MATERNAL ENVIRONMENT EFFECTS ON PLANT-GROWTH AND GERMINATION OF 2 STRAINS OF THLASPI ARVENSE L

The influence of maternal environment on plant development and seed ge rmination of early- and late-flowering strains of Thlaspi arvense L. w as studied. Compared to plants grown at 30 degrees/10 degrees C, those grown at 15 degrees/10 degrees C and 20 degrees/10 degrees C flowered more slowly, were shorter, and grew fewer leaves; seed production, ho wever, was greatest at 20 degrees/10 degrees C. Plants of the late-flo wering strain produced more leaves than those of the early-flowering s train, but there were no differences between strains in vegetative dry weight or height at harvest. On average, fresh seeds from plants of t he late-flowering strain germinated at a faster rate than those from p lants of the early-flowering strain. Seed dormancy increased with incr easing temperature in which they developed, thus explaining some of th e differences reported in the literature regarding germination of fres h seeds of T. arvense. The evolutionary implications of these results are discussed in relation to the single gene differences between the t wo strains.