水分胁迫下抗旱型水稻磷积累及其生理机制

Water consumption for rice production is accounting for 70% of total agriculture water use. However, water stress is still identified as the single most important constraint in rice production in many rice-producing areas of China for a number of reasons, including variation in the rainfall patterns from one year to another, uneven distribution of rainfall in the rice growing season in many areas. Drought resistance rice can maintain the higher water status to achieve normal metabolism in water-limited environments. Phosphorus (P) is critical in the metabolism of plants, closely related to rice yield formation and drought resistance. It is important, to study the P accumulation and its physiological mechanism of drought resistance rice under water stress, for explaining the mechanism of rice yield under water shortage environment. Drought resistance and drought sensitive rice were selected and 2 experiments were performed to study P uptake, translocation and accumulation and their physiological mechanism of different drought resistance types rice under water stress. The innovation of this study is revealing the relationship between capacity of the drought resistance and P use efficiency, and explaining the explaining the mechanism of rice yield under water shortage environment in terms of P, and then searching the mechanism of high phosphorus use efficiency and providing the new idea for water and fertilizer saving cultivation of rice.

水稻是我国农业用水最多的作物，水分缺乏易造成减产，抗旱型水稻的育成能稳定缺水稻区的粮食产量。磷与水稻产量和抗旱性紧密相关，对水分胁迫下抗旱型水稻磷的积累及其生理机制进行研究，有助于从磷营养角度解释缺水条件下抗旱型水稻产量形成的机制。本项目以不同抗旱性水稻品种为研究对象，设置不同水分胁迫处理。采用田间试验和根管试验相结合的研究方法，重点研究不同抗旱性水稻在磷吸收、转运和积累上的差异，探讨水分胁迫下抗旱型水稻磷吸收、转运和积累的生理机制。拟解决的关键问题为揭示水分胁迫下抗旱型水稻与旱敏感水稻磷积累在时间和空间上的差异；阐明水分胁迫下抗旱型水稻磷吸收、转运和积累的规律；探索抗旱性与磷利用效率之间的关系。本项目的创新性为在水分亏缺下，对不同抗旱性品种磷利用效率进行研究；从磷营养生理学的角度剖析抗旱型水稻产量形成的机制；探索水分缺乏条件下，水稻的磷养分高效利用问题，为水稻节水节肥栽培提供了新方向。

水稻是我国农业用水最多的作物，抗旱型水稻的育成能稳定缺水稻区的粮食产量。磷重要的营养元素，对水分胁迫下抗旱型水稻磷的积累及其生理机制进行研究，有助于从磷营养角度解释缺水条件下抗旱型水稻产量形成的机制，对水稻节水节肥高效栽培技术的研究，减少干旱灾害的影响，有积极意义。本项目以不同抗旱性水稻品种为研究对象，采用田间试验、盆栽试验和根管试验相结合的研究方法，研究不同抗旱性水稻在磷吸收、转运和积累上的差异，探讨水分胁迫下抗旱型水稻磷吸收、转运和积累的生理机制。主要结果如下：.（1）水分胁迫下，抗旱指数较高的品种，磷的收获指数及地上部分的积累量均较抗旱指数低的品种高。水分胁迫下，生育期内所有品种营养器官的磷含量呈先增加、后降低趋势，在成熟期时，降到最低。穗部的磷含量随生育时期变化差异不显著，灌浆过程中，茎鞘和叶片中的磷在向穗部转移，穗部是主要的磷吸收器官，作为磷库，穗部积累了大部分的磷。茎鞘和叶磷含量随胁迫程度加大，呈先降低后增加的趋势，而穗部的磷含量则呈增加趋势。在茎鞘和叶中，抗旱性品种旱优73的磷含量低于旱敏感品种H优518，由于旱优73的干物质量相对较大，说明旱优73磷利用效率更高。.（2）在重度胁迫时，旱优73的单茎根体积显著高于H优518。旱敏感品种H优518在受到干旱胁迫时，表现为提高根系长度，扩充根体积。而抗旱型品种旱优73的根系长度及单茎根体积受水分胁迫后相对稳定，降低的幅度较H优518低。在养分的吸收上，旱优73采取了与H优518不同的应对水分胁迫的策略。水分胁迫下，两个品种的根系分泌物均有部分出现上调，旱优73的根系分泌物上调的种类与H优518有明显差别。将水分胁迫下旱优73上调的酸类物质进行分类可知，上调的酸类分泌物一共56种酸类物质，分别属于吲哚酸类、苯甲酸类、羟基肉桂酸类、烯烃酸类、亚油酸类、氨基酸类和脂肪酸类等。其中，脂肪酸、十八烷酸、氨基酸和亚油酸等占总较大，占总分泌酸类的64.3%。