Herbicide and Inorganic Phosphate Influence on Phytase in Seedlings

Abstract

Phytase activity increased 2 to 3 fold in barley (Hordeum vulgareL.), 6 fold in corn (Zea maysL.), and 12 fold in squash (Cucurbita maximaDuchesne) seedlings 2 days after the initiation of germination in the dark. Most of the phytase was found in the embryo of the seed, presumably in the cotyledon(s). Gibberellic acid and benzyladenine supplied during germination exerted only limited influence on the development of phytase in these seedlings. Of the herbicides studied, only sodium arsenite exerted an influence on phytase activityper sethat was of physiological significance. The presence of 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine), 3-amino-2,5-dichlorobenzoic acid (amiben), 2-chloro-N-isopropylacetanilide (propachlor), 2,6-dichlorobenzonitrile (dichlobenil), or α,α,α-trifluoro-2,6-dinitro-N-N-dipropyl-p-toluidine (trifluralin) in the culture solution during germination partially inhibited the development of phytase activity. The herbicidal inhibition was enhanced if potassium phosphate at a non-inhibitory level also was present in the culture solution. The interaction of atrazine and amiben with phosphorus was not due to increased internal concentrations of inorganic phosphorus to a level inhibitory to the development of phytase activity.