【作者】 张映；

【导师】 刘富中；

【作者基本信息】 中国农业科学院 ， 蔬菜学， 2008， 硕士

【摘要】 茄子是喜温蔬菜作物,在温室越冬栽培、塑料大棚早春栽培及春季露地早熟栽培时,开花期常由于低温弱光引起授粉受精不良,导致落花、落果和效益降低。生产上急需耐低温弱光的茄子品种。单性结实性能克服低温引起的落花落果障碍,增强座果能力,提高产量,同时还可改进果实质量、降低栽培成本。本试验在茄子单性结实评价方法、表达特性和遗传规律等研究的基础上,研究其在逆境下的表达效应及其形成的分子机制。本试验以单性结实品系为试材,研究了茄子单性结实基因在冬温室、春温室和春露地不同环境条件下的表达效应;在自然低温条件下不同的授粉方式和花粉活力对茄子单性结实形成和果实发育的影响;利用cDNA-AFLP技术,从转录组学方面比较分析了单性结实品系与非单性结实品系果实发育过程中基因表达的差异。其主要研究结果如下:1.茄子单性结实品系D-55、D-56、D-62的单性结实性属温度敏感型,其单性结实基因的表达受温度的调控,单性结实基因在日平均最低温度为12.8℃的条件下能完全表达。2.单性结实品系比非单性结实品系更耐低温、弱光。通过冬温室、春温室以及早春露地试验表明,茄子单性结实品系及其F1代在自然低温条件下自然授粉时有较高的座果率,在正常的栽培条件下可获得较高的产量,表现出了较强的低温、弱光适应性和生产潜力。单性结实品系可用于耐低温优质茄子新品种的选育和种质材料的创新。3.供试单性结实品系的单性结实性与低温下花粉的活力无显著相关。通过分析开花温度、培养温度对茄子花粉活力的影响表明,单性结实品系和非单性结实品系的花粉在日平均最低温度16.1℃时均具有一定的活力,在培养温度18℃下花粉发芽率均较低,为1.88～7.29%,品系间差异不显著。通过低温下茄子的花粉活力、座果率和单性结实率的相关性研究表明,低温下花粉的活力与单性结实现象无显著相关,单性结实并非由于低温下花粉活力下降所致,单性结实的形成与花粉活力无关。4.花粉萌发培养基、培养温度和开花温度试验表明,茄子花粉萌发需要一定量的糖分和硼酸作为营养,但浓度过高则会抑制花粉萌发,以0.5%琼脂+ 5%蔗糖+ 10 mg·L-1硼酸的培养基效果最好,花粉萌发率最高。开花温度、培养温度及其交互作用对花粉萌发率的影响达到极显著水平,在低温(开花温度12.6℃、培养温度15℃)下花粉萌发率最低,在25℃培养条件下,花粉萌发率显著提高,25℃是茄子花粉发芽较适宜的温度。5.自然授粉、人工授粉和去柱头三种处理不影响单性结实品系果实的正常生长发育。茄子单性结实品系去柱头后果实纵横径的发育速度与自然授粉相比,表现出高度的一致性。单性结实材料在低温条件下未经花粉诱导和受精,其果实可正常生长发育,表明供试单性结实材料果实生长发育所需激素的来源并不依赖于种子的发育。低温下辅助授粉有利于非单性结实基因型果实的座果和生长发育。6.应用cDNA-AFLP方法,以茄子子房和果实为研究对象,研究低温和适温下单性结实基因的差异表达。通过120对引物组合的筛选,共分离了92条差异表达的TDFs。其中14条可能与单性结实的形成有关,并成功回收4条,对其进行克隆、测序和序列分析。结果表明:4个TDFs分别与糖荚豌豆的果荚储藏过程中与衰老相关蛋白基因、番茄成熟果实中的cDNA片段、番茄叶片中受外界病原菌诱导的cDNA片段和菜豆的18S rRNA序列有较高的相似性。这些基因可能会对核糖体的结构和合成,以及与果实成熟和衰老相关的蛋白合成产生影响,从而影响种子的形成和果实的膨大。更多还原

【Abstract】 Eggplant (Solarium melongena L.) is warm required vegetable. In flowering stage low temperature often induced bad pollination and fertitization, induced flower and fruit drop, and reduced income. The low temperature and weak light tolerance varieties are in urgent need in production. Parthenocarpy can conquer flower and fruit drop caused by low temperature, enhance the ability of fruit setting, increase yield, improve fruit qualities and decrease culture cost. The experiment researched the expression effects and its molecular genetic mechanism.The parthenocarpic eggplant cultivars were used in this study. This experiment studied the expreesion effects of parthenocarpic cultivars in winter greenhouse, spring greenhouse and spring field, the influence of pollen viability and different pollination methods to the parhenocarpic fruit formation and development. Furthermore, the cDNA-AFLP technology was used to compare and analyze the defferential expression of parthenocarpic cultivars and unparthnocarpic cultivars fruit. The main results were summed as follows:1. The parthenocapic lines D-55, D-56 and D-62 are temperature sensitive type. The expression of parthenocarpic gene is contolled by temperature, and the parthenocarpic gene can completely express at the average daily lowest temperature 12.8℃.2. Compared with unparthenocarpic cultivars, the parthenocarpic cultivars can tolerant low temperatures and weak light. Though the experiments of winter greenhouse, spring greenhouse and early field, the result showed that parthenocarpic cultivar and its F1 hybridization hold higher ratio of fruit setting under natural pollination, obtain higher yield, revealed adaptabilities for low temperature and weak light, and yield increasing potential. The parthenocapic cultivars can be used for new varieties breeding for low temperature resistance and create new germplasm.3. The parthenocarpic characteristic of the parthenocarpic lines have no significant relationship with pollen viability. Though analysis the influence of flowering temperature and culture temperature to pollen viability, the pollen of both parthenocarpic cultivars and unparthenocarpic cultivars have certain viability at the average daily lowest temperature 16.1℃. At the culture temperature 18℃the ratio of pollen germination is lower, it is 1.88～7.29%, and there is no significant differenc among cultivars. Through analysis pollen viability, ratio of fruit setting and ratio of parthenocarpy in low temperature, it revealed that there is no significant correlation between pollen viability and parthenocarpy. Parthenocarpy is not reduced by the decreasing of pollen viability. The formation of parthenocarpy fruit may have no relation with pollen viabity.4.The experiment for screening pollen germination medium and culture temperature showed that the germination of eggplant pollen need a certain amount sugar and boric acid, but if the concentration is too high it will hold back germination. The best culture medium is 0.5% agar + 5% sugar + 10mg·L-11 boric acid. it have the highest germination rate. The impacts of florescence temperature, culture temperature and their interaction to pollen germination are very significant. The ratio of germination is the lowest in low temperature, and when the culture temperature is 25℃, the germination rate greatly increased.5. The three treatments of natural pollination, controlled pollination and stigma treatment have no influence on parthenocarpic fruit growth and development. The speed of fruit development with stigma treatment was very accordant to the fruit with natural pollination. The parthenocarpic fruit can set and develop normally without pollination and fertilization, the result showed that the hormone for fruit growth and development of tested parthenocarpic cultivars isn’t dependent on the development of seeds. The controlled pollination can help fruit setting and developing of unparthenocarpy cultivars.6. cDNA-AFLP approach was used to detect differently expressed genes in ovary and fruit between parthenocarpy and unparthenocarpy cultivars under low temperature and suitable temperature. 120 pairs of primer were used for selective amplification. 92 TDFs were selected for the differential expression in different cultivar or stage. Among 92 TDFs, 14TDFs may related to parthenocarpy, 4 TDFs were cloned and sequenced, and expression patterns of 2 TDFs were conformed by RT-PCR approach. Compared with the publicly available databases, the 4 sequenced TDFs presented some significant similarity with the gene of putative senescence-associated protein, Lycopersicon esculentum maturing fruit gene, the gene of Solanum lycopersicum cDNA sequence, Phaseoleae environmental sample clone 18S ribosomalRNA gene. These genes may affect the structure and synthesis of ribosome, and influence the synthesis of maturing and senescence-associated protein, thus influence the seeds formation and fruit enlargement.更多还原