Anatomical Observation Of Grafting And Healing Of Potato And Lycium Barbarum And A Preliminary Study On Sexual Hybridization Between Genera

Potato late blight is the most important disease threatening the safety of potato.Lycium barbarum,which belongs to Solanaceae family,has the disease resistance characteristics of high resistance to late blight.Through grafting and hybridization,genetic and nutrient exchange,we hope to obtain new germplasm resources of potato and provide new ideas and methods for potato breeding against late blight.In this study,potato and wolfberry were grafted to form a grafting plant.The anatomical morphology of the junction at different stages after grafting was observed by paraffin section and freehand section,revealing the process of grafting healing and vascular tissue establishment of potato(herb)and wolfberry(woody);the hybridization between potato and wolfberry was preliminarily explored,and wolfberry and potato pollen were respectively given to the grafted plants In order to elucidate the reason of distant hybridization abortion between potato and Lycium barbarum,the dynamic development of hybrid ovary and embryo were observed.The test results are as follows:1.The process of grafting and healing of potato and Lycium barbarum can be divided into four stages:(1)the generation of isolation layer,5 days after grafting,the isolation layer at the grafting interface;(2)the formation of callus,9 days after grafting,the stimulation and regulation of endogenous hormones make the isolation layer cells dedifferentiate,and finally form callus;(3)the differentiation of callus,13 days after grafting,the differentiation of callus,Formation of callus bridge;(4)formation of new vascular tissue,17 days after grafting,formation of new phloem and xylem and vascular bridge,so that the rootstock and spike completely combined,the healing process ended.2.Grafting can significantly improve the compatibility between potato and Lycium barbarum.When the mother is the grafting plant and the father is the potato,the development of hybrid embryo is normal,and fertile progeny appears.When the mother is the grafting plant and the father is Lycium barbarum,the ovary expands after pollination,but then the abortion occurs.The development of the embryo of the progeny of the grafted plant when it was pollinated with potato pollen: 5 days after pollination,it belongs to the stage of early proembryo,and the cell divides and differentiates preliminarily;9 days after pollination,the early embryo develops to the stage of globular embryo;12 days after pollination,it gradually develops to rod-shaped embryo;16 days after pollination,a cavity is formed in the tissue of the suspensor system,and develops to heart-shaped embryo.20 days after pollination,the formation of prototypic stratification can be seen,and the embryo has developed and matured.The ovule development of the hybrid progeny of the grafted plant was basically completed 5 days after pollination;the ovule development was normal 9 days after pollination,the structure and morphology of the two ventricles were symmetrical,no further development of embryo was found by microscopy;12 days after pollination,the embryo seat disappeared,the ovule became black,necrotic,and the embryo sac was hollow;20 days after pollination,the peel was wrinkled,ovule,endosperm and other structures were found The nucellar tissue disintegrates completely,the inner ovule is shrunk together,and only the dried peel is left.At this time,the ovule development is abnormal,and the hybrid fruit loses its vitality completely.