A Preliminary Study On The Characteristics Of Reproductive Biology Of Quercus Mongolica

In order to grasp the characteristics of flowering and fruiting of Quercus mongolica,we studied the flowering phenology,flower bud differentiation,floral organ characteristics and fruiting regularity of Q.mongolica on the campus of Shenyang Agricultural University to lay the foundation for the cultivation of Q.mongolica and the breeding of new varieties.The main results are as follows:1.The phenological stage of Q.mongolica can be divided into 7 stages:flower bud germination stage,leaf development stage,inflorescence formation stage,flowering stage,fruit stage,deciduous stage and dormancy stage.The initial flowering of Q.mongolica is late April,and the microclimate has a significant impact on flowering.After blooming,it enters the full blooming period about 3 d?5 d,until the end of April and the beginning of May,the period of male inflorescences withering,the entire population blooming time lasts about 10d,and it's concentrated and large-scale blooming.The bulbs of group female flowers inflated in mid-to-early May,then appeared the cupular in the late May,the cupular bracteole warty was increasingly obvious,the cupular was basically formed in late June,the nuts slightly showed the cupular in early July,the nut revealed one-third of the cupular in early August,and entered the fruit matures in mid-August and the seeds begun to fall at the end of August.The period of group fruiting lasted about 125days,and the average period of individual fruiting was107days.2.The buds of Q.mongolica are mixed buds,which including leaf buds and flower buds.The buds are basically differentiated from August to mid-to-early March of the following year.The differentiation process of flower buds can be divided into:undifferentiated phase?August?,initial undifferentiated phase?mid-late September?,primordial differentiation phase?mid-to-late October?,stamen differentiation phase?mid-early March?,pistil differentiation phase?mid-late March?.Subsequently,from early April,it enters the stage of floral organs,where the differentiation speed is relatively fast and the development of floral organs last shortly.The male flowers of Q.mongolica gradually begin to bloom in mid-to-late April and reach the full blooming stage at the end of April.3.From the flowering process of the male and female flowers of Q.mongolica,according to the changes of anthers,the male inflorescence can be divided into four stages:the current stage of the medicine that the leaves are slightly exposed and peeled off the leaves the inflorescence primordium can be seen obviously,which appeared in the bottom of new branches;anther appear that the anthers can be seen completely and the inflorescence axis was elongated;the pollen powder disperses that the anthers were full and the pollen begun to spread with yellow pollen;the pollen dry phase that just filaments and drug spacers remained on the inflorescence then the entire inflorescence gradually withers.Female peanuts born in the top of new branches with red punctiform tuber.According to the change of the stigma,female peanuts can be divided into 4 stages:the stigma present stage that the stigma was gathered up straight,showed red fluff with white,and the stigma was slightly cracked;the stigma fission phase that the top of the style with flower petal,yellow,and the stigma split angle showed about 45°;the stigma total cleavage phase that the stigma was completely split and the protrusions on the surface of the stigma were obvious,which was easy for attachment of pollen;the stem dry phase that when the stigma received pollen,the stigmas'color changed from red to reddish brown,the stigma gradually became dry,and the pollen was not easy to stick to the stigma and smooth.According to observation,the optimal pollination period of the female stigma flowers was basically coordinately with male inflorescences.4.The shape of pollen grains of Q.mongolica showed oblong with three germination grooves can penetrate to the poles of the pollen grains,with thicker grains of outer wall decorated and obviously surface grains and folds.Through the research on the pollen germination of Q.mongolica,the pollen germination rate can reach 46.59%under the condition of 28?and sucrose 150 g·L^-1+boric acid 200 g·L^-1of culture medium.On the basis of the optimal culture medium,adding the material of plant growth regulators,K⁺and Ca²⁺,found that the concentration 0.1 g·L^-1of 2,4-D and concentration 0.5 g·L^-1of IBA promoted germination of Q.mongolica pollen while the germination rate decreased by adding NAA,GA₃,K⁺and Ca²⁺.5.Through the study of different storage conditions of Q.mongolica pollen,pollen inactivation was faster at temperature of greenhouse,while it can be preserved for a long time when it stored in a refrigerator at-20?,and after two years,the pollen vitality also can reach14.79%.6.The period of fruit growth and development of Q.mongolica was mid-early May to mid-to-late August.According to the external shape of the fruit,the fruit of Q.mongolica can be divided into bract formation period,young fruit period,cupule formation period,seed emergence period,seed formation period and fruit maturity.It can be seen from the section that the internal structure of Q.mongolica mainly includes ovules,pistillary cord and ovary.