Root morphology patterns of three grasses used to restore the desert on the Southeast Tibetan Plateau

The roots of plants are an important component in desert restoration. To understand the root morphology patterns of grasses being used to recover deserts, we studied grass roots in the Southeast Tibetan Plateau. Roots of the annual grass Avena sativa and the perennial grasses Elymus nutans and Roegneria hirsuta were collected from a field gene bank and sandy land. The tips, forks, average diameter, length, surface, and volume of the grass roots were compared and the ratios of the root tips, length, surface, and volume were analyzed. We discussed the suitability of different root morphologies to desert environments. The results show that the root surface and volume of A. sativa in the field gene bank were significantly higher than those in the sandy land. The root morphology of E. nutans had no significant differences between the field gene bank and sandy land. Additionally, the root tips, forks, length, and surface of R. hirsuta in the field gene bank were significantly lower than those from the sandy land; however, the average root diameter of R. hirsuta was significantly higher. There was a significant decrease in the root volume of A. sativa in the sandy land compared with the field gene bank. However, A. sativa increased the ratios of the root tips, length, surface, and volume, under a diameter of 0.2～0.4 mm, to suit desert environments. E. nutans did not significantly change its root morphology to suit desert environments. R. hirsuta increased the root length, surface, and volume patterns, under a diameter of 0.1～0.2 mm, to suit desert environments by decreasing the root length and surface between 0.7 and 0.8 mm. The root morphology patterns of E. nutans and R. hirsuta are more suitable to desert environments than those of A. sativa.