Contributions of glume and awn to photosynthesis, 14C assimilates and grain weight in wheat ears under drought stress

Xiaorui Li; Yan Tang; Chunju Zhou; Jinyin Lv

doi:10.1016/j.heliyon.2023.e21136

Contributions of glume and awn to photosynthesis, ¹⁴C assimilates and grain weight in wheat ears under drought stress

Heliyon. 2023 Oct 17;9(10):e21136. doi: 10.1016/j.heliyon.2023.e21136. eCollection 2023 Oct.

Authors

Xiaorui Li^{1

2}, Yan Tang², Chunju Zhou², Jinyin Lv²

Affiliations

¹ College of Agronomy, Shanxi Agricultural University, Taigu, 030801, China.
² College of Life Sciences, Northwest A & F University, Yangling, 712100, China.

Abstract

Ear photosynthesis plays a key role in wheat photosynthesis during the grain filling stage, particularly under drought stress. Thus, dissecting the responsibilities of the glume and awn in photosynthetic carbon fixation and assimilates transportation during the grain filling stage in spikes is imperative. In this study, the detachment of the glume (DG) and awn (DA) of a wheat variety (Pubing143) was used to estimate their influences on ear photosynthesis and dry matter distribution. Radioactive carbon-14 (¹⁴C) isotope was detected by a multifunctional liquid scintillation counting system. The accumulation of ¹⁴C assimilates and their contributions to grain weight were then calculated. Under well-watered conditions, ear photosynthesis was reduced by 16.8 % and 46.2 % 25 d after anthesis (DAA) in the de-glumed control (DGC) and de-awned control (DAC) treatments, respectively, compared with the intact ear control (IEC). Under drought stress, ear photosynthesis was reduced by 46 % and 74.2 % at 25 DAA after removing the glume and awn, respectively. Under normal conditions, the number of ¹⁴C assimilates of DGC, and DAC was reduced by 14.6 % and 20.9 % in grains at 25 DAA, respectively, compared with the IEC. Compared with IED, the ¹⁴C assimilates of DGD, and DAD declined by 17.2 % and 27 %, respectively, in grains at 25 DAA under drought conditions. Under well-watered conditions, the grain weight per pot was reduced by 11.2 % and 25.4 % in the de-glumed control (DGC) and de-awned control (DAC) treatments, respectively, compared with the intact ear control (IEC). The grain weight per pot was further reduced after removing the glume and awn (16 % and 32.2 %, respectively) under drought stress. Furthermore, the awn contribution to grain weight was twice that of the glume. Our results suggest that the glume and awn of ears play prominent roles during grain filling in wheat, especially under drought stress, and that the awn is more crucial than the glume.

Keywords: 14C assimilates; Drought stress; Ear photosynthesis; Grain weight; Organ contribution; Wheat.