Do plants derived from seeds that readily germinate differ from plants derived from seeds that require forcing to germinate? A case study of the desert mustard Lesquerella fendleri

We compared the performance of plants of the desert mustard Lesquerella fendleri derived from seeds that readily germinated ("natural" plants) with plants originating from seeds forced to germinate by the application of gibberellic acid which required an extended germination period ("induced" plants). Before transplanting from the greenhouse, induced plants were significantly larger in diameter but had significantly fewer leaves than natural plants. There were also significant differences between seed source populations, as well as seed source by germination treatment interactions, for both plant diameter and number of leaves. After transplantation to a desert shrubland site, there were highly significant differences in survivorship of natural and induced plants. Five months after transplantation, survival of natural plants (43.3%) was twice that of induced plants (21.3%). Natural plants transplanted beneath creosote bush shrubs were also larger in diameter than induced plants, while the converse was true for plants transplanted in the open intershrub areas. We argue that these results may be, at least partially, the result of genetic differences between seeds that readily germinate and seeds that remain dormant but viable under the same environmental conditions.