Plant development, while sharing some similarities with animal development, exhibits distinct characteristics that are crucial for understanding how plants grow and reproduce. One of the foundational processes in plant development is embryogenesis, which refers to the transformation of a fertilized ovule into a seed that contains a plant embryo. It is important to note that the seed itself is not the entire embryo; it includes the embryo along with supportive structures, akin to the role of the placenta in mammals.
A significant difference between plant and animal development is the mobility of cells. In animals, certain cells migrate during development to form specialized structures, such as the mesoderm and somites. In contrast, plant cells remain stationary due to their rigid cell walls, which prevent movement. This immobility is a key factor in how plants develop their structures.
After the seed germinates, two main types of development occur: vegetative and reproductive. Vegetative development focuses on the growth of non-reproductive parts of the plant, including roots, leaves, and stems. Reproductive development, on the other hand, involves the formation of the plant's reproductive structures. This process illustrates how a single plant cell can evolve into a fully germinated seed.
Additionally, plants have specific body axes that guide their growth. The apical-basal axis runs from the roots to the shoots, encompassing the stem and the tips of the leaves. This axis is crucial for understanding the orientation and growth patterns of plants. Another important axis is the radial axis, which can be visualized as extending from the center of a plant stem outward, providing insight into the plant's structure in cross-section.