The Vascular Plant Body Like animals, plants are made up of specialized cells that are organized into tissues, which are themselves organized into systems of organs. The various parts of plants are adapted to perform life-supporting functions that include: Photosynthesis Cellular respiration Absorption of water and minerals Transportation of substances throughout the plant.
Vascular Plant Systems Vascular plants have two organ systems: an aboveground shoot system and an underground root system. 1. The shoot system is made up of the stems and leaves, which are specialized to perform photosynthesis, provide structural support, and bear the reproductive structures of the mature plant. 2. The root system is made up of the roots of the plant, and it anchors the plant by penetrating into the soil and is responsible for absorbing the water and mineral nutrients that the plant needs.
Root and Shoot System
Plant Cells Plant cells have a cell wall, which provides support to the plant, a large central vacuole, and chloroplasts, which are used to carry out photosynthesis.
Types of Plant Cells - Parenchyma Cells Most of the cells throughout a plant are flexible, thin-walled cells called parenchyma cells. They are the basis for many plant structures and are capable of a wide range of functions, including storage, photosynthesis, gas exchange, and protection.
Types of Plant Cells - Collenchyma Cells Collenchyma cells are often elongated and occur in long strands or cylinders that provide support for the surrounding cells. These cells make up the long strings that can be pulled from a celery stalk.
Types of Plant Cells - Sclerenchyma Cells Sclerenchyma cells have very thick secondary cell walls that contain lignin, a strong substance that makes the cell walls very tough and hard. Their primary function is to provide support for mature plants. There are two types of sclerenchyma cells: 1. Sclereids, also called stone cells, are distributed randomly throughout the plant. They are responsible for the gritty texture of pears and the hard covering of seed coats. 2. Fibre cells are needle-shaped and have thick cell walls and small interior spaces. When they are stacked end-toend, fibres form a tough elastic tissue.
Types of Plant Cells
Plant Tissues Plants have four main types of tissue: 1. Meristematic tissue 2.Dermal tissue 3.Ground tissue 4.Vascular tissue
Meristematic Tissue Throughout their lives, plants can continue to produce new cells by mitosis in their meristematic tissues, which all vascular plants have. These embryonic tissues make up meristems areas of rapidly dividing cells.
Meristematic Tissue
Dermal Tissue The outer covering of a plant is made up of dermal tissue. The epidermis is a single layer of dermal tissue cells that forms a protective covering over the body of non-woody plants and young woody plants. Older woody plants also form dermal tissue, called periderm, which is produced as part of secondary growth.
Specialized Epidermal Tissue: Guard Cells, Trichomes, and Root Hairs Guard cells are specialized epidermal cells, that, functioning in pairs, regulate the opening of stomata (regulating the rate of gas exchange). Trichomes are tiny growths on the surface of the epidermis that: Keep leaf surfaces cool and reduce evaporation. Secrete sticky or toxic substances that repel herbivores. Are deadly and actually puncture the skin of herbivores that attempt to walk across them. Root hairs are fine, hair-like structures that cover the surface of the root of a plant; they increase the surface area available for gas exchange and the absorption of water and nutrients.
Specialized Epidermal Tissue: Guard Cells, Trichomes, and Root Hairs Guard Cells and Stoma A Trichomes; B Root Hairs
Ground Tissue Ground tissue forms most of the plant s internal and external material. Ground tissues have a wide range of functions, including photosynthesis, storage, and support.
Vascular Tissue Vascular tissue is an internal system of tubes that run lengthwise throughout the stem of a plant, connecting the roots and the leaves. The function of vascular tissue is to transport water and dissolved substances throughout the plant. There are two types of vascular tissue: 1. Xylem transports water and minerals from the roots to the leaves. 2. Phloem transports nutrients such as sugars to areas where they are needed for growth and metabolism, or to the roots for storage.
Xylem and Phloem Xylem Phloem