The Study On Flowering Biology And Drought And Salt Resistance Of Lysimachia Davurica

Lysimachia davurica is a perennial herbaceous flower,widely distributed in China.It is a traditional chinese medicinal material,with the function of calm,depressurization,curing insomnia and high blood pressure,and so on.Its flowering is long,beginning in the end of the spring and winding up in the early autumn.Lysimachia davurica has the very high ornamental value with the yellow,large and dense flowers.At the same time,Lysimachia davurica is a relatively ideal green resource of cold area,bacause its cold resistance is very strong and its roots can keep the vitality in the cold underground of northeast.It can be widely used in road and garden greening,enriching landscape resources.As a kind of wild resources,Lysimachia davurica has not been paid enough attention.At present,the research about Lysimachia davurica mainly focuses on the extraction of the chemical composition.The study about flowering biology and drought and salt resistance of Lysimachia davurica has not been visible.In this study,in order to reveal the rule in the process of growth and understand the the resistance of Lysimachia davurica and lay the foundation of protecting,developping and utilizing of wild resource,the study on flowering biology and drought and salt resistance were conducted using Lysimachia davurica as material.The primary results of the study are as follows:(1)Flower syndrome and breeding system: The single flower longevity was 4 days in general and individual infloreseenee flowering about 35-50 d.There are two peak in individual inflorescence flowering.The first peak appeared in the 6-10 d after flowering,the second peak appears in the 15 d after flowering.The time of pollen maturation was delayed than stigma.The receptivity of stigma can be strongest in the beginning 2 h after flowering.Combining the pollen-ovule ratio with hybrid index and bagged test,the result showed that the breeding system of Lysimachia davurica was outcrossing with partly self-compatible and needed pollinators during the pollination.(2)Flowering phenology of the Lysimachia davurica: The flowering span of population of Lysimachia davurica was from mid June to mid August.The biennial flowering period were 48 days,The flowering period of three years were 52 days and the flowering period of four years were 54 days.In terms of the open flowers population,the performance of the Lysimachia davurica was relatively concentrated and the performance of different age groups were basically similar,showing "M" type.The differences in flowering phenology between different age groups mainly were the decrease in the number of open flowers on the inflorescence of the biennial and four years plants.The plants of four years had a lot of bud abortive before flowering.In addition,the end flowering period of the biennial plants hadadvanced.(3)The drought resistance of seedings of the Lysimachia davurica: Under the natural drought conditions,with time and an increase of drought stress,the effect of drought stress on growth and development of Lysimachia davurica gradually increased.The top of seedling was firstly restraine when drought stress was less than 10 days and soil moisture content was higher than 14.52%.The seedling was restrained with the loss of leaf water and the decrease of leaf area,chlorophyll content,MDA content,soluble sugar,proline and the SOD,POD and CAT activities of seedling were increased.Net photosynthetic rate decreased significantly,but it was positive.Plant could grow back quickly except stem tip after re-watering.When drought stress for 15 days,the top of seedling was dry and the net photosynthetic rate was negative.66.66%new sprout grew after re-watering.Lysimachia davurica would be dying and could not be revived after re-watering if drought stress was last for 20 days.(4)Optimization of the seed germination of Lysimachia davurica: The optimum germination temperature was 30 ? and the germination rate was 53.33% when the seeds were soaked with gibberellin for 48 hours,which was consistent with the results of previous research results.Soaking the seed for 72 hours,the optimum temperature became22 ?.Compared with the previous study,the germination rate was significantly increased,reaching 71.67%.(5)The salt resistance of seeds and seedlings of the Lysimachia davurica: Under mixed salt and alkali stress of NaCl ? NaSO4 ? Na2CO3 and NaHCO3,the seed germination rate,potential germination and germination index were significantly lower than those of the control.The relative water content of leaves decreased continuously with the increase of pH.When pH increased to 9.65,the leaves relative water content gradually stabilize.chlorophyll content,the SOD and CAT activities,MDA content increased first and then decreased at pH 9.65.Therefore,the critical value of the Lysimachia davurica for alkali stress may be at pH 9.65.