Effects Of Stress On Seed And Seedling Of Glycyrrhiza Uralensis And Induction And Culture Of Callus

Glycyrrhiza uralensis Fisch.is a perennial herb of Glycyrrhiza Linn.,Leguminosae sp.,mainly distributed in Xinjiang,Inner Mongolia and Gansu.As one of the major medicinal materials in China,its market demand is huge.In recent years,the production and quality of medicinal materials have declined sharply,so cultivation and production of high quality Glycyrrhiza uralensis has become the best solution.The purpose of this paper is to study the effects of various stresses on the growth of Glycyrrhiza uralensis in order to scientifically guide the cultivation and production of high quality Glycyrrhiza uralensis,at the same time,to expand the resources of licorice by using plant tissue culture technology,so as to accelerate and improve it.The secondary metabolites of Glycyrrhiza uralensis can be obtained in a more convenient way,which can provide higher quality resources for medicine and food industries.In the first part of this paper,the effects of saline-alkali stress,drought stress and double stress on germination rate,germination potential,germination index,root length,stem length and fresh weight of Glycyrrhiza uralensis were studied.Meanwhile it attempted to research and analyze physiological and biochemical characteristics of Glycyrrhiza uralensis seedlings under different stress conditions.The results showed that the seeds and seedlings of Glycyrrhiza uralensis were salt-tolerant to two kinds of salt stress.Its salt tolerance was NaCl>Na₂CO₃,and the two stresses significantly promoted seed germination,seedling growth,enzyme activity and soluble matter accumulation in low concentration,it was inhibited the growth of seeds and seedlings in high concentration.The optimum stress concentration was 25 mmol/L.The mild drought stress could promote seed germination and seedling growth under drought stress,and the optimum stress concentration was 4%.Seedlings maintained high enzyme activity and increased the content of osmotic regulatory substances.With the intensification of stress,seed germination index,seedling growth status and physiological and biochemical characteristics were inhibited.Under moderate drought condition and moderate saline-alkali composition,the resistance of Glycyrrhiza uralensis was increased.The concentration of NaCl+Na₂CO₃ was25+25mmol/L and the concentration of PEG-6000 was 4%in NIP1 treatment group is the most suitable.In the second part,Box-Behnken method was used to optimize the optimal hormone ratio for inducing the callus of Glycyrrhiza uralensis,and the three hormones,2,4-D、6-BA and KT were used to induce the callus of Glycyrrhiza uralensis.The results showed that the best hormone ratio for hypocotyl was:6-BA 0.63 mg/L+2,4-D 1.75 mg/L+KT 2.00 mg/L.The best hormone ratio for radicle was 6-BA 0.22 mg/L+2,4-D 1.63mg/L+KT 1.98mg/L。In the third and fourth parts,the elicitor was added to the callus culture system of Glycyrrhiza uralensis to investigate the growth of callus,measure and compare the content of the liquiritin and glycyrrhizic acid by the HPLC method.Result:These elicitors were significantly different among the three inducers on the callus of Glycyrrhiza uralensis.Chitosan was the most suitable for increasing the fresh weight and dry weight of callus of Glycyrrhiza uralensis.The optimum concentration was 3.6629、0.3158g,while methyl jasmonate and salicylic acid were not suitable for the growth of Glycyrrhiza.callus.The quantitative analysis results showed that chitosan could promote the accumulation of glycyrrhizic acid and increase the content of liquiritin at low concentration.Salicylic acid inhibited the accumulation of glycyrrhizic acid,but at the same time promoted the increase of liquiritin content.Methyl jasmonate promoted the increase of glycyrrhizic acid content at low concentration,but inhibit of increase of the content of liquiritin.The results showed that,the fast secondary metabolite accumulation of Glycyrrhiza uralensis could be completed through establishing callus culture system and enlarging culture system.The effects of stress on seeds and seedlings of Glycyrrhiza uralensis were investigated.The results showed that the seeds and seedlings of Glycyrrhiza uralensis were resistant to saline-alkali and drought.At the same time also used the response surface method was used to investigate the optimum hormone ratio of callus induced by Glycyrrhiza uralensis.Secondary metabolite accumulation in the culture system of Glycyrrhiza uralensis callus was increased by adding different elicitors.It provides a reliable basis not only for the standardization of artificial cultivation techniques in the future,but also a new theoretical basis for the tissue culture techniques of Glycyrrhiza uralensis.