The Influence of Seed Density and Treatment on the Establishment of Halophytes: Implications for Rangeland Rehabilitation in the Dry Areas
Accepted, under review. Rehabilitation efforts that use direct seeding techniques often result in unsatisfactory returns and consequent low economic gains. Seed coat treatment techniques have being developed that improves germination and establishment success. The purpose of this study was to investigate the effects of seed density and seed coat treatment on the germination and establishment of seven halophytic species: Atriplex halimus, A. canescens, A. leucoclada, A. nummularia, A. lentiformis, Salsola vermiculata and Haloxylon aphyllum under semi-arid conditions. Each of these species was tested for emergence under three seeding densities (10, 30, 60 seeds per pot) and two seed treatments (fruits or naked seed), replicated in five randomly pots using a completely randomized block design. Results indicate a significant effect of seed treatment and a seed density X seed treatment interaction (P<0.001) on establishment rate. Except for A. leucoclada, which exhibited lower germination following seed bractiole removal, fruits with bractioles produced lower germination response than naked caryopses. A. halimus had the fastest germination followed by S. vermiculata. On the other hand, while A. nummularia had the slowest germination. The highest germination rate for A. halimus was recorded with naked seeds at the lowest density. However, seeding density did not have an effect on germination rate. These results suggest that traditional methods for sowing with high seed density do not affect overall germination rate. Seed treatments also helped reduce seed dormancy, improved germination and establishment of the tested species native to semi-arid ecosystems.