Photosynthesis and water-use efficiency of seedlings from northern Australian monsoon forest, savanna and swamp habitats grown in a common garden

Kim Orchard, Lucas Cernusak, Lindsay Hutley

    Research output: Contribution to journalArticle

    Abstract

    Islands of monsoon rainforest and Melaleuca swamp punctuate vast tracts of savanna in monsoonal northern Australia. Seedlings of species from each of these habitat associations were grown in a common garden. Monsoon forest species had higher specific leaf area, lower photosynthetic capacity and lower photosynthetic light compensation points, and required lower irradiance to achieve 50% of light-saturated photosynthesis compared with savanna or swamp species. These traits probably contribute towards greater shade tolerance beneath dense monsoon-forest canopies, whereas savanna and swamp canopies are relatively open. Swamp species, especially two Melaleuca species, had high stomatal conductance and small CO 2 drawdown during photosynthesis, and more negative leaf 13C, compared with monsoon forest and savanna species. Higher stomatal conductance increases carbon uptake during photosynthesis and a high transpiration rate would increase transport of nutrients to absorbing surfaces in the root by mass flow. Thus, a strategy of high transpiration and low water-use efficiency appears to be favoured in swamp species compared with monsoon-forest and savanna species. Instantaneous measurements of the ratio of intercellular to ambient CO 2 concentrations (c i/c a) explained 81% of variation in leaf 13C across 44 species sampled in this and other studies, suggesting that leaf 13C generally provides a robust proxy for comparisons of c i/c a, even when applied across species. � 2010 CSIRO.
    Original languageEnglish
    Pages (from-to)1050-1060
    Number of pages11
    JournalFunctional Plant Biology
    Volume37
    Publication statusPublished - 2010

    Fingerprint Dive into the research topics of 'Photosynthesis and water-use efficiency of seedlings from northern Australian monsoon forest, savanna and swamp habitats grown in a common garden'. Together they form a unique fingerprint.

    Cite this