转PEPC基因水稻种质的稳定光合生理特性

本文运用稳定和放射性碳同位素研究了第8代转PEPC基因水稻，并测定其光合速率和荧光特性，结果表明该种质为C₃植物，但C₄原初光合产物增多，表现出C₄光合特性有所改善；转PEPC基因水稻种质已稳定，为我国的高光效育种提供了一个新的种质资源。

The Stable Photosynthetic Characteristics of a PEPC Transgenic Rice Germplasm

The eighth generation of PEPC transgenic rice and an untransformed rice cultivar (Oryza sativa L. subsp. japonica cv. Kitaake) were need to study photosynthetic rate and chlorophyll fluorescence parameters by applying the stable and radioactive carbon isotope. The results showed that the germplasm of PEPC transgenic rice was a C₃ plant with certain C₄ photosynthetic characteristics.The light saturation photosynthetic rate of transgenic rice was higher than that of untransformed rice. In the treatment with high light intensity (3 h) and methyl viologen (MV), a photooxidative reagent, the PSⅡ photochemical efficiency (F_v/F_m) and photochemical quenching (q_P) of transgenic PEPC rice were decreased less, while the non-photochemical quenching (qN) were increased more as comparison with those of untransformed rice. The higher activities of antioxidative enzymes superoxide dismutase (SOD) and peroxidase (POD) in transgenic rice plants led to a lesser accumulation of endogenous active oxygen (O₂^．- , H₂O₂). As a result, the malondialdehyde (MDA, a product of membrane-lipid oxidation) content was reduced. Compared with the previous generations, the germplasm of PEPC transgenic rice has been steady in genetic, which may become a new germplasm resource in the breeding for high photosynthetic efficiency.