外施吲哚乙酸对棉铃蔗糖代谢及产量性状的影响

Effects of External IAA Application on Sucrose Metabolism With Cotton Bolls and Within-Boll Yield Components

为探究外施吲哚乙酸(IAA)对棉铃蔗糖代谢及棉铃产量性状的调控机制,以陆地棉(Gossypium hirsutum L.)品系A201为材料,用0.1 mg·L^(-1) IAA溶液连续处理开花前1 d至开花后2 d的棉铃,以去离子水处理为对照,研究IAA处理对棉铃胚珠外表皮纤维细胞突起、蔗糖代谢及棉铃产量性状的影响。结果表明,IAA处理能够显著提高棉铃单铃重,促进棉铃开花当日纤维细胞启动的密度。与对照相比,IAA处理可增强开花后30 d种胚磷酸蔗糖合成酶(SPS)活性,导致蔗糖浓度升高,为种胚大分子物质合成提供更多的底物;并提高了开花后30-40 d种胚和开花后20-30 d种皮蔗糖合成酶(SS)的活性,增加了种胚和种皮的淀粉浓度,促进了棉花种子库物质合成。另外,IAA处理棉铃可以促进棉铃种胚和种皮蔗糖代谢关键酶的活性,提高其碳水化合物特别是淀粉的浓度,有利于棉铃种子的发育,这可能是导致单铃重提高的重要原因。本研究结果对于利用IAA提高棉花产量具有指导意义。

The development of cotton boll is largely affected by phytohormone. It is unclear how phytohormone effects on the within-boll yield components as mediated by sucrose metabolism. An upland cotton line A201 was served as experimental material. Cotton bolls were subjected to the painting of 0.1 mg·L^(-1) indoleacetic acid(IAA) for successive four days from-1 d to 2 d post anthesis(DPA) with deionized water application as control. The objective of the present study was to examine the effects of endogenous IAA on fiber cell initiation from the cotton ovule outer epidermis, sucrose metabolism and within-boll yield components. Boll weight and fiber initials density on the flowering day were increased by the application of IAA. Cotton embryos had enhanced sucrose phosphate synthase(SPS) activity at 30 DPA under IAA treatment compared to the water regime, and thus resulted in increased sucrose concentration providing more substrates for the synthesis of macromolecules. Sucrose synthase(SS) activities were increased in cotton embryos at 30-40 DPA and in seed coats at 20-30 DPA by IAA application. In consistent with this, starch concentrations were increased in cotton embryos and seed coats at 20-40 DPA. These observations imply an enhanced sink activity of the cotton seed due to the application of IAA. IAA treated cotton bolls exhibited increased key sucrose metabolism enzyme activities and nonstructural carbohydrate concentrations, which contributed positively to the development of the cotton seeds. This may be a crucial cause for improved boll weight under IAA application regime. It is of guiding significance for the improvement of cotton yield by IAA application.