Approaches on physiological traits of four naturalized Crotalaria congeners in Taiwan

• Main Authors: Chen Chaio-Fen, 陳巧芬
• Other Authors: Wu Shan-Hua
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/30844374493182565807

碩士 === 國立臺灣師範大學 === 生命科學研究所 === 99 === Invasiveness is the ability of alien plants to spread beyond their introduced sites and become established in new locations. It has been shown that invasiveness is usually determined by reproductive, morphological, physiological traits and growth strategies. Previous studies have shown that four introduced Crotalaria spp., Crotalaria zanzibarica Benth, C. pallida Ait. var obovata, C. micans Link, and C. incana L., in Taiwan have siginificant difference in invasiveness. The order of the invasiveness is C. zanzibarica ＞C. pallida＞C. micans＞C. incana. To invegestigate the factors contributing to the invasiveness of the four species, I collected seeds of the four species and germinated them in greenhouse. I approached the invasiveness by comparing seed germination plasticity, seedling relative growth rate, total biomass and biomass allocation of adult plants, and photosynthesis capacity of the four Crotalaria congeners. I proposed following hypotheses to test the relationship between measured traits and invasiveness, species with higher invasiveness：(1) can germinate under wider temperature ranges and soil depth conditions；(2) have higher relative growth rate at seedling stage；(3) have more leaves per plant；(4) accumulate more biomass and allocate more biomass to leaves；(5) grow taller, and (6) have higher maximum photosynthetic rate per unit leaf area. The results showed that the trend of the seed germination traits, the seedling relative growth rate, and leaf photosynthetic traits of the four species were not consistent with their invasiveness of the four species. Among the traits invegestigated, the total biomass accumulated, leaf biomass and total leaf area, in plants of three month old were the best indicators of the invasiveness. The results support the hypotheses (3) and (4). Accordingly, I concluded whole plant biomass and leaf biomass were the most important factors contributing to these congeners’ invasiveness.