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Diurnal cycles of leaf extension in unsalinized and salinized Beta vulgaris
Author(s) -
WALDRON L. J.,
TERRY N.,
NEMSON J. A.
Publication year - 1985
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/1365-3040.ep11604611
Subject(s) - darkness , salinity , chenopodiaceae , diurnal temperature variation , botany , sugar , horticulture , sodium , sugar beet , biology , chemistry , zoology , ecology , food science , physics , atmospheric sciences , organic chemistry
. Continuous high resolution measurement of sugar beet leaf extension over 5 d in growth chambers showed average leaf extension rates (LER) in darkness to be from three to six times those in light for plants growing in non‐salinized media. The changes in LER in light‐dark transitions occurred within seconds, a response which was more rapid than stomatal opening or closing. When the growth medium was salinized to 100 mol m −3 NaCl, LER's were reduced by about 50% in darkness and 90% in light, markedly increasing the ratio of dark to light LER. A 2‐d episode of root‐zone salinity imposed midway through a 5‐d period of measurement decreased LER and produced higher leaf temperatures. LER and diurnal leaf temperature patterns reverted to their pre‐salinized levels when root‐zone salinity was removed. Thus, the effects of short episodes of high sodium chloride in the growth medium appear to be reversible, suggesting a water stress mechanism of growth reduction rather than toxicity effects of salt.