Photosynthesis–nitrogen relationships in tropical forest tree species as affected by soil phosphorus availability: a controlled environment study

Bloomfield, Keith J., Farquhar, Graham D., and Lloyd, Jon (2014) Photosynthesis–nitrogen relationships in tropical forest tree species as affected by soil phosphorus availability: a controlled environment study. Functional Plant Biology, 41 (8). pp. 820-832.

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View at Publisher Website: http://dx.doi.org/10.1071/FP13278
 
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Abstract

Tropical soils are often characterised by low phosphorus availability and tropical forest trees typically exhibit lower area-based rates of photosynthesis (Aa) for a given area-based leaf nitrogen concentration ([N]a) compared with plants growing in higher-latitude, N-limited ecosystems. Nevertheless, to date, very few studies have assessed the effects of P deprivation per se on Aa ↔ [N]a relationships in tropical trees. Our study investigated the effect of reduced soil P availability on light-saturated Aa and related leaf traits of seven Australian tropical tree species. We addressed the following questions: (1) Do contrasting species exhibit inherent differences in nutrient partitioning and morphology? (2) Does P deprivation lead to a change in the nature of the Aa ↔ [N]a relationship? (3) Does P deprivation lead to an alteration in leaf nitrogen levels or N allocation within the leaf? Applying a mixed effects model, we found that for these Australian tropical tree species, removal of P from the nutrient solution decreased area-based photosynthetic capacity (Amax,a) by 18% and reduced the slope of the Amax,a ↔ [N]a relationship and differences among species accounted for around 30% of response variation. Despite greater N allocation to chlorophyll, photosynthetic N use efficiency was significantly reduced in low-P plants. Collectively, our results support the view that low soil P availability can alter photosynthesis–nitrogen relationships in tropical trees.

Item ID: 38837
Item Type: Article (Research - C1)
ISSN: 1445-4416
Keywords: carboxylation capacity, leaf nutrient partitioning, leaf trait relationships, phosphorus deprivation, ribulose biphosphate regeneration
Funders: UK Natural Environment Research Council, Royal Society of London UK-Australia Exchange Award, Australian Research Council (ARC)
Projects and Grants: UK Natural Environment Research Council Reference NE/F002165/1, ARC DP0986823
Date Deposited: 12 May 2015 06:12
Downloads: Total: 5
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