兰州南北两山主要水土保持造林树种荧光特性比较

在兰州南北两山，以自然分布的柽柳（Tamarix chinensis）、柠条（Caragana intermedia）、红砂（Reaumuria soongorica）为研究对象，在生长季利用PAM-2000便携式叶绿素荧光分析仪对其叶绿素荧光参数及其环境因子进行了测定。结果表明:3种植物叶片的初始荧光（Fo）、最大光化学转换效率（Fv/Fm）、光化学淬灭系数（qP）、非光化学淬灭系数（qN）、光合有效辐射（PAR）、叶温（TMP）的日变化较明显。其中Fv/Fm和qP均呈反正态分布曲线日进程，在13:00强光下降低至最低值；Fo，qN，PAR和TMP则呈正态分布曲线日进程，在13:00达到最大值。3种植物的Fv/Fm在中午呈降低趋势，在13:00左右达到的最低值分别为0.778（柽柳），0.676（柠条）和0.65（红砂），表明均发生光抑制现象，但红砂受到的胁迫最大。

Research of Fluorescence Characteristics of Main Afforestation Tree Species for Soil and Water Conservation in Lanzhou Northern and Southern Mountains

The Tamarix chinensis, Caragana intermedia and Reaumuria soongorica naturally distributed in Lanzhou northern and southern mountains were selected as the research objects, a portable Chlorophyll fluorescence analyzer PAM-2000 was used to determine the chlorophyll fluorescence parameters and environmental factors in their growth season. The results showed that the initial fluorescence of three kinds of plant leaves (Fo), maximum photochemical conversion efficiency (Fv/Fm), photochemical quenching coefficient (qP), non-photochemical quenching Ccoefficient (qN), photosynthetically active radiation (PAR), leaf temperature (TMP), diurnal variation were obvious. The processes of Fv/Fm and qP follow the normal distribution curve, anyway, bright light reduces to the minimum at 13:00; the processes of Fo, qN, PAR and TMP follow the normal distribution curve, which reach the maximum at 13:00. The Fv/Fm of three plants shows the trend of lower at noon, reached the lowest at 13:00, which are 0.778 (Tamarix chinensis), 0.676 (Caragana intermedia) and 0.65 (Reaumuria soongorica), respectively, indicating that both the photo inhibition phenomenon, but the stress on Reaumuria soongorica is the greatest.