Photoinhibition of stem elongation by blue and red light. Effects on hydraulic and cell wall properties

Journal Article · Mon Apr 01 00:00:00 EST 1991 · Plant Physiology; (United States)

DOI:https://doi.org/10.1104/pp.95.4.1049· OSTI ID:5321839

Kigel, J; Cosgrove, D J ^[1]

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1. Hebrew Univ., Jerusalem (Israel) Pennsylvania State Univ., University Park (USA)

The underlying mechanism of photoinhibition of stem elongation by blue (BL) and red light (RL) was studied in etiolated seedlings of pea (Pisum sativum L. cv Alaska). Brief BL irradiations resulted in fast transient inhibition of elongation, while a delayed (lay approximately 60 minutes) but prolonged inhibition was observed after brief RL. Possible changes in the hydraulic and wall properties of the growing cells during photoinhibition were examined. Cell sap osmotic pressure was unaffected by BL and RL, but both irradiations increased turgor pressure by approximately 0.05 megapascal (pressure-probe technique). Cell wall yielding was analyzed by in vivo stress relaxation (pressure-block technique). BL and RL reduced the initial rate of relaxation by 38 and 54%, while the final amount of relaxation was decreased by 48 and 10%, respectively. These results indicate that RL inhibits elongation mainly by lowering the wall yield coefficient, while most of the inhibitory effect of BL was due to an increase of the yield threshold. Mechanical extensibility of cell walls (Instron technique) was decreased by BL and RL, mainly due to a reduction in the plastic component of extensibility. Thus, photoinhibitions of elongation by both BL and RL are achieved through changes in cell wall properties, and are not due to effects on the hydraulic properties of the cell.

• OSTI ID: 5321839
• Journal Information: Plant Physiology; (United States), Vol. 95:4; ISSN 0032-0889
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
PISUM
PLANT GROWTH
VISIBLE RADIATION
BIOLOGICAL EFFECTS
CELL WALL
HYDRAULICS
INHIBITION
PHOTOCHEMICAL REACTIONS
PLANT STEMS
CELL CONSTITUENTS
CHEMICAL REACTIONS
ELECTROMAGNETIC RADIATION
FLUID MECHANICS
GROWTH
LEGUMINOSAE
MAGNOLIOPHYTA
MAGNOLIOPSIDA
MECHANICS
PLANTS
RADIATIONS
551000* - Physiological Systems