Advantageous spike-to-stem competition for assimilates contributes to the reduction in grain number loss in wheat spikes under water deficit stress

作者：Juan Li, Zimeng Liang, Yakun Li, Kexin Wang, Vinay Nangia, Fei Mo, Yang Liu · 发表于：Agricultural Water Management · 年份：2024 · DOI：10.1016/j.agwat.2024.108675 · 被引用次数：18 · 研究领域：Crop Yield and Soil Fertility、Plant nutrient uptake and metabolism、Plant responses to water stress

This study was conducted to investigate the mechanisms of assimilate distribution and sugar metabolism in spike-stem that inhibit the formation of fertile florets and grains per spike in winter wheat under pre-reproductive drought stress. Two winter wheat cultivars, CH58 (relatively strongly drought tolerant) and LH6 (relatively weakly drought tolerant), were subjected to successive soil drought treatments from jointing to heading during the 2020–2022 growing seasons. The results showed that pre-reproductive drought stress intensified the degradation and abortion of wheat florets. Compared to CH58, the decrease in the number of fertile florets and grains per spike of LH6 under drought stress increased by an average of 5.3%−8.0% and 8.3%−9.0%, respectively. Drought significantly inhibited the distribution of 13C-photosynthates in wheat spikes (15.7%−24.7%) and stems (8.5%−11.7%) during the booting stage. The number of differentially expressed genes enriched in starch and sucrose metabolic pathways was much higher in the spike and stem of LH6 than in those of CH58. Drought significantly reduced sucrose and hexose in young spikes but increased hexose and fructan concentrations in stems. Compared to LH6, the higher invertase activity and accompanying high expression of sugar transporter protein (STP) in CH58 spikes under drought stress contributed to the utilization of sucrose in young spikes. Additionally, under severe drought, the higher fructan concentration and expression of ...