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青藏高原三种高山植物的传粉适应
侯勤正
Subtype博士
Thesis Advisor刘 建 全
2010-06-05
Degree Grantor中国科学院研究生院
Place of Conferral北京
Degree Discipline生态学
Keyword管花秦艽 麻花艽 线叶龙胆 达乌里秦艽 繁殖策略 花持续期 繁殖保障
Abstract传粉生态学研究有助于揭示花特征的进化与适应机制,而极端环境为研究这一问题提供了很好的参照背景(context)。生长在青藏高原的植物为保证它们的生存必须发展出适应极端严酷生态环境的特殊繁殖对策,但对这些适应方式目前还了解较少。本论文选择3种典型高山植物进行了系统的野外观察和传粉生态适应研究。主要发现和结论如下:
1. 在青藏高原中国科学院海北高寒草甸生态系统定位研究站(海北站)地区中晚期开花植物管花秦艽的有效传粉昆虫为苏氏熊蜂,其传粉频率为0.026次/花/min;在开花过程中管花秦艽表现出避免单花自交的雌雄异熟和雌雄异位现象,但是苏氏熊蜂的株内连续访问率高达87.8%,因此会导致同株异花自交的广泛存在。与同域分布近缘种麻花艽的比较发现,尽管两物种在花颜色、形态以及花序设计上有较大差别,但都是由苏氏熊蜂访问;管花秦艽与麻花艽在物候上有较长时间重叠,表现出不完全的传粉生殖隔离状态。
2. 在海北站地区晚期开花植物线叶龙胆的有效传粉昆虫为苏氏熊蜂和克什米尔熊蜂,但是但其访花频率非常低, 分别为0.006和0.005次/花/min;在开花过程中线叶龙胆表现出雌雄异位和不完全雌雄异熟现象,无法避免花内小型昆虫(蚂蚁和蓟马)的协助自交,繁育系统实验表明,部分套袋结实就可能是蚂蚁和蓟马等小型昆虫的协助自交所制;线叶龙胆花持续期和柱头可授能力都长于其他已报道的龙胆类植物,从而在温度低、传粉昆虫少的情况下延迟了授粉时间,提供了更多传粉机会。
3. 在青海省西宁市地区附近开花植物达乌里秦艽花期在 6-9 月,在开花过程中
表现出雌雄异熟和雌雄异位现象,繁殖过程依赖传粉媒介;存在较大的花粉限
制,虽然在传粉昆虫不足情况下花寿命会有延长,但延长花寿命仅能部分弥补
传粉者的不足,该物种在部分居群中仍有可能存在花粉限制。达乌里秦艽的传
粉昆虫在不同居群、不同年份以及不同的开花阶段都有较大变化,而且昆虫的
访问频率在不同的居群和年份也有差异,表现出明显的泛化主义繁殖策略。这
种泛化主义式的繁殖模式可能是由于不同居群所处的生境造成,而这种繁殖模
式可能是达乌里秦艽维持后代更新的保障。
Other AbstractThe results of pollination ecology are important in understanding the evolution and adaptation process of flowers. The flowers in the extreme environment provide a more advantageous context for such a study. Alpine plants growing in the Qinghai-Tibetan Plateau (QTP) must have evolved diverse adaptive strategies to sustain their populations in the arid environment with low temperature, unpredictable raining, strong wind and high concentration of UV-B radiation. However, little is known of their reproductive adaptation and successful productions of offspring. In this dissertation, I studied the pollination adaptation of three alpine species during the past five years in the high altitude region of the QTP. My investigations recovered interesting and exciting reproductive strategies of these species and major finding are summarized as follows.
1. Gentiana siphonantha is a perennial which flowers in the late of the autumn growing season in the QTP. This species is outrcrossing and the dominant pollinators are bumblebees in both examined populations, the visit frequency averaged to 0.026time/flowe/min. early.Flowers of G. siphonantha are characteristic of dichogamy and herkogamy and this floral development prevents occurrence of autonomous self-pollination, but among the pollinators’ bouts, the proportions of geitonogamous visits within an individual plant occupy about 87.8%. Such a case implied that geitonogamous selfing prevails in this specie. Compared with G. straminea, a sympatric congener specie with G. siphonantha, their flower color, morphology and inflorescence design varied significantly, but they shared the same pollinator Bombus sushikin. Although these two species difered in flowering phenology, their flowering stages overlapped for a few days,suggesting incomplete
pollination isolation between them.
2. Gentiana lawrencei began to flower late in the QTP. The main pollinators were Bombus sushikin and B. kashmirensis, but their visit frequencies were low,averaged to 0.006 and 0.005 time/flower/min. Combined characters of herkogamy and incomplete dichogamy indicate that pollinators are needed for complete pollination. Some individuals of G. lawrencei could produce seeds under bagging without emasculation, and it may be from selfing caused by thrips and ants. Floral longevity and stigma receptivity are relatively long compared with other Gentianaceae species, and these increase the probability of pollination chances under low temperature and low pollinator conditions.
3. Gentiana dahurica flower at July-September in the Qing-hai Xi-ning region. It showed out combined characters of herkogamy and dichogamy, indicating pollinator was needed to complete reproductive success. A strong pollen limitation occurred in Gentiana dahurica. Although the flower longevity would prolong in case pollinators were lack, Gentiana dahurica showed out a strong pollen limitation in some populations. The flower visitor fauna as well as the visitor frequency had a significant year-to-year and site-to-site variation, indicating a “generalized” pollination system. The “generalized” pollination system may caused by its growing environment, and this kind of pollination system may play an important role in the reproductive success of Gentiana dahurica.
Subject Area植物学
Language中文
Document Type学位论文
Identifierhttp://210.75.249.4/handle/363003/3397
Collection中国科学院西北高原生物研究所
Recommended Citation
GB/T 7714
侯勤正. 青藏高原三种高山植物的传粉适应[D]. 北京. 中国科学院研究生院,2010.
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