Separating multiple, short-term, deleterious effects of saline solutions on the growth of cowpea seedlings.
• 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°. The addition of Mg, Na or K may induce Ca deficiency in roots by driving {Ca²+}₀° to < 1.6 mM. Shoots were more sensitive than roots to osmolarity. Specific ion toxicities reduced root elongation in the order Ca²+ > Mg²+ > 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° (R²=0.924), allowing the quantification of their effects.
The University of Queensland, School of Land, Crop and Food Sciences, St. Lucia, Qld 4072, Australia.|Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC-CARE), The University of Queensland, St. Lucia, Qld 4072, Australia.
Peter M
PM
Kopittke
The University of Queensland, School of Land, Crop and Food Sciences, St. Lucia, Qld 4072, Australia.|Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC-CARE), The University of Queensland, St. Lucia, Qld 4072, Australia.
F Pax C
FPC
Blamey
Agricultural Research Service, USA Department of Agriculture, Beaver, WV 25813-9423, USA.
Thomas B
TB
Kinraide
State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.|Graduate School of Chinese Academy of Sciences, Beijing 100049, China.
Peng
P
Wang
School of Civil, Environmental and Chemical Engineering, RMIT University, Melbourne, Vic. 3001, Australia.
Suzie M
SM
Reichman
The University of Queensland, School of Land, Crop and Food Sciences, St. Lucia, Qld 4072, Australia.|Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC-CARE), The University of Queensland, St. Lucia, Qld 4072, Australia.
Neal W
NW
Menzies
D002118:Calcium / Q000172:deficiency; D007887:Fabaceae / Q000187:drug effects* / Q000254:growth & development*; D007477:Ions; D008954:Models, Biological; D009995:Osmosis / Q000187:drug effects; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development; D011188:Potassium / Q000633:toxicity; D036226:Seedlings / Q000187:drug effects* / Q000254:growth & development*; D012964:Sodium / Q000633:toxicity; D012965:Sodium Chloride / Q000633:toxicity*; D013997:Time Factors
D007477:Ions; D012965:Sodium Chloride; D012964:Sodium; D011188:Potassium; D002118:Calcium