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Contrasting nonstructural carbohydrate dynamics of tropical tree seedlings under water deficit and variability
Author(s) -
O'Brien Michael J.,
Burslem David F. R. P.,
Caduff Alexa,
Tay John,
Hector Andy
Publication year - 2015
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.13134
Subject(s) - seedling , biology , photosynthesis , stomatal conductance , drought resistance , resistance (ecology) , botany , agronomy , transpiration , horticulture
Summary Drought regimes can be characterized by the variability in the quantity of rainfall and the duration of rainless periods. However, most research on plant response to drought has ignored the impacts of rainfall variation, especially with regard to the influence of nonstructural carbohydrates ( NSC s) in promoting drought resistance. To test the hypothesis that these components of drought differentially affect NSC dynamics and seedling resistance, we tracked NSC in plant tissues of tropical tree seedlings in response to manipulations of the volume and frequency of water applied. NSC concentrations decreased in woody tissues under infrequent–high watering but increased under no watering. A faster decline of growth relative to stomatal conductance in the no watering treatment was consistent with NSC accumulation as a result of an uncoupling of growth and photosynthesis, while usage of stored NSC s in woody tissues to maintain function may account for the NSC decline under infrequent–high watering. NSC s, and specifically stem NSC s, contributed to drought resistance under severe water deficits, while NSC s had a less clear role in drought resistance to variability in water availability. The contrasting response of NSC s to water variability and deficit indicates that unique processes support seedling resistance to these components of drought.