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Nitrogen utilization in creeping bentgrass
Doctoral Committee Chair(s)
Fermanian, Thomas W.
Department of Study
Degree Granting Institution
University of Illinois at Urbana-Champaign
Biology, Plant Physiology
Efficient approaches for screening nitrogen utilization efficiency (NUE) of turfgrasses are needed, since nitrate contamination of ground water is a concern on golf courses. In the first study, the conditions of N utilization of fourteen bentgrass cultivars were compared in hydroponic solution culture. There were significant differences between cultivars in plant tissue dry weight, tissue N content, root absorption efficiency (RAE), and NUE. From a whole plant basis, 'Penncross' accumulated the highest N accompanied with the highest whole plant dry weight (WPDW). 'Regent' had the highest NUE while 'Allure' had the lowest NUE. Nitrogen absorption efficiency values were comparatively higher in 'Allure' than all the other cultivars. Differences in NUE among most cultivars were correlated to plant dry weight.
The second study was conducted to determine the conditions of N utilization, including plant dry weight production, N and nitrate N $\rm (NO\sb3$-N) content accumulation, nitrogen utilization efficiency, RAE, reduced N accumulation, and nitrate reductase activity (NRA), and some of their relationships in creeping bentgrass cultivars.
The results demonstrated the genotypic variation in N utilization and absorption. 'Putter' and 'Penncross' were the most efficient genotypes in utilizing N at low N conditions. The N assimilation capacity was not the primary factor involved in genotypic differences in NUE. However, nitrate reductase activity was probably the mechanism for the regulation of NUE. The NRA was influenced by environmental conditions. The behaviors of N utilization are very affected by the N supplied level.
The role of nutrition in the control of organ growth has been studied through the application of in vitro techniques. Roots can be considered the principal organ of uptake. The relationship between NUE and plant growth for two different creeping bentgrass cultivars was investigated through the use of tissue culture methods in the third study. 'Putter', a high NUE cultivar, had longer roots and shoots than the low NUE cultivar, 'National', on each level of N. The results suggest that root formation was probably one of the mechanisms for regulating the nitrate utilization in creeping bentgrass.