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EFFECTS OF LOCALIZED AND OVERALL WATER STRESS ON ASSIMILATE PARTITIONING IN BARLEY BETWEEN SHOOTS, ROOTS AND ROOT EXUDATES
Author(s) -
SHONE M. G. T.,
WHIPPS J. M.,
FLOOD ANN V.
Publication year - 1983
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.1983.tb03526.x
Subject(s) - shoot , peg ratio , chemistry , polyethylene glycol , osmotic shock , root system , osmotic pressure , botany , exudate , dns root zone , horticulture , biology , agronomy , biochemistry , irrigation , finance , gene , economics
SUMMARY Polyethylene glycol 4000 (PEG) at an osmotic potential of −0.3 MPa had no effect on uptake of 14 CO 2 and partitioning between shoots and roots in barley. When an osmotic potential of −0.8 MPa was applied to the upper zone of the root system, total 14 CO 2 uptake and partitioning were unaffected but assimilate accumulated in the tips of nodal roots exposed to PEG. There was a parallel accumulation of soluble sugars. Transport of assimilates to the seminal root system declined. Exudation of soluble, labelled compounds by the roots was markedly diminished. When PEG was supplied to the upper root zone at −0.8 MPa and the lower zone at −0.6 MPa total 14 CO 2 uptake and assimilate transport declined, but there was still some accumulation of labelled compounds and soluble sugars in the nodal root tips and root exudation was diminished. The results are discussed in relation to assimilate partitioning, growth and osmotic adjustment in nodal roots.