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    薹草的耐阴性研究及园林适用环境分析

    Evaluation of shade tolerance of Carex species available for garden-environment planting

    • 摘要: 以吉祥草作参照,对条穗薹草、仲氏薹草、栗褐薹草和三穗薹草进行遮光梯度为0、50%、75%、90%的遮光处理后,测定5种植物的叶宽、叶长、叶绿素a+b、叶绿素a/b、光--光响应曲线和叶绿素荧光特性值。结果表明:随遮光度增加,5种植物的叶宽无显著变化,叶长、叶绿素a+b含量、Fv/Fm、Fv/F0和Fv′/Fm′增加,叶绿素a/b、光补偿点和qN降低;仲氏薹草和三穗薹草的叶绿素a+b含量在遮光75%下达到最高,叶绿素a/b分别在遮光75%、50%下达到最低;栗褐薹草、仲氏薹草和三穗薹草的光饱和点在遮光50%下最大,条穗薹草和吉祥草分别在遮光0和75%下最大。综合分析表明:5种植物的耐阴能力由强到弱依次为栗褐薹草、吉祥草、条穗薹草、三穗薹草、仲氏薹草;条穗薹草和栗褐薹草对光照的适应范围较宽,而吉祥草、仲氏薹草和三穗薹草较窄。结合野外生境调查结果表明:条穗薹草适宜在水库边、河道旁的死水区和水位变化区等生态环境下栽种;栗褐薹草可用于林下、建筑北侧、桥梁下空地等荫蔽性较强处栽种;三穗薹草和仲氏薹草则因耐阴性弱,适宜于在常绿阔叶林林缘、路边坑边草丛中、山坡灌丛等环境下栽种。

       

      Abstract: The grass species, Carex nemostachys, C. chungii, C. brunnea and C. tristachya, were selected to investigate their shade-tolerance, with Reineckia carnea as control.Their morphological and physiological characteristics, i.e. lengths and widths of leaves, chlorophyll content (Chl a+b), the chlorophyll a/b ratio (Chl a/b), photosynthetic light-response curves and chlorophyll fluorescence, were investigated. There were no significant differences in leaf width when the degree of shade ranged from 0 to 90%; leaf length, Chl a+b, Fv/Fm,Fv/F0 and Fv′/Fm′ increased; but Chl a/b, the light compensation point (LCP) and qN decreased. The maximum Chl a+b occurred in C. chungii and C. tristachya under 75% shade, while the minimum Chl a/b occurred in C.chungii and C. tristachya under 75% and 50% shade, respectively. The maximum light saturation point (LSP) of C. brunnea, C. chungii and C. tristachya occurred under 50% shade, while that of C. nemostachys appeared without any shade. Under 75% shade, R. carnea had the highest LSP. Results indicated that among the five plant species, C. brunnea was the most shade-tolerant, followed by R. carnea, C. nemostachys, C. tristachya and C. chungii. Among these species, C. brunnea and C. nemostachys are better adapted to changes in light intensity than the other three species. Therefore, C. nemostachys should be selected as greening and beautifying species for both stagnant water areas and areas with changing water levels (i.e. reservoirs and rivers). C. brunnea could be used as a greening species under strong shade, such as undergrowth, the north side of buildings and open spaces under bridges. The other two species, C. tristachya and C. chungii are recommended for planting at the margin of evergreen broad-leaved forests, as roadside grasses and with hillside shrubs, due to their weak shade-tolerance.

       

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