摘要
对青藏高原东缘高寒草甸山地12科59种主要植物进行光合测定,并结合对不同坡向植物群落的样方调查,分析了各种植物之间以及不同功能群之间的净光合速率、气孔导度、蒸腾速率和水分利用效率等光合参数的差异。结果表明:1)合作地区高寒草甸山地主要物种在净光合速率(Pn)、气孔导度(Tr)、蒸腾速率(Gs)和水分利用效率(WUE)4个光合特性参数上的差异显著,表明各植物种以各自独特的方式适应高寒草甸山地环境;在功能群(莎草、禾草、豆科及杂草)水平上,各功能群之间的差异亦显著。光合速率从大到小依次为禾草>莎草>豆科>杂草,水分利用效率则是莎草>禾草>豆科>杂草;蒸腾速率除了禾草相对较高外,其他三个功能群变化不大;气孔导度则是莎草与禾草均低于豆科与杂草。2)坡向梯度上植物群落组成发生明显变化,阳坡主要组成物种为莎草和禾草;而阴坡则主要由杂草组成,豆科的相对多度在半阴坡、半阳坡达到最大。在蒸腾速率变化不大的情况下,莎草与禾草的水分利用效率明显高于豆科与杂草。因此,在高寒草甸保护和退化恢复过程中,所选出的高光效、高水分利用效率的植物种在当地植被恢复与重建过程中有很高利用价值。图3,表2,参21。
Photosynthetic characteristics of 59 species （12 families） was determined in an atpine meadow on the Qinghai-Tibetan Plat- eau of China. We investigated quadrats of plant community at different slope gradients. We also measured the photosynthetic parameters such as net photosynthesis rate （Pn） , transpiration rate （ Tr） , stomatal conductance （ G~ ） and water use efficiency （WUE） in differ- ent plant and functional groups. The results showed that the photosynthetic traits were different among species and functional groups （p 〈 0.05 ） . Various plant species adapted to mountain environment in their own ways. The Pn values of functional groups was in the or- der of grasses 〉 sedges 〉 legumes 〉 forbs while WUE was in the order of sedges 〉 grasses 〉 legumes 〉 forbs. Tr had no change between functional groups except for grasses. G^in grasses and sedges were lower than legumes or forbs. Species composition of the plant commu- nity had been changed at slope aspect gradients. The south-facing slope was dominated by sedges and grasses but the north-facing slope was dominated by forbs. Relative abundance of legumes was higher at the southwestern and northwestern slope. WUE in sedges and gras- ses was higher than any other functional groups, in which Tr had little change. Plant species with high photosynthetic efficiency and high water use efficiency are valuable to vegetation protection and restoration.
出处
《土壤与作物》
2015年第3期104-112,共9页
Soils and Crops
基金
国家自然科学基金(31360114)资助
关键词
光合作用
物种组成
水分利用效率
生境
高寒草甸
photosynthesis
species composition
water use efficiency
habitat
alpine meadow
