Phenological Observation And Embryology Of Prunus Cerasus In Guanzhong Plain,Shaanxi Province

Prunus Cerasus Linn is native to the southeastern Europe and western Asia.It can be used as rootstock as well as cultivated variety.Sour cherry has a great potential of the future market prospect.Across the world,sour cherries of about 230,000 hectares are used in the processing of liqueurs,jam,juice and dried fruit.Sour cherry research has just started in our country,and so far,studies of the sour cherry embryological are scarce,and uniform cultivation management techniques are lacking.In order to summarize the sour cherry’s embryonic development rule and critical period,with sour cherry in the center of Guanzhong Plain as research objects,this experiment studies sour cherry’phenophase,flower differentiation,size of microspores,endosperm developmenta and stigma activity.The main conclusions are as follows:1.According to morphology,the phenological period of sour cherry in Guanzhong Plain can be divided into: bud initiation and expansion(from late February to late March),inflorescence formation period(late March to early April),flowering period(from late March to mid-April),fruit developing period(from early April to mid-June),flower bud differentiation period(from late June to mid-August),deciduous and dormant period(from late October to late February of the following year).2.The flower bud of sour cherry is pure bud,and the flower-bud physiological differentiation begins when the fruit is fully ripe.The period from July to late August is the morphological differentiation stage,which includes five stages of flower primordium differentiation,calyx differentiation,corolla differentiation,stamen differentiation and pistil differentiation.The differentiation sequence and time of different parts of sour cherry’s flower bud are from bottom to top and from outside to inside.3.The research of sour cherry’ palynology indicates that in the process of microspore formation,the microspore mother cell is characterized by simultaneous cytokinesis according to the mode of cytokinesis,and the tetrad stage is tetrahedral.In addition,the mature stamen anthers are butterfly shaped and the mature pollen is 3-cell type.Under electron microscope,the polar surface of pollen grains is almost oblate triangle,with 3germination pores and ornamented outer wall.The ridges are closely arranged,the edge has small thorns,and the lower layer of the decoration has circular holes.The anther wall is a typical 5-layered structure.4.Sour cherry is monocarpouspistil with a single carpel and single locule,with 1-2inverted ovule characterized by a double perianth and thick nucellus in it.The embryo sac is polygonum type and has seven cells and eight nuclei in mature embryo sac.The stamens differentiateand mature earlier than the pistil,but both are active at anthesis and can self-pollinatewith similar length.5.Stigma receptivity of sour cherry is established 2 days before flowering,and becomes strongest on flowering day and the next day,and lasted 4-5 days after flowering.The outer wall of the ovary,the middle parenchyma cells and the inner wall of the ovary develop into the skin,sarcocarp and nutlet of sour cherry respectively,with reticular fibre in sarcocarp.