Anatomical and Functional Fеatures of Deschampsia Antarctica (Poaceae) Leaf Blade Growing on the Argentine Islands

Abstract

The objective of the work was to perform the comparative studies of the anatomical structure and reactive oxygen species (ROS) content in leaves of Deschampsia antarctica plants growing in extreme climatic conditions of Antarctica (Skua and Galindez Іslands). The leaf anatomy and surface ultrastructure were investigated by the methods of light and scanning electron microscopy. To determine the localization of monolignines a cytochemical method of dyeing tissues was used. The ROS content was registered by measuring the spontaneous chemiluminescence (SCL). The obtained results showed the similarity of leaf anatomical and ultrastructural features in plants collected on Scua and Galindez Islands. The localization of two monolignines (syringyl and quaiacyl) detected in leaf cell walls was also similar in the investigated plants. Syringyl is mainly localized in the walls of epidermal cell and quaiacyl is mainly localized in the walls of mesophyll cells and vessels. In epidermal cell walls, the syringyl relative content exceeded the quaiacyl content 6-8 times. The SCL level in D. аntarctica leaves is corresponded to mean values of leaf luminescence in other species under the normal conditions. This may indicate the adaptation of species to harsh habitats. In our opinion, it should be paid special attention on the study of D. аntarctica cell metabolism and its regulation for better understanding the mechanisms of its survival in the conditions of the Maritime Antarctic.

Influence of environmental change on monolignols and the micromorphology of leaf epidermis in hydrophytes and terrestrial plants

“…An increase in lignin, cellulose, and hemicellulose content was also observed in poplar seedlings and monocots with a decrease in air temperature [114,115]. The presence of two monolignins (syringyl and guajacyl) in D. antarctica leaf cell walls was revealed (Figure 7c-e) using cytochemical methods and confocal microscopy [109]. The study showed that the content of syringyl and guajacyl in the walls of the adaxial and abaxial epidermis was different, with the highest content of syringyl in the periclinal walls of the upper epidermis and the highest content of guajacyl in the inner walls of both epidermis, the walls of the mesophyll, and conducting bundles.…”

“…The epidermis of leaves of D. antarctica plants collected on the islands Scua and Galindez characterized the next ultrastructural signs. Oval cells of the adaxial epidermis were covered with an even, smooth cuticle layer (Figure 7a and b) [109]. It was shown that leaf blades were downy.…”

“…A study of the epidermis ultrastructure in the leaves of Deschampsia antarctica collected during the 20th Ukrainian Antarctic Expedition showed that the morphoanatomical traits of the leaves collected on the islands Scua and Galindez are similar to those of the species from other regions of the Maritime Antarctic [109][110][111][112]. It was found that all the leaves of the studied species twisted in a tube-shaped curl.…”