封育与施肥对高寒草甸4种优势植物叶绿素荧光特征的影响

为探寻更加合理的草地管理方式,以甘肃省夏河县桑科乡高寒草甸优势植物垂穗披碱草(Elymus nutans)、赖草(Leymus secalinus)、野胡萝卜(Daucus carota)、香薷(Elsholtzia ciliata)为材料,设置封育(non-grazing)、放牧(grazing)、放牧+施肥(grazing+fertilizing) 3个处理对其叶绿素荧光特征进行研究.结果表明:垂穗披碱草、赖草的最大量子产量(Fv/Fm)差异显著,光化学猝灭系数(qL, qP)施肥处理最大,非光化学猝灭(NPQ)和非光化学猝灭系数(qN)放牧处理最大.野胡萝卜和香薷的最大光合潜力对放牧干扰不敏感,且在放牧处理下光保护作用最强,垂穗披碱草和赖草在放牧状态下,最大光合潜力受到明显抑制,光保护作用受到破坏.表明施肥处理植被光合能力最强,封育处理次之.封育处理能显著提高禾草的光合能力,抑制杂类草;施肥处理杂类草光和能力的提高大于禾草.

Effects of Enclosure and Fertilization on the Chlorophyll Fluorescence Characteristics of Four Dominant Plants in Alpine Meadow

In order to explore the rational way of grassland management, Four dominant plants, including Elymus nutans, Leymus secalinus, Daucus carota and Elsholtzia ciliata in alpine meadow in the Xiahe County of Gansu Province, were selected to study the fluorescence characteristics of chlorophyll under three treatments of Non-grazing, grazing and grazing+fertilizing. The results showed that Fv/Fm value significantly differed between Elymus nutans and L. secalinus. The qL and qP parameters of four species were the highest under fertilizing treatment. And NPQ and qN were the highest under grazing treatment. The maximum photosynthetic potential of D. carota and Elsholtzia ciliata was not sensitive to grazing and their photoprotection was the strongest under grazing treatment, whereas that of Elymus nutans and Leymus secalinus was significantly inhibited and the photoprotection was damaged. From the standpoint of integrated consideration, the photosythetic ability of community treated with fertilization was the highest; following by enclosure treatment. The enclosure treatment significantly increased the photosythetic abilities of grasses and inhibited that of forbs. The fertilizing treatment greatly increased the photosythetic abilities of forbs than that of grasses.