摘要
本文以甘肃省河西走廊生长的四个不同生境芦苇为对象,比较研究了它们的叶解剖结构、光合关键酶活力、乙醇酸氧化酶活力和稳定碳同位素组成(δ^(13)C)。结果发现,沼泽芦苇叶中虽具有不典型的花环结构.但维管束鞘细胞中不含叶绿体,RUBPcase活力/PEPcase活力比值为24.4,乙醇酸氧化酶活力为1218Unitmgpro^(-1)·min^(1δ13)C值为-34‰,这些测值位于C_3植物(小麦)的范围内。生长于沙丘上的芦苇叶片具有明显的花环结构,维管束鞘细胞内含异型叶绿体,RUBPcase活力/PEPcase活力比值为0.985,乙醇酸氧化酶活力为504Unitmgpro^(-1)·min^(-1),δ^(13)C值为-20.9‰,这些测值与典型C_4植物(玉米)十分相似。盐化草甸芦苇和盐化草—沙丘过渡地带芦苇叶中均具有明显的花环结构,维管束鞘细胞中含大型叶绿体。RUBPcase活力/PEPcase活力比值分别为2.45和1.53,但乙醇酸氧化酶活力分别为1470和2058Unitmgpro^(-1)·min^(-1),δ^(13)C值分别为35.6和30.6%,综合盐化草甸芦苇和过渡地带芦苇的上述指标,似介于沼泽芦苇和沙丘芦苇之间。由这些结果可以认为,分布于甘肃省河西走廊的芦苇,在种内发生有由环境因子引起的光合碳代谢途径的适应性改变。
Leaf anatomical structure, photosynthetic enzyme activity, glycollate oxidase activity and stable carbon isotopic composition (δ^(13)C) in leaves from different habitat reed distributed over the Hexi corridor of Gansu province were comparatively investigated. The results indicate that the bundle sheath cells of swamp reed do not contain chloroplasts, the ratio of RUBP case activity/ PEP case activity, activity of glycollate oxidase and δ^(13)C value in leaves of swamp reed fall in ranges typical for C_3 photosynthetic plant (wheat). The typical Kranz structure and the bundle sheath cells containning dimorphological chloroplasts were observed in leaves from sand dune reed, the ratio of RUBP case activity/PEP case activity, activity of glycollate oxidase and δ^(13)C value are quite similar to that of typical C_4 photosynthetic plant (Maize). Salt meadow reed and salt-meadow-sand-dune reed compared with swamp, although there are Kranz structure and bundle sheath cells containning chloroplasts in the former leaves, and the ratio of RUBP case activity/PEP case activity in the former leaves are lower than in the latter leaves, activity of glycollate oxidase, especially δ^(13)C values in the former leaves are similar to that of the latter leaves. These results may suggest that, in the Hexi corridor of Gansu province, environmental factors induce an active evolution of the pathway of photosynthetic carbon metabolism within reed species.
基金
国家自然科学基金
关键词
芦苇
光合碳化途径
生态环境
reed
Kranz structure
RUBPcase activity/PEPcase activity
Glycollate oxidase
Stable carbon isotope composition(δ^(13)C)
