Plant Diversity ›› 2024, Vol. 46 ›› Issue (02): 265-273.DOI: 10.1016/j.pld.2023.04.001

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Photosynthetic response dynamics in the invasive species Tithonia diversifolia and two co-occurring native shrub species under fluctuating light conditions

Ju Lia,b, Shu-Bin Zhanga, Yang-Ping Lia   

  1. a. CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla 666303, Yunnan, China;
    b. University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2023-01-11 Revised:2023-03-15 Online:2024-03-25 Published:2024-04-07
  • Contact: Yang-Ping Li,
  • Supported by:
    This study was financially supported by the National Natural Science Foundation of China (Grant number: 32071661). We are grateful to the Institutional Center for Shared Technologies and Facilities of Xishuangbanna Tropical Botanical Garden, (CAS) for measuring the chemicals, and the National Forest Ecosystem Research Station of Xishuangbanna for providing the Li-6800 portable photosynthesis system.

Abstract: To determine the invasiveness of invasive plants, many studies have compared photosynthetic traits or strategies between invasive and native species. However, few studies have compared the photosynthetic dynamics between invasive and native species during light fluctuations. We compared photosynthetic induction, relaxation dynamics and leaf traits between the invasive species, Tithonia diversifolia and two native species, Clerodendrum bungei and Blumea balsamifera, in full-sun and shady habitats. The photosynthetic dynamics and leaf traits differed among species. T. diversifolia showed a slower induction speed and stomatal opening response but had higher average intrinsic water-use efficiency than the two native species in full-sun habitats. Thus, the slow induction response may be attributed to the longer stomatal length in T. diversifolia. Habitat had a significant effect on photosynthetic dynamics in T. diversifolia and B. balsamifera but not in C. bungei. In shady habitat, T. diversifolia had a faster photosynthetic induction response than in full-sun habitat, leading to a higher average stomatal conductance during photosynthetic induction in T. diversifolia than in the two native species. In contrast, B. balsamifera had a larger stomatal length and slower photosynthetic induction and relaxation response in shady habitat than in full-sun habitat, resulting in higher carbon gain during photosynthetic relaxation. Nevertheless, in both habitats, T. diversifolia had an overall higher carbon gain during light fluctuations than the two native species. Our results indicated that T. diversifolia can adopt more effective response strategies under fluctuating light environments to maximize carbon gain, which may contribute to its successful invasion.

Key words: Invasive plant, Photosynthetic induction, Photosynthetic relaxation, Carbon gain, Stomatal traits, Tithonia diversifolia