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SBI 3U: VASCULAR PLANT TISSUES NAME: _________________________ Please answer these questions using the ppt notes from today as well as the information given below to help you out. 1. In this unit, we examine vascular plants. What is the difference between vascular and non-vascular plants? Nonvascular plants: have no conductive tissues found in vascular plants. These plants are unable to pull up water and up from the ground to any significant distance. These plants do not flower; they reproduce via spores. Vascular plants: describes the system of supportive and conductive tissue found in plants to transport water and dissolved materials throughout a plant. This makes up the vascular system, which is the equivalent of a human circulatory system. Photosynthesis, the process by which plants synthesize their own carbohydrates, is the most important distinguishing feature of the plant kingdom. It is these carbohydrates which supply both stored chemical energy and building blocks for cell growth and reproduction. They also provide the food for all other organisms through food webs. Photosynthesis is a cellular process. How do plants, like angiosperms (plants that flower), ensure that their green cells receive the sunlight, carbon dioxide and water needed for photosynthesis? How do they distribute the manufactured carbohydrates to all their cells? How do plants store these products? We will examine these questions over the next few days. 2. What is photosynthesis? Why is it vital to the survival of plants? What are the reactants (starting substances) needed for photosynthesis and what products are created from this process? PS – process by which plants make their own carbohydrates through a process that involves trapping sunlight PS vital to survival of plants because it supplies energy for cell growth and reproduction. Reactants – carbon dioxide, water, sunlight Products – carbohydrates (glucose) and oxygen Cells of all multicelluar organisms are organized into tissues, tissue systems, organs and organ systems. A tissue is a group of cells, usually identical, that act together to carry out a specific function. These structures enable plants to successfully photosynthesize, grow and reproduce. The 2 main organ systems of a plant are the root system and the shoot system. Please examine the picture below to note these systems as well as various tissues and organs on the plant. Note that not all plants will have all the parts shown nor will parts with similar functions look the same from species to species. SHOOT SYSTEM ROOT SYSTEM 3. What is a meristem? What are apical and lateral meristems, and what results from their activity? Meristem – areas where plant cells divide to produce new plant cells by mitosis Apical meristems- located at the tips of roots and shoots and supply cells for the plant to increase in length Lateral meristems- located near the periphery of the plant; usually in the vascular tissue. Supply cells for the plant to increase in girth (width Primary growth includes all growth in the length of roots and stems throughout a plant’s entire life and all growth in the diameters of roots and stems which occurs in the first year of a plant’s life. Secondary growth is the result of lateral meristem activity; it results in increased diameters of roots and stems in the second and all subsequent years of a plant’s life. Plant tissues are specialized for functions such as absorption, transport, storage, photosynthesis, and reproduction. There are 3 major types of plant tissue – dermal tissue, ground tissue and vascular tissue – which are distributed throughout the plant body. Dermal tissue cells are found in the epidermis and the periderm. The epidermis is the outermost cell layer of a multicellular plant experiencing primary growth. Periderm is a protective covering that replaces the epidermis in plants that show extensive secondary growth. Epidermal tissue often contains highly specialized cells such as root hair cells and leaf guard cells, that help with water distribution in the plant. During secondary growth in roots and stems, the epidermis is replaced by the periderm. Some peridermal cells form many layers of special cells that soon die but leave behind a material that waterproofs the roots and stems and protects the inner tissues from structural damage. Ground tissue cells, the second major type of plant tissue, make up all of the internal nonvascular regions in the plant. Vascular tissue cells, the third major type of plant tissue, are specialized for conducting materials throughout the plant body. 4. Where are dermal tissue cells found? What type of role do they have on the plant? Dermal tissue – found in epidermis and periderm/outermost cell layer in plant. Role on plant - on parts of the shoot system, epidermis produces on its exterior surface a waxy, noncellular layer called the cuticle. Cuticle protects against excessive water loss and infection by microorganisms. Epidermal tissue has highly specialized cells called root hair cells and leaf guard cells that help with water distribution in the plant. 5. Fill in the following chart: SUMMARY OF GROUND TISSUE Parenchyma cells Function of these cells involved in photosynthesis and storage of nutrients, carbohydrates and water Collenchymas cells strengthen the plant and is specialized for supporting the plant’s primary growth areas; have thickened cell walls that allow for flexibility to plant parts that must be able to bend to withstand windy conditions Sclerenchyma cells Composed of cellulose and lignin, a material that provides added strength and rigidity to the cell; allows extra strength and support to various plant parts Sketch & Label a longitudinal view of these cells VASCULAR TISSUE Xylem conducts water and dissolved minerals (together called xylem sap) from the roots to all parts of the plant. There are two types of xylem cells: vessels or vessel elements and tracheids. Vessels elements are only found in angiosperms. A vessel consists of many vessel elements connected end-to-end. The ends are either absent or perforated which allows xylem sap to pass form one element to the next as it travels upward through the length of the vessel. Vessels are often packed side-by-side and may be connected to each other. These permit the lateral flow of xylem sap from one element to the next. Thus, xylem sap may flow straight upward or may change vessels part way by flowing laterally. Tracheids are much narrower than the vessel elements and their ends are so sharply angled that they appear pointed. Tracheids are found in all vascular plants, not just angiosperms. The substances cellulose and lignin are deposited on the exterior surfaces of xylem cells to form rigid cell walls. When the cell walls are complete, they cytoplasm dies, leaving dead, hollow xylem. They continue to transport water and dissolved substances until they get filled with various deposits. Wood, no matter what kind, is comprised almost entirely of xylem tissue. In some woody plants, xylem cells eventually become plugged with oils, gum, tannins and resin, resulting in the formation of heartwood. WATER FOOD 6. Describe the main difference between xylem and phloem cells. Xylem –The system of tubes and transport cells that circulates water and dissolved minerals. Xylem is made of vessels that connect the plant from end to end, for maximum speed to move water and minerals around. Xylem tissue dies after about one year, all that remains are the cell walls. These dead cells continue to transport water and dissolved minerals until they get filled with various deposits Phloem - these cells are laid out end to end throughout the entire plant, transporting the glucose created by the plant. Phloem is always a living tissue. 7. Draw a diagram of the 2 types of water-conducting xylem cells. Vessel element tracheid 8. A microscopic view of a plant section reveals a greater than usual number of xylem cells. What might this suggest about the plant’s ability to conduct and store water? In what kind of environment would a large number of xylem cells be beneficial to survival? Explain. The plant has an excellent ability to conduct and store water – the more water it can move, the greater the number of xylem cells it needs. As well, the more xylem cells, the greater its need for water. Larger plants have better developed xylem cells – to more efficiently get water from one area to another, which can be great distances in some cases. (akin to a human circulatory system 9. Identifying and learning the names of plant tissues can be challenging, even for experienced plant biologists! Create a table OR a concept map which lists the three major tissue types, the specific cell types in each, and their special structures (if given) and the function of these types of cells. Use a different piece of paper to answer this question if you prefer. This is something for YOUR benefit – you can make this in any way you wish.