Fig. 1. Effects of planting year on the carbon contents (a) and nitrogen contents (b) in cucumbers

Fig. 2. Mid-IR spectra of cucumbers growing in the greenhouses with different planting years

Fig. 3. Effects of planting years on the relative contents of polysaccharide (a), protein (b), and lignin (c) in cucumbers

Fig. 4. Effects of planting years on polysaccharide/protein (a) and polysaccharide/lignin components (b) in vegetable cucumbers

Fig. 5. Linear regression between organic components in cucumber and in cucumber leaf
(a): Polysaccharide; (b): Protein; (c): Lignin components

Fig. 6. Linear regressions between the ratio of cucumber organic components and the contents of carbon and nitrogen in cucumbers
(a): Polysaccharide/lignin with carbon content; (b): Polysaccharide/protein with nitrogen content