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研究狗牙花、红背桂和花叶假连翘叶片的光合作用对盐胁迫的响应,揭示3种幼苗耐盐胁迫的能力,以便为滨海盐土的园林植物选择提供参考。通过利用人工浇盐的方式模拟野外盐环境,测定植物光合指标,并用主成分方法评定各种园林植株的抗盐性。结果表明,随着盐胁迫时间的延长,在0.3%盐浓度胁迫下,3种幼苗的Pn不断下降;狗牙花与花叶假连翘的Gs和Ci不断下降,红背桂先升后降;狗牙花与红背桂的Tr不断下降,花叶假连翘先降后升。在0.6%盐浓度胁迫下,3种幼苗的Pn持续下降;狗牙花的Gs先降后升,红背桂与花叶假连翘下降。狗牙花、花叶假连翘的Ci先降后升,红背桂持续下降;3种幼苗的Tr先降后升。采用主成分分析法对3种植株的光合指标进行综合评价,显示盐浓度胁迫下的3种植物幼苗的光合指标得分为红背桂>狗牙花>花叶假连翘。3种苗木中,红背桂叶片能维持较高的光合活性,更适于盐碱地栽培,而花叶假连翘的耐盐胁迫能力弱。
The responses of photosynthesis to salt stress on the leaves of Baphicacium cuspidatum, Cinnamomum camphora and Ficus microcarpa were studied to reveal the ability of three seedlings to tolerate salt stress in order to provide reference for the selection of garden plants of coastal saline soil. By using artificial salt pouring to simulate the salt environment in the wild, the photosynthetic indexes of plants were determined, and the salt tolerance of various garden plants was evaluated by principal component method. The results showed that with the prolonging of salt stress, the Pn of three seedlings decreased under the stress of 0.3% salt stress. The Gs and Ci of A. fusiformis decreased continuously, ; Trichosanthes flowers and red back Gui Tr declining, floret false forsythia first and then rose. Under the stress of 0.6% salt concentration, the Pn of three seedlings decreased continuously; Cynodon dactylon, crested forsythia’s Ci decreased first and then rose, red-backed Gui continued to decline; Tr of three kinds of seedlings dropped first and then increased. Principal component analysis (PCA) was used to evaluate the photosynthetic characteristics of three plants. The results showed that the photosynthetic indexes of three plant seedlings under salt stress were as follows: Red-backed Gui> Bermudagrass> False-leaved Forsythia. Among the three kinds of seedlings, the red-backed leaves could maintain higher photosynthetic activity, which was more suitable for the cultivation of saline-alkali soil. However, the salt tolerance of Forsythia suspensa was weak.