UV-B辐射增强对长白山五种藓类植物生长的影响

Effects of enhanced UV-B radiation on the growth of five bryophytes in Changbai Mountains

对生长在中国长白山的5种藓类植物——垂枝藓、拟垂枝藓、塔藓、星塔藓和高山金发藓分别以辐射强度为0.2(自然光照,对照)、3.0(紫外线中等辐射强度)和6.0kJ.m-2.d-1(高剂量辐射强度)的UV-B照射40d后,测定其株高、生物量及叶绿素含量.结果表明:中等和高强度的UV-B辐射使拟垂枝藓和塔藓的株高、生物量和叶绿素含量分别下降了32.3%、62.4%、81.3%和21.4%、59.4%、62.8%,其相对生长速率均为负值;高剂量UV-B辐射处理下垂枝藓的生物量稍有上升,而高山金发藓地下部分的生物量增加1倍,但叶绿素含量变化不明显.高山金发藓和垂枝藓抵抗UV-B辐射的能力较强,拟垂枝藓和塔藓对UV-B辐射较敏感.

Five bryophytes （ Rhytidium-rugosum, Rhytidiadelphus triquetrus, Hylocomium splen- dens, Hylocomium pyrenaicum, and Polytrichum alpinum ） were exposed to 0. 2 kJ·m^-2·d^-1 （ visible light under native condition, CK）, 3.0 kJ ·m^-2·d^-1（ simulated dose of UV-B irradiance at the tundra in Changbai Mountains, medium dose of UV-B irradiance, T1） , and 6.0 kJ ·m^-2·d^-1（high dose of UV-B irradianee, T2 ） to investigate the effects of enhanced UV-B radiation on plant height, biomass, and chlorophyll content. The results indicated that medium and high UV-B radiations decreased the plant height, biomass, and chlorophyll content of R. triquetrus and H. splendens by 32. 3% , 62.4% , and 81.3% , and 21.4% , 59.4% , and 62. 8% , respectively, and the relative growth rates were negative. Enhanced UV-B radiations had less effect on P. alpinum chlorophyll content but doubled its below-ground biomass, and slightly increased the biomass of R. rugosum. P. alpinum and R. rugosum had higher tolerance against UV-B radiation, while R. triquetrus and 14. splendens were more sensitive to UV-B radiation.