Studies On Physiological And Morphological Adaptations As Well As Flowering Phenology Of Fagopyrum Dibotrys (D.Don) Hara Under Simulated Stress Conditions

Fagopyrum dibotrys (D.Don) Hara, a perennial herb of Fagopyrum Mill, in Polygonaceae, is recorded as the National Important Wild Conservative Plants in China. Its root contains many useful medicinal components. In this paper, we studied on physiological and morphological adaptations, the flowering phenology as well as and root medicinal components of Fagopyrum dibotrys under simulated stress conditions with acid rain, alkaline-salt and drought. We further put forward some suggestion for the conservation and exploiting of the species. The results show as followings:1) The one-way ANOVA shows that the differences of physiological characters of Fagopyrum dibotrys among 4 different simulated conditions with acid rain are not significant within short time. POD is the main membrane conservation enzyme before restoration, and SOD is that after restoration. The main function of the species is propagating and accumulating medicinal components during late period, and photosynthesis becomes weaker. The influences of acid rain on leaves number, basal stem diameter and 1 st-leaf length/width are significant. Because of the acid rain on the leaves, the leaves are easily falling off. Leaves number, young bud and basal stem diameter are affected by acid rain slightly, but they can grow normally after restoration. Caulis length, caulis node number and leaves length/width are not affected by acid rain. It shows that Fagopyrum dibotrys has strong capacity of adaptation to the simulated conditions with acid rain.2) The one-way ANOVA further shows that the differences of physiological characters of Fagopyrum dibotrys among 4 different alkaline-salt conditions are not notable within short time. POD is the main membrane conservation enzyme before restoration, and SOD is that after restoration. Fagopyrum dibotrys still contain many hydrogen peroxide, leaves become dying, and its photosynthesis is also affected duringrestore period. The differences of basal stem diameter and 3rd-leaf length/width are significant. Low concentration alkaline-salt conditions can't affect it greatly, but high concentration alkaline-salt conditions (higher than 0.5%) can affect it greatly and causing dying of the plants. It shows that Fagopyrum dibotrys can't adapt to the alkaline-salt conditions, especially high alkaline-salt conditions.3) The differences of SOD activity are significant before restoration. The function of SOD activity and POD activity is reciprocal. The plants become dry, and their photosynthesis function has been affected greatly under drought conditions. The differences of caulis length, 2nd-leaf length/width and 3rd-leaf length/width are significant mostly before restoration. Leaves number, young bud and basal stem diameter are affected, but caulis length and caulis node number are not affected. It shows that Fagopyrum dibotrys has certain capacity of adaptation to the drought conditions in short time.4) During the whole experiment period there are two flowering periods, i.e., the first ten days of June and from the last ten days of September to the first ten days of November. It shows that the flowering period of Fagopyrum dibotrys change ahead to June under the simulated stress conditions. The energy supplies for flowering has been spent partly ahead of the normal flowering period, while it can't blossom completely comparing with the normal conditions during the 2nd flowering period. The differences of flowering phenology is significant under simulated conditions,. Though Fagopyrum dibotrys can blossom more or less normally under the simulated conditions with acid rain, it doesn't blossom under higher concentration of alkaline-salt conditions. The differences of flowering phenology are not significant under the drought conditions. Short flowering time and higher mean flowering amplitude can guarantee the success of flowering of Fagopyrum dibotrys under the normal conditions.5) Low concentration of acid rain can seemingly accelerate the accumulation of the root medicinal components, which reveals that the Fagopyrum dibotrys has certain capacity of adaptation to the simulated conditions with acid rain. The differences of root medicinal components are significant under alkaline-salt conditions. High concentration of alkaline-salt can cause many soluble sugars storage in plants. Then those soluble sugars become medicinal components after restoration. But the total medicinal components content is not high. In terms of the contents of the total medicinalcomponents, alkaline-salt condition is not good for accumulating root medicinal components. Lower concentration of PEG can accelerate accumulating of root medicinal components under drought conditions, while higher concentration of PEG is not good for the accumulation of root medicinal component.6) Following procedures should be taken into consideration when conservation of this species is taken. Firstly, pay more attention to conserve medicinal plants resource and control excavating of Fagopyrum dibotrys. Secondly, consider the factors including acid rain, alkaline-salt, drought and so on, when ex-situs conservation of this species is taken. Thirdly, set up Fagopyrum dibotrys miniature conservation area.