盐生植物胀果甘草和光果甘草对UV-B以及盐胁迫的不同响应

Different Responses of Halophytes Plants Glycyrrhiza inflata Bat. and Glycyrrhiza glabra L. to UV-B Radiation and Salt Stress

盐胁迫及增强的UV-B辐射（280～320 nm）是影响干旱地区植物生长及生存的重要环境因子。在本研究中,研究单独的UV-B辐射和不同浓度盐胁迫及其复合作用对两种甘草属盐生植物（胀果甘草Glycyrrhiza inflata Bat.和光果甘草Glycyrrhiza glabra L.）的种子萌发、幼苗的抗氧化酶活性、丙二醛、脯氨酸、酚类物质含量以及生长相关指标的影响进行了分析。结果表明：UV-B辐射对两种植物的种子萌发都没有显著性影响,但是高盐胁迫的存在明显降低了它们的3种萌发相关参数,而胀果甘草表现出比光果甘草更快的萌发速率;两种甘草属植物除了地上及地下部分的干重外,其根长、株高、地上、地下部分鲜重都明显受高盐胁迫及其与UV-B复合作用的影响而降低。在本研究中所有的胁迫条件下,尤其是UV-B强辐射,都造成了胀果甘草的脂质过氧化,而光果甘草的脂质过氧化仅受到UV-B和高盐复合胁迫的影响。所有的胁迫条件都增加了两种植物的脯氨酸含量,而最高含量出现在两种植物的高盐胁迫组和UV-B处理的胀果甘草组中。不同胁迫处理对两种甘草的抗氧化酶系统有不同的效应,盐胁迫明显提高两种甘草的POD活性及光果甘草的SOD活性,但使光果甘草CAT活性明显降低。所有胁迫条件下植物的花青素及类黄酮类物质含量都得到了提升,而增强的UV-B辐射条件下最明显。从以上结果可以看出,两种甘草的生物量都没有受到胁迫环境的影响,这可能和脯氨酸、酚类物质及抗氧化酶所发挥的保护效应有关。此外,胀果甘草对盐胁迫以及UV-B胁迫的耐受性要高于光果甘草。

In arid area, salt stress and enhanced UV-B radiation（280～320 nm） are the most important environmental factors affecting plant growth and survival. In this study, the individual UV-B radiation, different concentration of salt stress, and interactive effect of UV-B and salt stress on seed germination, antioxidant enzyme activity,malondialdehyde（MDA）, β-proline, phenolics content and the related indexes of seedling growth were investigated in two halophytes plants（G. inflata Bat. and G. glabra L.）. The results showed that UV-B radiation alone had no significant effect on seed germination of the two plants, but the three germination parameters decreased significantly in both species with the treatment of high salt stress, while G. inflata showed faster germination rate than that of G.glabra. Except for the dry weight of the aboveground and underground parts, the root length, plant height, and the fresh weight of two parts all reduced due to the high salt stress and joint effects with UV-B. All those treatments caused serious lipid peroxidation on G. inflata, especially the enhanced UV-B radiation, while that of G. glabra was only affected by combination of UV-B and high salt stress. All the stress conditions increased the proline content of both plants significantly, and the highest content was observed in the group of high salt stress in two species and in the group of UV-B in G. inflata. The effects of different treatments on antioxidant enzymes were different in the two species. Salt stress significantly increased the POD activities of the two Glycyrrhiza species and the SOD activity of G. glabra, but significantly decreased the CAT activity of G. glabra. All the stress conditions had enhanced the content of anthocyanin and flavonoids in plants, but most obviously under the enhanced UV-B radiation environment. From the results obtained at present, the biomass of two species was not influenced by various stresses, which might be related to the protective effects of proline, phenolics and antioxidant enzymes.Moreover, it suggested that G. inflata had higher tolerance to salt stress and UV-B conditions than G. glabra.