A CASE STUDY OF NON-STRUCTURAL CARBOHYDRATES IN CREEPING BENTGRASS (AGROSTIS STOLONIFERA L.) TISSUE OF PUTTING GREENS IN JAPAN

摘要

Creeping Bentgrass (Agrostis stolonifera L.) is the predominant cool-season turfgrass of putting greens in Japan.The hot and humid climate of the transition zone translates to many management challenges especially in summer.It is suggested that monitoring the nonstructural carbohydrate levels in creeping bentgrass tissue by clipping analysis at actual putting greens under play would contribute to improved turf management.Nonstructural carbohydrate levels and their seasonal changes in field grown creeping bentgrass tissues were measured to evaluate the applicability of the clipping analysis.Among the nonstructural carbohydrates,fructan had the highest content (range of 12.6 - 144.4 mg/gDW),followed by fructose (2.6 - 47.1 mg/gDW) and sucrose (0.8 - 37.5 mg/gDW),with starch (5.0 - 14.0 mg/gDW) and glucose (1.0 - 5.7 mg/gDW) of relatively lower content.The seasonal change was most evident with the fructan in crown and leaf tissues,and there was correlation between its content in crown and in leaf.These results suggested that it is possible to monitor the nonstructural carbohydrate levels in creeping bentgrass by the clipping analysis of fructan.A calibration was established to measure the fructan content in creeping bentgrass clippings by near infrared spectroscopy,and clippings from putting greens were analyzed for five years.Monthly average of fructan showed significant seasonal changes,which reflected the carbohydrate balance in the creeping bentgrass in Japanese golf courses.The fructan analysis with turfgrass clipping is considered to be a tool to monitor the carbohydrate reserve level in creeping bentgrass,and can be used as the index of the carbohydrate balance.