Traits of seasonal dimorphism associated with adaptation to cold stress in Origanum dictamnus L. (Lamiaceae)

Table 1 Morphometric assessments of expanded leaves of winter and summer (±SD, n = 36)

	Winter leaves	Summer leaves
Leaf length (mm)	10.8 ± 3.1^a	23.4 ± 8.8^b
Leaf width (mm)	10.1 ± 2.5^a	21.7 ± 6.9^b
Leaf surface area (on each side) (mm²)	93.7 ± 6.7^a	408.6 ± 49.2^b
Leaf thickness (μm)	254.5 ± 25.6^a	190.1 ± 17.9^b
Relative volume percentage of leaf upper epidermis (leaf cross section)	12.8 ± 2.1^a	12.5 ± 1.4^a
Relative volume percentage of leaf palisade parenchyma (leaf cross section)	53.2 ± 9.3^a	52.9 ± 10.6^a
Relative volume percentage of spongy parenchyma (leaf cross section)	29.3 ± 4.7^a	23.3 ± 1.8^b
Relative volume percentage of leaf lower epidermis (leaf cross section)	5.8 ± 0.6^a	4.1 ± 0.7^b
Density of stomata on the upper leaf side (No mm⁻²)	*	*
Density of stomata on the lower leaf side (No mm⁻²)	564.4 ± 81.1^a	458.2 ± 66.3^b
Density of peltate glandular hairs on the upper leaf side (No mm⁻²)	3.5 ± 2.0^a	4.6 ± 1.4^b
Density of peltate glandular hairs on the lower leaf side (No mm⁻²)	4.8 ± 1.4^a	6.1 ± 1.4^b

Means between columns with different letters are significantly different at p < 0.05.
*Stomata on the upper leaf side are extremely limited.

ISSN: 2241-5793