Studies On Flowering And Seedling Characteristics Of Chionanthus Retusus Lindler.et Paxt

Directed by Professor,Xingshiyan; Senior engineer,LitaoThe materiala for this study were Chionanthus retusus Lindl. et paxt. The phenophase, flowering habit, the anatomical features of flower, fruit and seedling were studied. The results were showed as follows:(1)With regard to phenophase, the sprouting phase, leaf expansion phase, flowering phase and the time of young fruit appearance lagged 1-2 days compared with the plain.(2)The flowers of Chionanthus retusus could be classified into two types, i.e. perfect flower and imperfect flowe. The stamens of female Chionanthus retusus were all staminode. But there is no significant difference in the pollen grain size of them.(3)The carpodermis of young fruit of Chionanthus retusus could be divided into three types, i.e. the outer layer, the middle layer and the inner layer. And there was physiological fruit drop in fruiting period, may be resulted from nutrition deficiency and the competition of fruit.(4)The structural characteristic, e.g. the perfect flower and imperfect flower, short stamen(only 3mm long) embedded in floral-tube, limited pollen grains, the limit of pollen scatteration, dumpy gynoecia(only 2mm long) embedded in floral-tube, the limit of accepting pollen, the stamen located at the base of flower and between two petals, the dorsal splitting anther clung to the petal was on of the reason that lead to the lower fertility of Chionanthus retusus. Moreover, although perfect flower possessing anther, but the number was quite less than that of imperfect flower. The difficulty in self-pollination and the excessive dependence on anemophilous pollination was also another reason.(5)The tertiary lateral root of majority seed came into being 120 days after germination. When the length of taproot reached 10cm, the plantule and cotyledon was still not present, which may be one reason resulted in the failure to emerge in short period. Moreover, the thick and hard seed coat was also on of the reason that delayed the germination of Chionanthus retusus to at least one year later after sowing.(6)The growth model of seedling height. The r value ofâ…¡-class seedlings in four growth model, i.e Linear, Logistic, Gompertz and Richarss, all was above 0.9, but Richards model is the best(r=0.9352). The total root length ofâ… -class seedling was 65.7 times as longer as seedling height, while that of theâ…¡-class,â…¢-class is 55.6 and 63.4, respectively. We concluded that there was significant difference between the aboveground growth and the underground growth. The most prominent characteristic was well developed root system.The flowering and seedling characteristics of Viburnum macrocephalum and Chionanthus retusus were discussed.