Studies On Seeds Dormancy And Cold Resistance On Seedlings Of Meconopsis Racemosa Maxim. And Meconopsis Horridula Hook.

Meconopsis racemosa Maxim.and Meconopsis horridula Hook.are annual or perennial herbaceous plants of Papaveraceae,which are important Tibetan medicines in China.With the increasing awareness and deepening of the medicinal value of the plants of Meconopsis and the industrialized production of Tibetan medicines,the market demand for Meconopsis is also increasing.However,due to over-excavation of wild Meconopsis,the resources of wild Meconopsis are reduced year by year.In the face of increasing social demand for medicines,it is imperative to artificially cultivate M.racemosa and M.horridula.However,in actual production,the seeds dormancy phenomenon,the seed vigor identification,seed storage of M.racemosa and M.horridula,and the study on the growth and development of both seedlings are of great significance for cultivation and artificial domestication.In this experiment,the seeds of M.racemosa and M.horridula were used as experimental materials,through the endogenous inhibitory substances of the two species,different temperatures,different chemical reagents,and different stratification conditions treatment to explore the dormancy of M.racemosa and M.horridula.Through inquiry the seed dormancy of M.racemosa and M.horridula were studied,and provided the theoretical basis and technical basis for the inspection and evaluation of seedlings of M.racemosa and M.horridula,as well as the seed storage.At the same time,provided cultivation and planting technical guidance of M.racemosa and M.horridula.Below are key research findings:1.Through the determination of the water absorption of the seeds of M.racemosa and M.horridula,it was found that the water absorption characteristics of the two species seeds are satisfied with the commons seeds,so the seed coats of these two materials did not impede the seed germination.The effect can not cause the dormancy of the seeds of M.racemosa and M.horridula.2.Endogenous inhibitors with strong biological activity existed in the seeds of M.racemosa and M.horridula.The inhibitory activity between the two materials was also extremely significantly different(P<0.01).Through the determination of biological activity,the main components of the endogenous inhibitors of both seeds were water-soluble,and they all had extremely significant inhibitory effects on thegermination of wheat and cabbage seeds(P<0.01).The present study found that the presence of endogenous inhibitors is one of the major causes of dormancy in the seeds of M.racemosa and M.horridula.3.After germination experiments on the seeds of M.racemosa and M.horridula at different temperatures,it was found that M.racemosa seeds germinated best at20°C,and M.horridula seeds at 10-15°C.Under the optimal conditions,the germination status was the best,and physiological characteristics showed different responses under different temperature conditions.Among them,SOD,POD,CAT,soluble protein,MDA,and proline all showed different degrees of increase under optimal experimental conditions;When the temperature was higher or lower than the optimal temperature,SOD,POD,CAT,soluble protein,MDA,and proline were significantly or significantly increased compared with the control group(P<0.05 or P<0.01).Under high or low temperature conditions,SOD,POD,CAT,soluble protein,MDA,proline and other seed biology active substances will help the seed of M.racemosa and M.horridula to live through the unfavorable environment.4.After different concentrations of salicylic acid(SA),potassium dihydrogen phosphate(KH2PO4),polyethylene glycol(PEG),gibberellin(GA3),and indole acetic acid(IAA)soaking seeds germination for M.racemosa and M.horridula,the results showed that the germination rate of the two kinds of seeds reached the highest after treatment with 600 mg/L GA3,and there was significant or extremely significant difference compared with other treatment groups(P<0.05 or P<0.01).However,the physiological activities of the seeds treated with 0.7 mmol/L SA and the seeds treated with 0.5 mmol/L SA were stronger than those treated with GA3,indicating that the seeds treated with SA can help the M.racemosa and M.horridula spent unfavorable environment.5.After stratification tests on the seedlings of M.racemosa and M.horridula,it was found that M.racemosa seeds were mixed and stacked in wet sand at 20 cm depth and-10 °C for 60 days.The seedling germination of M.horridula seeds under the condition of 30 cm deep wet sand and-15 °C mixed layered for 75 days was the best,which was completely accordance with the two species seeds wild habitats.The results showed that M.racemosa and M.horridula seeds had physiologicalafter-maturing phenomenon.Therefore,in the production practice or artificial cultivation process,the low temperature stratification of the two seeds can significantly improve the germination rate and germination quality.6.After treatment of low temperature stress on the seedlings of M.racemosa and M.horridula,the seedlings of the two materials showed different degrees of response to low temperature,and the physiological indexes of the two materials under the temperature treatment conditions of 5-10 °C.The contents of two materials were significantly higher than those of other treatments(P<0.01),and the seedlings of M.horridula had a stronger response at low temperature than that of M.racemosa,indicating that the seedlings of M.horridula were more suitable for low temperature conditions,which was accordance with good conditions.The two material is in complete harmony with its habitat.