干旱胁迫对小麦花后不同器官果聚糖代谢和转运的影响

为探索干旱胁迫对小麦花后不同器官果聚糖生理代谢和转运的影响,以抗旱性有显著差异的两个冬小麦品种为材料,在干旱胁迫(drought stress,DS)和正常灌溉(well watered,WW)条件下,研究了小麦花后主穗颖壳和主茎不同节位果聚糖代谢转运动态规律及其与籽粒灌浆的相关性。结果表明,小麦灌浆期不同器官果聚糖代谢转运受基因型、器官、花后天数和水分环境以及各因子互作显著影响;器官、花后天数和花后天数与水分互作是调控小麦花后果聚糖代谢转运的主要影响因子。小麦花后不同器官果聚糖含量均呈先升后降趋势。与正常灌溉处理相比,干旱胁迫缩短了果聚糖含量峰值出现的时间(提前5d),对果聚糖代谢的影响表现为"先促积累、后促降解"效应,此效应在抗旱品种陇鉴19和小麦颖壳、穗下节和倒二节等器官中更显著。干旱胁迫显著抑制了小麦花后蔗糖:蔗糖果糖基转移酶(1-SST)活性,提高了果聚糖外水解酶(FEH)活性;果聚糖含量与FEH酶活性正相关。小麦粒重与不同器官的1-SST活性、倒二节和倒三节的FEH活性呈显著或极显著负相关;灌浆速率与不同器官的果聚糖含量、颖壳和穗下节的FEH活性呈显著或极显著正相关。干旱胁迫显著促进了小麦不同器官果聚糖的转运和再分配,其转运率和对籽粒粒重的贡献率分别达6.86%~70.52%和0.07%~4.93%,其中,花前显著高于花后,陇鉴19高于Q 9086,穗下节和倒二节高于颖壳和倒三节。

Effect of Drought Stress on Fructan Metabolism and Translocation in Different Organs of Wheat after Anthesis

In order to reveal the influences of drought stress on fructan metabolism and translocation in different organs of wheat in the duration of post-anthesis, two winter wheat cultivars with different drought tolerance were used to investigate the dynamic rule of fructan metabolism, along with its relationship with grain filling in glume of main spike and different internodes of main stems after flowering under drought stress (DS) and well watered (WW) conditions.Results showed that fructan metabolism and translocation of different organs of wheat in filling stage were significantly affected by the genotype, water condition, organ, day after anthesis, and interactions between these factors. Especially, such factors as organ and day after anthesis, and interactions of day after anthesis with water condition were more critical to modulate the fructan metabolism and translocation. The fructan content of different organs were all rise first and then fall during the grain filling. Compared to the WW, DS could shorten the peak appearance of fructan content by five days.To fructan content, DS promoted its accumulation first, and then boosted its degradation.This effects were more remarkable in the drought cultivar Longjian 19, and in glumes, peduncle and penultimate internodes. DS observably inhibited the activity of sucrose:sucrose 1-fructosyltransferase (1-SST),but significantly enhanced the activity of fructan exohydrolase (FEH) during the grain filling. The fructan content showed higher positive correlation with the FEH activity. Furthermore, significantly negative correlations were observed between the grain weight with the 1-SST activity in different organs and the FEH activity in the penultimate internode and third internode,whereas the positive correlations were indicted between the grain-filling rate in different organs, the fructan content and the FEH activity in glume and peduncle internode. DS could markedly improve the translocation and reallocation of fructan. In this case, fructan translocation rate and contribution rate to grain ranged from 6.86% to 70.52%, and from 0.07% to 4.93%, respectively, of which before anthesis were significantly higher than those after anthesis, in Longjian 19 than in Q 9086, and in peduncle and penultimate internodes than in glumes and third internodes from the top as well.