The response of leaf functional traits can provide vital insight into the adaptive strategies of plants under global change. However, acclimation of functional trade-off between leaf phenotypic plasticity and integration has been largely overlooked in seedlings, particularly within the context of enhanced nitrogen (N) deposition.
To understand how adaptive strategies promote plant fitness under N deposition, researchers from Xishuangbanna Tropical Botanical Garden (XTBG) evaluated the responses of leaf functional traits, their plasticity, and integration in dominant seedling species in a subtropical montane forest in Yunnan.
The researchers evaluated the changes of key leaf functional traits in two dominant tree seedling species (Machilus gamblei and Neolitsea polycarpa) in a subtropical montane forest through a two-year field N deposition experiment. Specifically, they examined the responses of 15 leaf functional traits to increased N treatments, and explored the shift of leaf economics spectrum (LES)-based resource acquisition strategies across various N deposition rates. Then, they determined the difference of phenotypic plasticity and integration of leaf traits between the two seedling species, and assessed the constrains of leaf phenotypic plasticity expression by its overall level of integration in those seedlings.
They found that an appropriate amount of N deposition promoted the development of seedling leaf traits toward the direction of faster resource acquisition, including improved N content, specific leaf area (SLA), and photosynthetic performance, which enabled the seedlings to better take advantage of increased N availability to compete in the understory.
Nevertheless, excessive N deposition might be detrimental for the development of leaf morphological and physiological traits, which inhibited the optimization of plants resource use efficiency, particularly in the process of photosynthesis.
Furthermore, the positive relationship between leaf phenotypic plasticity and phenotypic integration implies that the expression of leaf phenotypic plasticity is not constrained by its integration.
These findings imply that higher plasticity of leaf functional traits likely led to better integration than other traits in response to N deposition.
The study was published in Environmental Pollution.
"To our knowledge, this is the first study that confirms leaf phenotypic plasticity was not constrained by integration in subtropical forest tree seedlings, and the coordination between the variation of leaf functional traits and their association might facilitate the adaptation of plants to enhanced N deposition,” said SONG Liang of XTBG.
Contact
SONG Liang Ph.D Principal Investigator
Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
E-mail: songliang@xtbg.ac.cn
