Influence of drought acclimation and CO sub 2 enrichment on osmotic adjustment and chlorophyll a fluorescence of sunflower during drought. [Helianthus annuus var Hyson 30]

Journal Article · Fri Apr 01 04:00:00 EST 1988 · Plant Physiology; (USA)

DOI:https://doi.org/10.1104/pp.86.4.1108· OSTI ID:6937875

Conroy, J P; Virgona, J M; Smillie, R M; Barlow, E W ^[1]

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1. Macquarie Univ., North Ryde (Australia) Commonwealth Scientific and Industrial Research Organization, North Ryde (Australia)

Osmotic adjustment occurred during drought in expanded leaves of sunflowers (Helianthus annuus var Hysun 30) which had been continuously exposed to 660 microliters CO{sub 2} per liter or had been previously acclimated to drought. The effect was greatest when the treatments were combined and was negligible in nonacclimated plants grown at 340 microliters CO{sub 2} per liter. The concentrations of ethanol soluble sugars and potassium increased during drought but they did not account for the osmotic adjustment. The delay in the decline in conductance and relative water content and in the loss of structural integrity with increasing drought was dependent on the degree of osmotic adjustment. The relative water content remained constant at 85% for three days and fell to 36% on the sixth day. There was no evidence of leaf desiccation even on the eighth day. In contrast, the conductance of leaves showing minimal adjustment fell rapidly after the first day of drought and was negligible after the fourth, at which time the relative water content was 36%. By the sixth day of drought, areas near the margins of the leaves were desiccating and the plants did not recover upon rewatering. Despite the differences in the rate of change of conductance and relative water content during drought, photosynthetic electron transport activity, remained functional until desiccation occurred.

• OSTI ID: 6937875
• Journal Information: Plant Physiology; (USA), Journal Name: Plant Physiology; (USA) Vol. 86:4; ISSN 0032-0889; ISSN PLPHA
• Country of Publication: United States
• Language: English

Related Subjects

551000* -- Physiological Systems
59 BASIC BIOLOGICAL SCIENCES
ALKALI METALS
BIOLOGICAL ADAPTATION
BIOLOGICAL EFFECTS
CARBOHYDRATES
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CARBOXYLIC ACIDS
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMISTRY
CHLOROPHYLL
DIFFUSION
DROUGHTS
ELEMENTS
FLUORESCENCE
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
LEAVES
LUMINESCENCE
MAGNOLIOPHYTA
MAGNOLIOPSIDA
METALS
MOISTURE
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OSMOSIS
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOCHEMISTRY
PHOTOSYNTHESIS
PHYTOCHROMES
PIGMENTS
PLANTS
PORPHYRINS
POTASSIUM
PROTEINS
RESPONSE MODIFYING FACTORS
SACCHARIDES
SUNFLOWERS
SYNTHESIS