The effect of some salts and osmotic shock on phosphate uptake in maize roots
Chlorides, nitrates, and sulfates of alkali metals, ammonium, calcium, and magnesium inhibit Pi uptake into maize root cortex segments. The concentration 100 mM brought about 50–100% inhibition, whereas 10 mM concentration (with the exception of salts of NH4+, Ca2+, Mg2+) about 15–55%. Also potassium benzenesulfonate (100 mM) dramatically decreases Pi uptake.
Osmotic shock also inhibits Pi uptake. Marked decrease of Pi uptake ability proceeds in concentration range 0.12–0.13 M NaCl. Concomitantly, proteins are released into rehydration medium and their amount is proportional to the degree of Pi uptake inhibition.
The effect of 0.13 M NaCl on Pi uptake and protein release is about the same in roots of intact plants, excised roots, root segments and segments of isolated cortex and stele. Roots of intact plants and excised roots are more responsive to osmotic shock than studied segments.
The degree of salt tolerance of glycophytes is in correlation with NaCl concentration, which brings about 50% inhibition of Pi uptake.
KeywordsSalt Tolerance CaSO4 Maize Root Root Segment Intact Plant
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