Core cultivation or coring is routinely performed on putting greens for a multitude of beneficial purposes as outlined by McCarty (2001). However, coring is disruptive to the putting surface and causes mechanical injury to turf. Mechanical injury to plants would be expected to result in an increase in respiration and possibly a reduction in photosynthesis. A concomitant decrease in photosynthesis and increase in respiration could cause a harmful depletion of carbohydrates. Few studies have been performed that investigated the impact of mechanical injury on carbon metabolism in turfgrasses. However, Howieson and Christians (2008) investigated the effect of rolling and mowing (single and double cutting) on carbohydrate metabolism in creeping bentgrass grown in a greenhouse. They found that fructan levels in leaves were reduced in single- and double-cut creeping bentgrass compared with uncut plants by 52% and 45%, respectively. Glucose levels were reduced 31% in double-cut creeping bentgrass compared with uncut bentgrass (Howieson and Christians, 2008). However, leaf fructan levels in creeping bentgrass subjected to the two mowing practices reached the same level as that of uncut plants at 60 h following mowing (Howieson and Christians, 2008).
The rate of turf recovery from mechanical injury can depend on the availability of carbohydrates (Donaghy and Fulkerson, 1998). Carbohydrates in turfgrasses consist of the monosaccharides, glucose and fructose (reducing sugars), disaccharide sucrose, and various starches and fructans (Smith, 1972). Fructan can be hydrolyzed into fructose, which can be converted to glucose or used to form sucrose. Mono- and disaccharides are depleted during respiration, when new leaves and roots of perennial ryegrass (Lolium perenne L.) are produced (Amiard et al., 2003). Root growth in some grasses is more sensitive to a decrease in the availability of carbohydrates than leaf growth (Donaghy and Fulkerson, 1998). Therefore, root regrowth following coring may require a considerable amount of carbon investment.
Understanding how leaf and root carbohydrate levels change following coring may be important for maintaining high-quality creeping bentgrass greens. This is especially true in summer when high temperature stress reduces photosynthesis, root growth, and quality in creeping bentgrass (Xu and Huang, 2000). As previously noted, the effects of coring on carbohydrate metabolism during summer months in creeping bentgrass has not been documented. Therefore, the objectives of this field study were to quantify rates of photosynthesis (Pn) and whole plant respiration (Rw) rates as well as carbohydrate levels [i.e., water-soluble carbohydrates (WSC), storage carbohydrates (SC), and total nonstructural carbohydrates (TNC)] in creeping bentgrass leaves and roots in response to spring-only coring versus spring plus summer coring.
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U.S. Golf Association 2004 USGA recommendations for a method of putting green construction 11 June 2008 <http://www.usga.org/turf/course_construction/green_article/putting_green_guidelines.htm>.
Xu, Q. & Huang, B. 2000 Effects of differential air and soil temperature on carbohydrate metabolism in creeping bentgrass Crop Sci. 40 1368 1374