壳斗科栎属果实的生物学研究
夏珂
学位类型博士
导师周浙昆
2010-01
学位授予单位中国科学院研究生院
学位专业植物学
摘要广义的栎属(Quercus, Fagaceae)包括青冈亚属(subgenus Cyclobalanopsis)和栎亚属(subg. Quercus),广泛分布于北半球的热带、亚热带和温带森林,其中的许多种类还是北半球森林的主要建群种和优势种。栎属是生产顽坳性种子的植物最重要的组成部分之一。它的种子/果实的生物学研究是顽坳性种子生物学研究的重要内容,对于理解顽坳性种子的生理学机制和生态意义都有着重大的意义。栎属的青冈亚属主要分布在亚洲热带和亚热带,该亚属种类丰富,许多种类是亚洲常绿阔叶林的优势种。但是迄今为止,青冈亚属的果实/种子生物学研究几乎还是空白。为了全面地了解栎属果实的生理特性,填补青冈亚属果实/种子生理学研究的空白;为了进一步理解栎属果实的生理特性及其与生态环境的关系,并有效地保护栎属植物,本论文研究了11种采自中国的青冈亚属和11种采自中国和欧洲的栎亚属植物果实的脱水耐性和它们的萌发特性,并定量研究了其中9种栎属植物果皮的形态解剖学特征,测定了其中18种栎属植物果实的含油量,并对滇青冈(Q. schottkyana)果实的年产量和锥象甲(Curculio sp.)的种群动态做了相关性分析,研究发现:1. 青冈亚属与栎亚属果实都属顽拗性,但果实对于脱水的反应在种间和种内表现出了明显的差异。2.栎属植物的果脐占果皮表面积的4%-37%,是大多数种类吸收水分的主要部分。水分由维管束直接迅速地进入果脐,并沿果皮不分化层中的维管束到达果皮各部分,形成一个水分传输的纵向系统。栎属果皮的形态解剖学特征能够影响果皮各部分的水流通量和水流量,并造成了栎属果实种间脱水速率的差异。3. 青冈亚属果实大多适宜在较高的温度 (25 °C)下萌发。低温可以降低青冈亚属果实的萌发速率,最终可能影响果实的萌发率,但不影响栎亚属果实的萌发率和萌发速率。青冈亚属和栎亚属果实萌发特性的差异表现出了它们对生态环境的适应。4. 青冈亚属果实的含油量(0.70-3.77%)显著低于栎亚属果实的含油量(1.48%-18.01%)。该结果与已报道的另39种栎属果实的含油量的数据相结合,表明栎属果实的含油量在亚属间和亚属内有与栎属分类学相关的差异性。5.  滇青冈果实的年产量有着明显的年际差异,一平方米的滇青冈纯林一年可以生产果实245-854粒,但其中14%-48%的果实会受到虫害。5-6月的降雨量可以影响滇青冈果实的年产量而9月和11月“干季信号”(低降雨量)能够引导滇青冈果实散播高峰期的开始和散播期的结束。滇青冈果实的产量与锥象甲种群有着密度制约关系。这种关系使得滇青冈和锥象甲的种群大小在相应的范围内以相同的趋势变动,呈现出周期性的循环。
资助项目The genus Quercus consists of subgenera Quercus and Cyclobalanopsis and has approximately 531 species, making this the largest and most widely distributed genus within the Fagaceae family, occurring throughout temperate and subtropical montane areas of the Northern Hemisphere. The occurrence of recalcitrant (desiccation-sensitive) seeded plants is common in the genus Quercus, making it one of the key genera for understanding the physiology and the ecology of recalcitrant seeds. Due to habitat loss and poor regeneration, some populations of the genus Quercus are now declining. Moreover, the limited availability of good-quality seed may lead to its natural regeneration problems. To understand the cause of the population decline and to conserve iteffectively, knowledge on the seed/fruit biology of Quercus is necessary. Despite this, the seed/fruit biology of the Asian Quercus species is largely overlooked and the seed/fruit biology of Quercus subgenus Cyclobalanopsis,which is predominately distributed across tropical and subtropical Asia, is less well documented. To provide new data on the fruit biology of subgenus Cyclobalanopsis and to understand the fruit physiology and ecology of the genus Quercus comprehensively for a conservation aim, the germination and desiccation response of 11 species of subgenus Cyclobalanopsis (from S and SW China) and 11 species of subgenus Quercus (from both SW China and Europe) were investigated. The anatomic characteristics of the fruit coats was analysed on 9 of these species and the oil contents were quantified from 18 of these species. In addition, a study was carried out over 4 years on the fruit production of Q. schottkyana (subgenus Cyclobalanopsis) to fill the gap in knowledge. The data demonstrate that: 1. All 22 species of subgenus Cyclobalanopsis and subgenus Quercus had desiccation-sensitive (recalcitrant) fruits. For these 22 species which had fruit dry masses spanning 0.57 to 6.41 g and seed coat ratios spanning 0.15 to 0.48, there were wide differences in drying rates (0.26-4.10 %d-1). These differences were independent of fruit mass and seed coat ratio, but were related to the morphology of the fruit coat.2. The scar, composing 4% to 37% (surface area) of the whole fruit coat, was found to be the main water passage for most species. Water transferred directly and quickly through the scar. From the scar through to the pericarp and ending at the apex, there was a longitudinal passage of water flow. The anatomic characteristics of the fruit coats controlled the water flux, which furthermore introduced the wide differences in drying rates between the Quercus species.3. In comparison to species of Quercus subgenus Quercus, fruits in subgenus Cyclobalanopsis germinated faster and most had maximum germination at the highest temperature of 25°C. At lower temperatures (15°C, 20°C), germination of subgenus Cyclobalanopsis was slower and the germination percentage of most species was decreased, but germination of species in subgenus Quercus was not affected at these low temperatures. The thermal requirements for the germination of these two subgenera suggested an adaptability of these fruits to their habitats.4. Fruit oil content of subgenus Cyclobalanopsis (0.70% to 3.77%) was significantly lower than that of subgenus Quercus (1.48 to 18.01%) and across the 18 species studied, moisture content of the storage tissue (cotyledons) was negatively related to fruit oil content. These data were combined with that from the literature, resulting in a total of 57 species, and mapped against the current phylogeny for Quercus to reveal the highest fruit oil contents associated with sect. Lobatae. 5. The fruit production of Q. schottkyana varied markedly between years. Each square meter of Q. schottkyana pure forest produced 245-854 fruits but 14%-48% of them were infected by weevils (Curculio sp.). The annual production of Q. schottkyana was most likely affected by the average monthly rainfall during May and June, but the time of fruit dispersal was related to the rainfall of September and November. The infestation rates of weevils were density-dependent on the fruit production of Q. schottkyana that furthermore regulated the populations of these two species.
语种中文
文献类型学位论文
条目标识符http://ir.kib.ac.cn/handle/151853/16048
专题昆明植物所硕博研究生毕业学位论文
推荐引用方式
GB/T 7714
夏珂. 壳斗科栎属果实的生物学研究[D]. 中国科学院研究生院,2010.
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