Leaf anatomy of alpine plants as related to altitudinal stress

Abstract

. 1987. Leaf anatomy of alpine plants as related to altitudinal stress. -Nord. J. Bot. 7: 673-685. Copenhagen. ISSN 0107-055X.Alopecurus gerardi, Poa alpina, and Carex curvula are spontaneous, perennial forage plants distributed in the high elevation (2300-3200 m) pasture lands of Piedmont and Valle d'Aosta (Italy). Sedum atraturn is an annual succulent which grows at elevations up to 3200 m. The three monocotyledons have, in comparison with corresponding plants from the low-land, peculiar organographic and anatomic structures such as curling leaf lamina, vascular bundle sheath layer with chloroplasts arranged in a centrifugal fashion, low stomatal density (stomata number/cm*: upper epidermis f = 0-11.9; lower epidermis f = 7.6611.55), thick cuticles, as well as higher values of S (H,O; g/dm2; i = 0.&0.32), Sm (H20 g/mg Chl.; X = 0.11-0.16), SLW (g f. wt/dm2; i = 0.86-1.36), but lower SLA values (cmZ/g f. wt; f = 75.07-116.77). All these data are correlated to water stress. Even though the leaf lamina anatomy possesses some features typical of C, plants, the presence of starch grains in the mesophyll chloroplasts indicates that these plants are probably C3 ones. In spite of high values of thylacoid granakhylacoid intergrana ratios, typical of shade plants (mesophyll chloroplasts: f up to 3.81; bundle sheath chloroplasts: f up to 5.3), and Chl a/Chl b ratios (f up to 4.23 in C. curvula), the apparent absence of peroxisomes seem to indicate a very efficient dark phase of photosynthesis. S. atraturn, in comparison with the typical CAM succulents, which live in dryer and warmer habitats, has a higher values of stomatal density (upper epidermis, f = 2.59; lower epidermis, f = 3.15) and of SLA (X = 24.98), but lower S (X = 3.83), Sm (f = 1.19) and SLW (X = 4.15).

Plant Trait Variation along an Altitudinal Gradient in Mediterranean High Mountain Grasslands: Controlling the Species Turnover Effect

“…[ 38 ], but to our knowledge, it has not been observed in alpine herbs or creeping chamaephytes. Increasing leaf thickness with elevation has also been described [ 39 ]. Recent studies have related this increase to UV-B radiation and the need to protect underlining photosynthetic systems [ 40 ].…”

Taxonomic importance of leaf anatomical characters for the genus Alopecurus L. (Poaceae)

“…The entire or major part of the epidermis in A. gerardii and A. vaginatus is composed of thin-walled wide papillae. It was also noted by Codignola et al (1987) that A. gerardii has a bulbous epidermis. When evaluated in terms of this character (C3), A. goekyigitiana resembles A. lanatus and A. davisii.…”

Above‐ and below‐ground responses to experimental climate forcing in two forb species from montane wooded pastures in Switzerland

“…In their alpine environments, these latter plants thus show numerous adaptations to low temperatures and associated physical constraints (e.g. higher illumination, more frequent fog, recurring frosts; Larcher, 1983) but overall weak xeromorphy, even in the case of thickened and dense leaves (Codignola et al, 1987;Körner, 2003). Responding to changes both beneficial, regarding temperatures, and detrimental, regarding the moisture availability, ubiquitous plants such as Taraxacum or beech (de Carcer et al, 2017) appeared to sense multiple changes in environmental drivers more specifically and address their physiological consequences in a more integrative way.…”