| 5种毛茛科植物个体大小依赖的繁殖分配和性分配 |
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| 引用本文： | 赵志刚,杜国祯,任青吉.5种毛茛科植物个体大小依赖的繁殖分配和性分配[J].植物生态学报,2004,28(1):9-16. |
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| 作者姓名： | 赵志刚 杜国祯 任青吉 |
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| 作者单位： | 1. 兰州大学干旱农业生态国家重点实验室,兰州,730000
2. 甘南州草原工作站,甘肃合作,747000 |
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| 基金项目： | 国家自然科学基金，甘肃省科技攻关项目 |
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| 摘 要： | 植物繁殖分配和性分配是生活史理论的核心问题，一直受到生态学家、进化生物学家们的关注。通过对青藏高原东部高寒草甸(3 500 m)及亚高山草甸(2 900 m)毛茛科5种虫媒两性花植物花期的繁殖分配和性分配的研究发现：1）个体越大，繁殖投入越高，繁殖分配越低，与以往研究结果一致；2）性分配是个体大小依赖的，大个体更偏向雌性器官的资源投入，花粉胚珠比与个体大小的关系较复杂，因种而异；3）花期雌雄功能之间存在资源分配上的权衡（Trade-off），并且种群之间有差异，表明其受环境条件影响。
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| 关 键 词： | 繁殖分配 性分配 生活史理论 高寒草甸 两性 |
SIZE-DEPENDENT REPRODUCTION AND SEX ALLOCATION IN FIVE SPECIES OF RANUNCULACEAE |
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| ZHAO Zhi-Gang,DU Guo-Zhen and REN Qing-Ji.SIZE-DEPENDENT REPRODUCTION AND SEX ALLOCATION IN FIVE SPECIES OF RANUNCULACEAE[J].Acta Phytoecologica Sinica,2004,28(1):9-16. |
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| Authors: | ZHAO Zhi-Gang DU Guo-Zhen and REN Qing-Ji |
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| Abstract: | Reproductive allocation and sex allocation are central to plant life-history theory. Especially in recent years, more and more ecologists and evolutionists have focused on the sex allocation theory. Reproductive allocation discusses the trade-off between growth and reproduction, and sex allocation primarily studies the optimal allocation of resources to two sexes, which may explain the diversity of breeding systems in plants. To examine the adaptation of size-dependent resource allocation and discuss the effective factors on resource allocation, the variations of reproductive and sex allocation of five insect-pollinated hermaphrodite species in Ranunculaceae were studied in two populations, located separately at East Tibetan Alpine Meadow (3 500 m) and Sub-Alpine Meadow (2 900 m). Sampling positions were located in Maqu (101°53′ E, 35°58′ N) and Hezuo (102°53′ E, 34°55′ N) in Gansu Province, respectively. From June to September in 2001, we sampled stochastically by the different phenology of five species at floral stage including under- and above-ground parts. The samples collected were individually enclosed into sampling bottles and fixed in FAA (alcohol, formaldehyde, acetic acid, 8∶1∶1). The samples were heated to constant weight for 10 h at 65 ℃. Each individual was dissected into different parts, such as flowers (androecium, gynoecium and corolla etc.), roots, stems and leaves, then were weighed under the Sartorius Balances (10-4 g), and P/O (pollen/ovule ratios per flower) were counted in haemacytometer under the microscope. Individual size is represented by vegetative biomass. Reproductive allocation is the proportion of biomass of total flowers to vegetative biomass; sex allocation is the proportion of androecium biomass to biomass of total flowers. We used the power function Y=aXb to analyse relationships between individual size and reproductive components.Our results showed: 1) in all five species, the reproductive investment increases but the proportion of reproduction (reproductive allocation) decreases with increased individual size, which is consistent with the previous conclusions, indicating size-dependency of reproductive allocation at flowering. 2) there is significant negative size-dependent sex allocation in these species, in that the larger individual allocates more resources to female function (i.e. gynoecium). This means that plants can adjust the resource allocation between the two sexes by its status at flowering to gain higher fitness. However, the relationship between P/O (pollen/ovule ratio) and size is complicated and differs among species. 3) the trade-off between male and female allocation existed, and is influenced by environment. This result confirms the assumption of sex allocation theory |
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| Keywords: | Size-dependent East Tibetan alpine meadow Reproductive allocation Sex allocation Ranunculaceae Insect-pollinated Hermaphrodite P/O |
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