Seed Morpho-Anatomy and Germination Enhancement of the Australian Native Species Lomandra longifolia Labill. and L. hystrix (R.Br.) L.R. Fraser & Vickery

Abstract

Lomandra species are an important understory component of many Australian native ecosystems, contributing to the floristic richness and stabilizing soils. However, a limited understanding of their germination biology currently hinders their efficient use in seed-based restoration and ornamental plant production. The present study investigated Lomandra longifolia and L. hystrix diaspore morpho-anatomy and evaluated different mechanical and/or chemical treatments (nicking, leaching, smoke water and gibberellic acid [GA3]) and under light or dark conditions to enhance germination. Embryos of both species were small and linear with a low embryo to seed ratio (<0.45). Germination rates of both species were significantly hastened by leaching seeds in running water for 36 h as compared to a non-leached seed. The results suggest that pre-treating both Lomandra species by leaching could maximize the effectiveness of seed used by resulting in faster, more uniform and, therefore, reliable germination of these species. Finally, seeds of L. longifolia had low final germination (<40%), with a high presence of viable but dormant seeds. The ecological cues that promote germination in nature for both species should be further examined.