| To reveal the influence of global warming on the tundra plants, the effects of warming on nutrients and secondary metabolites of leaves of three dorminant plants-Vaccinium uliginosum, Rhododendron aureum and Dryas octopetala var. Asiatica and mineral elements in soil were studied using Open-top chambers (OTCs) during growing season. In addition, the optimum extraction methods of three secondary metabolites- phenol, terpene and flavone of leaves were determined. The air temperature, the soil temperatures in 5 cm and 10 cm depth were 1.41℃,1.74℃ and 1.78℃ higher in Open-top chamber than the control plots, respectively. Warming significantly changed carbon and other mineral elements contents in soil. The P contents of leaves of Rhododendron aureum and Vaccinium uliginosum were decreased by 16.26% and increased by 10.34% by wrarming. Warming also obviously changed C:N ratio of leaves of three plant species, and the C:P ratio of Dryas octopetala var. Asiatica. The K content of leaves of Rhododendron aureum was increased by 8.17% by warming and had significantly monthly fluctuation. The Mg and Mn contents were 66.39% and 14.73% higher than those in the control plots. Compared to the control, warming resulted in increased K, Al and Zn contents of Vaccinium uliginosum by 15.24%,5.45% and 15.24%. The secondary metabolite contents of three plant species had significantly monthly change. Warming decreased total phenol contents of Vaccinium uliginosum, Rhododendron aureum and Dryas octopetala var. Asiatica by 3.69%,7.32% and 3.69% respectively. Warming increased the leaf flavonoids contents of Rhododendron aureum, but not for Vaccinium uliginosum and Dryas octopetala var. Asiatica. Therefore, warming stimulated the limitation of P element for plant growth in Changbai Mountain tundra, and reduced the contents of secondary metabolites of dormniant plants, which indicating that plants will allocate more on growth than defense. |
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