Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Date: _______________________________ Plant Cells and Tissues (13.2) Organization Within Plants Fill in using the words: companion cells, dermal tissue, fibres, ground tissue, phloem, root, sclereids, shoot, sieve tubes, tracheids, vascular tissue, vessels, xylem Plant Body is divided into... SHOOT system ROOT system made up of one or more roots made up of stem, leaves, flowers, and fruit ...which are both composed of.... DERMAL TISSUE VASCULAR TISSUE GROUND TISSUE the outer covering the transport system all other types of tissue ...that contain the cell types: XYLEM PHLOEM transports water transports sugars, ions, minerals parenchyma VESSEL ELEMENTS sclerenchyma ...which can be classified as.... ...which is composed of.... TRACHEID S collenchyma SIEVE TUBES COMPANIO N CELLS FIBRES SCLEREIDS Meristematic Tissue Meristematic tissue is undifferentiated – it has the potential to become any of the three other types of tissue. You can think of these as being the plant equivalent to animal stem cells. Meristem is only found in certain parts of the plant body, but it is responsible for all of the growth and division that occurs in the plant. It can be found only at the tips of shoots and roots, and at nodes along the shoots. Type of growth Primary Secondary Description of growth Primary growth increases the plant’s HEIGHT. Secondary growth increases the plant’s WIDTH Occurs in all plants? (Y/N) yes Type of meristem responsible Apical Intercalary no lateral Classification of Meristem Type Based on Position Label: apical, intercalary, lateral Dermal Tissue Dermal tissue makes up the outer covering of all parts of a plant. There are two different types of dermal tissue: 1. Epidermis: green fleshy (herbaceous) stems 2. Periderm: woody stems Ground Tissue Function Cell types Examples Parenchyma tissue photosynthesis food storage healing and tissue regeneration Collenchyma tissue support in young stems, roots, and petioles healing and tissue regeneration parenchyma cells collenchyma cells mesophyll in leaves strings of a celery stalk Sclerenchyma tissue rigid support in older parts of plant protection sclereid cells (“stone cells”), fibre cells nutshells, apple cores, hemp and jute fibres Picture a – lengthwise b – cross section Vascular Tissue The transport system of the plant. Two major types of vascular tissue: 1. Xylem: transports water and minerals 2. Phloem: transports nutrients The conducting parts of both the xylem and phloem are made up of two types of cells: Xylem All types of xylem tubes are dead at maturity. This means that they have no cytoplasm or organelles, but their cell walls remain, fortified by supportive ground tissue. Type of cell Tracheids Diameter wide Shape tapered Arrangement overlapping Vessel elements narrow cylindrical end-to-end Found in gymnosperms angiosperms angiosperms Both the gymnosperms and angiosperms have tracheids, but only the angiosperms have vessel elements. Based on this observation, which evolved later – the tracheids, or the vessel elements? ___________________ Phloem Though phloem cells are alive at maturity, some cells – the sieve tube elements - are specialized so that they do not perform any essential life functions. Instead, these sieve tubes have attached companion cells that do this. Type of cell Alive? (Y/N) Relative size Function large Has nucleus & organelles? (Y/N) No Sieve tube elements yes Companion cells yes Small Yes Perform life functions for itself & sieve tube (includes pumping sugars) Conduct nutrients Ground Tissue The ground tissue system is important because it serves a variety of essential functions for plants. Each type of ground tissue has its role, such as food creation and storage or support during and after growth. Filling all the spaces that are not used by the dermal and vascular tissue systems, ground tissue can be found throughout the plant. There are three types of ground tissue, and each one has a specific function or set of functions for the plant. A. Parenchyma is a very versatile type of ground tissue, and it is responsible for photosynthesis and food storage. Parenchyma cells are also responsible for healing in the plant - this tissue can go through cell division and regenerate when needed. You are likely familiar with parenchyma cells, because this is what the pulp in fruit is comprised of. Parenchyma is suited for its function because: It has a thin cell walls that allow the water and other nutrients to pass through Figure 1 Cross section to another cell with ease A large vacuole is constantly filled with water allowing the soft tissue to remain of parenchyma cells firm The air spaces allow gases like O2 and CO2 to pass through the plant efficiently A permeable cell wall allows gases to diffuse through it B. Collenchyma is ground tissue that provides structural support to growing parts of the plant. Like parenchyma cells, collenchyma cells also go through cell division and therefore elongate parts of the plant such as stems and leaves. Collenchyma cells are long and thin, have very thick cell walls, and are grouped in strands. This structure makes them very well suited to support the parts of the plants that are growing and have not become established yet. The thick, rigid structure of celery is due to collenchyma tissue. Figure 2 Cross section of collenchyma cells How is Collenchyma suited for its function?: Strong cell wall allows for the plant's structure to be supported but also flexible enough to bend The weaker parts of the wall allow nutrients to pass through The air spaces allow gases to pass freely through the cell C. Sclerenchyma is the ground tissue that provides structural support to the parts of the plant that are no longer growing. There are two types of sclerenchyma cells: fibres and sclereids. Fibres are long and thin and are responsible for many materials you use on a daily basis, such as clothing fabrics and rope. Sclereids are compact and dense, and they are what makes up that tough texture in apple cores. Figure 3 Cross section of parenchyma cells Sclerenchyma's suitability for its function: Evenly thickened cell walls help to support the plant's structure The lignified cell wall makes the plant rigid Parts of the sclerenchyma act as supports for the plant as they are tightly packed and do not contain air spaces