<正>用Licor-6400便携式光合作用测定系统测定了陕北吴旗县柠条在年生长季内叶片净光合速率随光照度和CO：浓度的变化规律，并测定了柠餐叶片的蒸腾速率（Tr）和水分利用率（WUE）随光照度的变化规律。结果表明：在年生长季内。柠条叶片光补偿点（LCP）的变动范围为37.4～70.92μmol/（m2·s），光饱和点（LSP）为1324.07～1626.04μmool/（m2·s）。表观光量子效率（φ）为0.00899～0.01476μmmol/mol；柠条叶片的CO2补偿点（CCP）为56.76～126.80μmol/mol,CO2饱和点（CSI’）为1154.60～1828.86μmol/mol。说明柠条为C。植物。不耐荫。应栽植在阳光充足的地方。柠条在年生长季内莓睛速率（Tr）的大小排序为：Tr9月>Tr8月>Tr6月>Tr7月>Tr5月；水分利用率（WUE）高低排序为：WUE5月>WUE7月>WUE8月>WUE6月>WUE9月。

The content of nutrition, storage and distribution of 5-year-old Pinus radiata young forest plantation were studied in arid valley region in the upper reaches of Minjiang River. The results showed that the P. radiata’s growth and content of nutrition and storages varied greath under different site conditions and climates. The contents of nutritions were different in P. radiata with various height of trunk. The element with the highest content in each apparatus was N. The element Fe were rich in the root system of shrub and herb. The contents of nutrition of P. radiata young forest plantation were 310.47kg/hm2, the contents of nutrition in tree layer, shrub layer、 herb layer and litter layer were 52.25%, 15.25%, 30.84% and 1.66% respectively. There was great diversity of nutrient storages in tree layer under different habitats.