The effect of different harvesting intensities on non- structural carbohydrate reserves in underground part of two species Stipa hohenackeriana and Salsola laricina

Non- structural carbohydrate reserves in plants show their ability for regrowth after grazing. This study aimed to clarify the effectts of different harvesting intensities on changes of soluble carbohydrate reserves in Stipa hohenackeriana and Salsola laricina. From each species, 40 individuals (bases) were selected during 2007-2010. The treatments consisted of different harvesting intensities (treatments) including control, 25, 50 and 75%. Sampling of treated base took place in autumn and spring. Soluble carbohydrates were measured using the phenol - sulfuric acid procedure. Split plot design based on CRD was used. To analyze the data, ANOVA and to compare the means Duncan test was made. Based on obtained results, the effect of species and season on amount of carbohydrate was significant. Different harvesting intensities of control, 25, 50 and 75 percent had amount of 2.75, 2.73,2.64 and 2.51(mg/g-1) carbohydrates, respectively. Although the amounts numerically were different but no significant differences were observed among them. Existing of sufficient amount of soil moisture in autumn leads to re-growth in Stipa hohenackeriana, coinciding with seed ripening in Salsola laricina. Therefore, regrowth and seed ripening causes carbohydrate depletion in both understudy species. On the other hand, spring is the growth season of both species in which carbohydrate is consumed for growth initiation. Consequently, the depletion of carbohydrate reserves happens. These reasons lead to no-significant effect of different harvesting intensities on carbohydrate reserves in underground part of Stipa hohenackeriana and Salsola laricina.