Morphological responses to different flooding regimes in Carex brevicuspis
13 November 2015
Han, Gao; Tan, huai; Xie, yonghong; zhou, ming; li, feng; zhu, lianDespite growing recognition of the importance of water regimes in the regulation of plant growth and distribution, the components of water regimes that determine plant growth are not clear. To identify the causative components, 72 ramets of Carex brevicuspis were grown under six different water regime treatments. Biomass accumulation, below:above ground biomass ratio, number of ramets, and proportions of spreading and clumping ramet were assessed. Biomass accumulation decreased only in association with length of flooding. The highest biomass accumulation occurred in the 120-day + 0-cm water level treatment, intermediate in the four 60-day + 30-cm water level treatments, and the lowest was in the 120-day + 30-cm water level treatment. Likewise, the below:above ground ratio only decreased with increasing length of flooding. Ramet number was the highest in the 120-day + 0-cm water level treatment, intermediate in the four 60-day + 30-cm water level treatments, and the lowest in the 120-day + 30-cm water level treatment. The proportion of spreading ramets increased from 28.0% in the 120-day + 0-cm water level treatment to 76.4% in the 120-day + 30-cm water level treatment, whereas that of clumping ramets decreased from 72.0% to 23.6%. These data suggest that the growth of C. brevicuspis was only limited by the length of flooding. Reduction of the below:above ground ratio and change from phalanx to guerrilla growth form are effective strategies for C. brevicuspis to acclimate to flooding stress, because they allow the plant to grow above the water surface and escape from anoxic conditions. Our study provides experimental information on the role of different components of water regimes in regulating plant growth, and may assist in protection and restoration of the C. brevicuspis community.