13.2 The Vascular Plant Body

Agenda Lesson 13.2 The Vascular Plant Body Read p Vocabulary Review Questions p. 551 # 1, 2, 6, 10.

Learning Goals 1.Students will define the following terms: shoot system, root system, meristematic tissue, dermal tissue, epidermis, guard cell, stoma, root hairs, ground tissue, xylem, phloem. 2.Students will identify the two systems found in a plant. 3.Students will describe the types of cells and their functions found in plants. 4.Students will identify the types of plant tissues, providing details about each.

Plants Like animals, plants are made up of specialized cells, tissues, organs and organ systems.

The various parts of plants are adapted to perform life-supporting functions that include: Photosynthesis Cellular respiration Absorption of water and minerals Transport of substances throughout the plant

Plants are classified into two main groups: 1. Those that have vascular tissue (vascular plants) 2.Those that do not vascular tissue(non- vascular plants).

Vascular Plant Systems Vascular plants have two organ systems: 1.An above-ground shoot system 2.An underground root system.

The root system is made up of the roots The shoot system is made up of stems leaves. reproductive structures of the mature plant

Plant Cell chloroplast plasma membrane nucleus cell wall central vacuole A typical plant cell is surrounded by a cell wall and contains a nucleus, chloroplasts, and a central vacuole, which stores food, enzymes, and other materials needed by the cell.

Parenchyma Cells flexible, spherical in shape, thin-walled cells that flatten when they are packed tightly together found in many plant structures Functions: storage photosynthesis gas exchange protection tissue repair and replacement Parenchyma cells found in leaves and green stems have many chloroplasts, Parenchyma cells found in roots and fruits, lack chloroplasts but have large central vacuoles that can store substances, such as starch, water, or oils. With chloroplasts Without chloroplasts

Collenchyma Cells cells are often elongated and occur in long strands or cylinders that provide support for the surrounding cells. cell walls unevenly thickened as the cell grows, the thinner portions of its cell wall can expand. this makes collenchyma cells flexible, which allows plants to bend without breaking. Functions: support surrounding tissues provide flexibility for plant tissue repair and replacement

Sclerenchyma Cells thick secondary cell walls that contain lignin, which makes the cell walls very tough and hard. most sclerenchyma cells die once they have completed growth and development. they lack cytoplasm and other living components when they mature Function: provide support for mature plants. There are two types of sclerenchyma cells: 1. Sclereids 2. Fibres

Sclereids. also called, stone cells distributed randomly throughout the plant. Shorter with an irregular shape. Responsible for the gritty texture of pears and the hard covering of seed coats.

Fibres needle shaped cells thick cell walls and small interior spaces. when stacked end-to-end, fibres form a tough elastic tissue. People have used fibres for centuries to make ropes, linens, and other textiles.

Plant Tissues Four types of tissue : 1. meristematic tissue where new cells are produced 2. dermal tissue, forms the outer covering of the plant it includes epidermis and periderm 3. ground tissue makes up most of the inside of a plant includes parenchyma, collenchyma, and sclerenchyma cells 4. vascular tissue transports water, minerals, and other substances throughout the plant provides support it includes xylem and phloem

Meristematic Tissue undifferentiated embryonic plant tissue from which all other plant tissues develop plants can continue to produce new cells by mitosis in their meristematic tissues Meristems—areas of rapidly dividing cells located in different regions of a plant

Apical meristem Found in the tips of a plant’s root and stems Intercalary meristem found along the stems and at the base of the leaf blades of some vascular plants, such as grasses cause roots, stems, and leaves to grow longer throughout the life of the plant. called primary growth If grasses had no intercalary meristems, they would stop growing after the first time they were mowed.

Lateral meristem Causes an increase in the circumference, or girth, of roots and stems called secondary growth since it adds vascular tissue, strengthens the stem, and provides support as the plant grows taller Two types of lateral meristems: 1.Vascular cambium a thin layer of meristematic tissue that can run along the length of roots and stems and produces new vascular tissue. 2. Cork cambium cells develop tough cell walls and form a protective layer on the outside of stems and roots. Cork tissue makes up the outer bark on woody plants,

shoot apical meristem vascular cambium cork cambium cork cambium vascular cambium root apical meristem root cap Stem Root

Dermal Tissue the outer layers of cells that form a protective covering for the plant includes epidermis and periderm Epidermis a single layer of dermal-tissue cells that forms a protective covering over the body of non-woody (herbaceous) plants and young woody plants. Periderm found in older woody plants produced as part of secondary growth. replaces the epidermis to form cork in woody stems and roots.

Specialized Epidermal Tissue: Guard Cells, Trichomes, and Root Hairs Some epidermal cells are specialized to perform a specific function. Guard cells paired cells that surround a stoma (plural stomata) control the size of the stomata. Stomata are small openings or pores, usually in the leaf. When stomata are open, gas exchange can occur. During the day, carbon dioxide diffuses in through the stomata and oxygen diffuses out. Water in the form of water vapour also diffuses out stoma guard cells

Trichomes tiny growths on the surface of the epidermis found on stems and leaves can make the plant appear fuzzy or woolly keep leaf surfaces cool and reduce evaporation. Some trichomes may secrete sticky or toxic substances that repel herbivores. trichomes on passion vines, are deadly and actually puncture the skin of herbivores that attempt to walk across them

Root hairs tiny extensions of individual epidermal cells on plant roots. increase the surface area available for the absorption of water and nutrients

Ground Tissue Ground tissue forms most of the plant’s internal and external material Contains parenchyma cells, collenchyma cells, and sclerenchyma cells. wide range of functions: photosynthesis, storage, and support. In some stems, roots, and seeds, the cells of ground tissue store starch and oils.

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. Function: transport water and dissolved substances throughout the plant. There are two types of vascular tissue: xylem and phloem Xylem transports water and minerals from the roots to the leaves. Phloem transports nutrients such as sugars to areas where they are needed for growth and metabolism, or to the roots for storage. In non-woody flowering plants, vascular tissue in the stems is organized into groups called vascular bundles that are scattered throughout the ground tissue. In woody flowering plants, vascular bundles are arranged in concentric rings in the ground tissue near the epidermal layer.

Xylem Xylem is the water-conducting tissue of plants. Gymnosperms - xylem consists of cells called tracheids. Angiosperms - xylem consists of two types of cells: tracheids and vessel elements. Tracheids and vessel elements begin as living cells growing end to end in an immature stem. When mature, the living contents die, leaving the non-living cell walls in place. Fluids are passed from one tracheid or vessel element to the next through pores known as pits. Vessel elements are long, continuous tubes formed from dead, hollow, cylindrical cells arranged end to end. Tracheids are dead cells that taper at the ends and overlap one another

Phloem Phloem is the food-conducting tissue in vascular plants. There are two types of phloem cells: sieve tube elements and companion cells. Both are alive at maturity. Sieve tube elements: have no nuclei. have plates at both ends that are perforated with holes, making them resemble a sieve. each sieve tube element has an associated companion cell. Companion cells have a nucleus carry out life functions to maintain both types of cells.

Activity 13.2 Plant Cell Types In this activity, you will investigate three types of plant cells by observing slides of some common plant parts. Materials microscope prepared slides from root, leaf, and stem tissues of plants Procedure 1. Observe the first prepared slide under the microscope on low power, and then under high power. Draw the cells you see. Label any structures or organelles that you can identify. 2. Use the information in the text and in Table 13.3 to identify the type of cells you observed. 3. Repeat steps 1 and 2 with the remaining slides. Questions 1. What types of cells did you identify? Explain how you determined the identity of each cell type. 2. Why are there different types of cells in plants?

Section Summary 1.The organs of a plant are contained in two organ systems—the root system and the shoot system. 2.Different types of plant cells include parenchyma cells, collenchyma cells, and sclerenchyma cells. 3.Meristems are areas of rapidly dividing cells that can develop into different types of specialized cells throughout the plant. 4.The outer covering of a plant is called the epidermis and is made up of dermal tissue. 5. Plants are made up mostly of ground tissue. 6.Vascular tissue is an internal transport system that runsthroughout the plant, carrying water and dissolved nutrients and minerals.

Success Criteria 1.I am able to define the following terms: shoot system, root system, meristematic tissue, dermal tissue, epidermis, guard cell, stoma, root hairs, ground tissue, xylem, phloem. 2.I am able to identify the two systems found in a plant. 3.I am able to describe the types of cells and their functions found in plants. 4.I am able to identify the types of plant tissues, providing details about each.