Anatomical features of overground organs of Crataegus ambigua C.A. Mey., native to Western Karatau Gorges of the Mangyshlak Peninsula

Abstract

The article presents the results of the study of the anatomical structure of annual shoots, leaves and seeds of rare species in Kazakhstan – Crataegus ambigua C.A. Mey., growing in the three gorges of the Western Karatau of Mangistau region: Akmysh, Samal and Zhemsemsay. There was a significant difference in anatomical indicators sheet and annual shoots of Crataegus ambigua growing in a variety of gorges. Young shoots of Crataegus ambigua have the same body plan. Outside the stem is covered with a single layer of the epidermis, the top layer of cells are covered with a thick cuticle. The area between the endoderm and crustal part filled with parenchymal cells in the 5-6 series. Endoderm placed in a row. Bunches are collateral and open type. The number of vascular bundles are 16-18 units. Primary xylem is a flat column, secondary is in the form of irregular portions. Outwards from the xylem phloem arranged small cells, at which a "cap" placed portions of sclerenchyma. The central part is filled with loosely arranged round cells of core parenchyma. Comparing metrics of Crataegus ambigua shoots from 3 gorges shows that  that plant cells vary in size and thickness of plant tissues.

For the main indicators of the maximum results are obtained for the plants growing in Samal gorge, minimum - for the plants from Zhemsemsay gorge. It is worth noting that many of the shoots of Crataegus ambigua from Zhemsemsay gorge have a gradual destruction of the core to form an air cavity.

Crataegus ambigua leaf is flat, it has dorsoventral structure. The  upper and lower epidermis cells, thin-walled, externally coated with a thin layer of cutin can be easily seen on cross section. The surface is smooth, free from trichomes. Mesophyll is differentiated into columnar and spongy tissue. Collateral bundles of closed type; they consist of 10-15 series of xylem and 5-8 series phloem.

For plants of Akmysh gorge serving below average vein has no protrusions, whereas leaf blades of Samal and Zhemsemsay gorges are marked thickening of the lower side of the lateral blunt-pointed "ears" in the midrib.

Analysis of metrics of cross-section of the leaf shows a similar picture, as well as metrics for annual shoots. The highest parameters of cell and tissue cords marked for plants collected from Samal gorges, while the minimum parameters marked for  plant from Zhemsemsay gorge.

The biggest difference between metric parameters observed for indicators of spongy mesophyll thickness and area of vascular bundles.

Pericarp, endosperm and cotyledons can be clearly distinguished in anatomical structure of the seed. Pericarp of seeds consists of 3 layers (eczocarp, mesocarp and endocarp). Eczocarp is thin, covered with cuticle. It consists of a single layer of dead cells. Mesocarp cells are thin-walled, tightly spaced, parenchymal. Endocarp is very weak, comprises in one layer of the thin-walled living cells. Endosperm cells are same shape, spherical, arranged in 8-10 rows.

Epidermal cotyledon cells are elongated, large, arranged in a single layer. Embryo is 2-cotyledonary, elongated in the form of a disk, it completely captures the internal cavity in shear.

In anatomy seeds have low variability. The biggest difference noted on pericarp thickness, while on the thickness of the endosperm and cotyledons significant difference was not observed.