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Relative humidity has dramatic impacts on leaf morphology but little effect on stomatal index or density in Nothofagus cunninghamii (Nothofagaceae)
journal contribution
posted on 2023-05-17, 15:00 authored by Mark HovendenMark Hovenden, Jacqueline Vander SchoorJacqueline Vander Schoor, Osanai, YReconstructing past environmental conditions using proxies based on fossil and subfossil leaves is difficult because leaf form is influenced by many interacting environmental factors such as temperature, CO2 concentration, light, soil water availability and, potentially, atmospheric relative humidity (RH). We used a species important for palaeoenvironmental reconstruction, the southern beech, Nothofagus cunninghamii, to test for the effects of a 50% difference in RH on leaf morphology and epidermal anatomy in a glasshouse experiment. Leaf size, shape and thickness were all strongly affected by RH with leaves from high humidity being larger, narrower and thicker than those from low humidity regardless of plant accession. RH impacts on epidermal characters were generally slight and dependent upon accession. In particular, epidermal cell size was remarkably consistent across accessions and RH levels. Thus, gross leaf morphology of N. cunninghamii was sensitive to changes in RH but, on average, epidermal characters were not. Thus, palaeoenvironmental signals from the epidermis of this species are unlikely to be affected by variation in RH, provided sufficient numbers of leaves are investigated. Gross leaf morphology, however, was strongly related to RH and should not be used for palaeo-climatic reconstruction if changes in RH are likely.
Funding
Australian Research Council
History
Publication title
Australian Journal of BotanyVolume
60Issue
8Pagination
700-706ISSN
0067-1924Department/School
School of Natural SciencesPublisher
C S I R O PublishingPlace of publication
150 Oxford St, Po Box 1139, Collingwood, Australia, Victoria, 3066Rights statement
Copyright CSIRO 2012Repository Status
- Restricted