Effects of nanocarbon solution treatment on the nutrients and glucosinolate metabolism in broccoli

•Nanocarbon application could enhance the total protein in broccoli, directly.•18.75 L·ha−1 nanocarbon solution greatly increase 22.9 % of glucoraphanin.•Nanocarbon solution obviously reduces 4 indolic glucosinolate productions.•Nanocarbon has great great impact on glucosinolate biosynthesis and pathway.