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Salt tolerance in Aster tripolium L. II. Ionic regulation
Author(s) -
SHENNAN C.,
HUNT R.,
MACROBBIE E. A. C.
Publication year - 1987
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/j.1365-3040.1987.tb02081.x
Subject(s) - shoot , salinity , halophyte , dry weight , chemistry , sodium , botany , horticulture , zoology , biology , ecology , organic chemistry
Measurements of tissue ion contents (Na, K and Cl) were carried out at frequent intervals on plants of Aster tripolium L. grown at a range of salinities for 36 d. Aster tripolium behaved as a typical halophyte showing high levels of inorganic ion accumulation even at low salinities. As salinity increased Na replaced K to a large extent in the shoot but root K was unaffected up to 500 mol m −3 external NaCl. Shoot (Na + K) concentration on a tissue water basis was maintained constant in all treatments throughout the experiment, whereas shoot (Na + K) on a dry weight basis showed marked fluctuations in some treatments. An increase in (Na + K) per gram dry weight was, however, accompanied by a parallel increase in fresh weight: dry weight (FW : DW) ratio. Transport of (Na + K) to the shoot per unit root weight changed during the experiment in the manner expected, given the observed changes in shoot relative growth rate and FW : DW to result in a constant shoot (Na + K) concentration on a water basis. Chloride was the major balancing anion in the shoot at high salinity, but never accounted for more than 38% of the (Na + K) found in the root tissue. At all salinities (Na + K) salts accounted for the majority of the measured shoot sap osmotic potential. The interactions between salinity, growth, ion transport and osmotic adjustment are discussed.