Phytochemistry of Argemone ochroleuca Sweet Extracts and Their Inhibitory Effects on Maize Seed Germination

Argemone ochroleuca Sweet is an alien invasive weed dominating most cultivated lands, however, the phytochemicals present in this plant and the effects of these on the germination and growth of economically important crops such as maize are not well-documented. The objective of the study was to characterize the phytochemistry of the shoots and roots of A. ochroleuca and determine whether the extracts could inhibit the germination of maize seeds. The shoots and roots of A. ochroleuca were extracted in water, hexane, and acetone. Ten maize seeds were used in the germination bioassay. A phytochemical analysis was conducted using gas chromatography-mass spectrometry (GC-MS). The effects of the A. ochroleuca water, hexane, or acetone extracts on maize seed germination were concentration and plant-part dependent. The highest reduction was recorded from the water extract with 82%. Identified compounds with high percentages in A. ochroleuca were 9,12-octadecadienoic acid (Z,Z) and 9,12,15-octadecatrienoic acid, (Z,Z,Z)-. The present study indicated that A. ochroleuca extracts suppress the germination of maize seeds, likely due to the presence of both the identified and potentially unidentified phytochemicals that were not detected by the selected method. There is, however, a need to establish the relationship between the phytochemical compounds and the enzymes responsible for germination.