Seed Treatment of Mojave Desert Shrubs1

Abstract

AbstractInformation is needed for revegetation of barren scars left from destruction of native shrubs by recreational vehicles and right‐of‐way clearance. Numerous seed treatments were tested for improvement of field establishment of Mojave Desert shrubs and reduction of establishment costs.Scarification, 4‐hour 60 C and 80 C dry heat, stratification, activated carbon, 3‐hour and 15‐hour soaking, 100 ppm and 1,000 ppm ethylene, hot water (5 min), 0.5 and 6% sodium hypochlorite, 3% thiourea, and 6% hydrogen peroxide were used on the following species considered promising for revegetation: 1) Larrea divaricata Cav., 2) Atriplex polyycarpa (Torr.) Wats., 3) Atriplex canescens (Pursh.) Hutt., 4) Hymenoclea salsola T. & C., 5) Ephedra nevadensis Wats., 6) Ambrosia dumosa (Gray) Payne Franseria dumosa), and 7) Lepidospartum squamatum Gray.Activated carbon was the most effective treatment in improving fruit germination on 5 of 6 species tested (spp. 1, 2, 4, 5, 6). Stratification was effective on improving the germination of 3 of 6 species (spp. 2, 3, 6). Thiourea (3%) was effective in improving the germination of both the carpels and seeds of Larrea divayicata, The 15‐hour soaking, 100 ppm ethylene, 4‐hour 60 C, and scarification treatments improved the germination of only one species each. Treatments having no effect on germination were 3‐hour soaking, 6% hydrogen peroxide, and 1,000 ppm ethylene. The 4‐hour 80 C dry heat depressed the germination of 5 of the 7 species and 6% sodium hypochlorite depressed the germination on all species tested. Hot water (5 min) killed the embryos on all species tested.