Differential effect of whole-ear shading after heading on the physiology, biochemistry and yield index of stay-green and non-stay-green wheat genotypes

PLoS One. 2017 Feb 3;12(2):e0171589. doi: 10.1371/journal.pone.0171589. eCollection 2017.

Abstract

Two winter wheat cultivars (the functional stay-green CN12 and non-stay-green CN19) were used to investigate the effects of ear-shading on grain yield and to elucidate the differential mechanisms of different cultivars. The photosynthetic parameters, chlorophyll fluorescence, antioxidant enzyme activities, and chlorophyll contents were measured 0, 15 and 30 days after heading (DAH) under both shaded and non-shaded conditions. The final grain-yield index was also measured. Shading had a smaller effect on the net photosynthetic rate (Pn), intercellular CO2 concentration (Ci), stomatal conductance (Gs), maximal photochemical efficiency of PSII (Fv/Fm) and coefficient of non-photochemical fluorescence quenching (qN) but a greater effect on both superoxide dismutase (SOD) and catalase (CAT) activities in CN12 than it did in CN19. Shading slightly altered the timeframe of leaf senescence in CN12 and may have accelerated leaf senescence in CN19. Moreover, shading had only a small effect on the weight of grains per spike (WGS) in CN12 compared with CN19, mainly resulting from the number of grains per spike (NGS) rather than the 1000-grain weight (SGW). In conclusion, the flag leaves of functional stay-green wheat could serve as potential "buffers" and/or "compensators" for ear photosynthesis, which is actively regulated by the antioxidant enzyme system and prevents yield loss. Thus, a functional stay-green genotype could be more tolerant to environmental stress than a non-stay-green genotype.

MeSH terms

  • Carbon Dioxide / metabolism
  • Catalase / genetics
  • Catalase / metabolism
  • Edible Grain / genetics
  • Edible Grain / metabolism
  • Edible Grain / physiology
  • Genotype
  • Photosynthesis / genetics
  • Photosynthesis / physiology
  • Plant Leaves / genetics
  • Plant Leaves / metabolism
  • Plant Leaves / physiology
  • Plant Stomata / genetics
  • Plant Stomata / metabolism
  • Plant Stomata / physiology
  • Superoxide Dismutase / genetics
  • Superoxide Dismutase / metabolism
  • Triticum / genetics
  • Triticum / metabolism*
  • Triticum / physiology

Substances

  • Carbon Dioxide
  • Catalase
  • Superoxide Dismutase

Grants and funding

This work was supported by the National Natural Science Foundation of China (31271721 and 31571661), the Committee of Science and Technology of Fuling of Chongqing (FLKJ-2015ABB1048) and Chongqing Industry and Trade Polytechnic (ZR201507). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.