Root Acid Phosphatase Activity Research Articles

Phosphatase activity in corn and soybean roots: Conditions for assay and effects of metals

Studies with sterile root materials showed that the optimum pH values of phosphatase activity in three varieties of each of corn (Zea mays L.) and soybean (Glycine max. L.) were 4 and 5, respectively. The activity on either side of the optimum pH fell sharply, and there was no activity at pH 9. Thus, these roots contain acid but no alkaline phosphatase activity. Acid phosphatase activity was not uniformly distributed in roots and root hairs. Studies with 20 metals showed that their effectiveness in inhibiting acid phosphatase activity of roots varied with the type of plant used. When the metals were compared at 250 μM (1.25 μmole. 5 mg−1 of homogenized roots), the inhibition of acid phosphatase of corn and soybean roots showed that Ag(I), Fe(III), Se(IV), V(IV), As(V) and Mo(VI) were the most effective inhibitors of this enzyme in corn roots, with percentage inhibition ≥30%. In addition to these metals, Sn(II), Hg(II), and W(VI) inhibited acid phosphatase in soybean roots by >30%. Other metals and one non-metallic element that inhibited acid phosphatase activity in corn and soybean roots were: Cu(I), Cu(II), Cd(II), Ni(II), Fe(II), Pb(II), Ba(II), Co(II), Mn(II), Zn(II), B(III), As(III), Cr(III), and Al(III); their degrees of effectiveness varied with type of roots used. Generally, the inhibitory effect of the metals was much less when their concentration was decreased by 10-fold. In addition to the effect of these elements, phosphate ion inhibited acid phosphatase activity of corn and soybean roots. Related anions such as NO 2 − , NO 3 − , Cl−, and SO 4 2− were not inhibitory.

Undestructive measurement of acid phosphatase activity in the root of rice seedlings.

Conditions for undestructive assay system of acid phosphatase in the intact roots of rice ( Oryza sativa L.) seedlings as a marker of physiological activity of roots using p-nitrophenyl phosphate as a substrate were investigated Phosphatase activity was linear up to 3h at the concentrations from 0.5 to 10mM. Optimum acid phosphatase activity was obtained between pH 3 and 6 at 25-30°C. The enzyme activity of the whole roots including seminal and crown ones at the 4th leaf stage plant was higher than that at younger or older seedling stage. Using this method, we also investigated the effect of isoprothiolane (IPT), which is known as a plant growth regulator, on acid phosphatase activity in roots of rice seedlings. This compound promoted acid phosphatase activity in rice roots.