强化条件下白桦提早开花结实的机理研究

Firstly, the anatomic study of the development of male and female flower, the megasporegensis, microsporegensis and the development of embryo in Betula platyphylla indicated that: due to the growth of male inflorescence primordium, inflorescences and bracts were differentiated from the end of May to the beginning of June. In the late of June, the inflorescence and the bracts of male flower became bigger and bigger, globular male flower primordium appeared on the bract. The differentiation of stamens undergone from Later June till Middle July. Meiosis was happened in earlier August. Then microspore mother cell turned into tetrad in the middle of August. After that it was isolated into four independent microspores and germinal aperture appeared. Then they stoped growing and development until next spring when the microspores got mature. On the basis of the anatomic observation, the time for studying flower-timing gene and soluble proteins of the initiation of flower was identified from Late May to Early June, the exactly time was varied by the change of the temperature..Secondly, the investigation of the relationship between 4 endogenous hormone during the development of male flower of Betula platyphylla and flowering and bearing showed that GA3 content always maintained at a low level during male flower bud development. It appeared that GA3 did not effect the whole development of male flower, significantly. The change of ABA, IAA, ZR contents fluctuated in a certain level when inflorescence started to differentiate and male flower primordium came into being, but the change trend of those three hormones were increasing for the development of male flower in the end of the May to the end of June. However, the ABA content varied in the oposite way to ZR and IAA, approximately. This interaction maybe promote the differentiation of male inflorescence meristem..Thirdly, flower-timing genes related in flower initiation of Betula platyphalla were cloned by using RT-PCR technology. First, we overcame the difficulty which involved RNA extraction in flower bud tissues that are full of hydroxybenzene compounds, amylose and some unknown second metabolizable products. It proposed 3 extraction methods of birch flower buds: CTAB、CTAB-DNAase digest method and SDS-DNAase digest method. And the initial reversion transcription system were established for birch flower buds tissue. After optimized amplified system and amplification process, RT-PCR technology system was established elementarily. Next, 3 bands of DNA fragment wereisolated. it showed that one of the bands had 80 percentage of homology with pectinesterase gene after sequencing analysis. The other two are in the process of analyzing..Finally, the change of soluble protein in male flower buds of Betula platyphylla was studied using SDS-PAGE and two dimensional electrophoretic analysis. We have established optimized method for extracting soluble protein and silver staining. That is to say the modified acetone diposition method(extraction solution I)was used to extract the protein, the sample was 10μg, AgNO3 concentration was 0.16% in the silver dyeing medicament, and the time for staining was 12min. We have got three distinct protein spots and the peptide mass spectrum analysis of them are undergoing..

在塑料大棚内，通过控制温度、光照、施肥、湿度、处理、施加外源激素及二氧化碳等综合及单一措施、使白桦开花结实时间由自然条件下15-20年缩短到2-3年。研究单一或多种条件变化与开花结实的关系，弄清影响白桦提早开花结实机理，缩短白桦育种周期、加速白桦遗传改良、提供天然林保护工程又一新的造林树种具有重要理论意义和生产实践价值。