Nitrite in the root zone and its effects on ion uptake and growth of wheat seedlings |
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Authors: | Ferenc Zsoldos,Ernst Haunold,Á gnes Vashegyi,Peter Herger |
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Affiliation: | Dept of Plant Physiology, Attila József Univ., PO Box 654, H-6701 Szeged, Hungary.;Inst. of Agric., Austrian Research Center, A-2444 Seibersdorf, Austria. |
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Abstract: | The immediate and posteffects of various concentrations of NaNO2 on ion uptake of wheat ( Triticum aestivum L. cv. GK Öthalom) seedlings were studied at different pH values. Without pretreatment, the higher the concentration of NaNO2 the greater was the decrease in uptake of K+ into the roots, both at pH 4 and pH 6. At pH 6 but not at pH 4 the reverse was true when the seedlings were pretreated with NaNO2. Due to the high Na+ content of the roots, an effect of Na+ in this process cannot be excluded. Nitrite was taken up by the roots more rapidly than nitrate. Nitrite at 0.1 m M in the medium induced the development of an uptake system for both NO−2 and NO−3 in wheat roots. At higher concentrations pretreatment with NO−2 decreased NO−3 uptake by the roots, but NO3 did not inhibit the uptake of NO2. The toxic effect of NO−2 was strongly pH dependent. Lower pH of the external solution led to an increased inhibition by NO−2 of both ion uptake and growth of seedlings. The inhibitory effect of NO−2 differed considerably for roots and shoots. The roots and especially the root hairs were particularly sensitive to NO−2 treatment. |
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Keywords: | Ion uptake nitrate nitrite toxicity pH potassium root hairs shoot-root growth sodium Triticum aestivum. |
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