This paper presents a comparative study on the anatomy of the Antarctic hairgrass (Deschampsia antarctica É. Desv.) from natural populations of two distant maritime Antarctic regions: the Argentine Islands (Antarctic Peninsula region) and the Point Thomas oasis (King George Island, South Shetland Islands). Comparison of D. antarctica plants from natural populations of Argentine Islands region and plants originated from seeds of these populations cultivated in vitro also was made. Additionally anatomical features of Deschampsia antarctica were compared with ones for D. caespitosa. The results of our study do not provide enough evidence to assert more pronounced xerophytic anatomical features in D. antarctica plants from more harsh conditions of Argentine Islands region. Such features (both qualitative and quantitative) of D. antarctica mainly depend on local conditions, and not on the latitudinal or climatic gradient. In both regions it is possible to find individuals that represent different ecotypes which are adopted to open arid or more humid habitats. It has been shown that Antarctic hairgrass plants germinated from seeds and cultivated in vitro retain the qualitative anatomy features that are typical to plants from the initial natural populations. This is especially noticeable in the case of plants from Berthelot Island (BE1 study plots), which might indicate a genetic fixation and a manifested differentiation similar to DNA haplotypes or chromosomal forms. However, quantitative characteristics, in particular the epidermis parameters, are subject to changes due to the transfer to more favourable conditions. Also qualitative and quantitative difference of D. antarctica in contrast with D. caespitosa have been described. These differences could be useful for identifying these two species. Additionally the quantitative differences (such as the area of the epidermal cells and the number and size of stomata on the adaxial surface) of Alaskan D. caespitosa grown from seeds were detected in contrast to the naturally grown plants of the same species from Ushuaia.

This study investigated the quantitative anatomy of photosynthetic tissues (leaf mesostructure) of wild ginseng Panax ginseng C.A. Mey. (Araliaceae) plants from different natural habitats. The structural and functional traits of the photosynthetic apparatus shown to be especially elastic were mesophyll cell volume (Cv >40%) and traits related to filling of the leaf with cells and plastids (Cv≥21%). P. ginseng possesses relatively few cells per leaf area (44.6-107.2 103/cm2) and chloroplasts (1.7-4.9 106/cm2). Also low are the values of such integral indexes as relative surface of mesophyll cells (Ames/A, 2.78-5.28) and relative surface of chloroplasts (Achl/A, 1.9-3.2). The leaf mesostructure of wild ginseng shows traits of a plant typically found in shady forest habitats. The photosynthetic apparatus of ginseng adapts to various habitat conditions on the level of leaf mesostructure, through structural transformations of mesophyll tissue, such as changes in the number and size of cells and chloroplasts and also the integral surface indexes Achl/A and Ames/A.