Root and shoot development of Rumex species under waterlogged conditions

The responses of Rumex acetosa, Rumex crispus, and Rumex palustris to different levels of waterlogging were studied in sand culture experiments. Rumex crispus and R. palustris developed new flooding-resistant roots as a response to waterlogging. The growth of these new roots caused a changed vertical distribution of the root length in these species; most root length was concentrated in the upper 10 cm of the soil. Rumex acetosa did not show significant development of flooding-resistant roots and did not change its vertical root distribution during flooding of the soil. The results of the experiments indicate that growth expressed as relative growth rate is positively correlated to the development of new flooding-resistant roots under waterlogged conditions. We concluded that R. crispus and R. palustris are more resistant to waterlogging than R. acetosa; this agrees with the distribution of these Rumex species in the field. However, waterlogging resistance is probably only one of the factors influencing differences in field location between the Rumex species.