Effect of fencing on reproduction strategies of Imperata cylindrical

Imperata cylindrical was a dominant plant in the degraded mountain meadow that was in the restoration process by fencing, in Malong of Yunnan Province. The features of asexual organs of I.cylindrica in the meadow were studied. The results showed that three different types of vegetation community were formed at a gradient with three degradation levels under fencing condition. In fenced light degraded area, the rhizomes of I. cylindrical became longer with the fencing time, but the number of tiller branches did not change, and the stem density increased with the fencing time. In fended moderate and heavy degraded areas, the rhizomes of I. cylindrical became shorter and thinner with the fencing time while the change of rhizome number in heavy degraded area was significant (P0.01) and the change in moderate degraded area was significant (P0.05). The growth through asexual reproduction was limited in moderate and heavy degraded areas.