Significance of rice sheath photosynthesis: Yield determination by 14C radio-autography.

Abstract

Using high-yielding hybrid rice Liangyopeijiu (LYP9), its male parent 9311 and hybrid rice Shanyou 63 (SY63) as the experimental materials, the photosynthesis of rice sheath was studied by ¹⁴C radio-autography. The results showed that rice sheath could trap sunlight and produce photosynthates, and these photosynthates were transported mainly to the spikes. The ¹⁴C-labeled photosynthates transported to the spikes of LYP9 and 9311 were significantly more than those of SY63 after 72 hr, which indicated that differences among genotypes existed for contribution rates of sheath photosynthesis to economical yield. Transport of the ¹⁴C-labeled photosynthates to the spikes was faster in the sheaths of LYP9 than in those of 9311and SY63 at 12 and 72 hr after treatment. Hybrid rice housed the heterosis and were influenced by the inheritable characters of its parents. Since photosynthesis of rice sheath is an important supplement to rice yield, inefficient photosynthesis in rice sheaths could cause serious yield reduction.

Key Words: Hybrid rice, photosynthates, spikes