Post-flowering Soil Waterlogging Curtails Grain Yield Formation by Restricting Assimilates Supplies to Developing Grains

Abstract

Soil waterlogging is among the major factors limiting the grain yield of winter wheat crops in many parts of the world, including the middle and lower reaches of the Yangtze River China. In a field study, we investigated the relationship between leaf physiology and grain development under a varying duration of post-flowering waterlogging. A winter wheat cultivar Ningmai 13 was exposed to soil waterlogging for 0 (W0), 3 (W3), 6 (W6), and 9 d (W9) at anthesis. Increasing waterlogging duration significantly reduced flag leaf SPAD (soil plant analysis development) values and net photosynthetic rate (Pn). There was a linear reduction in flag leaf Pn and SPAD as plant growth progressed under all treatments; however, the speed of damage was greater in the waterlogged leaves. For example, compared with their respective control (W0), flag leaves of W9 treatment have experienced 46% more reduction in Pn at 21 d after anthesis (DAA) than at 7 DAA. Increasing waterlogging duration also induced oxidative damage in flag leaves, measured as malondialdehyde (MDA) contents. The capacity to overcome this oxidative damage was limited by the poor performance of antioxidant enzymes in wheat leaves. Inhibited leaf Pn and capacity to sustain assimilate synthesis under waterlogged environments reduced grain development. Compared with W0, W6 and W9 plants experienced a 20 and 22% reduction in thousand grain weight (TGW) in response to W6 and W9, respectively at 7 DAA and 11 and 19%, respectively at 28 DAA. Sustained waterlogging also significantly reduced grain number per spike and final grain yield. Averaged across two years of study, W9 plants produced 28% lesser final grain yield than W0 plants. Our study suggested that wheat crops are highly sensitive to soil waterlogging during reproductive and grain filling phases due to their poor capacity to recover from oxidative injury to photosynthesis. Management strategies such as planting time, fertilization and genotype selection should be considered for the areas experiencing frequent waterlogging problems.

GWAS in a Collection of Bulgarian Old and Modern Bread Wheat Accessions Uncovers Novel Genomic Loci for Grain Protein Content and Thousand Kernel Weight

“…The effects of these patterns of drought (timing and severity) explain well the significantly higher mean TKW value obtained in 2021 than those in 2017. The considerably lower mean TKW recorded in 2014 is consistent with research showing that prolonged soil wetness after anthesis restricts the amount of assimilates available to growing grains, hence diminishing the development of grain yield [45]. The observed variance in the protein content in the collection under study may potentially be explained by the precipitation oscillations among the three crop seasons.…”

Photosynthetic adaptation mechanisms of waterlogged wheat (Triticum aestivum) at flowering under exogenous nitric oxide donor application

“…However, in this study, the photosynthetic performance did not fully recover on the 16th day for all water treatments and cultivars compared to the 8th day (Figures 2, 3, S1). This incomplete recovery of photosynthetic potential might be caused by leaf senescence after flowering, especially for the waterlogged wheat plants (Hossain et al, 2011; Ma et al, 2022b). In addition, cultivar YM15 showed a smaller decrease in photosynthetic performance on the 8th day after flowering, 1000‐kernel weight and yield in the WL treatment compared to cultivar YM24 when compared with their respective CK treatments (Figures 2A, S1A; Tables 2, 3).…”

“…A decrease in the actual photochemical efficiency (Φ PSII ) of photosystem II in wheat plants compared to conventional water management has been observed during waterlogging (Ma et al, 2022b).…”

“…A decrease in the actual photochemical efficiency ( Φ PSII ) of photosystem II in wheat plants compared to conventional water management has been observed during waterlogging (Ma et al, 2022b). Several studies have also demonstrated that photochemical efficiencies are reduced in stressed plants as P n decreases (He et al, 2014; Yi et al, 2016).…”

Integrated physiological, transcriptomic and metabolomic analyses reveal the mechanism of peanut kernel weight reduction under waterlogging stress

“…Melatonin also triggers ethylene production and alleviates growth inhibition induced by WS in Alfalfa plants (Zhang et al, 2019). In summary, plant hormones play crucial roles in seed development and previous studies have reported that WS leads to the upregulation of genes such as ACO, ACS , and TDC in plants (Ma, Hou, et al, 2022; Nguyen et al, 2018) that promotes an increase in melatonin or ethylene content to enhance WS tolerance. However, research has found that under WS, the starch synthases SUS and AGPase are inhibited by increasing ethylene content in the wheat endosperm and restricted kernel development (Kuanar et al, 2019).…”