Effects of burial in sand and seed size on seed germination and seedling emergence in two leguminous shrubs in the Otindag Sandland, China

Caragana microphylla and Hedysarum laeve are two dominant leguminous shrubs that occur in the Otindag sandy areas of China. Freshly harvested seeds of both species germinated well in light and poorly in darkness. The optimal temperature for germination was 10 to 15 oC in both species. We investigated the influences of the depth of burial in sand (1, 2, 4, 6, 8, 10, 12, or 14 cm) and seed size (small, medium, or large) on seed germination and seedling emergence in these two species. Results showed that both plants had a similar response to burial in sand. The seedlings of C. microphylla emerged from deeper in the sand than those of H. laeve. Within each species, the deeper the seeds were buried in the sand, the lower the germination and emergence rates and the slower the seed germination and seedling emergence. A depth of 2 cm was the optimal depth for seed germination and seedling emergence in both species.