The effect of nitrate and gibberellin treatment on carbon storage and nitrogen uptake efficiency following defoliation of lolium perenne

Type of content
Theses / Dissertations
Publisher's DOI/URI
Thesis discipline
Biological Sciences
Degree name
Master of Science
Publisher
University of Canterbury
Journal Title
Journal ISSN
Volume Title
Language
English
Date
2017
Authors
Brennan, Mariann Phyllis
Abstract

Agriculture accounts for almost 50 % of New Zealand’s greenhouse gas emissions. The high level of nitrogenous fertilisers used to stimulate plant growth causes emissions of NO2 and leaching of N into waterways. In order to address these issues and improve N uptake efficiency in Lolium perenne L., a widely used forage grass, the effect of the day (postdefoliation) of N application, in conjunction with the addition of GA3, on plant growth was observed. Parameters measured included N uptake and fructan levels which are the main storage carbohydrate of grasses. Results indicate that the application of fertiliser between day 6 and 11 post‐defoliation may be beneficial in increasing N uptake and reducing leaching of N as carbohydrate levels have been restored in leaves, leaving the plant less C starved and more able to take up N. The application of GA3 was not found to have an effect on N uptake. The effect of N form and concentration on root system architecture in vitro, indicates that arginine, an organic form of nitrogen, may be beneficial in improving N uptake and growth of plants if used as a fertiliser, compared to nitrate, a commonly used inorganic form of fertiliser.

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All Rights Reserved