Home – Home – Jornals – Flora and Vegetation of Asian Russia 2021 number 3

The structural regulation of photosynthesis is based on the features of the organization of plant chlorenchyma at the cellular and tissue levels. In the chlorenchyma of grasses, there is wide presence of cells of complex shape with pronounced folds and projections, among which cellular and lobed cells are distinguished. The aim of this study was to compare the structure of chlorenchyma, parameters and the three-dimensional form of assimilative cells in the vegetative and generative organs at festucoid grasses. On the example of 25 species of festucoid grasses of different ecological groups growing in Western Siberia, a comparative study of the spatial organization of photosynthetic tissue in leaf blades, leaf sheaths and glumes of spikelets was carried out. Plant samples were fixed in a Gammalund mixture. Transverse and longitudinal sections were made in the middle part of the leaf blades and glumes and in the upper part of the leaf sheaths. In the description of chlorenchyma cells were allocated simple (with straight or slightly wavy walls) and complex (differing in branching of walls) forms of assimilative cells. Cells of complex shape can be flat if complex contours exist only in one direction or multi-complex if they are found in two or three directions. It is shown that in glumes of spikelets, in comparison with the leaf blades, the thickness is reduced and the structure of the chlorenchyma is simplified, while the density of chloroplasts sharply decreases, which may indicate a weakening of the photosynthetic function. At the same time, for the glumes of spikelets are characterized by the complication of spatial cellular configurations in comparison with leaves, mainly due to the predominance of cellular cells of different degrees of expression up to thrice complex cellular-lobed, having lobular contours in a cross-section and cellular in longitudinal direction. The cells are arranged in rows along the organ and come into contact with the cells of the neighboring row in mainly convex parts, which leads to an increase in the intercellular space. In general, in the glumes of spikelets of festucoid cereals in comparison with leaves the assimilatory cells differ in more complex shapes, smaller cross-sectional area and more elongated in the longitudinal direction, which, possibly, creates a structural basis for enhancing gas exchange and to some extent can compensate for a decrease in the development of chlorenchyma.