Fire Effects on Bud Viability and Growth of Stipa tenuis in Semiarid Argentina

摘要: Numbers of total, metabolically active, dormant or dead axillary buds, and growth characteristics were determined before after controlled burnings in Stipa tenuis Phil., a native forage grass the Calden District central Argentina. One-hectare plots burned on 25 Mar. (Burn 1) 4 Apr. 1991 2), remained unburned (control). Bud metabolic activity was examined using tetrazolium test vital stain Evans' blue. Before fire, more than 83% buds previous-season stems S. active all treatments. After that produced tiller control Burn 2 had 75% alive, but those did not produce them 82% their areas. This high bud mortality associated with direct fire effects fate buds; most showed visible signs dehydration. Since 97% plant stem bases tillers number per reduced (P < 0·05) to fewer 22% values controls. Plant 50% higher at 1 site probably because first 43% lower soil moisture content 0·05). At end growing season, however, different set plants both sites similar dry weight These areas lighter fuel loads exposed less intense fire.