Carbohydrate Level, Photosynthesis, and Respiration in Creeping Bentgrass as Influenced by Spring and Summer Coring.

Carbohydrates provide energy required to maintain healthy plant growth in summer. Coring is performed periodically on creeping bentgrass (Agrostis stolonifera L.) putting greens for numerous reasons; however, its impact on carbohydrate metabolism in creeping bentgrass is unknown. The objectives of this 2-year field study were to examine the effects of coring on rates of photosynthesis (Pn) and whole plant respiration (Rw), and to quantify water-soluble carbohydrates [WSC (i.e., glucose, fructose, and sucrose)], storage carbohydrates [SC (i.e., fructan and starch], and total nonstructural carbohydrates [TNC (i.e., WSC + SC)] in creeping bentgrass leaves and roots during the summer. The study site was 'Providence' creeping bentgrass grown on a sand-based root zone and was maintained as a putting green. Three coring treatments were assessed as follows: spring-only coring, spring plus three summer corings, and a noncored control. Pn and Rw were measured about 21 d following coring with hollow tines. Pn and Rw rates generally were similar among all three coring treatments in both years. Hence, summer coring had no apparent negative impact on Pn or Rw. Leaf and root WSC, SC, and TNC levels were similar among coring treatments throughout the summer of each year. However, root TNC levels were lower in July of each year in spring plus summer-cored bentgrass versus other coring treatments. By September, leaves and roots from spring plus summer-cored creeping bentgrass had higher TNC levels when compared with spring-only or noncored bentgrass. Leaf and root SC levels from spring plus summer-cored bentgrass were also higher in September than were observed in noncored bentgrass. Spring plus summer coring benefited creeping bentgrass by promoting an accumulation of carbohydrates in late summer, which could assist plants in their recovery from summer stresses. [ABSTRACT FROM AUTHOR]