| P. pedatisecta Schott’s tuber is of one of the main sources of traditional Chinese medicine-Arisaema heterophyllum. In recent years, the favor at Chinese medicine of people at home and abroad gradually deepened, P. pedatisecta Schott are in short supply on the market. Simultaneously, because of its over-excavation, the wild P. pedatisecta Schott resources are scarcity, at the same time, with the deteriorating environment, the quality are declined. To promote P. pedatisecta Schott cultivation, improve the stress resistance, especially to improve drought resistance of P. pedatisecta Schott is the first thing to do. P. pedatisecta Schott likes damp and fertile soil, but fear of light. Drought stress is an important restricted factor on P. pedatisecta Schott development. How to improve the drought tolerance of P. pedatisecta Schott, clarify the mechanism of how P. pedatisecta Schott susceptible to drought stress and find a method to improve the drought tolerance of P. pedatisecta Schott become the imperative to the P. pedatisecta Schotts’large-scale, intensive, scientific production.In this paper, we gave the15% PEG-6000to simulate drought stress, researched the morphological index, the contents of leaves’Photosynthetic pigments, superoxide anion, malondialdehyde and osmolytes, the active of superoxide dismutase, peroxidase, catalase and ascorbate peroxidase, the contents of effective medicinal ingredients such as total alkaloids, total flavonoids and total free amino acid of P. pedatisecta Schott under drought Stress by giving exogenous glycinebetaine, ALA and sodium nitroprusside in different contents. Filter out the appropriate concentration of GB, ALA and SNP to ease the drought stress of P. pedatisecta Schott, explore the mechanisms of exogenous glycinebetaine, ALA and sodium nitroprusside on the physiological and biochemical ease of drought stress and compared the effects of this three kinds of exogenous substances, provide a theoretical basis for P. pedatisecta Schott on agricultural cultivation. The elaboration of the results is as follows:1With the drought stress of15%PEG-6000, the leaf area, stem length, biomass of P. pedatisecta Schott reduced significantly, the P. pedatisecta Schott leaf chlorophyll a, chlorophyll b, carotenoids and chlorophyll a/chlorophyll b are reduced. Drought stress also improve P. pedatisecta Schott leaves O2-and MDA content significantly, reduced the activity of SOD, CAT, POD and APX enzyme. P. pedatisecta Schott leaves osmotic adjustment substance such as free proline content increased significantly under drought stress when soluble sugar and soluble protein content decreased.2After exogenous GB, AlA and SNP treatment, P. pedatisecta Schott’s leaf area, stem length and biomass were grown varying. By the treatment of given exogenous GB in10～40mmol·L-1concentration range,20～30mmol·L-1GB treatment can significantly improve the growth of P. pedatisecta Schott, and rise its biomass. By the treatment of given exogenous ALA in25～100mg·L-1, concentration range,50mg-L’1ALA treatment can promote P. pedatisecta Schott growth more obviously, indicating that this concentration of ALA could ease the damage of drought stress on P. pedatisecta Schott’s growth best. While in0.1～0.75mmol·L-1SNP,0.25mmol·L-1SNP had the most significant effect on promote P. pedatisecta Schott’s leaf area; stem length and biomass growth, indicating that this concentration of SNP could best deal with drought stress. Compare these three kinds of exogenous substances to P. pedatisecta Schott’s growth under drought stress, SNP treatment have the best effect.3The effect to oxidative damage and antioxidant enzymes activity of P. pedatisecta Schott leaves, by given exogenous GB, ALA and SNP, P. pedatisecta Schott Leaves O2-and MDA content decreased in different degree, but SOD, CAT, POD and APX activity were raised in different degree. By the treatment of given exogenous GB in10～40mmol·L-1concentration range, at20～30mmol·L-1, when O2- and MDA content were decreased significantly the SOD, CAT, POD and APX activity were raised significantly. By the treatment of given exogenous ALA in25～100mg·L-1concentration range, at the content50mg·L-1,ALA treatment could decrease O2and MDA content in the maximum degree, at the same time, it can also rise the SOD, CAT, POD and APX activity in the maximum degree, reduced oxidative damage of P. pedatisecta Schott under drought stress. By the treatment of given exogenous SNP in0.1～0.75mmol·L-1concentration range, at the content0.25mmol·L-1SNP treatment could significantly suppressing the generation of O2and MDA, improve the activity of four enzymes, that is SNP concentration at0.25mmol·L-1could best reduce the oxidative damage of drought stress on P. pedatisecta Schott. To compare the effects on slow down P. pedatisecta Schott leaves oxidative damage and antioxidant protection degree of these three kinds of exogenous substance, SNP content at0.25mmol-L"1had the best effect,50mg·L-1of ALA treatment effect followed by a little, the GB treatment effect is relatively poor.4Exogenous GB, ALA and SNP played an important role on drought stress on the P. pedatisecta Schott leaves osmolytes contents also. They improve under drought stress proline, soluble sugar and soluble protein content.20～30mmol·L-1GB processing can be slowed down to some extent drought stress the next P. pedatisecta Schott soluble sugar, soluble protein content decreased trend and further improve the the P. pedatisecta Schott proline content.50mg·L-1ALA obviously improved the soluble sugar, soluble protein and proline of the P. pedatisecta Schott.0.25mmol·L-1SNP also obviously improved the soluble sugar, soluble protein and proline of P. pedatisecta Schott.5Exogenous GB, ALA and SNP also have a larger impact to the leaf photosynthetic pigment content of P. pedatisecta Schott under drought stress. They improved chlorophyll a, chlorophyll b, total chlorophyll, carotenoid content and chlorophyll a/chlorophyll b of P. pedatisecta Schott under drought stress. In content20-30mmol·L-1, GB treatment could Slow down the decreasing trend of photosynthetic pigments content of P. pedatisecta Schott under drought stress. When the content50mg·L-1ALA treatment could rise photosynthetic pigments content of P. pedatisecta Schott under drought stress, and at the content0.25mmol·L-1, GB treatment could maximum extent possible to improve the photosynthetic pigments content of P. pedatisecta Schott under drought stress.6By given exogenous GB、ALA or SNP, the effective medicinal composition content of P. pedatisecta Schott under drought stress have a larger impact, all of them can improve the medicinal composition content of P. pedatisecta Schott respectively. By the treatment of given exogenous GB in10～40mmol·L-1concentration range, when GB content at20·30mmol·L-1, total alkaloids, total flavonoids and total free amino acid content of P. pedatisecta Schott increased significantly, improved the Medicinal value of P. pedatisecta Schott in some extent. In the25～100mg·L-1concentration range of ALA treatment, To the greatest extent improved total alkaloids, total falconoid and total free amino acid content of P. pedatisecta Schott when given ALA at50mg·L-1. In the0.1～0.75mmol·L-1concentration range of SNP treatment, To the greatest extent improved total alkaloids, total falconoid and total free amino acid content of P. pedatisecta Schott when given SNP at0.25mmol·L-1. |
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