树木稳定碳同位素比率的方位差异及其机理初步研究

Preliminary study on direction variabilities of stable carbon isotope ratios and its mechanisms in trees

测定了祁连山一棵千年圆柏不同方位上树木稳定碳同位素比率 (δ13 C值 )和光合作用色素 .结果显示 ,树木中 δ13 C值具有明显的方位差异 :北面的 δ13 C值相对较高 ,西面的 δ13 C值相对较低 .树叶中叶绿素含量、类胡萝卜素含量和类黄酮含量的方位变化趋势与δ13 C值类似 .分析表明 ,后者的方位变化是树木对局部环境的光辐射差异长期适应的结果 ,而树木中δ13

Stable carbon isotope ratios (δ 13C values) and photosynthetic pigments in a 1000 a cypress (Sabina przewalskii) were investigated. The direct variations of δ 13C values were significant,with the highest δ 13C values in the north and the lower δ 13C values in the west.The changes of chlorophyll,carotoniod and flavoniod contents in tree leaves were similar to δ 13C variations.The results indicated that the latter was a long-term adaptation to local differences of light radiation,while the former was attributed to the effect of light radiation on photosynthesis and respiration.