Nonstomatal limitations are responsible for drought-induced photosynthetic inhibition in four C4 grasses

A - Papers appearing in refereed journals

Ghannoum, O., Conroy, J. P., Driscoll, S. P., Paul, M. J., Foyer, C. H. and Lawlor, D. W. 2003. Nonstomatal limitations are responsible for drought-induced photosynthetic inhibition in four C4 grasses. New Phytologist. 159 (3), pp. 599-608.

AuthorsGhannoum, O., Conroy, J. P., Driscoll, S. P., Paul, M. J., Foyer, C. H. and Lawlor, D. W.
Abstract

Here, the contribution of stomatal and nonstomatal factors to photosynthetic inhibition under water stress in four tropical C(4) grasses was investigated (Panicum coloratum, Bothriochloa bladhii, Cenchrus ciliaris and Astrebla lappacea ). Plants were grown in well watered soil, and then the effects of soil drying were measured on leaf gas exchange, chlorophyll a fluorescence and water relations. During the drying cycle, leaf water potential (Psi(leaf)) and relative water content (RWC) decreased from c. -0.4 to -2.8 MPa and 100-40%, respectively. The CO(2) assimilation rates (A) and quantum yield of PSII (Phi(PSII)) of all four grasses decreased rapidly with declining RWC. High CO(2) concentration (2500 mul l(-1)) had no effect on A or Phi(PSII) at any stage of the drying cycle. Electron transport capacity and dark respiration rates were unaltered by drought. The CO(2) compensation concentrations of P. coloratum and C. ciliaris rose sharply when leaf RWC fell below 70%. In P. coloratum, 5% CO(2) did not prevent the decline of O(2) evolution rates under water stress. We conclude that inhibition of photosynthesis in the four C(4) grasses under water stress is dependent mainly on biochemical limitations.

KeywordsPlant Sciences
Year of Publication2003
JournalNew Phytologist
Journal citation159 (3), pp. 599-608
Digital Object Identifier (DOI)doi:10.1046/j.1469-8137.2003.00835.x
Open accessPublished as non-open access
Funder project or code414
521
Project: 014148
ISSN0028646X
PublisherWiley

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