Comparative research on sodium as a beneficial element for crop plants
1998
Takahashi, E. (Kinki Univ., Higashiosaka, Osaka (Japan). Faculty of Agriculture) | Maejima, K.
To investigate the beneficial effects of sodium related to available potassium levels, 20 kinds of crops classified in 9 families were pot-cultured with Masa soil (weathered granitic soil) of low potassium availability. The main treatments were [+K-Na], [-K-Na], [-K+Na], [+K+Na]. Potassium and sodium were supplied at equimol as chlorides. The results obtained were as follows: 1) Growth responses to sodium much differed among the crops t tested. The effect of sodium was most remarkable on chard (Beta vulgrais). The growth of -K+Na plants was quite normal and better than that of the control (+K-Na) plants, while -K-Na plants showed potassium deficiency symptoms and the growth was decreased half that of the control plants. A similar but lesser effects were obtained for barley, okahijiki, spinach, kikuna, portulaca, Chinese cabbage, pak-choi, turnip, nozawana, komatsuna, cabbage, rice, and slight effect on wheat, lettuce, and tomato. Contrary to these crops, sodium did not have any effect on edible amaranthus, strawberry, kidney bean and maze. 2) The differences in the effects of sodium were mainly attributable to the differences in the rates of sodium uptake by the plant top. The beneficial effects of sodium seemed to be mainly due to the substitutional effect of sodium for potassium in producing osmotic pressure in the apoplast of pants. This might contribute to keeping water content in the plant tissue and increasing the fresh weight
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