Boron nutrition and the composition of glucosinolates and soluble nitrogen compounds in two broccoli (Brassica oleracea var. italica) cultivars

• Published in: Canadian journal of plant science 1992-07, Vol.72 (3), p.889-899
• Main Authors: Shelp, B.J, Shattuck, V.I, McLellan, D, Liu, L
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; boron; Brassica oleracea var. italica; cultivars; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; glucosinolates; Micronutrients fertilization; nitrogen compounds; nutrient deficiencies; plant nutrition; Soil-plant relationships. Soil fertility. Fertilization. Amendments; trace element deficiencies
• ISSN: 0008-4220; 1918-1833
• DOI: 10.4141/cjps92-112

The effects of boron (B) nutrition on the composition of glucosinolate and soluble nitrogen (amino acids, NO 3 − , NH 4 + ) compounds, as well as the distribution of B, were investigated in two cultivars of broccoli (Brassica oleracea var. italica ’Baccus’ and ’Commander’). The plants were grown to commercial maturity in vermiculite under glasshouse conditions and supplied continuously with B levels ranging from 0 to 2.5 mg L −1 of nutrient solution. Visible symptoms and inflorescence characteristics confirmed that Commander was more tolerant to B deficiency than Baccus. Eight glucosinolates were identified by high performance liquid chromatography and mass spectrometric analysis including 4-hydroxy-3-indolylmethyl-glucosinolate and 4-methoxy-3-indolylmethyl-glucosinolate which have not previously been reported for broccoli. The predominant glucosinolates were 3-indolylmethyl-glucosinolate, 1-methyoxy-3-indolylmethyl-glucosinolate and 4-methylsulfinylbutyl-glucosinolate. Baccus, but not Commander, also had considerable 2-hydroxy-3-butenyl-glucosinolate. In response to induced B deficiency [tissue B concentrations from 9–18 μg (g DW) −1 ], the total glucosinolates increased by about threefold in the young leaves, but not in the florets. In both the young leaves and florets, there were increases (54–175%) in the proportion of indolyl-glucosinolates. In both cultivars, the pool sizes of the glucosinolate precursor amino acids (phenylalanine, tryptophan and methionine), and of NO 3 − and NH 4 + were not markedly affected.Key words: Boron nutrition, Brassica, broccoli, cultivars, glucosinolates, nitrogen