Shi Sheng-Bo, Shang Yan-Xia, Zhu Peng-Jin, Zhang De-Gang
Ministry of Education Key Laboratory of Grassland Ecosystem/Sino-U. S. Center for Grazingland Ecosystem Sustainability, College of Pratacultural Science, Gansu Agricultural University, Lanzhou 730070, China.
Ying Yong Sheng Tai Xue Bao. 2011 Jan;22(1):53-60.
Taking the main companion species Saussurea superba in an alpine Kobresia humilis meadow on Qinghai-Tibet Plateau as test material, a UV-B exclusion experiment with UV-B excluding and UV-B transmitting filters was performed to study the effects of strong solar UV-B on the photosynthesis, photosynthetic pigments, and UV-B-absorbing compounds of S. superba, aimed to examine the adaptation capability of alpine plants to strong solar UV-B radiation. The removal of UV-B components from natural sunlight increased the net photosynthetic rate (P < 0.05) and PS II photochemistry efficiency of S. superba. The relatively increased leaf thickness under ambient UV-B could compensate the photo-oxidation of photosynthetic pigments, an inherent characteristic of alpine plants growing in intense UV-B. Short-term removal of UV-B radiation had no obvious effects on the UV-B-absorbing compounds, suggesting that these compounds in epidermal layer of S. superba could hardly be affected by the environment. It was concluded that the increase of photosynthetic pigment contents due to the enhancement of leaf thickness was a specious phenomenon, but the strong solar UV-B radiation on Qinghai-Tibet Plateau still had a potential negative impact on the photo-physiological processes in alpine plant S. superba.
以青藏高原高寒矮嵩草草甸主要伴生种羽裂风毛菊为试验材料，利用UV-B阻隔滤光片和UV-B透过滤光片进行UV-B去除试验，研究强太阳UV-B对羽裂风毛菊光合作用、光合色素及UV-B吸收物质的影响，以探讨高山植物对强太阳UV-B辐射的适应能力。去除自然阳光中的UV-B成分后，羽裂风毛菊的净光合速率增加（P<0.05），PS II光化学效率提高。在环境UV-B条件下相对增加的叶片厚度可补偿光合色素的光氧化作用，这是高山植物在强UV-B环境下生长的固有特性。短期去除UV-B辐射对UV-B吸收物质无明显影响，表明羽裂风毛菊表皮层中的这些物质几乎不受环境影响。研究得出结论，叶片厚度增加导致光合色素含量增加是一种假象，但青藏高原强太阳UV-B辐射仍可能对高山植物羽裂风毛菊的光生理过程产生负面影响。
