanjing) and in the Yellow River Valley (Anyang), China. The cotton seeds were planted on Apr. 25th and May 25th, 2006, respectively, which could result in different growth temperatures for the bolls and their subtending leaves at the same site, and the growth regulators were sprayed at flowering stage. The results showed that the application of 6-BA significantly increased contents of sucrose and starch, and sucrose transformation rate in subtending leaf, while the application of ABA only regulated the balance of endogenous hormones. The application of 6-BA increased boll weight and enhanced fiber qualities in cotton plants with planting dates of Apr. 25th and May 25th, whereas the decrease ranges of cotton yield and qualities in Anyang were less for the application of ABA in cotton plants with planting date of May 25th, compared to those with planting date of Apr. 25th. However, the qualities of cottonseeds were not affected by the applications of 6-BA or ABA significantly. The application of 6-BA or ABA improved relative cotton qualities of late planted cotton, whereas the action mechanisms were different. The application of 6-BA improved cotton yield and quality via enhancing the photosynthate contents and sucrose transformation rate. However, the application of ABA improved cotton yield and qualities via increasing the stress resistance of cotton plants.