Impact of nitrogen supply on glucosinolate content and phenolic acids in cauliflower varieties

• Published in: Acta Agriculturae Scandinavica, Section B — Soil & Plant Science
• Main Authors: Madonna N. Mashabela, Martin Maboko, Puffy Soundy, Dharini Sivakumar
• Format: Article in Journal/Newspaper
• Language: English
• Published: Taylor & Francis Group 2019
• Subjects: antioxidant property; bioactive compounds; fertiliser application; glucoiberin; sinigrin; vegetable crop; Plant culture; SB1-1110; eskimo*
• Online Access: https://doi.org/10.1080/09064710.2019.1611915; https://doaj.org/article/3f197980ffce410089bb5cdbd64c6820

Application of nitrogen (N) is a common practice used to achieve profitable yields in horticultural crops and N application can be used as a tool to manipulate the enhancement of phytochemicals in vegetable crops to address consumer-oriented quality production. Our previous findings recommended 90 kg ha−1 for certain types of cauliflower varieties without compromising yields. Thus, this study was aimed to investigate the effect of N application on glucosinolates and phenolic acids, at harvest, in varieties ‘Largardo’, ‘Eskimo’ and ‘CF-744’ grown in the field. N was applied as ammonium nitrate (NH4NO3) at concentrations from 0, 60, 90, 120, 150 to 180 kg ha−1. Variety ‘CF-744’ was more sensitive to N supply and at 180 kg ha−1 N it showed the highest accumulation of glucosinolates (sinigrin, glucoiberin, progoitrin, 4-methoxyglucobrassicin) at harvest. However, 90 kg ha−1 N supply demonstrated the highest accumulation of majority of the glucosinolates in varieties ‘Largardo’ and ‘Eskimo’. Different varieties responded differently to N supply and glucosinolate levels in cauliflowers. Also, different varieties responded differently to N supply and antioxidant property. In all three varieties, the N supply at 120 kg ha−1 showed the highest accumulation of protocatechoic acid, 4-hydroxy benzoic acid, ρ-coumaric acid and caffeic acid.