Resumo

BUSSO, Carlos A.; MAZZOLA, Mónica  e  PERRYMAN, Barry L.. Seed germination and viability of wyoming sagebrush in northern nevada. INCI [online]. 2005, vol.30, n.10, pp.631-637. ISSN 0378-1844.

Seed size and germination behavior affect performance of early seedlings. The purpose of this study was to investigate relationships between seed size and germination percentage, germination rate, time course of germination and seed viability in Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis Beetle and Young). Working hypotheses were: 1) for single seeds, germination percentages and rates are positively related to seed weight; and 2) some TTC-unstained seeds are not unviable, but dormant. Seed collection was conducted at Battle Mountain and Eden Valley sites in northern Nevada during November 2002 and 2003. Individual sagebrush seeds were placed into weight classes, using 0.05mg·seed-1 increments, ranging from £0.15 to >0.40mg·seed-1. Seeds were incubated in darkness at 15ºC, seedlings with radicles ³1.0mm were removed daily during the first 10 days, and every other day thereafter until day 32. The study terminated on day 37. Triphenyl tetrazolium chloride (TTC) test was used to determine viability of ungerminated seeds, and Evan’s blue to sort out ungerminated seeds into either dead or dormant categories. Results supported both hypotheses. Maximum germination at both sites, years and all seed weight ranges was reached in 5 to 6 days after imbibition. This suggests that moist soil for several consecutive days would help provide optimum field germination in this species. Use of the vital stain Evan’s blue demonstrated that, albeit in a small percentage (£5%), some TTC-unstained seeds were not dead but only dormant with germination potential given appropriate conditions. When sagebrush is used for restoration, relatively heavy seeds should be used because they have the greatest germination potential.

Palavras-chave : Artemisia tridentata ssp. wyomingensis; Rangeland Restoration; Seed Weight Versus Seed Germination and Viability.