Physiological evaluation of Sonchus oleraceus L. seeds with different pre-germinative treatments under high tropical latitudinal conditions

Abstract

Sonchus oleraceus L. is an invasive species that negatively affects the quality and yield of different crops. This research aimed to evaluate the physiological behavior of seeds from the weed S. oleraceus L., which were subjected to different treatments in three experiments. In experiment 1, different gibberellic acid (GA) concentrations were applied (0, 200, 400, and 600 mg L-1). In the second experiment, apical, basal, and apical-basal cut treatments were carried out on the seeds. In a third experiment, seeds were placed at different sowing depths (0.5, 1, 2, 5, and 10 cm) in peat as the substrate. The results indicated that GA at concentrations higher than 200 mg L-1 inhibited seed germination and, consequently, seedling growth. Germination was similar between the 200 mg L-1 GA treatment and the control, but germination occurred faster in the control. The apical-basal cut in the seeds generated the highest percentage of germination, the highest average speed of germination, and a significantly lower time of germination than the control; however, the longest shoot was observed in the seeds without a cut, and the longest root was detected in the seeds with the basal cut. Seedling emergence was affected by sowing depth, where it was significantly greater at 0.5, lesser at 2 cm, and, at greater depths, seedlings did not emerge.