| Leonurus heterophyllus,a herbaceous annual or biyearly of the Lamiaceae family,is traditional Chinese medicine used for gynecological medicine with the blood hemostasis and relieving menstrual pain and so on.The total alkaloid and flavonoid contents are different as result of L.heterophyllus season growth,ecological type,plant morphology,as well as environmental conditions.This experiment studied the dynamic changes which the total alkaloid and.flavonoid contents of leaves,stems and roots in L.heterophyllus occurred to during the soil drought and PEG stress.It lays the foundation for L.heterophyllus reasonable and effective use of resources.The major findings of this study are as follows:It was closely related that drought stress time and the total alkaloid content of leaves, stems and roots in L.heterophyllus.The different parts corresponding to the difference during drought stress.With increasing in the number of the soil natural drought days,the total alkaloid content of leaves in L.heterophyllus was a gradual increase and the total alkaloid content of the stem in L.heterophyllus tended to slow after the first 5d,while that in root shows single-peak curve.With gradual increase in the concentration of PEG which used to simulate drought stress, it was found that the leaves and stems total alkaloid contents start to increase when he first 3 d of drought stress in L.heterophyllus;the root total alkaloids content started to increase in the dry pre-processing.The high concentration of PEG used to deal with 4 h,the L.heterophyllus leaf,stem and root did not occur in the accumulation of total alkaloids,with no significant difference in control.Therefore,that a short period of time to deal with the drought did not make the total alkaloid content in L.heterophyllus increase;The total alkaloid content of leaves and stems in L.heterophyllus started to increase until dealed with at least 3 days.Compared to leaves and stems,it was ealier that the time of the total alkaloids content in root starting to increase.It is directly related between drought stress time and total flavonoid content of leaf,stem and root in L.heterophyllus.The flavonoids content of leaves,stems and roots of in L. heterophyllus started to increase in the third day during soil drought.With gradual increase in the concentration of PEG which used to simulate drought stress,the flavonoids from the leaves and stems in L.heterophyllus started to increase at 3 day,but roots is earlier.Afer the high concentration of PEG stress L.heterophyllus,it was found that the flavonoids content in L. heterophyllus reduced,but only the stem part significantly reduced.Therefore,short-term drought stress did not make L.heterophyllus increase the flavonoids content;The stem and leaf flavonoids contents increased until 3 d,and the root flavonoids content started to increase at 1 d during the drought stress. The total alkaloids content of roots,stems and leaves in L.heterophyllus reached highest values at different times during drought stress,time sequence early and late:root＞stems＞leaves.It was most likely the root of total alkaloids transfer to the leaves through the stem, which need the further experiment.Throughout the drought process,it was similar changes in flavonoid content of leaves,stems and roots of L.heterophyllus.The flavonoid content of roots, stems and leaves in L.heterophyllus reached highest values at different times during drought stress,at the 3 d,5 d and 3 d,respectively.This explains that the total alkaloids and flavonoid contents changes take on tissue difference in L.heterophyllus.Rehydration after drought effected the total alkaloids content of different parts in L. heterophyllus.The total alkaloid content of leaves and stems in L.heterophyllus was reduction except root.Flavonoids in different Parts of the rewatering after drought or less the same response,were a different degree of reduction;The flavonoid content changes in different parts of L.heterophyllus took place in different degrees of reduction.
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