Involvement of abscisic acid and cytokinins in the senescence and remobilization of carbon reserves in wheat subjected to water stress during grain filling
Involvement of abscisic acid and cytokinins in the senescence and remobilization of carbon reserves in wheat subjected to water stress during grain filling
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DOI：
10.1046/j.1365-3040.2003.01081.x
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发表时间：
2003-10
影响因子：
7.3
通讯作者：
Jianchang Yang;Jianhua Zhang;Zhiqing Wang;Qing-sen Zhu;Lijun Liu
中科院分区：
文献类型：
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作者：
Jianchang Yang;Jianhua Zhang;Zhiqing Wang;Qing-sen Zhu;Lijun Liu
本研究探讨了脱落酸(ABA)和细胞分裂素可能介导水分亏缺促进植物衰老和预先储存的碳储量的再动员的可能性。两个高抗倒伏小麦(Triticum aestivum L.)在田间种植不同品种，在抽穗期进行正常氮素或高氮素处理。充分浇水(WW)和水分胁迫(WS)处理从开花后9d开始实施，直到成熟。WW植株旗叶的叶绿素(Chl)和光合作用速率(Pr)下降速度快于WW植株，说明水分亏缺加剧了衰老。水分胁迫促进了茎中非结构性碳水化合物的减少，促进了14C从茎到籽粒的重新分配，缩短了籽粒灌浆期，提高了籽粒灌浆速率。水分胁迫显著增加了茎和叶中的ABA，但降低了玉米素(Z)+玉米素核苷(ZR)的浓度。旗叶ABA与Pr、Chl呈显著负相关，Z+Zr与Pr、Chl呈正相关。ABA与预存碳素再动员和籽粒灌浆速率呈显著正相关，而与Z+ZR无显著相关。外源ABA降低了旗叶Chl含量，促进了旗叶的再动员，提高了籽粒灌浆速率。喷洒激动素则有相反的效果。这些结果表明，ABA和细胞分裂素都参与了控制植物衰老的过程，水分胁迫下小麦植株体内ABA水平的提高导致了碳素再动员的增强和籽粒灌浆速率的加快。
This study investigated the possibility that abscisic acid (ABA) and cytokinins may mediate the effect of water deficit that enhances plant senescence and remobilization of pre-stored carbon reserves. Two high lodging-resistant wheat (Triticum aestivum L.) cultivars were field grown and treated with either a normal or high amount of nitrogen at heading. Well-watered (WW) and water-stressed (WS) treatments were imposed from 9 d post-anthesis until maturity. Chlorophyll (Chl) and photosynthetic rate (Pr) of the flag leaves declined faster in WS plants than in WW plants, indicating that the water deficit enhanced senescence. Water stress facilitated the reduction of non-structural carbohydrate in the stems and promoted the re-allocation of prefixed 14C from the stems to grains, shortened the grain filling period and increased the grain filling rate. Water stress substantially increased ABA but reduced zeatin (Z) + zeatin riboside (ZR) concentrations in the stems and leaves. ABA correlated significantly and negatively, whereas Z + ZR correlated positively, with Pr and Chl of the flag leaves. ABA but not Z + ZR, was positively and significantly correlated with remobilization of pre-stored carbon and grain filling rate. Exogenous ABA reduced Chl in the flag leaves, enhanced the remobilization, and increased grain filling rate. Spraying with kinetin had the opposite effect. The results suggest that both ABA and cytokinins are involved in controlling plant senescence, and an enhanced carbon remobilization and accelerated grain filling rate are attributed to an elevated ABA level in wheat plants when subjected to water stress.