首页 > 分享 > 喷施生长调节剂缓解甘薯干旱胁迫的机理

喷施生长调节剂缓解甘薯干旱胁迫的机理

花匠小妙招
2024-11-07 22:00

摘要：

【目的】探讨干旱胁迫下喷施生长调节剂对甘薯光合产物分配的影响以及对干旱胁迫的缓解效应。【方法】采用人工旱棚和旱池模拟薯块膨大高峰期（100—120 d）干旱胁迫,结合 13C标记方法,研究喷施6-苄氨基嘌呤（6-BA）、α-萘乙酸（NAA）和脱落酸（ABA）3种外源激素对甘薯干旱胁迫的缓解效应。测定甘薯叶片 13C积累量和分配率、内源激素含量、碳代谢酶活性、光合荧光特性等生理生化指标,并进行逐步回归分析、通径分析和RDA分析。【结果】与正常供水相比,干旱胁迫导致甘薯产量下降了18.76% （P＜0.05）,而喷施生长调节剂可以显著降低干旱胁迫条件下甘薯减产的幅度（P＜0.05）,喷施6-BA效果最佳,其次分别是喷施ABA和NAA。干旱胁迫下喷施生长调节剂可显著提高功能叶光合效率,从而促进薯块膨大期光合产物的合成。其中,喷施6-BA与喷清水处理相比,叶片净光合速率（Pn）提高了10.93%,最大光化学效率（Fv/Fm）增加了20.00%。干旱喷施不同生长调节剂均能显著提高甘薯瞬时 13C积累量和向块根的分配率,6-BA处理分别提高了75.68%和27.68%,促进了光合产物（ 13C）由叶片向块根中的转移和分配。此外,喷施生长调节剂可提高叶片碳代谢酶活性,喷施6-BA、NAA和ABA与喷清水处理相比,SS酶活性分别提高29.59%、19.25%和13.03%。喷施生长调节剂可以缓解因干旱引起的ZR和IAA含量下降,喷施6-BA与喷清水处理相比,ZR和IAA分别增加了18.72%和10.97%。逐步回归分析表明,光合特性、叶绿素荧光特性、碳代谢酶活性和内源激素是调控薯块膨大高峰期光合产物（ 13C）分配的关键指标（R=0.997）;通径分析表明,对甘薯光合产物（ 13C）由叶片向块根中转移与分配的影响直接作用系数较大的是Pn、SPS、ABA、ZR、SS和Fv/Fm。RDA分析表明,喷施6-BA与甘薯 13C总积累量、块根 13C分配率、ZR、Pn、Fv/Fm、SS和SPS具有很好的相关性。【结论】干旱胁迫下,喷施生长调节剂能提高内源激素含量和SPS、ADPGase为主的碳代谢酶活性,改善叶片光合特性,促进薯块膨大期光合产物（ 13C）由叶片向块根转运,缓解干旱胁迫的影响。

关键词: 甘薯, 干旱胁迫, 生长调节剂, 13C转移分配

Abstract:

【Objective】The study was conducted to investigate the effects of spraying growth regulators on the distribution of photosynthetic products in sweet potato and the alleviation effects on drought stress.【Method】Artificial dry shed and dry pond were used to simulate the drought stress of potato swell (100-120 d), and based on 13C labeling method, the alleviation effects of spraying three exogenous hormones such as 6-benzylaminopurine (6-BA), α-naphthyl acetic acid (NAA) and abscisic acid (ABA) on drought stress of sweet potato were studied. The physiological and biochemical indexes, such as the accumulation and distribution rate of 13C, endogenous hormone content, carbon metabolism enzyme activity and photosynthetic fluorescence characteristics of sweet potato leaves, were analyzed. And then we performed stepwise regression analysis, path analysis and RDA analysis.【Result】Compared with normal water supply, drought stress decreased the yield of sweet potato by 18.76% (P＜0.05). The degree of the decrease of yield was greatly smaller with the spraying of growth regulator under drought stress (P＜0.05). The best effect of spraying was 6-BA which was followed by ABA and NAA. Spraying growth regulators under drought stress could significantly improve the photosynthetic efficiency of functional leaves, which could promote the synthesis of photosynthetic products during the expansion of potato tubers. Compared with the spraying of water, the spraying of 6-BA promoted the net photosynthetic rate (Pn), which increased by 10.93% and the maximum photochemical efficiency (Fv/Fm) which increased by 20.00%. Spraying different growth regulators in drought could significantly increase the instantaneous accumulation of 13C and the rate of distribution to the roots of sweet potato. Different growth regulators could promote the transfer of photosynthetic products ( 13C) from leaves to roots and distribution which increased by 75.68% and 27.68% by spraying 6-BA, respectively. In addition, spraying growth regulators increased leaf carbon metabolizing enzyme activity. Compared with the spraying of water, the spraying of 6-BA, NAA and ABA increased SS enzyme activity increased by 29.59%, 19.25% and 13.03%, respectively. Spraying growth regulators alleviated the decrease of ZR and IAA content caused by drought. Compared with the spraying of water, the spraying of 6-BA increased ZR and IAA by 18.72% and 10.97%, respectively. Stepwise regression analysis showed that photosynthetic characteristics, chlorophyll fluorescence characteristics, carbon metabolism enzyme activity and endogenous hormones were key indicators for regulating the distribution of photosynthetic products ( 13C) at the peak of potato tube expansion (R=0.997); Path analysis showed that Pn, SPS, ABA, ZR, SS and Fv/Fm had the higher direct interaction coefficient on the transfer and distribution of the product ( 13C) from the leaves to the roots for sweet potato photosynthesis; RDA analysis showed that the spraying of 6-BA had a good correlation with the total 13C accumulation of sweet potato, the distribution of 13C in roots, ZR, Pn, Fv/Fm, SS and SPS.【Conclusion】Spraying growth regulators under drought stress raised endogenous hormone content, carbon metabolism enzyme activity based on SPS and ADPGase, improved leaf photosynthetic characteristics, and promoted the transport of photosynthetic products ( 13C) from leaf to root in potato tube expansion stage, besides which could relieve the effects of drought stress.

Key words: sweet potato, drought stress, plant growth regulators, 13C distribution