【作者】 陈建业；

【导师】 石雪晖；

【作者基本信息】 湖南农业大学 ， 果树学， 2002， 硕士

【摘要】 沙田柚（Citrus grandis var．shatinyu Hort）是我国亚热带的名优果品，以其风味浓郁、耐贮藏等优良的经济性状而受到国内外消费者的青睐，但其种子偏多，因而影响了其商品价值和在国际市场上的竞争力。因此，进行沙田柚少核机理及其调控研究对促进沙田柚的商品生产具有重要意义。 1．为充分利用开发无核或少核品种，以吉首少核沙田柚为试材，在对吉首少核沙田柚性器官观察、分析的基础上，经自然授粉、花粉隔离和人工杂交授粉等处理，研究了其少核原因，并对吉首少核沙田柚的果实品质进行了测定。结果表明：吉首少核沙田柚单果平均种子数2-33粒；其雄性器官可育，雌性器官可孕；初步认为其少核机理可能是由于多数幼胚中途停止发育所致；少核沙田柚果皮变薄，可食率增加，但单果平均重、总糖含量、可溶性固形物含量与多核沙田柚有显著差异。本次研究结果，为沙田柚无核或少核品种资源的利用与开发提供了理论参考。 2．为探明少核沙田柚的坐果生理，以吉首少核沙田柚及其亲本品种为试材，对少核沙田柚与多核沙田柚内源激素动态变化进行比较研究。结果表明，少核沙田柚与多核沙田柚相同，授粉处理使少核沙田柚子房内源IAA、GA₃、CTK_s等生长促进物质的含量水平上升，且异花授粉上升幅度大于自花授粉。而ABA的含量水平也上升，但异花授粉减缓了ABA上升的速度，未授粉处理使沙田柚子房内源生长促进物质含量持续下降，ABA含量却急剧上升，由此可以初步认为吉首少核沙田柚不具有单性结实特性；少核沙田柚幼果内源激素含量变化在授粉后49-56d之间与多核沙田柚有差异。此期少核沙田柚幼果内IAA、GA₃、CTK_s有一个下降的阶段，而ABA水平却上升，这可能导致少核沙田柚的坐果率低于多核沙田柚，但仍保持相对较高的TAA水平和较低的ABA水平，并没有使少核沙田柚因缺乏种子而落果严重。 3．以普通沙田柚成年树为试材，研究了植物生长调节剂诱导其单性结实的效果及对果实品质的影响。用一定浓度的IAA+GA₄₊₇+6-BA的混合液于花瓣全露期和花后7天进行涂花处理，并以红囊柚的花粉人工授粉为对照。结果表明，外源生长调节剂可成功的诱导沙田柚单性结实，获得无籽果实，果实品质与多核沙田柚果实相比，可溶性固形物、总糖、总酸、维生素C含量等均无显著差异，且果皮厚度减少，可食率明显增加，具有较高的商品价值。但坐果率偏低，果实略小，其中以IAA150mg／L+GA₄₊₇100mg／L+6-BA100mg／L和IAA150mg／L+GA₄₊₇150mg／L+6-BA100mg／L的混合液处理效果较好。更多还原

【Abstract】 Shat i anyou (Ci trus grandis Osbeck), a famous subtropical fruit in our country, was enjoyed by consumers all over the world because of its super economical characters, such as full flavour and strong storability. However, its commercial value and competitive ability in the international market were affected by excessive seeds. Therefore, studies on the seedless mechanism and regulation have important significance for the production of Shatianyou.l.Jishou Shatianyou, a seedless pummelo, was used as material to investigate its quality and seedless causation by treating with pollen isolation, natural and artificial pollination based on the examination and analysis of its sexual organs. The results showed that the average seed number per fruit ranged from 2 to 33. Its male and female organs were fertile. Abortion of most embryos was considered as the causation of the seedlessness. With the fruit coat becoming lighter, the edible section increased, while the average weight per fruit, contents of sugar and soluble solids decreased. The results provide referential bases for exploring and utilizing variety resources of seedless pummelo.2. In order to prove fructuation mechanism of seedless Shatian pummelo, Jishou seedless Shatian pummelo and its parent cultivars were used as materials for endogenous hormonal analysis. The results are as follows: Similar to common seedy Shatian pummelo, the content of growth promoting substances in ovaries, such as endogenous IAA^ GA3v CTKS, were increased by the treatment of pollination. The increasing range of the growth promoting substances under the treatment of cross-pollination was bigger than that under the treatment of self-pollination. The content of ABA also increased. But the decreasing speed of the cross-pollination treatment was slower than that of self-pollination treatment, the endogenous promotive hormone contents in non-pollinated ovary kept in a low level, While ABA content increased. The change patterns of endogenous hormones were different between young fruits of seedless Shatian pummelo and common seedy Shatian pummelo during 49~56d after pollination. During this period, the levels of endogenous It\.t\.^ GA3> CTKS in young fruits of seedless Shatian pummelo were decreased, while ABA content increased. That is the reasonwhy the fructuation rate of seedless Shatian pummelo was lower than that of common seedy Shatian puramelo. But the endogenous IAA was still kept in a higher level and ABA was kept in lower level. The fruit abscission was not serious, although it has fewer seeds.3. Using common adult shatian pummelo as materials, the effects on fruit quality and parthenocarpy of plant growth regulators were studied. IAA+GA4+7+6-BA solution was sprayed before flowering and 7d after flowering, and the Hongrang pummelo-pollination was considered as the control(CK). The results showed that plant growth regulator at appropriate phase can successfully induce the parthenocarpy; the quality of seedless fruits is similar to that of the control, the fruit peel became lighter, the rate of edible section increased. But the rate of fructuation is lower and the fruit weight is reduced. Treatments of IAA 150mg/L+ GA4+- 100mg/L+6-BA lOOmg/L and IAA 150mg/L+ GA4,- 150mg/L+6-BA lOOmg/L were found to be better than others.更多还原