Chen Xinyu, Zhu Yu, Ding Yuan, Pan Rumo, Shen Wenyuan, Yu Xurun, Xiong Fei
Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops/Joint International Research Laboratory of Agriculture & Agri-Product Safety of the Ministry of Education, Yangzhou University, Yangzhou, Jiangsu, China.
PeerJ. 2021 Aug 19;9:e12015. doi: 10.7717/peerj.12015. eCollection 2021.
Drought is a common yield limiting factor in wheat production and has become a significant threat to global food security. Root system is the organ responsible for water uptake from soil and root growth is closely associated with yield and quality of wheat. However, the relationship between morphological and structural characteristics of root growth and caryopsis enrichment in wheat under drought stress is unclear. In this study, two wheat cultivars (YM13 and YN19) were treated with drought from flowering to caryopsis maturity stage. The changes in morphological structure of roots and characteristics of endosperm enrichment were investigated. Drought stress significantly reduced the root length, plant height, root dry weight and aboveground parts dry weight, whereas the root-shoot ratio of YM13 and YN19 increased by 17.65% and 8.33% under drought stress, respectively. The spike length, spike weight, grains number per spike and 1,000-grains weight of mature wheat also significantly declined under drought stress. Meanwhile, the cross section structure of roots was changed with the enlargement of vascular cylinder and dense distribution of xylem vessels under drought stress. Additionally, drought stress affected the substance enrichment in wheat caryopses, decreasing starch accumulation and increasing protein accumulation of endosperm. Correlation analysis suggested that the root length was closely correlated with the relative areas of amyloplast (0.51) and protein body (0.70), and drought stress increased the correlation coefficient (0.79 and 0.78, respectively). While the root dry weight had a significantly positive correlation with the plant height and aboveground parts dry weight. The results can provide theoretical basis for root architecture optimization, water-saving and high-yield cultivation and quality improvement in wheat.
干旱是小麦生产中常见的产量限制因素，已成为全球粮食安全的重大威胁。根系是负责从土壤中吸收水分的器官，根系生长与小麦的产量和品质密切相关。然而，干旱胁迫下小麦根系生长的形态结构特征与颖果充实之间的关系尚不清楚。本研究对两个小麦品种（YM13和YN19）从开花期到颖果成熟期进行干旱处理，研究了根系形态结构变化和胚乳充实特性。干旱胁迫显著降低了根长、株高、根干重和地上部分干重，而干旱胁迫下YM13和YN19的根冠比分别增加了17.65%和8.33%。干旱胁迫下，成熟小麦的穗长、穗重、每穗粒数和千粒重也显著下降。同时，干旱胁迫下根系横切面结构发生变化，维管束增大，木质部导管密集分布。此外，干旱胁迫影响小麦颖果的物质积累，减少胚乳淀粉积累，增加蛋白质积累。相关性分析表明，根长与淀粉体相对面积（0.51）和蛋白体相对面积（0.70）密切相关，干旱胁迫增加了相关系数（分别为0.79和0.78）。而根干重与株高和地上部分干重呈显著正相关。研究结果可为小麦根系构型优化、节水高产栽培及品质改良提供理论依据。
