Impact of water depth on root morphology of Juncellus serotinus (Cyperaceae)

Root morphological adaptation is an important mechanism for wetland plants to adapt to environmental conditions. The objective of this study was to investigate the impact of water depth on biomass allocation and root morphology (including root mean diameter, root length, root surface area and root volume) of a wetland plant species, Juncellus serotinus (Cyperaceae). Four levels of water depth were chosen: 10, 30, 50 and 70 cm. Due to the enormous root system, and for easy observation, five groups were used according to the distance from the rhizome: 0–5, 5–10, 10–15, 15–20 and longer than 20 cm (> 20 cm). Results showed that with increasing water depth plant total biomass and root biomass decreased significantly (p < 0.05), and that biomass was mainly allocated to shoots resulting in decreased root to shoot ratio. Root morphology parameters also changed significantly with increasing water depth (p < 0.05). Root mean diameter in all treatments and all other root morphology parameters decreased with increasing distance from the rhizome, while maximum root length, root surface area and root volume in 10 and 30 cm occurred between 5 and 15 cm from the rhizome. The results indicate that shallow water (less than 30 cm in depth) is favorable for the development of J. serotinus root system, and that root morphological characteristics shift with increasing distance from the rhizome.