| ‘Fu yu' was the main cultivated variety of persimmon which had large planting area,high yield and good quality.As early as 1980,‘Fu yu' was imported from Japan and gained high popularity from consumers in our country,and there were many different reasons to fail develop on a large scale,and the most important reason was lacking proper rootstock.Many problems were shown in many aspects when ‘Fu yu' was grafted on different rootstocks,such as poor resistance,low survival rate,poor compatibility and plant death causing by incompatibility.Choosing superior rootstocks became a key-problem to promote ‘Fu yu' rapidly in our country,and resistance and compatibility selection of rootstocks was the key of the problem.Three species of Diospyros were chosen as the experimental material.And the study was used to analyze the differences of salt and drought tolerance of Diospyros resources respectively by different concentration salinity treatment and natural continuous drought stress.A comprehensive resistance evaluation on Diospyros was given according to mathematical multi-factor statistical method and the subordinate function through physiological and biochemical indexes combined morphological indexes.Meanwhile ‘Fu yu' persimmon was grafted on twelve accessions of persimmon rootstocks were studied.Results listed as following:1)Studying the influence of salinity on germination ability of three species of Diospyros [ten accessions of Diospyros lotus,one of Diospyros kaki var.sylvestris(869);and one of Diospyros virginiana(844)].We obtained many data,such as germination percentage,which was incubated for 30 d with different concentrations of Na Cl solutions at 0,0.5,1,1.5 and 2.0 %.The results showed seeds of D.kaki var.sylvestris 869 all germinated under non-saline(control)condition,followed by D.lotus 852 and D.virginiana 844,and germination rate of the other nine accessions of D.lotus were lower than the three former.The highest germination percentage was found in D.kaki var.sylvestris 869 under 0.5 % Na Cl solution,and D.lotus 852 had the highest germination percentage under 1.0 % Na Cl solution.None of twelve accessions germinated in 1.5 and 2.0 % Na Cl solutions.Pre-process seeds by exposure to high-salinity solution were to be reversible from re-watering that ungerminated seeds by salt treatment began to germinate.D.kaki var.sylvestris 869 was the most salt tolerance species followed by D.lotus and D.virginiana 844 in three species of persimmon seeds under salt treatment;differences in salt tolerance of ten accessions of D.lotus: 852 was the best,the following was 824,847 and 849 were the worst.2)The salt tolerance of young seedlings(seedling stage was about 90 days)in twelve accessions of Diospyros L.with different concentrations of Na Cl solutions were evaluated based on physiological data,according to the methods of principal components analysis and subordinate function.The results showed that D.virginiana 844 was the most salt tolerance species followed by D.kaki var.sylvestris 869 and D.lotus,but 824,846 and 847 had good salt tolerance in ten accessions of D.lotus.3)90-days-old potted healthy seedlings of three species of Diospyros L.(three accessions of Diospyros lotus,referred to as accession No.824,846,and 847;one accession of Diospyros kaki var.sylvestris referred to as 869;and one accession of Diospyros virginiana referred to as 844)were chosen for the 25 days salt stress experiment,and the effects of salt stress on seedling growth,photosynthetical system,membrane lipid peroxidation,antioxidant system were compared.Plant growth,biomass accumulation,morphological changing of leaves,salt injury index combined physiological parameters indicated initially that salt resistance of D.virginiana 844 was higher than that of D.kaki var.sylvestris 869,and D.kaki var.sylvestris 869 was higher than that of D.lotus,and D.lotus had the lowest capacity in response to salt stress in three persimmon species.4)1-year-old potted healthy seedlings of three species of Diospyros L.(three accessions of Diospyros lotus,referred to as accession No.824,846,and 847;one accession of Diospyros kaki var.sylvestris referred to as 869;and one accession of Diospyros virginiana referred to as 844)were chosen for the 20 days drought stress experiment,and the effects of water stress on net photosynthetic rate,photosynthesis parameter,membrane lipid peroxidation,antioxidant system,and antioxidant in leaves of three species were compared.The leaves,root system and growth of five accessions of Diospyros seedlings were inhibited under drought stress.From morphological observation,physiological indexes and drought injury of five accessions of Diospyros demonstrated that D.virginiana 844 was drought-tolerant species and Diospyros kaki var.sylverstris 869 was drought-sensitive species.In D.lotus,824 had a higher antioxidation capacity in response to drought than the other two accessions of D.lotus.5)Three species of Diospyros L.(ten accessions of Diospyros lotus,one of Diospyros kaki var.sylverstris,and one of Diospyros virginiana)were chosen for graft compatibility on ‘Fu yu' persimmon,to determine a proper rootstock for ‘Fu yu' on graft compatibility by surveying the survival rate,conserving rate in two years after grafting,scion growth and morphology and anatomy on graft union.The results showed that performance of three species rootstocks on graft survival rate was different significantly,survival rate of D.lotus was higher than the other two species,D.kaki var.sylverstris 869 was higher than D.virginiana 844,and D.lotus ludong67 had the highest survival rate among all accessions,reached 97.69 %;average conserving rate of two year ranking of the tested species was found as: D.lotus>D.virginiana 844>D.kaki var.sylverstris 869,and D.lotus 824 had the highest conserving rate in two years.There was positive relationship between scion growth and graft survival rate;it was also found that rootstocks with poor compatibility on ‘Fu yu' showed phenomenons on graft union,such as swelling,warping and crack among twelve accessions of rootstocks.Healing process was similar in all accessions rootstocks after grafting from morphology observation,but callus initiation time of D.kaki var.sylverstris and D.virginiana was about a week later than D.lotus.From growth investigation and anatomical observation,it may be concluded that D.lotus had better compatibility on ‘Fu yu' than D.kaki var.sylverstris and D.virginiana.Because of good graft compatibility,824,848 and ludong 67 of D.lotus were used as good rootstocks on ‘Fu yu'.6)D.lotus 824 was considered the proper rootstock for ‘Fu yu' through salt and drought stress treatment and graft compatibility studying in three persimmon species. |
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