Shading tolerance in rice is related to better light harvesting and use efficiency and grain filling rate during grain filling period

Published Date

15 August 2015, Vol.180:54–62, doi:10.1016/j.fcr.2015.05.010

Title 

Shading tolerance in rice is related to better light harvesting and use efficiency and grain filling rate during grain filling period

• Author 

• Li Wang ^1,
• Fei Deng ^1,
• Wan-Jun Ren ^,

• Key Laboratory of Crop Ecophysiology and Farming System in Southwest China, Ministry of Agriculture, Sichuan Agricultural University, Chengdu 611130, Sichuan, China

Received 24 March 2015. Revised 11 May 2015. Accepted 15 May 2015. Available online 5 June 2015.

Highlights

• •
  Shading stress and variety affected photosynthetic characters and yield of rice.
• •
  Chl contents in rice increased, while Pn, ETR, PAR_sat, and J_max decreased.
• •
  IIyou can be selected as a shade-tolerant variety in low-light regions.

Abstract

Low radiation caused by industrial development and environment change has become a limitation in crop production in China. Field experiments were conducted to investigate the effect of shading stress on photosynthetic and chlorophyll fluorescence characters, as well as grain yield and yield components of rice from 2010 to 2012, in Sichuan, China. Rice cv. IIyou 498, Gangyou 188, Dexiang 4103, Gangyou 527, and Chuanxiang 9838 were selected and shaded during grain filling period, which resulted in 53% shading environment (achieved with white cloth above the rice canopy). Shading increased the flag leaf chlorophyll (Chl) content and maximum efficiency of PSII photochemistry under dark-adaption (F_v/F_m), but decreased the net photosynthetic rate, electron transport rate (ETR), saturation irradiance (PAR_sat), and maximum electron transport (J_max), which resulted in a sharply falling grain yield mainly due to reduced spikelet filling and grain weight. The shading tolerances were different in different rice varieties. Maximum net photosynthetic rate (P_max), light saturation point (LSP), quantum yield of PSII (ΦPSII), and photochemical quenching (qP) of Gangyou 188 were reduced under shading. However, IIyou 498 had its adaptive capacity to shading enhanced by increasing the Chl content to improve light-harvesting potential as well as increased P_max, LSP, F_v/F_m, and ΦPSII. In addition, there was reduced non-photochemical quenching (NPQ), while maintaining a more stable ETR, PAR_sat, and J_max to enhance light-use efficiency and reduce the dissipation of light energy, which relieved damage to spikelet filling and resulted in a smaller reduction in grain yield of IIyou 498. Therefore, the improvement in light-harvesting and -use capability and increased spikelet filling under shading stress might be important characteristics for plant breeders. For example, IIyou 498 can be selected as a shade-tolerant variety.

Keywords

• Rice
• Shading
• Yield
• Chlorophyll fluorescence characters
• Photosynthesis

Abbreviations

• AQE, apparent quantum yield
• Chl, chlorophyll
• ETR, electron transport rate
• F_v/F_m, maximum efficiency of PSII photochemistry under dark-adaption
• J_max, maximum electron transport
• LCP, light compensation point
• LSP, light saturation point
• NPQ, non-photochemical quenching
• PAR_sat, saturation irradiance
• P_max, maximum net photosynthetic rate
• Pn, photosynthetic rate
• qP, photochemical quenching
• ΦPSII, quantum yield of PSII.

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• ⁎ 
  Corresponding author. Tel.: +86 028 86290972; fax: +86 028 86290870.

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