| Southwest China’s ecological fragile karst areas, rocky desertification is serious,affecting the local plant growth, economic development, the most significantecological factors, ecological restoration is an effective way of governance in KarstAreas, Suitability high karst plants can effectively play Karst ecological restorationutility, karst ecological restoration in the selection of plants, while taking into accountthe economic value and if the carbon sink effect of the karst ecosystem restoration andimprovement of great significance, we choose elderberry widespread karst areas ofGuizhou and Guizhou gold peach silk compare physiological and ecological aspects,the main conclusions are as follows:(1)Non stress-induced Fv/Fm value at0.832±0.004, change the structure andfunction of PS Ⅱ plant under adversity will have different levels of. Studies showthat both Fo, Fm and Fv/Fm were very close; two species of medicinal plants ofFv/Fm ratio of0.80to0.81, were lower than the ratio of non stress conditions. Twospecies of medicinal plants by means of regulating itself has adapted to the Karstrocky desertification area.(2)δ13C value range of different plants in karst areas-30.280‰~-25.546‰,with an average of-28.040‰±1.208‰. The δ13C value of the study of medicinalplants in two-28.42‰and-27.22‰, stable carbon isotope composition of leaf δ13Cvalues may reflect the intrinsic water use efficiency of plants, in general, δ13C valuesmore negative, the more plant water use efficiency low, photosynthesis andtranspiration and environmental and physiological factors diurnal variation of leaves,leaf temperature and photosynthetic rate in addition to no correlation outside, PAR-Pn,PAR-Tr, gs-Pn, T-Tr and gs-Tr have similar morphology positive linear correlation,and have reached a significant level. Drawn in relation Tr-Pn in;Hypericumkouytcheouense water use efficiency is higher than Sambucus williamsii.(3) The inorganic carbon source utilization of plants including inorganic carbonin atmospheric CO2and soil, and is alternately used them for inorganic carbonfixation, so as to improve the plant to inorganic carbon carbon sink capacity. When the plants suffered stress will be shown a series of harm avoidance or tolerancestrategies. And carbonic anhydrase in plant carbon sink has played a great role.Carbonic anhydrase activity of leaf Karst suitable plants increased, hand causestomatal conductance decreases or closed, to prevent further dehydration reducingtranspiration plant; on the one hand the bicarbonate ion in cell into water and CO2.Can directly affect the GS carbonic anhydrase activity hand in this process, also affectthe CO2concentration indirectly impacts GS; on the other hand, bicarbonate intowater vapor on the surface of blade pressure affects the saturation difference. The twoaspects affect the plant transpiration, thereby improving plants to drought resistance.The elder of carbonic anhydrase activity is far greater than the Hypericumkouytcheouense. decreased stomatal conductance elder two medicinal plantscompared to cope better with stress caused by the insufficient supply of CO2.To bettercope with the arid environment in Karst area.(4)Effects of Polyethylene Glycol on photosynthesis elderberry is significantlyless than the impact on the photosynthesis of Hypericum kouytcheouense. This is notonly reflected in the net photosynthetic rate, but also reflected in the original PS lIenergy conversion efficiency, the actual efficiency and photosynthetic electrontransport capacity. Elderberry adaptability to drought stress induced by PEG is acomprehensive reflection of these aspects. On the one hand, in the face of adversityelderberry PEG has a higher carbonic anhydrase activity, carbon anhydrase activitycan be affected by drought in the leaves, add water and carbon dioxide, improving thephotosynthetic rate; hand, under PEG stress on Elderberry photosynthesis inhibitionwas significantly less than in Hypericum kouytcheouense, which makes elderberrythan hypericin in Hypericum kouytcheouense PEG stress photosynthetic rate declineis smaller; Moreover, the smaller the impact of energy conversion efficiency byelderberry PEG, and with a more high electron transfer capability, which makeselderberry under PEG stress can maintain strong photosynthetic capacity. |
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