Research On The Reproductive Biology And Abortion Mechanism Of Manglietia Glauca

In this paper,the man-made forest of Manglietia glauca in Baiyun,Fubo experimental field and Arboretum in Experimental Center of Tropical Forestry of Chinese were selected as the study area,the characteristics of sexual reproduction embryology,flowering and breeding of M.glauca were studied systematically for the first time.The reproduction characteristics of M.glauca and the reasons of its abortion were discussed with the perspective of individual and group from embryo development to external factors.The main results were concluded as follows:1.The flowering period of M.glauca in the arboretum was from early of March to early May,started to bloom in early of March,and reached full bloom in middle April,terminated flowering in early-May.The early flowering period of Baiyun experimental field and Fubo Experimental Field was delayed by 8 ~ 10 d and 12 ~ 15 d,full bloom period was delayed by 8 ~ 10 d and 12 ~ 15 d,and the final bloom date was delayed 6 ~ 7 d and 8 ~ 10 d.The flowering of M glauca happen in 17: 00 ~ 18: 00 stably,the flowering intensity was moderate,but the flowering was relatively concentrated and the synchronization index was higher.The distribution of reproductive components was mainly affected by stand density,and the altitude is not a key factor affecting the distribution of reproductive components of M.glauca.With the increase of stand density,the branches / branches and flowers / branches of the leaves were decreased,and the number of reproductive organs per plant was significantly higher than that of the forest plants.2.Two-times opening-closure flowering of the M.glauca has experienced the following stages: petals exposed stage,the first opening stager,closure stage,the complete opening stage and decay stage.There were great difference in the pattern of two-times opening-closure flowering,the time in each flowering process and intervaltime in two-times flowering opening due to different temperature.M.glauca showed dichogamy and protogyny in its flowering process,and the pistil was located in the upper stamens and avoid the possibility of self-pollination occurred both in time and space.M.glauca bloomed for centralized synchronization in plant level.When the flower pollen released during the first round flowering,the pistil viability of second round flowering was strongest.The time both male and female sexuality of strongest expression overlapped up to 1-6h,and the time guaranteed pollination success in its limited receptivity period.3.The process of flower bud differentiation M.glauca was divided into the following stages: leaf bud stage,flower primordium differentiation stage,flower organ formation period,male and female maturation stage and bud formation stage.The floral organ formation with this order as following: calyx-petal-stamens-pistil.The stamens were consisting of 140-185 stamens,and the type of anther was the same as dicotyledons with 2-6 adult pollen sac and glandular tapetum,and the number of pollen sac were mostly 4 or 2-6 seldom.In the meiosis of microsporocyte,cytokinesis was modified simultaneous type,the arrangement of tetrad concludes overlapping type and symmetrical mainly,“T” type and in-line arrangement seldom.Mature pollen is two-cell type with a boat shape and a germinal aperture in a single groove.There were 45-85 carpel per gynoecium,with 8-14 ovules per carpel,and the ovule is of anatropous,double integument and thick cellus,and cellulosum embryo sac.4.There are some abnormalities in the process of male and female gametophytes of M.glauca.When the microspore mother cells enter the meiosis,most of tapetum and middle cells disintegrate,leaving only a small amount of residue.The microspores from the tetrads happen some degrees of deformation,and most of them could developed well and a little part of them could not developed as normal microspores,and the rate of unnormal development was about 16%.In the formation of female gametophytes from the formation of mononuclear embryo sac to eight nuclear embryo sac,there were degeneration in the nucleolus,nuclear membrane,cell becomes shrinkage and smaller,or disappear.The central cells,synergid and antipodal cells appear at different times with atrophy,or nucellus and germ cells disintegrated simultaneously in the phase of mature embryo sac.Whiles a few nucellus and integument stop developing and the integument was separated from nucellus with nucellus cell condensing and melting,Edge cells of embryo sac collapse at the same time,and the rate of female abortion was about 22%.5.The breeding system of M.glauca is a mixed mating type with the outcrossing and partial selfing.Selfing incompatibility happened in self-pollination mainly,and self-compatible happened in geitonogamy.6.There are about 13 species of flower-visiting insects,including 1 species of Thysanoptera,7 species of Coleoptera,3 species of Hymenoptera and 2 species of Diptera.There were different visiting insects in different standings,and more stable and effective pollinators were mainly bee,beetle and fly.The frequency of visits to insects was greatly affected by number of flowering and weather.At the beginning of the flowering period,the frequency of insects was the lowest,with an average of 0.5 times per day,10.3 times per day at the full bloom stage.There were few bees and flies insects to visit flowers when it rain and wind,in addition to thrips and beetles visiting occasionally.