Seed germination: Mathematical representation and parameters extraction

Abstract

A method for mathematically describing cumulative seed germination using the four-parameter Hill function is described. The function's four parameters allowed both direct or indirect biological interpretation of germination behavior and the impact of seed pretreatments on germination improvement. Three parameters, a, b, and c, allowed direct assessment of germination capacity (%), the shape and steepness of the germination course, and germination speed (time to reach 50% germination). The fourth parameter y0 permitted estimation of the lag time (germination onset). The mathematical expression of cumulative seed germination of unstratified and stratified seed made it possible to quantitatively estimate seedlot dormancy and the amount of germination improvement caused by a specific seed pretreatment. This was accomplished by estimating the area between the two cumulative germination curves through integration. The utility of the proposed approach was demonstrated using germination data from wind-pollinated, individual genotypes (half-sib families) of lodgepole pine (Pinus contorta var. latifolia) and bulk seedlots of lodgepole pine and white spruce (Picea glauca). Copyright © 2008 by the Society of American Foresters.