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This tissue system is present between the dermal tissue and forms the main bulk of the plant body. Parenchyma cells have thin primary walls and usually remain alive after they become mature. Parenchyma forms the "filler" tissue in the soft parts of plants, and is usually present in cortex , pericycle , pith , and medullary rays in primary stem ...
Vascular bundles are present throughout the monocot stem, although concentrated towards the outside. This differs from the dicot stem that has a ring of vascular bundles and often none in the center. The shoot apex in monocot stems is more elongated. Leaf sheathes grow up around it, protecting it. This is true to some extent of almost all monocots.
The stem in section shows a distinct layer of the plant directly under the skin of the stem. The border between the collenchyma and stem is poorly scratched. In the parenchyma, starch grains are randomly distributed. The tissue of the stem also contains idioblasts with calcium oxalate crystals and drusen. The stem also contains secretory cells ...
The rhytidome is the most familiar part of bark, being the outer layer that covers the trunks of trees. It is composed mostly of dead cells and is produced by the formation of multiple layers of suberized periderm, cortical and phloem tissue. [33] The rhytidome is especially well developed in older stems and roots of trees.
While new pith growth is usually white or pale in color, as the tissue ages it commonly darkens to a deeper brown color. In trees pith is generally present in young growth, but in the trunk and older branches the pith often gets replaced – in great part – by xylem. In some plants, the pith in the middle of the stem may dry out and ...
In monocots, the tunica determines the physical characteristics of the leaf edge and margin. In dicots, layer two of the corpus determines the characteristics of the edge of the leaf. The corpus and tunica play a critical part of the plant physical appearance as all plant cells are formed from the meristems.
The epidermis is the outermost cell layer of the primary plant body. In some older works the cells of the leaf epidermis have been regarded as specialized parenchyma cells, [1] but the established modern preference has long been to classify the epidermis as dermal tissue, [2] whereas parenchyma is classified as ground tissue. [3]
Despite this, only three families of monocots use C 4 carbon fixation compared to 15 dicot families. Of the monocot clades containing C 4 plants, the grass ( Poaceae ) species use the C 4 photosynthetic pathway most. 46% of grasses are C 4 and together account for 61% of C 4 species.