Biodiv Sci ›› 2021, Vol. 29 ›› Issue (10): 1321-1335.DOI: 10.17520/biods.2021081

• Original Papers: Plant Diversity • Previous Articles     Next Articles

Sexual system characteristics of Lilium concolor var. megalanthum in peatland

Yeqin Du1, Di Zhang1, Sai Wang1, Lei Wang1, Xingfu Yan2,*(), Zhanhui Tang1,*()   

  1. 1 State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, School of Environment, Northeast Normal University, Changchun 130117
    2 Key Laboratory of Ecological Protection of Agro-pastoral Ecotones in the Yellow River Basin, National Ethnic Affairs Commission of the People's Republic of China, College of Biological Science and Engineering, Beifang Minzu University, Yinchuan 750021
  • Received:2021-03-07 Accepted:2021-06-25 Online:2021-10-20 Published:2021-10-20
  • Contact: Xingfu Yan,Zhanhui Tang

Abstract:

Aims The sexual system characteristics of flowering plant is a reproductive strategy gradually formed during the process of long-term adaptation and evolution, which affect the population structure of plant and its distribution pattern to a certain extent. Therefore, sexual system characteristics have always been a hot topic in the field of plant evolution and ecology.
Methods In this study, a survey was conducted to determine the sexual system characteristics and the proportion, density and spatial distribution pattern of Lilium concolorvar. megalanthum with different sexual phenotypes, and to explore the relationship between individual plant size and sexual expression in Jinchuan peatland of Jilin Province in 2012 and 2020. We compared the actual pollen fertility with different sexual phenotypes and the seed viability after pollination treatment with different pollination sources.
Results The results showed that at the plant level L. concolor var. megalanthum has three sexual phenotypes: male flower, hermaphrodite flower, and andromonoecy. At the population level, the plants with male flower act as male parents and transmit genes to the next generation through pollens, while the plants with hermaphrodite flower mainly act as female parents and transmit genes through ovules. The plant with male flower accounted for 39.14% of flowering plants in the population in 2020, which increased by 22.80% compared with the proportion in 2012. The population density of L. concolor var. megalanthum was 0.06 plants/m2in 2020, which was 0.09 plants/m2lower than that in 2012. Compared with 2012, the population density decreased and the relative proportion of plants with male flowers increased in 2020. Hermaphroditic and male flower plants mainly showed aggregated distribution in small scale, and tended to random distribution with the increase of scale. The plants with male flower are significantly smaller than plants with hermaphrodite flower, but the resource allocation of bulb is significantly higher than that of the plant with hermaphrodite flower. The sexual expression of L. concolor var. megalanthumfollowed the hypothesis of size- dependent sexual allocation. The smaller plant produces only one male flower, while the larger plant produces hermaphroditic flower or are andromonoecious. The results of seed set and germination of different pollination treatments showed that the seed set and fruit set of self-pollination are significantly lower than those of cross-pollination. There was no significant difference in pollen fertility between male and hermaphroditic flower plant. There was also no significant difference in seed viability pollinated by pollen from male and hermaphroditic flower plant.
Conclusion The appearance of male flower may be the result of L. concolor var. megalanthum adaptation to limited environmental resources, and it reflects the trade-off strategy between growth and reproduction of this plant under the stressful condition in peatland. The emergence of this sexual system has a certain adaptive significance for L. concolor var. megalanthum with the long-term peatland succession.

Key words: Lilium concolor var. megalanthum, size-dependent, sexual expression, pollen fertility, seed viability