variations of water soluble carbohydrate in plant organs of bromus tomentellus and festuca ovina in three phenological stages

information on quality characteristics of forage species help the range managers to select a suitable grazing program that minimizes the damages to vegetation. water soluble carbohydrates (wsc) -the main photosynthetic products- are stored in various plant parts and are more likely to be consumed when plants require them. in order to investigate the changes of wsc in distinguishable organs in three phenological stages, samples were taken from bromus tomentellus and festuca ovina in three phenological stages (vegetation, flowering and maturity). samples of roots and aerial parts were taken for both species using a completely randomized factorial arrangement-based design with the phenological stages regarded as the first factor and herbage parts as the second factor with 5 replications. higher wsc values were observed in the leaves of b. tomentellus (4.6%) and f. ovina (4.5%) in maturity and flowering stages, respectively. maximum wsc values of roots were obtained in b. tomentellus (3.2%) and f. ovina (3.5%) at vegetation and maturity stages, respectively. it was suggested that range utilization in a phenological stage might be managed in which forage species can withstand the defoliation without severe reserve depletion. results indicate that except flowering stage in b. tomentellus, wsc was increased with the increase of panicle weight in the maturity stage and there was an inverse relationship between plant components and wsc content percent in the other phenological stages.