RT Journal Article
SR Electronic
T1 Stomatal anatomy, leaf structure and nutrients of tropical rainforest tree species respond to altitude in a coordinated manner in accordance with the leaf economics spectrum
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2022.01.16.476499
DO 10.1101/2022.01.16.476499
A1 Bhagya Weththasinghe
A1 Iroja Caldera
A1 Nimalka Sanjeewani
A1 Dilum Samarasinghe
A1 Himesh Jayasinghe
A1 Asanga Wijethunga
A1 Janendra De Costa
YR 2022
UL http://biorxiv.org/content/early/2022/01/17/2022.01.16.476499.abstract
AB Understanding taxon level responses of key plant traits to environmental variation across tropical rainforests (TRFs) is important to determine their response to climate change. We used an altitudinal gradient (from 150 to 2100 m above sea level, asl) across TRFs in Sri Lanka to answer the following questions: (a) Does the response to altitude by stomatal traits differ among plant taxa in TRFs?; (b) Are the altitudinal responses of key leaf structural traits (e.g. leaf mass per area, LMA) and major leaf nutrient (nitrogen, N, and phosphorus, P) concentrations linked to the corresponding variation in stomatal traits in a coordinated response across taxa?; (c) How strong is the influence of climatic variation on responses of leaf traits to altitude?. Leaf samples were collected in permanent sampling plots within rainforest reserves at Kanneliya (150 m asl), Sinharaja-Enasalwatta (1050 m), Hakgala (1800 m) and Piduruthalagala (2100 m) from 19 species in three plant genera (Calophyllum, Semecarpus and Syzygium). Stomatal density, guard cell length and epidermal density showed variation among taxa, but did not respond to altitude. Potential conductance index (PCI), a proxy for photosynthetic capacity, decreased with increasing altitude, in a common response across taxa. We found evidence that altitudinal responses of LMA, leaf N and P were linked to stomatal responses in a coordinated manner, where key features were the negative correlations between PCI and LMA and between proxy photosynthetic N- and P-use efficiencies (‘PNUE’ and ‘PPUE’) and LMA. We found strong responses to climatic variation across taxa and altitudes, where PCI, ‘PNUE’ and ‘PPUE’ increased and LMA decreased with increasing temperature, precipitation and solar irradiance. We conclude that stomatal traits of tree species in TRFs form part of a coordinated leaf trait response to environmental change which is in accordance with the leaf economics spectrum.Competing Interest StatementThe authors have declared no competing interest.