The literature indicated that Na increased availability of phosphate in the soil. In the plant Na was shown to strengthen tissues, particularly vascular and supporting tissues, to influence cell permeability and imbibition, and to decrease transpiration. In contrast to Rb (like Na able to replace K), Na proved to be selectively absorbed. It may also be selectively bound to cell substances.Through autoradiographs with 22Na 3 groups of plants could be distinguished for quantitative transport of Na from the root to the stem and leaves. This distinction was consistent with the influence on production, which could be estimated within 6 weeks after sowing. Na +accumulated in the meristematic parts. The uptake and excretion of 22Na by oats was studied for three growth stages: germination until about 8 cm long, the cultural stage of 3 weeks and the experimental period of 6 days. Na was bound in plants in 3 ways: 1. Readily exchangeable with Na, Ca, K or Mg; 2. Fairly readily exchangeable with Na, but less readily with Ca, K or Mg (selective); 3. No easy exchange with other Na ions (specific).The effects of top-dressing oats with NaNO 3 were extensively studied.
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