Low to moderate sodium is beneficial to wheat genotypes grown under potassium deficient conditions
Krishnasamy, K., Bell, R. and Ma, Q. (2013) Low to moderate sodium is beneficial to wheat genotypes grown under potassium deficient conditions. In: ComBio 2013, 29 September - 3 October, Perth, Western Australia.
Whilst high Na is known to be detrimental to plant growth and K nutrition, low to moderate Na can be beneficial to plant growth especially when soil available K is deficient, since Na can substitute for specific biophysical functions of K. Potassium deficiency are common in agricultural soils but the role of Na in K nutrition of wheat genotypes is not well understood. We hypothesised that K-efficient cultivars would be less affected by excess Na than K-inefficient cultivars under high saline conditions, and less responsive to Na substitution under low to moderate Na and low K supply. In a pot experiment, Triticum aestivum L. cvv Wyalkatchem and Cranbrook (K-efficient cultivars), and cvv Gutha and Gamenya (K-inefficient cultivars) were grown in soil containing 40 or 100 mg K/kg in combination with nil, 25, 50, 100 or 200 mg Na/kg for 8 weeks. High soil Na levels (100 and 200 mg Na/kg) greatly reduced plant growth in all four cultivars especially at low soil K (40 mg K/kg). Low to moderate soil Na levels (25 and 50 mg/kg) stimulated wheat growth when soil K was deficient, particularly with a significant increase in root growth in K-efficient cultivars compared with K-inefficient cultivars. The beneficial effect on photosynthesis and stomatal conductance of wheat with the addition of low soil Na levels at K deficiency was similar to that under K adequate supply. Further research is under way to determine whether moderate Na levels stimulated growth by promoting K uptake or by substituting for biophysical functions of K in wheat.
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|Murdoch Affiliation:||School of Veterinary and Life Sciences|
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