Assessing the effect of herbicide use (Glyphosate) on fruiting and phytochemical characteristics of edible soil mushroom (Pleurotus ostreatus)

Abstract

This study investigated the effect of herbicide (glyphosate GLY) on the growth and development of Pleurotus ostreatus (Jacq.Ex.Fr) P. Kumm fruiting bodies. The experiment was conducted in a Randomized Complete Block Design (RCRD). Three treatment levels of GLY (1, 2 and 3%) and control were administered on mycelium surface using a hand sprayer after the culture matured with sawdust as substrates at 12 days after inoculation (DAI). Data on growth, fruiting body weight, stipe length and mineral content were collected and analyzed using analysis of variance (ANOVA), while mean separation was done by Duncan Multiple Range Test (DMRT) at the least significant difference (LSD). The result of fruiting body yield (g) and biological efficiency (BE%) of 249.04g  (31.12) were produced by 3% GLY level produced the highest yield of 249.04g,  31.12 BE%  followed  by 1% (241.79g) and 30.22 BE% while 0.02% had the least fruiting body yield (222.62g) andBE 27.82%. The 3% GLY level produced fruiting bodies with the highest mean weight of 3.12±0.75g 18DAI as control had the lowest (2.35g) fruitingbody mean weight, 36DAI. The control produced the highest (145.00) number of fruiting  bodies, followed by 0.02%Gly (141.00), while the lowest was recorded at 1%Gly level. Fruiting bodies from 3%Gly had the longest (1.96cm) stipe while those of 2% gave the shortest (1.34cm) 26DAI. Cap diameter of fruiting bodies was not significantly different at p≤0.05 across all Gly treatment levels and control. Fruiting bodies from 3%Gly had the highest (4.38±0.01g µg/ml /l) crude protein (CP) content, followed by those of control (4.16±0.01g/l) but lowest (3.50±0.01µg/ml) in those of 1%Gly while Carbohydrate (CHO) content was highest (94.54±0.01 µg/ml) in fruiting bodies from 1%Gly, but lowest (94.20±0.01 µg/ml) in those of control. The highest calorific value was recorded in fruiting bodies from control (398.12±0.01 µg/ml) while the lowest was obtained at 3%Gly (393.33±0.01 µg/ml). Flavonoids content of fruiting bodies decreased with exposure to GLY by 31% while phenols and phythetes increased with exposure to GLY by 54.5% and 288.8% for 3% GLY level over control. Phosphorus, carbon and hydrogen contents of the fruiting bodies increased by 163%, 26.0% and 291 respectively over the control and had respective concentrations as 0.55, 28.24 and .024. Although Glyphosate had positive effect on fruiting bodies and Biological efficiency, it also increased very significantly levels of P, C and H which may indicate that glyphosate accumulated in pleurotusostreatus.