Branched-chain Amino Acids for Use as a Nitrogen Source on Creeping Bentgrass

Abstract

<jats:p>Amino acids have been reported to improve turfgrass growth compared with mineral nutrition; however, amino acid catabolism in plants has not been well studied. A number of turfgrass fertilizers contain amino acids; however, some amino acids may be more effective additives in fertilizers than others. Three amino acids that could be effective nitrogen sources for plant growth are the branched-chain amino acids (BCAAs). The BCAA leucine (L), isoleucine (IL), and valine (V) could be effective additives because they are nonpolar and hydrophobic, which can promote plant uptake of these compounds. Although the effect of exogenously applied BCAA on plant growth is not well known, BCAAs have been reported to increase protein synthesis in humans, and that rate of increase is related to the intake ratio of L to IL and V. The objective of this study was to evaluate the use of L, IL, and V as a nitrogen sources on creeping bentgrass (<jats:italic>Agrostis stolonifera</jats:italic>) and to investigate the effect of BCAAs on plant growth when all three are applied as a combination. Using specially made rooting tubes, L, IL, and V were applied in a complete factorial and compared with equal urea nitrogen at four rates, as well as an untreated control. Where all three BCAAs were applied in combination, the application ratios of 2:1:1 and 4:1:1 (L:IL:V) were tested. At 63 days after seeding, there were no differences in root length, root weight, or shoot weight; however, BCAA 2:1:1 and 4:1:1 increased creeping bentgrass shoot density by 24% and 32%, respectively, compared with equal urea nitrogen. Where shoot density was increased, nitrogen application rate had no effect. On the basis of these results, BCAAs applied in a complete combination using ratios of 2:1:1 or 4:1:1 (3.03 lb/acre N) will provide a greater creeping bentgrass shoot density compared with equal urea nitrogen.</jats:p>

Utilizing Branched-chain Amino Acids for Increasing Shoot Density and Establishment Rate in Creeping Bentgrass

“…These results coincide with earlier findings and confirm the use of BCAA for increasing creeping bentgrass shoot density when applied in a three-way combination (Mertz et al, 2019). Compared with the commercially available AA product, increases in shoot density with the three-way BCAA combinations were similar, however, increases in creeping bentgrass shoot density observed with these treatments do not appear to translate to an increased rate of establishment compared with urea N, based on DIA results from this study.…”

“…Creeping bentgrass plants were initially cut when the samples had reached a 1.3-inch height on average, and then maintained at a 1-inch height of cut (HOC) weekly with hand shears. This HOC was chosen based on the methods used by Mertz et al (2019), and limitations of the hand shears. At the time of cutting, samples The commercially available amino acid product GreenNCrease was obtained from Ajinomoto North America, Inc. (Eddyville, IA) and is a combination of amino acids, sugars, organic acids, polysaccharides, and ammonium sulfate.…”

“…The BCAA are capable of increasing protein synthesis, with the degree of increase being related to the intake ratio of L to IL and V (Hole cek, 2002;Jefferson, 2001, 2006;Pasiakos et al, 2011 a three-way application of BCAA (L:IL:V) may also result in additional beneficial plant growth compared with mineral nutrition only (Mertz et al, 2019). In that study, BCAA increased creeping bentgrass shoot density by 30% and 40% compared with urea N (3.03 lb/acre N) when applied at a 2:1:1 and 4:1:1 ratio (L:IL:V) (Mertz et al, 2019). No such increases were observed when BCAA were applied as single AA or in two-way combinations, which was found to be similar to previous studies (Hole cek, 2002;Jefferson, 2001, 2006;Pasiakos et al, 2011).…”

Nostoc talks back: Temporal patterns of differential gene expression during establishment of the Anthoceros-Nostoc symbiosis

“…as N sources for growth (Miller et al, 2008;Paungfoo-Lonhienne et al, 2008;Mertz et al, 2019). Amino acid and other organic N transporters were present in the differential transcriptome; the transporters with the highest levels of expression are for lysine and histidine and they are present in cluster 7 (Dataset S3), which is inconsistent with N-limited complementation function.…”

Evaluation of humic fertilizers on turfgrass

“…Experiments were conducted in 2018 and 2019 in a greenhouse at the Iowa State University (Ames, IA, USA). Rooting tubes were constructed using modified methods described by and Mertz et al (2019). Clear polyethylene tubing (2.5 cm diameter)…”