甘薯内源激素变化与块根形成膨大的关系

 研究了不同基因型甘薯块根内源激素含量变化对块根形成和膨大的影响。结果表明，块根形成前后和膨大高峰期，甘薯栽培种徐薯18和Minamiyutaka的ZR、DHZR、ABA、IAA和IPA含量均显著高于近缘野生种I.trifida(K123)，差异达极显著水平。块根日鲜重增长速率与ZR、DHZR和ABA的含量变化动态高度一致。块根形成前后及块根膨大中期和高峰期，块根干重与块根ABA、ZR和DHZR含量间呈显著（或极显著）正相关, 与IAA、iPA和GA4间无明显相关性。ZR、DHZR和ABA含量的高低，在不定根能否转化形成块根和块根膨大的速率方面起关键的作用。块根不同部位（顶部、中部和尾部以及外部、中部和内部）各种激素含量差异显著，块根的顶部激素含量最高、生理活性最强,内部和中部（ABA除外）也是各种激素含量高的部位。膨大前期大块根的ZR、DHZR、ABA及IAA含量显著高于小块根，膨大中期中等大小块根激素含量最高，膨大后期小块根的激素含量显著高于中等大小的块根和大块根。

Formation and Thickening of Tuberous Roots in Relation to the Endogenous Hormone Concentrations in Sweetpotato

A field trial was conducted to investigate the changes of endogenous hormone concentration during formation and thickening of tuberous roots in sweetpotato (Ipomoea batatas L.) of different genotypes (Xushu 18, Minamiyutaka and I .trifida-K123). The present results suggested that the concentrations of zeatin riboside (ZR), dihydro-zeatin riboside (DHZR), abscisic acid (ABA), indole-3-acetic acid (IAA) and isopentenyl-adenine (IPA) of Xushu 18 and Minamiyutaka were significantly higher than those of I.trifida-K123. Dry tuberous root yields were positively correlated with the concentrations of ABA, ZR and DHZR at 1% or 5% significant level, but not correlated with the concentrations of IAA, IPA and GA4. The concentrations of ABA, ZR and DHZR played very important roles for the tuberous roots formation and thickening in sweetpotato. The concentrations of ZR, DHZR, ABA and IAA in the top or inner parts of tuberous roots were significantly higher than those of in the end or outer parts. Meanwhile, endogenous hormone concentrations of big tuberous roots were significantly higher than that of middle or small ones at early thickening period. In fast thickening period of tuberous roots, endogenous hormone concentrations of middle tubers were the highest. However, at late thickening period, endogenous hormone concentrations of small tubers ranked the highest.