Dai Zhi-Cong, Fu Wei, Qi Shan-Shan, Zhai De-Li, Chen Si-Chong, Wan Ling-Yun, Huang Ping, Du Dao-Lin
Jingjiang College, Jiangsu University, Zhenjiang, 212013, China.
Institute of Environment and Ecology, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, 212013, China.
J Chem Ecol. 2016 Feb;42(2):85-94. doi: 10.1007/s10886-016-0670-6. Epub 2016 Feb 15.
The invasive clonal plant Wedelia trilobata contains higher levels of ent-kaurane diterpenes, which are precursors of gibberellins (GAs), and higher rates of clonal growth than its native congener W. chinensis in invaded habitats. We hypothesized that the higher levels of endogenous GAs facilitate greater ramet growth in W. trilobata compared with W. chinensis. We quantified endogenous levels of GA1+3 in the two species and compared their growth responses to the changes of endogenous and exogenous GA3 by using short-term and long-term hydroponics experiments. After a period of homogeneous cultivation, levels of endogenous GA1+3 were higher in W. trilobata than in W. chinensis. The reduction of endogenous GAs repressed the emergence of adventitious roots and the growth of W. trilobata in the initial cultivation stage, and inhibited its shoot elongation and biomass. Levels of endogenous GA1+3 were positively correlated with the length of shoots and adventitious roots of W. trilobata. Adventitious roots of W. trilobata also emerged earlier and grew faster when treated with exogenous GA3. In contrast, exogenous GA3 treatment inhibited the length of adventitious roots in W. chinensis, and levels of endogenous GA1+3 did not correlate with shoot or adventitious root length. Our study suggests that GAs accelerate the rapid clonal growth of W. trilobata, more than that of its native congener W. chinensis, illustrating the relationship between plant hormones and the clonal growth of invasive plants. These findings are important for understanding the mechanisms associated with the invasiveness of clonal plants and their potential management.
入侵克隆植物三裂叶蟛蜞菊所含的贝壳杉烷二萜水平较高，而贝壳杉烷二萜是赤霉素（GAs）的前体，并且在入侵生境中，其克隆生长速率比其本地同属植物中华蟛蜞菊更高。我们推测，与中华蟛蜞菊相比，三裂叶蟛蜞菊中较高水平的内源赤霉素促进了更多分株的生长。我们通过短期和长期水培实验，对这两个物种中GA1+3的内源水平进行了量化，并比较了它们对内源和外源GA3变化的生长反应。经过一段时间的同质培养后，三裂叶蟛蜞菊中内源GA1+3的水平高于中华蟛蜞菊。在初始培养阶段，内源赤霉素的减少抑制了三裂叶蟛蜞菊不定根的出现和生长，并抑制了其地上部分的伸长和生物量。三裂叶蟛蜞菊中内源GA1+3的水平与地上部分和不定根的长度呈正相关。用外源GA3处理时，三裂叶蟛蜞菊的不定根也更早出现且生长更快。相比之下，外源GA3处理抑制了中华蟛蜞菊不定根的长度，并且内源GA1+3的水平与地上部分或不定根的长度没有相关性。我们的研究表明，赤霉素促进三裂叶蟛蜞菊快速克隆生长的作用比其本地同属植物中华蟛蜞菊更强，这说明了植物激素与入侵植物克隆生长之间的关系。这些发现对于理解克隆植物入侵性相关机制及其潜在管理具有重要意义。
