| Actinidia arguta(Sieb.et Zucc.)Planchex Miq.is a kind of perennial,large deciduous vine in Actinidia of Actinidiaceae,also known as soft date,kiwifruit,etc.It is widely distributed in the mountainous areas of the north and south.Actinidia arguta is rich in vitamin C and other nutrients,is one of the emerging fruits in recent years,known as the fourth generation of the "king of fruits".Although Actinidia arguta can overwinter safely at-38℃ and has strong cold resistance,it is more sensitive to low temperature once germination begins.In the winter and spring season in northeast China,the temperature is low,which is easy to cause the occurrence of freezing damage of Actinidia arguta,and even lead to the death of the plant when the situation is serious,which seriously hindering the development of Actinidia arguta industry.At present,there are few studies on the cold resistance of Actinidia arguta,and they do not consider the dioecious characteristics of Actinidia arguta,and do not compare the cold resistance of female and male strains,which is not conducive to the subsequent research work related to the breeding of cold resistant varieties.Therefore,the study on the response and cold resistance difference of male and female Actinidia arguta under low temperature stress can lay a theoretical foundation for deep understanding and understanding of the internal mechanism of differences between male and female Actinidia arguta,and also provide reference for the identification of male and female Actinidia arguta,physiological and ecological studies,species protection and agricultural and forestry production practice.In this study,the annual branches of four excellent Actinidia arguta varieties(strains)’LD133’,’Long cheng No.2’ ’LD126’ and ’Kui lu’ planted in Changchun Agricultural School were used as experimental materials.During the natural overwintering period from November 2021 to March 2022,By measuring the tissue water content,cytoplasmic membrane permeability,osmotic regulatory substances and protective enzyme activities of male and female branches of Actinidia arguta,and combining with their morphological and anatomical structures,this paper studied the response of male and female branches of Actinidia arguta to low temperature stress during natural overwintering,and compared the differences in morphological and anatomical structures,physiological and biochemical indexes of male and female branches.The cold resistance difference between male and female plants of Actinidia arguta was analyzed.The main results are as follows:(1)Observation,measurement and analysis of the anatomical structure of the branches of the male and female strains of the four Actinidia arguta showed that the xylem area and xylem ratio of the male branches of the four cultivars were higher than that of the female.The cortical area and proportion of male branches were lower than that of female branches.(2)During the natural overwintering period,the bound water/free water,soluble sugar content,soluble protein content,free proline content and the activities of superoxide dismutase and peroxidase of branches of the four male and female Actinidia arguta increased first and then decreased with the change of natural external temperature.Tissue water content and catalase activity decreased first and then increased.(3)During natural overwintering,the relative electrical conductivity,malondialdehyde content and catalase activity of the male cultivars were lower than those of the female cultivars,but the soluble sugar content,soluble protein content,free proline content,superoxide dismutase activity and peroxidase activity of the male cultivars were higher than those of the female cultivars.(4)The membership function method was used to comprehensively evaluate the cold resistance of male and female plants of the four varieties.The results showed that the male plant had stronger physiological basis to adapt to low temperature stress and stronger cold resistance than the female plant. |
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