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Separating multiple, short‐term, deleterious effects of saline solutions on the growth of cowpea seedlings
Author(s) -
Kopittke Peter M.,
Blamey F. Pax C.,
Kinraide Thomas B.,
Wang Peng,
Reichman Suzie M.,
Menzies Neal W.
Publication year - 2011
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.1469-8137.2010.03551.x
Subject(s) - vigna , shoot , osmotic concentration , potassium , sodium , calcium , elongation , chemistry , magnesium , salinity , saline , seedling , horticulture , botany , biology , biochemistry , ecology , materials science , organic chemistry , ultimate tensile strength , metallurgy , endocrinology
Summary• Reductions in plant growth as a result of salinity are of global importance in natural and agricultural landscapes. • Short‐term (48‐h) solution culture experiments studied 404 treatments with seedlings of cowpea ( Vigna unguiculata cv Caloona) to examine the multiple deleterious effects of calcium (Ca), magnesium (Mg), sodium (Na) or potassium (K). • Growth was poorly related to the ion activities in the bulk solution, but was closely related to the calculated activities at the outer surface of the plasma membrane, { I z } 0 o . The addition of Mg, Na or K may induce Ca deficiency in roots by driving {Ca 2+ } 0 o to < 1.6 mM. Shoots were more sensitive than roots to osmolarity. Specific ion toxicities reduced root elongation in the order Ca 2+ > Mg 2+ > Na + > K + . The addition of K and, to a lesser extent, Ca alleviated the toxic effects of Na. Thus, Ca is essential but may also be intoxicating or ameliorative. • The data demonstrate that the short‐term growth of cowpea seedlings in saline solutions may be limited by Ca deficiency, osmotic effects and specific ion toxicities, and K and Ca alleviate Na toxicity. A multiple regression model related root growth to osmolarity and { I z } 0 o ( R 2 = 0.924), allowing the quantification of their effects.