Effects of phosphine on enzyme activities and available phosphorus in rhizospheric and non-rhizospheric soils through rice seedlings

Abstract

The objective of this study was to investigate phosphine-induced changes in enzyme activities (acid phosphatase (ACP), urease, invertase, dehydrogenase) and effects of phosphine on available phosphorus in rhizospheric and non-rhizospheric soils. Rice seedlings, as model plant, were exposed to different ambient concentrations of phosphine (0, 1.4, 4.2 and 7.0 mg m−3) for a period of 30 days, and the enzyme activities and available phosphorus in both rhizospheric and non-rhizospheric soils were monitored for different phosphine concentrations and exposure times. In the first 2 weeks in the rhizospheric soil, the activities of urease, invertase and dehydrogenase increased slowly with phosphine exposure time in both rhizospheric and non-rhizospheric soils, although ACP activity displayed a slight drop in the rhizosphere; however, the activities of all these enzymes dramatically increased with phosphine concentration and exposure time after 15 days. Enzyme activities in rhizosphere soil are generally greater than those in non-rhizosphere soil, exhibiting effects of the rhizosphere. Increase in phosphine exposure concentrations also increased the available phosphorus in rhizosphere and non-rhizosphere soils. Phosphine exposure increases soil enzyme activities and available phosphorus in both rhizosphere and non-rhizosphere which is beneficial for rice growth.