| Andrographis herba is the dried aboveground parts of Andrographis paniculata(Burm.f.)Nees belongs to Acanthaceae family.It has the functions of clearing away heat and detoxification,cooling blood and detumescence.It is used to treat cold,sore throat,sore mouth and tongue,cough,diarrhea and dysentery,heat,astringent pain,carbuncle,sore ulcer,snake bite,etc.Traditional cultivation of A.paniculata requires a large amount of chemical fertilizer,especially nitrogen fertilizer.Overuse of chemical fertilizer has brought many problems,such as environmental pollution,energy consumption,soil hardening and fertility decline,which seriously affects the quality and sustainable development of A.paniculata.Therefore,it is imperative to find high-yield,high-quality and green planting technology of A.paniculata.Rhizobium and non-leguminous plant symbiotic nitrogen fixation can improve crop’s yield and stress resistance,It has been successful in wheat,tobacco,ect,but there are few studies on medicinal plants.This study investigated the effects of Sesbaniacannabina(Retz.)Poir.and Aeschynomene americana L.root nodule grinding solution,Sinorhizobium fredii,A.caulinodans,radioactive rhizobium on the promoting of A.paniculata.The effects of rhizobium on the growth,content of effective components and seed germination under drought and salt stress of A.paniculata were evaluated by measuring the growth,tissue morphology,chlorophyll content,nitrogen content and effective components.This study will provide technical support for deeper study of the growth-promoting mechanism and stress-resistant mechanism of rhizobia on A.paniculata,and cultivate high-yield,high-quality organic A.paniculata,also provide a special bacterial fertilizer for A.paniculata.The results are indicated as fllows:1.The hypocotyl of A.paniculata ould be promoted by soaking seeds with suitable concentration of Sesbaniacannabina(Retz.)Poir.and Aeschynomene americana L.nodule grinding fluid.After 40 days of transplantation,the leaf area,fresh and dry weight of above ground part and underground part of A.paniculata could be significantly increased by the treatment of Sesbaniacannabina(Retz.)Poir.nodule grinding fluid soaking.The activity of T-SOD and CuZn-SOD in A.paniculata was increased by soaking seeds with 2 kinds of nodule grinding solution.2.Tissue culture conditions:There was no significant effect on the growth of A.paniculata by radioactive rhizobium,Sinorhizobium fredii and A.caulinodans treatment.3.A.paniculata seeds were soaked in sinorhizobium fredii,A.caulinodans and radioactive rhizobium solution,24 h.This treatment inhibited the germination potential of A.paniculata seeds and had no significant effect on its germination rate and hypocotyl elongation,but its radicle elongation and seed vigor index was significant promoting.A.caulinodans treatment reduce its germination index,while other treatment had no significant effect on its germination index.After 40 days of transplantation,the plant’s height,root length,leaf number and fresh weight of A.paniculata were not significantly affected by 3 kinds of rhizobium(soaking treatments).The A.caulinodans treatment significantly promoted the growth of A.paniculata leaves.After 40 days of transplantation(irrigated treatment),there was no significant effect on plant height,root length,leaf number,leaf area and fresh weight of A.paniculata.After 40 days of transplantation(soaked treatment or irrigated treatment),the activity of T-SOD and CuZn-SOD in sinorhizobium fredii,A.caulinodans and radiation rhizobium treatment group had no significantly different from that in control group.4.The 107 cell/mL of A.caulinodans treatments had the most obvious effect on the growth of A.paniculata.The plant height,the number of branches and leaves of this treatments were 13.40%,16.75%and 57.73%higher than those of the control group.The fresh weight and the dry weight of the above-ground parts were 60.80%and 67.08%higher than those of the control group,the fresh weight and the dry weight of the underground parts were 24.40%and 14.75%higher than those of the control group.107 cell/mL of A.caulinodans treatments could advance the flowering of A.paniculata,the number of flowering plants in this treatment was 2.5 times than control group.The chlorophyll content and nitrogen content of A.paniculata were increased and then decreased slowly within the plant growth period.The treatment of A.caulinodans had no significant effect on the pollen morphology,stomatal number,chloroplast number and seed number of A.paniculata.The results of plate coating and confocal microscopy showed that A.caulinodans could colonize A.paniculata.107 cell/mL of A.caulinodans treatments had the most obvious effect on the effective components in A.paniculata.The content of effective components in A.paniculata roots was 93.33%higher than that in control group,the content of effective components in stems was 11.63%lower than that in control group,the content of effective components in leaves and above-ground parts was 44.04%and 15.91%higher than that in control group.5.Under the PEG 6000 drought stress,the drought resistance of A.paniculata seeds could be improved by the treatment of sinorhizobium fredii,radioactive rhizobium and A.caulinodans.Radioactive rhizobium had the best effect,followed by A.caulinodans,and then sinorhizobium fischeri.Under the NaCl salt stress,the salt tolerance of A.paniculata seeds was enhanced by the treatment of sinorhizobium fredii,radioactive rhizobium and A.caulinodans.Radioactive rhizobium had the best effect,followed by A.caulinodans and sinorhizobium fredii. |
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