Document Type: Research Paper
Key Laboratory of Crop Ecophysiology and Farming System in Southwest China, Ministry of Agriculture, Sichuan Agricultural University, Chengdu 611130, China
Mianyang Institute of Agricultural Sciences, Mianyang 621023, China.
Key Laboratory of Crop Ecophysiology and Farming System in Southwest China, Ministry of Agriculture, Sichuan Agricultural University, Chengdu 611130, China.
The measurement of carbon isotope discrimination (∆) provides an integrated insight into the
response of plants to environmental change. To investigate the potential use of ∆ for identifying
shade tolerance in rice, five rice varieties were selected and artificially shaded (53% light
reduction) during the grain-filling period in 2010 and 2011, in Sichuan, China. Shading
treatment had a significant influence on the ∆ of rice organs, resulting in clear increases in the ∆
of stems plus sheaths (∆Sm), rice grains (∆Gm) and rice flour (∆Fm) at maturity, but a reduction
in the ∆ of leaves (∆Lg) at the grain-filling stage. The relationships between ∆ and leaf
photosynthetic and chlorophyll fluorescence characteristics and grain yield showed a close
dependence on plant organs and light regimes. Under shading treatment, photosynthetic rate
was negatively associated with ∆Gm and the ∆ of stems plus sheaths at the grain-filling stage
(∆Sg), whereas ∆Sm was significantly (PPSII (PSII), photochemical quenching (qP) and non-photochemical quenching (NPQ).
Moreover, grain filling and grain weight under shading treatment were positively correlated
g, but negatively related to ∆Sm in 2011. In contrast, a significantly (Passociation between grain weight and ∆Lg was observed in 2010. It was found that lower values
g, ∆Sm and ∆Gm in rice indicated better light-harvesting and light-use capability and also
higher grain filling and grain weight of rice.