Reading Essentials for Biology Glencoe (794133), страница 60
Текст из файла (страница 60)
Note: This section discussed more than seven adaptations.Seed PlantsAdaptationsVisit the Glencoe Science Web site at science.glencoe.com to findyour biology book and learn more about seed plants.256Chapter 22READING ESSENTIALSNameDateClassSection23.1 Plant Cells and TissuesSC.F.1.4.2 The student knows that body structures are uniquely designed and adapted for their function.
SC.F.1.4.7 Thestudent knows that organisms respond to internal and external stimuli.◗ Before You ReadIn health class you may have learned about the circulatory system. Most arteries in your body carryoxygenated blood throughout your body. Veins return blood to the heart, then the blood moves tothe lungs where it receives more oxygen. Similarly, vascular tissues in plants have specific functions.You can see vascular tissues at work if you take fresh celery and slice off the ends of several stalks.Place them in a glass of water.
Add a few drops of food coloring to the water. Check back in a coupleof hours. Can you predict what might happen? Write your prediction on the lines below.____________________________________________________________________________________________________________________________________________________________________________________________________________________________________◗ Read to LearnCopyright © by Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.Types of Plant CellsIn this section you will learn about different types of plantcells and tissues.
Plant cells are different from animal cells. Plantcells have a cell wall, a central vacuole, and can contain chloroplasts. A vacuole is a membrane-bound, fluid-filled space in thecytoplasm. Chloroplasts are organelles that capture light energyand convert it to chemical energy.What is the function of parenchyma cells?The plant cells that are the most numerous arethe parenchyma (puh RENG kuh muh) cells.They are found throughout the tissues of a plant.These sphere-shaped cells have thin, flexiblewalls.
Most parenchyma cells have a large centralvacuole, which sometimes is filled with a fluidcalled sap.Parenchyma cells have two main functions: storage and food production. The large vacuole can befilled with water, starch grains, or oils. The partwe eat of many fruits and vegetables is mademostly of parenchyma cells.
The many chloroplasts sometimes found in parenchyma cells produce glucose during photosynthesis.LocateInformation Draw a linefrom the words or phrases inthe text to the correspondingpart of the illustration.Central vacuoleChloroplastCell wallREADING ESSENTIALSChapter 23257NameDateClassSection23.1Plant Cells and Tissues, continuedWhat are collenchyma cells?Collenchyma (coh LENG kuh muh) cells are long cells withunevenly thickened cell walls.
The walls of collenchyma cells canstretch as the cells grow. Collenchyma cells are arranged in tubelike strands, or cylinders, that provide strength and support forthe surrounding tissue. The long, tough strands found in celeryare made of collenchyma cells.What do sclerenchyma cells do?________________________________________________________________________Plant TissuesA tissue is a group of cells that function together to perform anactivity. Tissues can be referred to as plant subsystems. There areseveral tissue types in plants. You will learn about four plant tissues in this section.Is dermal tissue like animal skin?2. What is the function ofthe stomata?________________________________________________________________________258Chapter 23The dermal tissue, or epidermis, is made of flattened cells thatcover all parts of the plant. It functions much like the skin of ananimal, covering and protecting the body of the plant.
The cellsof the epidermis produce the waxy cuticle that helps preventwater loss.A structure called a stoma in the epidermal layer also helps control water loss. Stomata (STOH mah tuh) (singular, stoma) areopenings in leaf tissue that control the exchange of gases. Stomataare found on green stems and on the surfaces of leaves. Two cellscalled guard cells surround each stoma. Guard cells control theopening and closing of stomata.
The opening and closing ofstomata controls the flow of water vapor from leaf tissues.READING ESSENTIALSCopyright © by Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.1. How are fibers useful topeople?The walls of sclerenchyma (skle RENG kuh muh) cells arethick and rigid.
When sclerenchyma cells mature, they often die.However, they still have a function in the plant. The cytoplasmbreaks into smaller and smaller pieces until it disappears, but thestrong, thick cell walls remain. They provide support for theplant. There are two types of sclerenchyma cells found in plants,fibers and sclerids (SKLER idz).Fibers are long, thin cells that form strands. They provide support and strength for the plant. They are the source of fibers usedfor making rope and linen.
Sclerids are irregularly shaped andoften found in groups. The gritty texture you find in pears iscaused by sclerids. They also are a major part of the pits found inpeaches and other fruits.NameDateClassSection23.1Plant Cells and Tissues, continuedThe dermal tissue that covers roots may have root hairs. Roothairs are parts of individual epidermal cells that help the rootabsorb water and dissolved minerals. If you see hairlike projections on stems and leaves, they are called trichomes.
Trichomes(TRI kohmz) give a stem or leaf a fuzzy look. They help reducethe evaporation of water from the plant. In some plants, trichomes release poisonous substances that help protect the plantfrom plant-eating animals and insects.Copyright © by Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.What do the vascular tissues transport?3. What is transported byxylem?Food, dissolved minerals, and water are moved throughout the________________________plant by vascular tissue. Xylem and phloem are the two types ofvascular tissue.
Xylem is made of tubelike cells that transport water________________________and dissolved minerals from the roots to the rest of the plant. Inseed plants, xylem is made of parenchyma, fibers, tracheids, and________________________vessel elements.Tracheids (TRA kee uhdz) are tubelike cells tapered ateach end. The cell walls between tracheids have smallopenings through which water and dissolved minerals flow.Vessel elements also are tubelike cells in the xylem thatVessel elementtransport water and dissolved minerals from the roots to thestem. They are wider and shorter than tracheids and haveopenings in their end walls. In some plants, mature vesselelements lose their end walls completely, making it easierfor water and dissolved minerals to flow from cell to cell.Almost all vascular plants have tracheids.
Vessel elementsTracheidare most common in anthophytes. This may be one reasonanthophytes, which are true flowering plants, are the mostsuccessful plants on Earth. The vessel elements in anthophytes can transport water more efficiently than tracheids.The other type of vascular tissue is phloem. Phloemtransports sugars and other carbon compounds. Like xylem,phloem has long tubelike cells that are arranged end to end.These cells are called sieve tube members. Sieve tubemembers are alive at maturity.
They are unusual becausethey contain cytoplasm but do not have a nucleus or ribosomes. Next to each sieve tube member is a companion cell.Sieve tube memberCompanion cells are cells with nuclei that help movematerials through the sieve tubes. In anthophytes, the endwalls between two sieve tube members are called sieve plates.Companion cellThe sieve plates have large pores or openings that allow sugars and organic compounds to move from sieve tube memberSieve plateto sieve tube member. Phloem tissue also contains fibers.READING ESSENTIALSChapter 23259NameDateClassSection23.1Plant Cells and Tissues, continuedThe fibers do not transport materials, but are important becausethey provide support for the plant.What is ground tissue?4. What are the functions ofground tissue?________________________________________________________________________Despite the name, ground tissue is found throughout a plant.Ground tissue is made mostly of parenchyma cells, but can includecollenchyma and sclerenchyma cells.
The functions of groundtissue include photosynthesis, storage, and support. The cellsof ground tissue in leaves and some stems contain many chloroplasts that carry on photosynthesis. Ground tissue cells in somestems and roots contain large vacuoles that store starch grainsand water.Apical meristemLeavesVascular tissuesStemA growing plant produces new cells inareas called meristems. Meristems are areasof actively dividing cells. Meristematic cellsare parenchyma cells with a different shape.They also have large nuclei.There are different types of meristems.Apical meristems are found at the tips ofroots and stems.
They produce cells thatallow the roots and stems to increase inlength. Lateral meristems are cylinders ofdividing cells located in roots and stems.The production of cells by the lateral meristems increases the diameter, or thickness, ofroots and stems. Woody plants have twokinds of lateral meristems—vascular cambium and cork cambium. The vascularcambium produces new xylem and phloemcells in the stems and roots.
The cork cambium produces cells with tough cell walls.These cells cover the surface of stems androots. The outer bark of a tree is producedby the cork cambium.A third type of lateral meristem is foundin grasses, corn, and other monocots. Thismeristem adds cells that lengthen the partof the stem between the leaves. These plantsdo not have a vascular or cork cambium.Apical meristems260Chapter 23READING ESSENTIALSCopyright © by Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.What are the meristematic tissues?NameDateClassSection23.1Plant Cells and Tissues, continued◗ After You ReadMini Glossaryapical meristem: regions of actively dividing cellsnear the tips of roots and stems; allow rootsand stems to increase in lengthcollenchyma (coh LENG kuh muh): long plantcells with unevenly thickened cell wallscompanion cells: cells with nuclei that helptransport sugars and other organic compounds through the sieve tube members ofthe phloemcork cambium: lateral meristem that produces atough protective covering for the surface ofstems and rootsepidermis: in plants, the outermost layer of flattened cells that covers and protects all partsof the plant; produces the waxy cuticleguard cells: cells that control the opening andclosing of the stomata; regulate the flow ofwater vapor from leaf tissueCopyright © by Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.lateral meristem: cylinders of dividing cellslocated in roots and stems; allows roots andstems to increase in diametermeristems: regions of actively dividing cells inplantsparenchyma (puh RENG kuh muh): most abundant type of plant cell; spherical cellswith thin, flexible walls and a large central vacuole, important for storage andfood productionphloem: vascular plant tissue made up of tubularcells joined end to end; transports sugarsand other organic compounds to all parts ofthe plantsclerenchyma (skle RENG kuh muh): plant cellswith rigid, thick cell walls; die when theyare mature, but still provide support forthe plantsieve tube members: tubular cells in phloem;each cell lacks a nucleus and ribosomesstomata (STOH mah tuh): openings in leaf tissues that control gas exchange and helpcontrol water losstracheids (TRA kee udz): tubular cells in thexylem that have tapered ends; have smallopenings for transport of water and dissolved mineralstrichomes (TRI kohmz): hairlike projections thatextend from a plant’s epidermis; helpreduce water evaporation and may provideprotection from predatorsvascular cambium: lateral meristem that produces new xylem and phloem cells in thestems and rootsvessel elements: hollow, tubular cells in thexylem; transport water and dissolved minerals from the roots to the stem; have openends through which water passes freelyfrom cell to cellxylem: vascular plant tissue composed of tubularcells that transport water and dissolved minerals from the roots to the rest of the plant1.
![](https://s.studizba.com/z.php?f=/templates/si/i/noavatar.png&w=100&h=100&t=1"){kind=avatar}
