Response Of Hormones During Flower Bud Differentiation Process In Commelina Benghalensis L.and Seed Clustering Effect Research

Commelina benghalensis L. is a kind of swart grass which spreads all over the world widely. It has complex way of reproduction, strong ability of photosynthesis and fertilizer utilization and is not easily prevented. The current research was based on the plant morphological anatomy and the hormone detection technology to ascertain syngenesis relationship between initial flower bud differentiation and euphylla growth, dynamic analysis of endogenous hormones during flower bud differentiation, effect of exogenous gibberellin on flower sex differentiation and geotropic differentiation. As well as analyzing the seed clustering effect which accorded to the population distribution pattern.To provide the theoretical basis by seeking for the scientific, efficient and environmental protection means of controlling. The preliminary results were as follows:1. The syngenesis relationship between initial flower bud differentiation and euphylla growth showed that the top of eustipes began to differentiate when vegetative growth of seedlings was to 4-6 leaf stages. The process of flower bud differentiation which lasted for about 15 days was positively correlated with the number and the area of euphylla. In 4-leaf stage, flower bud differentiation entered bract primordium and inflorescence primordium differentiation period. In 5-leaf stage, flower bud differentiation entered sepal primordium and petal primordium differentiation period. In 6-leaf stage, flower bud differentiation entered stamen primordium and pistil primordium differentiation period and stamens completed differentiation earlier than pistil in bisexual flowers.2. Dynamic analysis of endogenous hormones during aerial flower bud differentiation showed that during flower bud differentiation of aerial male flowers, contents of auxin, zeatin and abscisic acid were almost at the same level, contents of gibberellin showed a declining trend which waved at petal primordium (contents at this period were 29.23 μg·g-1 FW) and stamen mature period (contents at this period were 32.92μg·g-1 FW). During flower bud differentiation of aerial bisexual flowers, contents of auxin and abscisic acid showed a significantly reducing volatility at petal primordium period (contents of auxin were 0.85μg·g-1 FW and contents of abscisic acid were 0.18μg·g-1 FW), contents of zeatin showed a significantly increasing volatility at pistil primordium period (concentrations were 4.46μg·g-1 FW). But contents of gibberellin fluctuated greatly, the highest contents in pistil mature period were 108.79μg·g-1 FW and the lowest contents in sepal primordium period were 66.02μg·g-1 FW.3. Ratio analysis of endogenous hormones during the aerial flower bud differentiation showed that causes of sex differentiation were associated with the dynamic balance of gibberellin. The hormonal ratio with gibberellin was significant difference in aerial male flowers and aerial bisexual flowers. Flower sex differentiation of aerial bisexual flowers regulated by high level of gibberellin while the hormone level of gibberellin relatively low in the whole flower sex differentiation process in male flowers.4. The effect of exogenous gibberellin and chlormequat chloride on aerial flower sex differentiation showed that high level of gibberellin could significantly reduce the differentiation of male flowers and promote the differentiation of bisexual flowers. Under 100 mg·L-1 treatment of gibberellin, the lowest incidence of male flowers was only 1.57% and the highest incidence of bisexual flowers was 98.43%.Treatments of gibberellin significantly delayed the initial flower bud differentiation and reduced the differentiation velocity. Effects of chlormequat chloride on flower sex differentiation were antagonistic to gibberellin but not significant in this study.5. Hormones effect on geotropic differentiation of flower bud showed that contents of gibberellin accumulated largely in two kinds of geotropic flower buds and the level of accumulation existed significant differences. Contents were 262.25μg·g-1 FW in surficial flower buds and 193.87μg·g-1 FW in hypogeal flower buds, but contents of auxin, zeatin and abscisic acid were almost at the same level in surficial and hypogeal flower buds. Gibberellin significantly inhibited the geotropic flower bud differentiation, hypogeal flower buds were at least 1.9 under the treatment of 500 mg·L-1. Effects of chlormequat chloride on geotropic flower bud differentiation were not significantly antagonistic to gibberellin.6. Effects of seed clustering mainly displayed in aerial large seeds and surficial large seeds, thoes seeds were very vigorous. Seed vigor of aerial small seeds and surficial small seeds would be improved and show some gathered germination advantages when mixed with its large seeds, however there hardly had seed clustering effect in hypogeal large seeds and hypogeal small seeds.