TY - JOUR

T1 - Observation of nutrient uptake at the adaxial surface of leaves of tomato (Solanum lycopersicum) using Raman spectroscopy

AU - Butler, Holly

AU - Martin, Frank

AU - Roberts, Mike

AU - Adams, Steven

AU - McAinsh, Martin

N1 - This is an Accepted Manuscript of an article published by Taylor & Francis in Analytical Letters on 04/9/2019, available online: https://www.tandfonline.com/doi/full/10.1080/00032719.2019.1658199

PY - 2020/1/1

Y1 - 2020/1/1

N2 - Foliar application of nutrient fertilizers is standard practice in agricul- tural environments, and has been shown to increase crop yield and quality more efficiently and economically than soil-based fertilizers. The adsorption of macro- and micro-nutrients through the upper epidermis of leaves is largely species dependent; reliant upon pene- tration through the cuticle and stomata, and also upon the plant’s ability to translocate the nutrient. Herein we describe a method to observe nitrate (NO3) uptake at the adaxial leaf surface to deter- mine the efficacy of foliar fertilizers. We use Raman microspectro- scopy as a sensitive approach to monitor NO3 associated vibrational modes, complemented by ion probe measurements and measurements of leaf nutrient status using flame atomic absorption spectroscopy. The results show that NO3 uptake can be observed down to concentrations as low as 15 mM using Raman microspectro- scopy over a defined surface area, and that the rate of uptake can also be quantified using this approach. These observations could also infer information regarding the transport of other ions present in nitrate salts, such as calcium (Ca), via the indirect monitoring of NO3- specific bands. We believe that Raman microspectroscopy pro- vides a novel method for monitoring nutrient movement throughout plant tissue, and provides a potential tool for nutrient screening.

AB - Foliar application of nutrient fertilizers is standard practice in agricul- tural environments, and has been shown to increase crop yield and quality more efficiently and economically than soil-based fertilizers. The adsorption of macro- and micro-nutrients through the upper epidermis of leaves is largely species dependent; reliant upon pene- tration through the cuticle and stomata, and also upon the plant’s ability to translocate the nutrient. Herein we describe a method to observe nitrate (NO3) uptake at the adaxial leaf surface to deter- mine the efficacy of foliar fertilizers. We use Raman microspectro- scopy as a sensitive approach to monitor NO3 associated vibrational modes, complemented by ion probe measurements and measurements of leaf nutrient status using flame atomic absorption spectroscopy. The results show that NO3 uptake can be observed down to concentrations as low as 15 mM using Raman microspectro- scopy over a defined surface area, and that the rate of uptake can also be quantified using this approach. These observations could also infer information regarding the transport of other ions present in nitrate salts, such as calcium (Ca), via the indirect monitoring of NO3- specific bands. We believe that Raman microspectroscopy pro- vides a novel method for monitoring nutrient movement throughout plant tissue, and provides a potential tool for nutrient screening.

KW - Crop screening

KW - food security

KW - nutrient uptake

KW - Raman spectroscopy

U2 - 10.1080/00032719.2019.1658199

DO - 10.1080/00032719.2019.1658199

M3 - Journal article

VL - 53

SP - 536

EP - 562

JO - Analytical Letters

JF - Analytical Letters

SN - 0003-2719

IS - 4

ER -