Photosynthesis occurs in which type of plant tissue

When the plant is photosynthesising during the day, these features allow carbon dioxide to diffuse into the spongy mesophyll cells, and oxygen to diffuse out of them. To enter the leaf, gases diffuse through small pores called stomata. As the stomata open, water is lost by the process of transpiration. Closing the stomata helps to control water loss.

The thylakoid membrane encloses an internal space called the thylakoid lumen. Learning Objectives Describe the main structures involved in photosynthesis and recall the chemical equation that summarizes the process of photosynthesis. In plants, the process of photosynthesis takes place in the mesophyll of the leaves, inside the chloroplasts. Chloroplasts contain disc-shaped structures called thylakoids, which contain the pigment chlorophyll. Chlorophyll absorbs certain portions of the visible spectrum and captures energy from sunlight.

Key Terms chloroplast : An organelle found in the cells of green plants and photosynthetic algae where photosynthesis takes place. Overview of Photosynthesis Photosynthesis is a multi-step process that requires sunlight, carbon dioxide, and water as substrates. Oxygen is generated as a waste product of photosynthesis. In reality, the process includes many steps involving intermediate reactants and products. Glucose, the primary energy source in cells, is made from two three-carbon GA3P molecules.

Photosynthesis and the Leaf In plants, photosynthesis generally takes place in leaves, which consist of several layers of cells. Like animals, plants are multicellular eukaryotes whose bodies are composed of organs, tissues, and cells with highly specialized functions. The relationships between plant organs, tissues, and cell types are illustrated below. The stems and leaves together make up the shoot system.

Each organ roots, stems, and leaves include all three tissue types ground, vascular, and dermal. Different cell types comprise each tissue type, and the structure of each cell type influences the function of the tissue it comprises. We will go through each of the organs, tissues, and cell types in greater detail below.

The text below was adapted from OpenStax Biology Vascular plants have two distinct organ systems: a shoot system , and a root system. The shoot system consists stems, leaves, and the reproductive parts of the plant flowers and fruits. The shoot system generally grows above ground, where it absorbs the light needed for photosynthesis.

The root system , which supports the plants and absorbs water and minerals, is usually underground. The organ systems of a typical plant are illustrated below. The shoot system of a plant consists of leaves, stems, flowers, and fruits.

The root system anchors the plant while absorbing water and minerals from the soil. Image credit: OpenStax Biology. The roots of seed plants have three major functions: anchoring the plant to the soil , absorbing water and minerals and transporting them upwards , and storing the products of photosynthesis. Some roots are modified to absorb moisture and exchange gases.

Most roots are underground. Some plants, however, also have adventitious roots , which emerge above the ground from the shoot. Stems are a part of the shoot system of a plant. Their main function is to provide support to the plant, holding leaves, flowers and buds. Of course they also connect the roots to the leaves, transporting absorbed water and minerals from the roots to the rest of the plant, and transporting sugars from the leaves the site of photosynthesis to desired locations throughout the plant.

They may range in length from a few millimeters to hundreds of meters, and also vary in diameter, depending on the plant type. Stems are usually above ground, although the stems of some plants, such as the potato, also grow underground. Plant stems, whether above or below ground, are characterized by the presence of nodes and internodes shown below. Nodes are points of attachment for leaves and flowers; internodes are the regions of stem between two nodes.

The tip of the shoot contains the apical meristem within the apical bud. An axillary bud is usually found in the area between the base of a leaf and the stem where it can give rise to a branch or a flower. Leaves are attached to the plant stem at areas called nodes. An internode is the stem region between two nodes.

The petiole is the stalk connecting the leaf to the stem. The leaves just above the nodes arose from axillary buds. Leaves are the main sites for photosynthesis: the process by which plants synthesize food. Most leaves are usually green, due to the presence of chlorophyll in the leaf cells.

However, some leaves may have different colors, caused by other plant pigments that mask the green chlorophyll. A typical eudicot leaf structure is shown below. Typical leaves are attached to the plant stem by a petiole , though there are also leaves that attach directly to the plant stem.

The vascular tissue xylem and phloem run through veins in the leaf, which also provide structural support. Illustration shows the parts of a leaf. The petiole is the stem of the leaf. The midrib is a vessel that extends from the petiole to the leaf tip. Veins branch from the midrib. The lamina is the wide, flat part of the leaf. The margin is the edge of the leaf.

The thickness, shape, and size of leaves are adapted to specific environments. Each variation helps a plant species maximize its chances of survival in a particular habitat. Coniferous plant species that thrive in cold environments, like spruce, fir, and pine, have leaves that are reduced in size and needle-like in appearance.

These needle-like leaves have sunken stomata pits that allow gas exchange and a smaller surface area: two attributes that aid in reducing water loss. In hot climates, plants such as cacti have leaves that are reduced to spines, which in combination with their succulent stems, help to conserve water.

Many aquatic plants have leaves with wide lamina that can float on the surface of the water, and a thick waxy cuticle waxy covering on the leaf surface that repels water. Content below adapted from OpenStax Biology Plant tissue systems fall into one of two general types: meristematic tissue , and permanent or non-meristematic tissue. Meristematic tissue is analagous to stem cells in animals: m eristematic cells are undifferentiated continue to divide and contribute to the growth of the plant.

In contrast, permanent tissue consists of plant cells that are no longer actively dividing. Meristems produce cells that quickly differentiate, or specialize, and become permanent tissue. Such cells take on specific roles and lose their ability to divide further. They differentiate into three main tissue types: dermal, vascular, and ground tissue.

Each plant organ roots, stems, leaves contains all three tissue types:. Each plant organ contains all three tissue types.