Table 1.

Parameters of microstructures of fresh tobacco leaves inside and outside the greenhouse

Treatment	Thickness of lamina (μm)	Thickness of upper epidermis (μm)	Thickness of lower epidermis (μm)	Thickness of palisade tissues (μm)	Thickness of spongy tissues (μm)	Ratio of thickness of palisade tissues to that of spongy tissues (tissue ratio)
Inside the greenhouse	335.09A	30.37A	30.72A	110.31A	162.12A	0.68A
Outside the greenhouse	133.10B	15.82B	9.53B	53.76B	58.76B	0.91A

Different capital letters indicate significant differences between different treatments at the same stage (P < 0.05). Values represent the averages of three biological replicates