Establishment of resistance to stresses caused by soil moisture fluctuation through strengthening the ability of plastic response ability of root system in rice

本研究的目的是研究植物随着环境条件的变化而改变其发育的能力的功能作用，这被称为作物适应水分胁迫（如干旱和土壤水分波动胁迫）的表型可塑性。本研究利用水稻SNP种质资源、日本晴和Kasalath杂交的染色体片段代换系（CSSL）、IR 64 INLs以及包括非洲新稻（NERICA）在内的几种具有抗逆性的基因型，对水稻根可塑性的功能作用进行了一系列的研究。在田间条件下，采用根箱-插接板法、倾斜管法、安装线源喷灌系统的试验床和增加根系深度的倾斜床对根系性状进行表型分析。这些结果一致表明，除了深根，根系的可塑性发育是植物适应水分胁迫的关键性状。我们还发现，整个根系的发展的可塑性是重要的，在响应进行性干旱，而在侧根的发展和通气组织的形成是重要的，在响应短暂的干旱和O2不足的条件。我们定量地显示了水分胁迫下根系可塑性通过增强水分吸收对干物质生产的贡献。

This study aimed to examine the functional roles of the ability of the plant to change its development as environmental conditions change, which is known as phenotypic plasticity in crop adaptation to water stress such as drought as well as soil moisture fluctuation stress, and. We conducted a series of experiments to evaluate the functional roles of root plasticity by using various accessions/populations such as OryzaSNP germplasm set, chromosome segment substitution lines (CSSL) derived from Nipponbare and Kasalath cross, IR 64 INLs and a few promising genotypes for stress tolerance including NERICA (New Rice for Africa that is an interspecific cross between Oryza sativa and Oryza glaberrima). We used the rootbox-pinboard method, slant tube method, experimental bed installed with line source sprinkler system that can create gradient in drought stress intensities, and sloping bed that can create increasing rooting depths under field conditions for phenotyping root traits. These results consistently showed that in addition to deep roots, the plastic development of the root system is a key trait for plant adaptation to water stress. We also found that the plasticity in development of the entire root system is important in response to progressive drought, while that in lateral root development and aerenchyma formation is important in response to transient drought and O2 deficient conditions. We quantitatively showed the contributions of root plasticity to dry matter production through enhanced water uptake under water stress.