Abstract:

Activities of several key enzymes of C4 photosynthesis pathway and stable carbon isotope discrimination were investigated in flag leaves of a super high-yield hybrid rice (Oryza sativa L.) cv. Peiai 64S/E32 and a traditional hybrid rice cv. Shanyou 63 at different developing stages. Results show that the activity of PEP carboxylase (PEPCase) increased with age of flag leave; the activity of NADP-malate dehydrogenase (NADP-MDH) increased and reached to a peak value at grain filling stage (68-75 d after transplanting), then fell down; the activity of NADP-MDH in cv. Peiai 64S/E32 was much higher than that in cv. Shanyou 63. Before ripening stage (95 d after transplanting), NADP-malic enzyme activity rose gradually. The level of stable carbon isotope discrimination (D13C) in flag leaves and grains at different developing stages were similar and exhibited a comparative high value at ripening stage. The average D13C in leaf of cv. Peiai 64S/E32 during different developing stages was 0.43‰ more than that in cv. Shanyou 63.

超高产杂交稻剑叶中C ₄ 途径酶活性和稳定碳同位素分异作用的变化
阳成伟 林桂珠 彭长连  陈贻竹 欧志英
(中国科学院华南植物研究所，广州 510650)

摘要： 以超高产杂交水稻(Oryza sativa L.)“培矮64S/E32”和多年来大面积推广的杂交稻“汕优63”为材
料，研究孕穗后剑叶中C₄ 途径酶和对稳定碳同位素分异作用的变化。结果表明，籽粒灌浆期(移栽后68~75 d)的两个品种剑叶中NADP-MDH 活性最高，随后下降；超高产杂交水稻“培矮64S/E32”的NADP-MDH 的活性明显高于“汕优63”；PEPCase 和NADP-ME 活性在黄熟期之前的叶片中持续上升。不同生育期的叶片与籽粒的 D1₃C 值相近（19.49‰~19.82‰），在成熟期时较高。超高产水稻“培矮64S/E32”叶片的平均D₁₃C 值比“汕优63”高0.43‰。
关键词： 超高产水稻；C ₄ 途径酶；稳定碳同位素；剑叶

通讯作者。 E-mail: <pengchl@scib.ac.cn>。