Osmoregulation in Vicia faba guard cells during a daily cycle of opening

Conference · Sat May 01 00:00:00 EDT 1993 · Plant Physiology; (United States)

OSTI ID:6247959

Talbott, L D; Zeiger, E ^[1]

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1. Univ. of California, Los Angeles (United States)

Previous work from several laboratories has shown that Vicia guard cells in epidermal peels can use ions (K[sup +], Cl[sup [minus]]), organic acids (mainly malate) and carbohydrate (mainly sucrose) as osmotica during stomatal opening. Experimental manipulation of light quality can separate distinct osmoregulatory pathways: under red light, guard cells accumulate sucrose, and under blue light, there is starch breakdown, transient potassium and malate increase in the early opening phase, and accumulation of sucrose in later phases. In the present study, we measured carbohydrate and organic acid content in stomata of intact leaves from green house and growth chamber-grown plants over a daily cycle of opening. At each time point, abaxial epidermal peels were removed manually, sonicated, and used for aperture measurements and HPLC analysis. In both growing condition, transient malate accumulation was seen primarily during predawn opening and the initial rapid phase of opening in the early morning (approx. 1.5 fold increases, 2.5 hour durations). A second phase of malate accumulation was sometimes seen during the period of maximum mid-day opening. Mid-day and afternoon apertures were supported primarily by accumulation sucrose(three-fold increase at mid-day), which began in the mid-morning and did not decline until stomata closed in the evening. Starch breakdown, as indicated by maltose levels, occurred primarily during periods of malate accumulation. These data indicate that both the sugar and the malate-potassium osmoregulatory pathways are used in isolated guard cells and the intact leaf for stomatal movements. Selective use of each pathway could be related to the required rate of opening, and the perception of different environmental signals.

• OSTI ID: 6247959
• Report Number(s): CONF-9307119-; CODEN: PLPHAY
• Journal Information: Plant Physiology; (United States), Vol. 102:1; Conference: 1993 joint annual meeting of the American Society of Plant Physiologists (ASPP) and the Canadian Society of Plant Physiologists (CSPP), Minneapolis, MN (United States), 31 Jul - 4 Aug 1993; ISSN 0032-0889
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
OSMOSIS
BIOLOGICAL PATHWAYS
PLANT CELLS
VICIA
STOMATA
BIOLOGICAL ACCUMULATION
IONS
LEAVES
MALTOSE
MEMBRANE TRANSPORT
ORGANIC ACIDS
POTASSIUM
SACCHAROSE
VISIBLE SPECTRA
ALKALI METALS
CARBOHYDRATES
CHARGED PARTICLES
DIFFUSION
DISACCHARIDES
ELEMENTS
LEGUMINOSAE
MAGNOLIOPHYTA
MAGNOLIOPSIDA
METALS
OLIGOSACCHARIDES
OPENINGS
ORGANIC COMPOUNDS
PLANTS
SACCHARIDES
SPECTRA
550200* - Biochemistry