Understanding Other Plant Macrostructures

Meristem tissue contains undifferentiated cells and allows for plant growth. Apical meristems are found in areas of growth, which include the shoot and roots—cells in these tissues divide rapidly.

The vascular cambium is a type of secondary meristem tissue located between the xylem and phloem of the stems and roots. Secondary meristem tissues are responsible for lateral growth; more specifically, the vascular cambium is responsible for secondary xylem and phloem development.

The cork cambium is a type of secondary meristem tissue found in the periderm. Cork cambium controls lateral growth; specifically, it is the source of secondary epidermis growth.

Plants grow so as to maximize the elongation of their stems as much as possible. Cells on the lighter side of the stem are already being provided with photosynthetic energy, while cells on the darker side are receiving less of this energy input. This causes the cells on the darker side to elongate toward the energy source. When one side of the stem is longer than the other, it causes a curve in the growth, resulting in a directionality of the growth of the stem.

Fibrous root systems are common in seedless vascular plants and in most monocots, such as grasses. Many small roots grow from the stem of the plant and are considered adventitious (a term describing a plant organ that grows in an unusual location).

Fibrous roots have no main root and do not penetrate deeply into the soil, usually penetrating only a few centimeters. As such, fibrous root systems are best adapted to shallow soil. This also helps prevent erosion, as the shallow, highly-branched roots hold the topsoil in place.

The root cap occurs on the end of any root. It protects the tip of a plant's root. Specifically, it protects the apical meristem of the plant, which lengthens the root and helps it grow. Also root cap secretes a polysaccharide slime called mucilage. The zone of elongation does occur in roots, but it is not contained to the root cap. The root cap grows towards the pull of gravity. The root cap occurs only on the tip of the root, not over the entire surface of the root. These cells only protect the root; they are not xylem cells, which function in transport of water and nutrients from the roots up to the leaves.

Parenchyma cells make up a type of ground tissue in plants. Parenchyma cells compose most of the soft tissues in plants including leaves, roots, stems, and seeds. The functions of parenchyma cells include photosynthesis, storage, and wound repair.

Roots are usually underground and not exposed to sunlight, do not usually contain chlorophyll, thus they do not perform photosynthesis. However, roots do provide stabiity, obtain water and nutrients from the soil, and store carbohydrates.

The receptacle is the part of an angiosperm out of which the flower grows; thus, the receptacle is at the top of the stem.

The carpel is a part of the female angiosperm reproductive system. The carpel includes the ovary, ovules, style, and stigma. Flowers may have several carpels clustered into a pistil.