Vol 108, No 2 (2023)

A comparative analysis of the formation and natural course of development of plant communities was carried out in two plots: (1) passed through by a stable ground fire and (2) subjected to experimental clear cutting with preserving young generation of tree species in liana-varied-shrub broad-leaved-dark-coniferous-Korean-pine forests of the mid-mountain belt of the Southern Sikhote-Alin. The features of natural recovery, course of growth, development and dynamics of the number of woody plants in the first 35 years of the reforestation process are considered. Taxation characteristic of the forest stands before their destruction by the fire and cutting, as well as at the first stages of the formation of young tree stands, are given. The dynamics of the species composition and phytomass of the aboveground parts of plants of the shrub and low-shrub-herb layers is considered.

The crown of model trees growing in natural habitats is characterized. An attempt was made to identify more conservative and stable traits of crown axes of different orders. The dependence of the composition of shoots of second-order axes on their position in the first-order axis of the maternal growth is shown. The relationship between the lifetime of the axes and the time of their growth (aging) is revealed. Skeletal axes of the second order show similar pattern of changing the number of shoots from year to year, but differ in the length of their constituent shoots. The axes of the third, fourth and fifth orders determine individual differences of trees, by adjusting them to specific habitats. It was revealed that the change in the dominance of the fourth order over the third one in the crown reflects the regulation of the crown development under specific conditions and the rate of ontogeny. Acrotonia in the form of a stronger development of lateral shoots in the second and third positions from above on the mother shoot is characteristic of all branching orders. With an increase of the branching order, the manifestation of acrotonia is smoothed out. In this regard, the shoots of high orders become more and more similar to each other, which is particularly associated with the manifestation of the aging effect.

The genus Calamus in the family Arecaceae is embryologically not well studied. The present work on the embryology of Calamus prasinus is the first investigation. A transverse section of young male staminate flower shows 6 tetrasporangiate anthers. The anther wall comprises an epidermis, an endothecium, a middle layer and a tapetum. The tapetum is of secretory type and its cells are 2–3 nucleated. The successive meiotic division in the pollen mother cells resulting in the formation of isobilateral and tetrahedral microspore tetrads. Occasionally, T-shaped and linear tetrads have been observed. The pollen grains are shed at 2-celled condition. The ovary is superior, tricarpellary, syncarpous and contains 3 ovules on an axile placenta. The ovule is anatropous, bitegmic and crassinucellate. The archesporial cell divides periclinally to form a primary parietal cell and a sporogenous cell. The sporogenous cell differentiates transformsin to megaspore mother cell, which undergoes meiotic division and subsequent cytokinesis forming a linear tetrad. The chalazal functional megaspore undergoes three successive mitotic divisions without cytokinesis that results in the formation of an 8‑nucleate embryo sac. The embryo sac contains two synergids, one an egg cell at the micropylar end, three antipodal cells at the chalazal end and a central cell with two polar nuclei. The development of female gametophyte conforms to the Polygonum type.