A plant cell contains a polysaccharide cell wall, a central vacuole and chloroplasts, which distinguish them from animal cells. Plant cells also contain mitochondria, a nucleus, Golgi apparatus, endoreticulum membranes, plasma membranes. On plasma membrane and cell wall, there are channels called plasmodesmata connecting neighboring cells for cell-cell communication.
Plants are also made of tissues like animals do. There are three basic types of plant tissues, vascular tissues, ground tissue and dermal tissues. Vascular tissues include xylems and phloems, which are responsible for water, solute and organic chemical transportation. Ground tissues include tissue surrounding the vascular tissue. Its main function is for photosynthesis and storage. Dermal tissues cover the surface of a plant. Different tissue types include different types of cells.
A plant body is made up of three major parts: root, leave and stem. Leaves and stems form a shoot. Each part contains the three major tissue types.
Root and Stem
Root is often under the ground and anchors the plant. From cross section, a typical root contains epidermis, cortex, endodermis and vascular bundles. From longitudinal view, a root contains a root tip which functions in gravity sensing, a zone of cell division, zone of elongation and zone of maturation. The function of a root is for anchorage of the plant, and water and mineral uptake. A stem is the part of the plant from which shoots and buds arise. The function of stem is for support of the plant, for transportation of water, mineral and food. Some stems have storage and reproduction function. Stems have specialized structure celled xylem and phloem for transportation.
Meristem, Leaves and Flowers
Meristem is found in areas of the plant where growth is or will take place - the roots and shoots. Apical meristem is on tips of roots or shoots, where growth results in increase in length of stems and roots by cell division and enlargement. A bud is an undeveloped shoot and normally occurs in the axial of a leaf or at the tip of the stem. Once formed, a bud may remain for some time in a dormant condition, or it may form a shoot immediately. A bud can be differentiated into a leaf or a flower. Leaves are the major sites for photosynthesis which provide food for almost all life forms. Upper surface of leaves are covered by cuticular wax, trichomes may be seen on some cells. The lower dermis cells have a specialized type called guard cells which regulate the opening of stomata. Flowers are the reproduction organs for plants.
Monocots and Dicots
Flower plants can be divided into monocots and dicots. The major difference is that monocots have one cotyledon, and dicots have two; Monocots usually have parallel leave veins and dicots have net-like veins; monocots have flower numbers of 3, dicots have flower numbers of 4 or 5; monocots have scattered vascular bundle and dicots have their vascular bundles arranged in a ring.