Canola Seed Glucosinolate Content as Affected by Boron Availability Under Water Stress

Abstract

It is hypothesized that soil boron (B) availability is influenced by water stress and affects canola glucosinolate content. This research was conducted to determine if added B can overcome water stress-induced changes in seed glucosinolate content in canola. The cultivars Cyclone and American A112 were grown in a continuously recirculating hydroponic system with modified Hoagland solutions. The experimental design was a randomized incomplete block. Two B concentrations and one water stress treatment (maintained with polyethylene glycol 8000, PEG) were used: 0.04 mg·L–1 B (not water stressed, without PEG), 0.04 mg·L–1 B (water stressed, with PEG), and 0.60 mg·L–1 B (water stressed, with PEG). Osmotic potential was maintained at –0.1 MPa (with PEG) or 0.05 MPa (without PEG). The 0.04-mg·L–1 B treatment without PEG had significantly lower total glucosinolates than the 0.04-mg·L–1 B treatment with PEG. This indicates that at low available B levels, glucosinolate content is increased by water stress. The 0.04-mg·L–1 B treatment with PEG had significantly higher total glucosinolates than the 0.60 -mg·L–1 B treatment with PEG. Thus, under water stress, the higher available B treatment resulted in lower seed glucosinolate content.