Study On The Photosynthetic Characteristics And Photosynthetic Efficiency Of Different Plum Germplasm Resources

Plum had a wide variety of resources and adaptability.In the long term natural selection and artificial domestication,the cultivars of different provenances and origins had been established.They included Chinese plum(Prunus salicina L.),apricot plum(Prunus simonii Carr.),American plum(Prunus americana Marsh.),European plum(Prunus domestica L.),cherry plum(Prunus cerasifera Ehrh.),sloe(Prunus spisona L.)and so on according to the provenance.In addition,there were a large number of interspecific hybrids.Photosynthesis was the energy source and material basis of plants.Research on the photosynthesis was of great significance to the cultivation and breeding of fruit trees.In recent years,with the popularization of portable photosynthetic measuring instruments,people had already had a certain research on the photosynthetic characteristics of Li,but there were few studies on the photosynthetic physiology of different provenances and origins of plum resources.In this study,the photosynthetic characteristics and chlorophyll fluorescence characteristics in three periods of spring(late May),summer(early August)and autumn(early October)were researched with different plum resources as materials,and the morphological differences of different plum resources were compared.The results showed that:(1)A comparative study was conducted on the morphological traits of eight plants of Twenty-two plum germplasm resources,and the grey relational analysis and fuzzy comprehensive evaluation method were applied to comprehensively evaluate the growth indexes of different plum germplasm resources.The results showed that 'Furongli','Pissardii','Sata Rosa','Dashizhongsheng' and 'Oishiwase' were ranked in front,while'Xiangbian','Great Rosa' and 'Conghuasanhuali','Zuili' and'Aluqia' were ranked at the rear.The equal weight and the weighted evaluation results obtained by the grey relational analysis and the fuzzy comprehensive evaluation method had a very high degree of anastomosis,and the evaluation results were generally consistent.(2)Most of the resources in late may,net photosynthetic rate,li integral value(DIV of Pn)and apparent quantum efficiency(AQY)is the highest,other two periods is different by different resources;Transpiration rate,integral value(DIV of Tr)characterized by early August>later this month in early October,water use efficiency(WUE)is the lowest in early August,Light saturation point(LSP)in the three periods are"high-low-high " change,light compensation point(LCP)has no obvious change rule in the three periods.The provenance of 22 resources and source were analyzed,and the resources of Europe and America li li net photosynthetic rate,the integral value(DIV of Pn)and apparent quantum efficiency(AQY)in early August a big decline in late may,shows these two kinds of resources is not high temperature and high wet summer climate in east China;Sloe and hybrid resource indicators lee has been at a higher level in the three period,showed a strong photosynthetic capacity;Chinese plum local varieties photosynthetic capacity difference is bigger,show the abundant genetic diversity,and presents a certain regularity of regional variations in the north and the south.(3)The difference in fluorescence parameters between different plum resources was extremely significant,which may be related to genetic factors.F0,Fm,?PAII,and qP of the majority of plum resources were at higher levels in late May and early August,and the lowest values in late October in the three periods,indicating that plum had flourished during the spring and summer season.The Fv/Fm didn't differ significantly in the three periods and it slightly decreased in early August,in which the Fv/Fm of 'Xiangbian','Damas-1869' and 'Great Rosa' were lower.NPQ and ETR were at the highest values in early August in three periods,explaining that plum could resist the summer strong light damage by increasing the heat dissipation,with the most significant increase of NPQ in the 'Meizhouli' and 'Changli No.15' in the early August.The correlation analysis showed that the correlation coefficients of ? PS ? and qP in fluorescence parameters were the highest,and the correlation coefficients of photosynthetically active radiation,environmental temperature and ETR were relatively large,reaching 0.759 and 0.781.There was a high correlation between carotenoids and fluorescence parameters.(4)The photosynthetic parameters were classified numerically,and principal component analysis and cluster analysis were carried out.Plum resources had the highest net photo synthetic rate in spring and it showed a trend of gradually decreasing in three periods.Water use efficiency was lowest in summer and higher in spring and autumn.Different seasons differ greatly between different plum resources.Twenty-two plum resources can be classified into 3 categories:high,middle and low photosynthetic rate according to the net photosynthetic rate.According to the values of water use efficiency,four categories of high,medium,and low water use efficiency could be divided.Further principal component analysis showed that DIV of Pn,DIV of Tr,Gs and WUE were the main factors influencing photosynthetic physiology.According to the four indicators of DIV of Pn,DIV of T0,Gs,WUE,Twenty-two plum resources were clustered into three categories.Six selected resources with better comprehensive photosynthetic characters(sole 'Damas-1869',European plum'Great Rose',Chinese plum 'Furongli' and 'Jiaqingzi',hybrid plum 'geleno','Sata Rosa')can be used for high photosynthetic efficiency breeding of plum.