Biodiv Sci ›› 2018, Vol. 26 ›› Issue (5): 519-526.DOI: 10.17520/biods.2018038

• Original Papers • Previous Articles     Next Articles

Temporal variation of plant sexes in a wild population of Tulipa sinkiangensis over seven years

Juan Wang, Yaxin Zhai, Aiqin Zhang*()   

  1. College of Life Science and Technology, Xinjiang University, Urumqi 830046
  • Received:2018-02-05 Accepted:2018-04-26 Online:2018-05-20 Published:2018-09-11
  • Contact: Zhang Aiqin
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Abstract:

Understanding the variation in plant sexual strategies provides insights into the evolution of plant sexual systems. In hermaphrodite plants, floral gender is thought to be a plastic response that allows individuals to vary resource allocation to both female and male function under variable environmental conditions. Tulipa sinkiangensis is known to be hermaphroditic, early spring ephemeral plant, but our preliminary investigation showed that some populations had perfect flowers whereas other populations had staminate flowers. To understand correlates of occurrence and temporal variation of staminate flowers in T. sinkiangensis, we examined flower sex and its variation among individuals in a population of nearly 1,000 plants in Xinjiang, northwestern China from 2011 to 2017. (1) In the study population one-flower and two-flower plants comprised 74.5% (4,373) and 23.0% (1,358) of all flowering individuals (5,863), respectively. Sex differentiation was seen primarily in drier areas with shallow soils. Perfect and staminate flowers randomly occurred on different plants, constituting a hermaphroditic based population with some male and andromonoecious individuals. (2) Compared to perfect flowers, staminate flowers appeared later within individual plants and in the whole population during flowering. Staminate flowers were smaller and had aborted ovaries without visible ovules. However, pollen number and size, pollen morphology and fertility were not significantly different from perfect flowers when the two floral morphs were the same size. (3) During 2011 to 2014 of the study period, percentage of staminate flowers in the population declined from 23.4% to 3.1% but remained at stable (1.5% to 1.0%) from 2015 to 2017. The number of one-flower plants and two-flower plants fluctuated with time. (4) Our observations suggest that the production of staminate flowers in this endemic tulip flower was likely a plastic response to plant resource status, environmental conditions and other ecological factors.

Key words: Tulipa sinkiangensis, gender differentiation, staminate flowers, sex ratio, temporal variation