Morphological,Anatomical, and Physiological Assessment of Ramie [<Emphasis Type="Italic">Boehmeria Nivea</Emphasis> (L.) Gaud.] Tolerance to Soil Drought

Fiber yield is reduced when ramie Boehmeria nivea (L.) Gaud.] is produced under drought stress. Responses in Leaf morphology, root development and stem anatomy, and physiology of six cultivars, varying in tolerance to drought stress, were measured to identify plant characteristics for adaptation to drought stress. Ramie plants, established from 10-cm sections of shoots, were grown in pots with soil. When plants were 60 cm tall (about 40 days), moisture content in the medium was maintained at 55% of water-holding capacity for 28 days by weighing the pots and sparingly watering. Medium was maintained at 80–85% of water-holding capacity for the control. Drought-tolerant cultivars of ramie had more fine hairs on abaxial leaf surfaces, produced thicker leaf cuticles, better preserved leaf shape, and erectness, lost fewer leaves. They also generated longer roots with larger root masses and more storage organs, preserved higher root-to-shoot ratios, produced larger diameter stem vessels, and better conserved cell integrity than drought-sensitive cultivars of ramie when plants were grown under drought stress. Fiber yield was better in drought tolerant cultivars of ramie, because these cultivars had adapted root systems, leaf responses, cellular responses, and biochemical activities to allow plants to continue higher levels of photosynthesis and carbon deposition under more stressful environments than the less drought tolerant cultivars. Cultivars ‘Huangketong’ and ‘Qingkezi’ were best adapted to drought tolerance in the study.