Contrasting seed morphology dynamics in relation to the alleviation of dormancy with soil storage

We examined the effect of prolonged (up to 450 days) soil burial in the fie ld on seed morphological traits (seed coat structure, permeability) to iden tify their potential roles in seed dormancy and release. Such traits were e xamined in species with seeds that demonstrated an obligate requirement for soil storage before germination: the dormant seeds of Anigozanthos mangles ii D. Don, Conostylis neocymosa Hopper, Stylidium affine Sonder, and Stylid ium crossocephalum F. Muell., and the deeply dormant fruits of Leucopogon c onostephioides D.C. We detected species-specific and environmentally induce d variation in seed morphology following soil burial. In A. manglesii and L . conostephioides, a significant deterioration of the seed coat or fruit wa ll and an increased permeability of the seed coat to water and solutes were correlated with germination responses. In these species, the seed coat and (or) fruit wall delayed germination until (morpho) physiological dormancy was broken. In C. neocymosa, S. affine, and S. crossocephalum, weathering o f the seed coat, permeability, and germination were not correlated traits. These species appeared to possess physiological dormancy mechanisms and req uired environmental cues for dormancy release.