Abstract
Rattail fescue (Vulpia myuros (L.) C.C. Gmel.), a winter annual grass weed, originated in the Mediterranean region, and widely distributed in temperate region across the world. Lodging characteristics of the rattail fescue are utilized as a crop cultivated in orchard garden for the purpose of various weed control, protecting against soil erosion and maintaining ground temperature. Although mechanism of lodging resistance in crops has been studied, the causative factor of lodging in rattail fescue remains unknown. Lodging of the plant culm was enhanced by 25℃ and followed by 20, 30, 15℃ treatments. NMR spin-lattice relaxation times (T_1 and T_2 ) of fresh leaves and culms in Arrhenius plots decreased when temperature elevated from 0 to 50℃. However, there was no distinctive feature in water status of the tissues between 15 and 30℃. Furthermore, electrolyte leakage, contents of water, chlorophyll and nitrogen of the plant leaves and other organs did not significantly change when the plants began to lodge. In contrast, node angle markedly decreased due to remarkable cell elongation of convex side in individual nodes, especially in the basal node at the lodging stage. These results indicate that lodging characteristics of rattail fescue coincided with initiation of epinasty of the basal node.
