The physiological light response of two tree speci

Authors: H J Dalmagro F de A Lobo G L Vourlitis  C Dalmolin M Z Antunes C E R Ortíz J de S Nogueira

Publish Date: 2013/11/21

Volume: 52, Issue: 1, Pages: 22-35

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Abstract

Tropical savanna ecosystems are extremely diverse and important for global carbon storage In the state of Mato Grosso tropical savanna locally known as the Cerrado turns from welldrained upland areas into seasonally flooded areas within the Pantanal however the Cerrado and the Pantanal share many common tree species such as Vochysia divergens a floodadapted tree native to the Amazon Basin and Curatella americana a tree adapted native to the welldrained the Cerrado We measured the photosynthetic light response of these species in the the Cerrado and the Pantanal over a 1year period to determine how these species physiologically adjust to these hydrologically distinct habitats We hypothesized that neither species would experience a significant decline in maximum lightsaturated photosynthetic rate P max in their naturalized habitat Physiological performance of each species was generally higher in the habitat that they were adapted to however our data indicated that both species have broad tolerance for seasonal variations in hydrology allowing them to tolerate seasonal drought during the dry season in the Cerrado and seasonal flooding during the wet season in the Pantanal In V divergens flexible wateruse efficiency higher specific leaf area SLA and a greater ability to adjust massbased P max P maxm to variations in leaf N and P concentration appeared to be key traits for withstanding prolonged drought in the Cerrado In C americana increases in SLA and higher nutrientuse efficiency appeared to be important in maintaining high rates of P maxm in the seasonally flooded Pantanal Flexibility in physiology and resourceuse efficiency may allow these species to survive and persist in habitats with broadly differing hydrology

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