| 土壤水分亏缺对水稻茎秆贮藏碳水化合物向籽粒运转的调节 |
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| 引用本文： | 王维,蔡一霞,蔡昆争,张建华,杨建昌,朱庆森.土壤水分亏缺对水稻茎秆贮藏碳水化合物向籽粒运转的调节[J].植物生态学报,2005,29(5):819-828. |
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| 作者姓名： | 王维 蔡一霞 蔡昆争 张建华 杨建昌 朱庆森 |
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| 作者单位： | 华南农业大学农学院 |
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| 基金项目： | 香港研究资助局资助项目，国家自然科学基金，华南农业大学校科研和教改项目 |
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| 摘 要： | 以两个茎秆贮藏物质利用效率不同的水稻(Oryza sativa)杂交组合(‘汕优63’和‘Pc3 11/早献党’)为材料，进行土壤水分亏缺处理(Water_deficit)，以水层灌溉为对照(Well_w atered)，研究水分亏缺对水稻茎贮藏性碳水化合物运转及其关键酶活性的调节作用。结果表明，水分亏缺促进了水稻茎秆贮藏物质的运转和对籽粒产量的贡献，开花前茎秆贮藏的碳水化合物对产量贡献率分别提高了1.9～3.0倍(与水层灌溉相比)。土壤水分亏缺诱导了水稻茎节间醎淀粉酶、鈅淀粉酶、醎葡萄糖苷酶、D_酶活性上升，但淀粉磷酸化酶受到了抑制，说明土壤水分亏缺加强水稻茎秆贮藏淀粉水解途径，而不是磷酸解途径。就蔗糖代谢而言，土壤水分亏缺提高了蔗糖磷酸合成酶的活性和活化状态，抑制蔗糖转化酶活性，促进蔗糖合成，加速贮藏物质快速降解和转移，从而调节稻株贮藏碳水化合物向籽粒的分配。
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| 关 键 词： | 水分亏缺 非结构性糖 淀粉水解酶 蔗糖磷酸合成酶 水稻 |
| 收稿时间： | 2004-09-24 |
| 修稿时间： | 2005-06-12 |
REGULATION OF SOIL WATER DEFICITS ON STEM-STORED CARBOHYDRATE REMOBILIZATION TO GRAINS OF RICE |
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| WANG Wei,CAI Yi-Xia,CAI Kun-Zheng,ZHANG Jian-Hua,YANG Jian-Chang,ZHU Qing-Sen.REGULATION OF SOIL WATER DEFICITS ON STEM-STORED CARBOHYDRATE REMOBILIZATION TO GRAINS OF RICE[J].Acta Phytoecologica Sinica,2005,29(5):819-828. |
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| Authors: | WANG Wei CAI Yi-Xia CAI Kun-Zheng ZHANG Jian-Hua YANG Jian-Chang ZHU Qing-Sen |
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| Affiliation: | College of Agronomy, South China Agricultural University |
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| Abstract: | Grain yields of rice in China are often low and vary substantially due to the shortages of available water. Assimilates stored prior to grain filling have been identified as important contributors to grain yield in drought environments, but evaluating their benefit has been hampered by an inadequate understanding of the physiological mechanism of remobilization to grains of stored carbon reserves during grain filling. A moderate soil drying applied at grain filling period can enhance plant senescence and may improve the yield through remobilizing more pre_stored food to grains. The study was designed to test the following hypo thesis: if soil drying is controlled properly at the mid_late stage of grain filling, an early senescence induced by drought stress would accelerate the rate of grain filling by enhanced relocation of carbon stored reserves, and improved use of pre_stored carbon reserves may increase yields where photosynthetic assimilation is decreased by soil drying. Further evaluation of enzyme regulation in the remobilization process will help to understand the physiological mechanisms.
In the current study, two rice combinations (cvs `Shanyou63' and `Pc311/Zao') were grown in cement containers and pots at Yangzhou University. Controlled soil water deficit were imposed at 9 d after anthesis in consideration that the division of endosperm cell is sensitive to water deficit.
We found that, compared to well_watered treatments, the remobilization of stored carbohydrates in the rice stem was significantly enhanced under water_deficit conditions, and the increased contribution to grain yields was 1.9-3.0 times as that of rice grown under well_watered conditions. Pronounced effects of water_deficit treatment on carbohydrate metabolism were observed in rice stems. Sugar concentrations and carbon distribution among sugar components were altered under water_deficit conditions. Starch breakdown in rice stems under soil water deficit occurred through action via the hydrolytic pathway: α¬_amylase,β_amylase,α¬_glucosidase and D_enzyme were induced and enhanced by soil drying. Starch phosphorylase activity was decreased under water_deficit conditions, indicating that phosphorylase was not involved in the processes of starch remobilization. Water deficit markedly altered the pattern of sucrose metabolism by shutting down the bypass of carbon flow through the sucrose synthase (SuSy) catalyzed system and enhanced the unidirectional flow through the irreversible sucrose_phosphate synthase (SPS) and acid invertase (AINV) catalyzed pathway. SPS was induced and activated by water deficit, and played a pivotal role in enhancing synthesis of sucrose through the conversion of stored carbon into sucrose. During rapid remobilization of stored sugar, the sucrose content was increased by 10.3% in `Shanyou63' and 20.45% in `Pc/Zao' as compared to the well_watered treatments. It is concluded that the enhanced remobilization of stored non_structural carbohydrates (NSC) in rice stems under soil water deficit was due to induced hydrolytic enzyme activities, in creased SPS activity and activation state, but decreased invertase activity. |
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| Keywords: | Water deficit Non-structural carbohydrate Starch-hydrolytic enzymes Sucrose-phosphate synthase Rice |
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