title: Enhancing crop yield with the use of N-based fertilizers co-applied with plant hormones or growth regulators.
abstract: Crop yield, vegetative or reproductive, depends on access to an adequate supply of essential mineral nutrients. At the same time, a crop plant's growth and development, and thus yield, also depend on in situ production of plant hormones. Thus optimizing mineral nutrition and providing supplemental hormones are two mechanisms for gaining appreciable yield increases. Optimizing the mineral nutrient supply is a common and accepted agricultural practice, but the co-application of nitrogen-based fertilizers with plant hormones or plant growth regulators is relatively uncommon. Our review discusses possible uses of plant hormones (gibberellins, auxins, cytokinins, abscisic acid and ethylene) and specific growth regulators (glycine betaine and polyamines) to enhance and optimize crop yield when co-applied with nitrogen-based fertilizers. We conclude that use of growth-active gibberellins, together with a nitrogen-based fertilizer, can result in appreciable and significant additive increases in shoot dry biomass of crops, including forage crops growing under low-temperature conditions. There may also be a potential for use of an auxin or cytokinin, together with a nitrogen-based fertilizer, for obtaining additive increases in dry shoot biomass and/or reproductive yield. Further research, though, is needed to determine the potential of co-application of nitrogen-based fertilizers with abscisic acid, ethylene and other growth regulators.
authors.affiliation: Ballance Agri-Nutrients Limited New Zealand, Private Bag 12503, Tauranga Mail Centre, Tauranga, 3143, New Zealand.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Zaman
authors.affiliation: Department of Biology, Western University, London, Ontario, Canada, N6A 5B7.
authors.forename: Leonid V
authors.initials: LV
authors.lastname: Kurepin
authors.affiliation: Ballance Agri-Nutrients Limited New Zealand, Private Bag 12503, Tauranga Mail Centre, Tauranga, 3143, New Zealand.
authors.forename: Warwick
authors.initials: W
authors.lastname: Catto
authors.affiliation: Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada, T2N 1N4.
authors.forename: Richard P
authors.initials: RP
authors.lastname: Pharis
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism; D064751:Ammonium Compounds / Q000378:metabolism; D001622:Betaine / Q000378:metabolism; D018556:Crops, Agricultural / Q000254:growth & development* / Q000378:metabolism; D003583:Cytokinins / Q000378:metabolism; D005030:Ethylenes / Q000378:metabolism; D005308:Fertilizers; D005875:Gibberellins / Q000378:metabolism; D007210:Indoleacetic Acids / Q000378:metabolism; D009566:Nitrates / Q000378:metabolism; D017672:Nitrogen Compounds / Q000378:metabolism*; D010937:Plant Growth Regulators / Q000378:metabolism*; D011073:Polyamines / Q000378:metabolism; D014508:Urea / Q000378:metabolism
chemical_list: D064751:Ammonium Compounds; D003583:Cytokinins; D005030:Ethylenes; D005308:Fertilizers; D005875:Gibberellins; D007210:Indoleacetic Acids; D009566:Nitrates; D017672:Nitrogen Compounds; D010937:Plant Growth Regulators; D011073:Polyamines; D001622:Betaine; D000040:Abscisic Acid; D014508:Urea; C036216:ethylene
keywords: abscisic acid; auxins; cytokinins; ethylene; gibberellins; glycine betaine; polyamines