植物生态学报 ›› 2015, Vol. 39 ›› Issue (4): 343-351.DOI: 10.17521/cjpe.2015.0033

所属专题: 青藏高原植物生态学:群落生态学

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甘南亚高山草甸围封地群落演替及植物光合生理特征

陈世伟, 刘旻霞*(), 贾芸, 安琪, 安嫣菲   

  1. 西北师范大学地理与环境科学学院, 兰州 730070
  • 收稿日期:2014-07-07 接受日期:2015-01-28 出版日期:2015-04-01 发布日期:2015-04-21
  • 通讯作者: 刘旻霞
  • 作者简介:

    # 共同第一作者

  • 基金资助:
    国家自然科学基金(31360114)

Community succession and photosynthetic physiological characteristics of pasture plants in a sub-alpine meadow in Gannan, China

CHEN Shi-Wei, LIU Min-Xia*(), JIA Yun, AN Qi, AN Yan-Fei   

  1. College of Geography and Environmental Science, Northwest Normal University, Lanzhou 730070, China
  • Received:2014-07-07 Accepted:2015-01-28 Online:2015-04-01 Published:2015-04-21
  • Contact: Min-Xia LIU
  • About author:

    # Co-first authors

摘要:

为了解甘南亚高山草甸围封地恢复演替动态, 探究围封恢复进程中植物光合生理特征的变化规律及其影响因子, 对围封试验地内5个典型群落样地进行样方调查, 测定了各群落优势种及3个共有种的光合参数和叶性状参数, 并测定了群落表层土壤(0-20 cm)的水分含量及全氮含量。结果显示: 该围封地内形成一个以草本植物→半灌木→灌木的演替序列, 群落表层土壤含水量及全氮含量随着演替的进行逐渐增加; 在演替的时间尺度上, 各演替阶段优势种光合生理特征间存在明显差异, 随着演替的进行, 群落优势种的净光合速率(Aarea)、光合水分利用效率(WUE)、相对叶绿素含量(SPAD)呈降低趋势, 其叶片氮含量(Nmass)、光合氮利用效率(PNUE)、比叶面积(SLA)随演替变化没有严格一致的规律, 而更多地表现为不同植物功能型之间的差异; 从演替前期到后期, 同种植物的AareaSPAD值逐渐降低, 非豆科植物披碱草(Elymus dahuricus)、老鹳草(Geranium wilfordii)的PNUEWUE随演替进行呈降低趋势, 其NmassSLA随演替进行却呈增加趋势, 然而豆科植物紫苜蓿(Medicago sativa)由于具有固氮能力, 受养分限制不明显, 这些光合生理特征值没有随演替发生明显的变化。这些结果表明, 在恢复演替过程中, 该围封地由一个物质获得能力强的群落向物质保持能力强的群落过渡, 土壤水分含量及全氮含量是推动这种过渡发生的主要因子。掌握围封地群落演替过程中的光合生理动态对于亚高寒退化草甸恢复具有一定的理论指导意义。

关键词: 功能群, 光合生理特征, 恢复, 演替, 资源利用效率

Abstract: <i>Aims</i>

A plant’s photosynthetic characteristics reflect its adaptive strategies to a given environment. Using pasture plants within enclosures representing communities at different stages of habitat restoration, our objective was to determine how photosynthetic characteristics vary between these different communities and what causes these differences in order to find the theoretical basis to foster rehabilitation of degraded grassland in sub-alpine meadows.

<i>Methods</i>

We predicated a succession sequence according to the species richness and the Shannon-Wiener diversity indices, the important values of the main species, and the biotype of five different communities. We measured several photosynthetic parameters including area-based leaf CO2 assimilation rate (Aarea), special leaf area (SLA), foliar nitrogen content based on mass (Nmass), photosynthetic nitrogen-use efficiency (PNUE), water-use efficiency (WUE) and chlorophyll content (SPAD) of dominant species and three common species in each succession stage. Soil water content and total nitrogen of surface soil (0-20 cm) for each community were measured as well. One-way ANOVA was used to find the differences between dominant species, while principal components analysis (PCA) was used to reveal the variation in different communities for each measured parameter.

<i>Important findings</i>

Photosynthetic traits were different among dominant species and different succession communities. The Aarea, WUE and SPAD of the dominant species decreased as succession progressed, but the Nmass, PNUE and SLA showed no consistent patterns related to succession; they varied between different functional groups. For each of the non-dominant species, the Aarea and SPAD gradually decreased as succession proceeded from initial stage to climax stage. With succession, WUE and PNUE of the non-leguminous plants (Elymus dahuricus and Geranium wilfordii) decreased while SLA and Nmass increased. However, there were no obvious changes in these parameters for the leguminous plant (Medicago sativa). Soil water content and total nitrogen increased with succession, suggesting that water content and nitrogen are two important factors affecting variation of community photosynthetic characteristics in different stages of restoration succession.

Key words: functional group, photosynthetic physiological characteristics, restoration, succession, resource-use efficiency