Journal of Plant Ecology ›› 2023, Vol. 16 ›› Issue (4): 0-rtad003.DOI: 10.1093/jpe/rtad003

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  • 收稿日期:2022-03-23 修回日期:2022-05-10 接受日期:2023-01-10 出版日期:2023-08-01 发布日期:2023-02-23

Floral traits and pollination biology of Epimedium chlorandrum Stearn (Berberidaceae)

Yi-Fan Qian1,2, Wen Du3, Lan-Ying Chen4, Qiu-Mei Quan1,*, Yun-Xiang Li1,*   

  1. 1College of Environmental Science and Engineering, China West Normal University, Nanchong 637009, China;
    2Nanchong Ecological and Environmental Monitoring Central Station of Sichuan Province, Nanchong 637000, China;
    3Department of Languages and Literatures, North Sichuan College of Preschool Teacher Education, Guangyuan 628017, China;
    4College of Life Science, China West Normal University, Nanchong 637009, China
  • Received:2022-03-23 Revised:2022-05-10 Accepted:2023-01-10 Online:2023-08-01 Published:2023-02-23
  • Contact: E-mail: (Q.-M.Q.); (Y.-X.L.)

摘要: 植物花部特征的表达和进化是对生长环境长期适应的结果,生长环境的不同虽然会导致花部特征出现显著的差异,但是并不影响花在植物繁殖方面发挥的作用。淫羊藿属(Epimedium)植物具有雌雄异位和雌雄异熟机制,能有效地避免自交现象的发生,而恶劣的生长环境是否会使自交不亲和性发生改变?本文以生长于夜雨频发和潮湿环境中的绿药淫羊藿(Epimedium chlorandrum)为研究对象,通过野外观察绿药淫羊藿的花部特征和访花者,测定花粉数、胚珠数、花粉活力、柱头可授性、花蜜量和糖浓度以及人工授粉实验等方法,探究绿药淫羊藿的花部特征对其生长环境的适应性,以及花在传粉和繁殖中发挥的作用。研究结果表明,绿药淫羊藿的花朵向地生长,内萼片和高度弯曲的距共同形成了一把保护伞,保护花药和柱头免受雨水的冲刷,同时防止花蜜被雨水稀释;绿药淫羊藿的访花者共有6种,以花蜜为食的三条熊蜂(Bombus trifasciatus)是唯一的有效传粉者,其传粉效率与花蜜的含糖量呈正相关关系;绿药淫羊藿的每朵花能够分泌花蜜约17.06±0.57 µL,花蜜含糖量约为29.19±0.22 g/100 mL;花粉胚珠比约为7701.30 ± 116.85,表明绿药淫羊藿的繁育系统为专性异交类型;人工异交授粉和人工自交授粉处理均能结出可育种子,表明绿药淫羊藿是自交亲和的。综上所述,绿药淫羊藿受到夜雨频发和传粉者短缺的生长环境限制,自交亲和机制在一定程度上能够缓解花粉短缺的限制。

关键词: 夜雨, 花特征, 距状花瓣, 三条熊蜂(Bombus trifasciatus), 自交亲和性, 雄蕊先熟, 花蜜

Abstract: The evolution and expression of floral traits are responsive to selection pressure from biotic and abiotic factors. Although floral traits significantly vary among environments, the flower remains unchanged. We aimed to understand the adaptation of Epimedium chlorandrum of floral traits to a frequently nocturnally rainy and wet environments and the roles of floral traits in pollination and reproduction. We observed flowering phenology, measured floral characteristics including the number of pollen grains and ovules per flower, measured pollen viability and stigma receptivity, tested the volume and sugar concentration of nectar and conducted flower-visit observations in this species. Different pollination treatments were performed to characterize the breeding system. The inner sepals and highly curved longer spurs of E. chlorandrum jointly formed an umbrella that shielded the anthers and stigma from rain wash and prevented nectar dilution. Epimedium chlorandrum was visited by six species, while Bombus trifasciatus was the only effective pollinator and fed on the nectar. One flower secreted approximately 17.06 µL of nectar with a 29.19 g/100 mL sugar concentration, and the pollination efficiency of B. trifasciatus was positively associated with the nectar sugar concentration. The self- and open-pollination treatments resulted in fewer fertile seeds than the cross-pollination treatment. In contrast, the autonomous self- pollination treatment failed to yield fertile seeds. In summary, pollen limitation caused by harsh weather and pollinator shortage occurred during the pollination process of E. chlorandrum, which was partially alleviated by self-compatibility.

Key words: nocturnal rain, floral traits, spur-shaped petal, Bombus trifasciatus, self-compatibility, protandry, floral nectar