Germination and seedling performance of five native legumes of the Arabian Desert

Abstract

Introducing nitrogen-fixing legumes in desert land could enhance rangeland productivity and help in soil reclamation. However, detailed information about germination and seedling performance of many desert legumes species is still lacking. We investigated these plant characteristics for five native legumes of the Arabian Desert in Qatar: Crotalaria aegyptiaca, Crotalaria persica, Rhynchosia minima, Senna alexandrina and Senna italica. Germination of the species was tested under laboratory conditions using different temperature and light treatments: 15/25, 20/30 and 25/35 °C, in either continuous darkness or cycles of 12 h light/12 h darkness. The germination percentage recorded under the different temperature and light conditions was very low. Therefore, four scarification treatments, water soaking (12 and 24 h) and concentrated sulfuric acid application (5 and 10 min), were applied. The scarification treatments improved the germination of all the species. However, the different species did not equally respond to the scarification treatments tested. In general, the treatments with sulfuric acid were the most effective. Subsequent seedling survival and growth were evaluated under greenhouse and field (nursery) conditions. All the studied species exhibited higher seedling survival inside (69-96%) than outside the greenhouse (53-89%). Regarding growth, these species did not show much difference in terms of shoot and root length when placed in the greenhouse or the nursery. However, the species showed differences in biomass allocation (aboveground vs. belowground biomass) between greenhouse and nursery but with species-specific responses. The information provided here on scarification requirements and seedling survival and biomass allocation as dependent on the growth environment is helpful for conservation and landscape agencies interested in using these species for conservation, restoration and landscaping projects.