Light Crude Oil Contamination Suppresses Seed Germination And Early Seedling Development In Amaranthus Hybridus L.: A Concentration-Dependent Phytotoxicity Assessment

Abstract

Petroleum hydrocarbon (PHC) contamination poses significant risks to agricultural productivity and food safety in oil-producing regions. This study examined the phytotoxic effects of light crude oil (0.0–10.0% v/v) on the germination and early seedling growth of Amaranthus hybridus L. using a controlled Petri-dish bioassay. Seed germination, germination velocity indices, biomass, and vigor metrics were analyzed using one-way ANOVA followed by Tukey's HSD tests (n = 6). Germination percentage decreased significantly at concentrations above 1.0% v/v (P < 0.001) and was entirely inhibited at 10.0% v/v. Higher oil concentrations significantly and dose-dependently reduced all germination velocity indices, seedling emergence, vigor, tolerance indices, seedling length, and fresh weight (all P < 0.001). In contrast, dry weight was not affected, and relative water content declined only at the highest concentration (10.0% v/v, P < 0.01).

In summary, light crude oil demonstrates pronounced phytotoxicity toward A. hybridus, with germination being more adversely affected than post-emergence dry biomass accumulation. Because of its high sensitivity, A. hybridus serves as an effective bioindicator of crude oil contamination in agricultural soils and a valuable model for regional risk assessments