Development of LA-ICP-MS and Associated Techniques Towards Analysis of Crop Enhancement Products

Wheat is the most significant crop grown globally for human consumption, contributing around 20 % of the total dietary calories and protein consumed worldwide. It is also the most widely grown crop in the world, cultivated on 217 million hectares of agricultural land. Zinc is an essential micronutrient which plays a vital role in healthy plant growth and development. Zinc is the only metal to be present in all six classes of enzymes found in plants and is a cofactor in more than 300 proteins. It has been shown that zinc is the most important micronutrient when it comes to crop yields and a deficiency of zinc has the greatest impact on yield of any micronutrient deficiency. Zinc deficiency is the most common micronutrient deficiency globally, with over 50 % of agricultural land classified as zinc deficient. Seed applied treatments are commonplace in agriculture, with some being used as a method to deliver micronutrients to plants during the early stages of development. Seed treatment is an environmentally approach to nutrient delivery to plants due to the targeted nature of the application and the smaller amounts of active ingredients used compared to crop spraying. Adjuvants are materials added to formulations, designed to increase the efficacy of active ingredients. This thesis outlines novel methods and results investigating the effect of adjuvant inclusion in a ZnO-containing seed coating on the uptake and effects of Zn, using winter wheat as a model crop. Analysis methods include ICP-MS, and LA-ICP-MS, both of which are widely established in life sciences, but have never been applied to study the effects of seed-applied adjuvant on nutrient uptake. The thesis also includes supporting data using micro-CT and SEM to image seed-applied Zn for the first time. The aim of this research was to investigate the effect of adjuvants on the uptake of zinc from seed film coatings, to determine the effect of adjuvant on zinc uptake, localisation and concentration in winter wheat, and to determine the extent to which adjuvant inclusion may negate the drawbacks of using ZnO as the Zn source for the film coatings.