Angelica Archangelica As Bronchodilator

Anemarrhena asphodelioides (see Chinese lily) Anemone Anemone canadensis Angelica dahurica (see Dahurian angelica) Angelica polymorpha (see Chinese angelica) Anise Pimpinella anisum Apocynum androsaemifolium (see Dogbane, bitter) Apocynum venetium (see Dogbane, venetian) Ashwagandha Asian epimedium Asian skullcap Prunus armeniaca Arnica spp. Withania somnifera High silica content makes aerial parts of plant useful as an astringent to stop bleeding Leaf concentrates shown to promote desirable...

Tym

Mons Pubis Hair

Dutchman's breeches plant (Dicentra cucullaria). B. Squirrel corn (Dicentra canadensis). is constructed so that it is highly unlikely that a pollinium of one species will be inserted within the stigma of another species. As a result, many species of related orchids can be sympatric without genes being exchanged. Four closely related sympatric species of Peruvian Catasetum orchids, which can be artificially hybridized very easily, have no known natural hybrids, despite their being...

The Stem Of Flowering Olant

Sansevieria Varieties

Chemically Speaking, What Is Caffeine Caffeine is a plant alkaloid found not only in coffee beans but also in tea leaves and cola nuts. It works as a stimulant of the central nervous system and the respiratory system, as well as increasing heart rate and constricting blood vessels. As a stimulant, caffeine makes us more aware and alert and able to work without drowsiness. It is reported that coffee was discovered in the Near East perhaps in Yemen by goats, which became frisky and sleepless...

Origin And Development Of Stems

Woody Plant Combinations

There is an apical meristem tissue in which cells actively divide at the tip of each stem, and it is this meristem that contributes to an increase in the length of the stem. The apical meristem is dormant before the growing season begins. It is protected by bud scales of the bud in which it is located and also to a certain extent by leaf primordia singular primordium , the tiny embryonic leaves that will develop into mature leaves after the bud scales drop off and growth begins. The apical...

Minerals and Food

Kelp Haevesting Ships

Brown algae also produce a number of other useful substances. Many seaweeds, but particularly kelps, build up concentrations of iodine to as much as 20,000 times that of the surrounding seawater. Although it is cheaper to obtain iodine from other sources in North America, dried kelp has been used in the treatment of goiter, which results from iodine deficiency, in other parts of the world. Kelps are relatively high in nitrogen and potassium and have been used as fertilizer for many years....

M

Pressed Flower Wall Art

An insect follows a nectar-secreting furrow on a petal until it reaches the center of the flower. Pollinia are removed when they adhere to the insect following an explosion initiated by the insect bumping a sensitive point below an anther. When the insect flies to another flower, the pollinia on its head catch on the sticky surface of the stigma and are pulled off at the same time new pollinia are being attached. Orchids pollinated by butterflies and moths may have a clamp at the base of the...

Summary

Xylem Springwood

Stem structure and function need to be examined to understand practical uses of stems. 2. The shoot system of plants is usually erect, but some stems may be horizontal or modified for climbing or food water storage. 3. Leaves of woody twigs may be arranged alternately, oppositely, or in a whorl. Nodes are stem regions where leaves are attached internodes occur between nodes. Most leaves have petioles and blades. Axillary buds occur in leaf axils. Most buds are protected by bud scales....

Selected Families Of Flowering Plants

The following is a survey of a few of the well-known plant families, indicating not only past uses of some of their members but also possible future uses in a few instances, along with biological notes and miscellaneous observations. The reader is cautioned against assuming that past medicinal uses were always effective or without harmful side effects and is urged to refrain from experimenting with such plants. More than 300 families of flowering plants are recognized today. Flowers and fruits...

Cross Section Of Lily Leaf

Flowering Trees For Pots

Leaves, the main site of photosynthesis by most plants, function in light interception and gas exchange. Since the uptake of carbon dioxide through leaf stomata must be balanced against water loss, leaf structure usually shows clear connections to prevailing environmental conditions. For instance, plants in arid environments often have thick leathery leaves, with fewer stomata, and a dense covering of hairs that reflect light and may reduce water loss from the leaf surface. On an individual...

Southren Tshangshu

Astragalus membranaceus see Membranous milk-vetch Atractylodes lancea see Southern tsangshu Atractylodes macrocephala see Southern tsangshu Balm of Gilead Populus x gileadensis Balsam poplar Populus balsamifera Bifidobacterium bifidum Helicobacter pylori, B. breve, B. infantis, B. longum, and others Vaccinium spp. Root flavonoid extracts used to relieve menopausal problems Root extracts used to boost the immune system said to be good for colds, flu, and immune-deficiency disorders also lowers...

Uses

Chrysanthemum indicum see Indian chrysanthemum Cinchona spp. Potentilla erecta Lycopodium clavatum Vaccinium oxycoccum Larrea divaricata Dogbane, bitter Apocynum androsaemifolium Green algae that boost the immune system, relieve constipation, and can remove heavy metals from food Seed extracts are good source of L-arginine and magnesium and are believed when combined with other chocolate constituents to elevate serotonin levels chocolate also contains theobromin somewhat similar to caffeine in...

The Basidiomycetes Club Fungi

Asexual Reproduction Plants

At the end of my first year in college, I did odd jobs during the summer, including various types of yard work. On one occasion while cleaning dead leaves and debris from a shaded garden area, I noticed a peculiar, unpleasant odor. On checking to see where the odor was coming from, I noticed two or three growths, about the width of a pencil and the length of a finger, rising above the surface of the ground. On closer inspection, I saw that these growths had the consistency and appearance of a...

Plant Hormones

Oat Coleoptiles

A relatively small number of plant hormones regulate plant development, and each type of hormone can have multiple effects. It is believed that hormones act by chemically binding to specific receptors. The observed effect is thought to be initiated by this hormone-receptor association, which triggers a series of biochemical events, including turning genes on and off. The biochemical events are called signal transduction and may include changes in the complement of enzymes produced in a tissue...

How To Determine The Origin Tendrils And Spines

Waterlily Nymphaea

Since tendrils and spines can be either modified leaves or modified stems, how might you determine the origin of a given specimen Visit our web page at www.mhhe.com botany for interesting case studies, practice quizzes, current articles, and animations within the Online Learning Center to help you understand the material in this chapter. You'll also find active links to these topics Characteristics of Plants Architectural Pattern of Plants Leaves and the Movement of Water Economic Uses of...

Plant Cell Photomicrograph

Electron Micrograph Young Plant Cell

Figure 3.4 Anatomy of a young leaf cell. A. Generalized drawing. B. Transmission electron micrograph of a small leaf cell with cross sections of two chloroplasts visible, x20,000. A. From Sylvia S. Mader, Biology, 7th edition. 2001 The McGraw-Hill Companies. All rights reserved. B. Newcomb Wergin BPS. Figure 3.4 Anatomy of a young leaf cell. A. Generalized drawing. B. Transmission electron micrograph of a small leaf cell with cross sections of two chloroplasts visible, x20,000. A. From Sylvia...

Asexual Plant Propagation

Plant Propagation Crown Division

In recent years, we have heard amazing stories about scientists who have cloned animals such as sheep and cows. Botanists are far ahead in that arena. They have been cloning plants for centuries Many plants are easy to propagate asexually, using vegetative parts rather than seeds. For example, crown division is a simple technique in which a plant is separated into several pieces, each of which contains a crown and a portion of the root system Fig. 14.17 . This is commonly used for many...

The Rose Family Rosaceae

Rosaceae Flowers

The Rose Family includes more than 3,000 species of trees, shrubs, and herbs distributed throughout much of the world. The flowers characteristically have the basal parts fused into a cup, with petals, sepals, and numerous stamens attached to the cup's rim Fig. 24.8 . The family is divided into subfamilies on the basis of flower structure and fruits. The flowers of one group have inferior ovaries and produce pomes for fruits. Flowers of other groups have ovaries that are superior or partly...

Photoperiodism

Photoperiodism Plants

In the early 1900s, two American plant physiologists, Wightman W. Garner and Henry A. Allard, became curious about a tobacco plant growing at a research center in Beltsville, Maryland. The plant grew 3 to 4 meters 10 to 13 feet tall during the summer but failed to flower in August when the normal-sized tobacco plants flowered. They brought the giant plant into a greenhouse for protection during the winter and were surprised when it flowered in December. Garner and Allard decided to conduct some...

Wood And Its Uses

Wood And Its Uses

The use of wood by humans for fuel, clubs, and other purposes dates back into antiquity, and present uses are so numerous that it would be impossible to list in a work of this type more than the most important ones. Before discussing the economic importance of wood, let's take a brief look at its properties. In a living tree, up to 50 of the weight of the wood comes from the water content. Before the wood can be used, seasoning reduces the moisture content to 10 or less, either by air-drying it...

The Nitrogen Cycle

Nitrogen Cycle Steps

Most of the nitrogen in living organisms is in the protoplasmic proteins of their cells, with much of protoplasm being water. Nitrogen, the most abundant element in our atmosphere, constitutes about 18 of the protein. There are nearly 69,000 metric tons of nitrogen in the air over each hectare of land 35,000 tons per acre , but the total amount of nitrogen in the soil seldom exceeds 3.9 metric tons per hectare 2 tons per acre and is usually considerably less. This discrepancy results from the...

P

Palisade mesophyll pal-uh-sayd' mez'uh-fil mesophyll having one or more relatively uniform rows of tightly packed, elongate, columnar parenchyma chlorenchyma cells beneath the upper epidermis of a leaf p. 115 palmately compound palmately veined pahl'mayt-lee kom'pownd pahl'mayt-lee vaynd having leaflets or principal veins radiating out from a common point p. 110, 112 1. Ribosomes, which are considered organelles, are an exception in that they are not bounded by a membrane. papilla pl. papillae...

Tissue Patterns In Stems

Base Coleus Stem Tip

Primary xylem, primary phloem, and the pith, if present, make up a central cylinder called the stele in most younger and a few older stems and roots. The simplest form of stele, called a protostele, consists of a solid core of conducting tissues in which the phloem usually surrounds the xylem. Protosteles were common in primitive seed plants that are now extinct and are also found in whisk ferns, club mosses see Chapter 21 , and other relatives of ferns. Siphonosteles, which are tubular with...

Discussion Questions

Respiration Roots

Most plant meristems are located at the tips of shoots and roots and in cylindrical layers within stems and roots. What could happen if they were present in leaves 2. The cambium produces xylem toward the center of a tree and phloem toward the outside. Do you think it would make any difference if the positions of the xylem and phloem were reversed Why Visit our web page at www.mhhe.com botany for interesting case studies, practice quizes, current articles, and animations within the Online...

Phylum Zygomycota The Coenocytic True Fungi

Images For Bread Mold

Although black bread molds are probably the best-known members of Phylum Zygomycota, they are not the only fungi that grow on bread. So many organisms can, in fact, contribute to bread spoilage that nearly all commercially baked goods have, in the past, had chemicals such as calcium propionate added to the dough to prevent or retard the growth of such organisms. There is now a trend toward eliminating preservatives from bread, pies, and other bakery items since the chemicals that have made the...

Micropropagation And Jello

Plant Tissue Culture Instruments

Figure 14.24B Some specific examples of specialized stems that are easily propagated asexually. Left A tulip bulb. Center. Crocus corms. Right A ginger rhizome. antibiotic we can administer as a cure. The best way to eliminate the effects of plant disease is to prevent exposure to pathogens. This is nearly impossible in greenhouse and field environments. However, it is possible to maintain plants in a disease-free status if we grow them in sterile test tubes through micropropagation. Other...

Apomixis and Parthenocarpy

Some embryos of seeds can develop apomictically that is, without development or fusion of gametes sex cells but with the normal structures e.g., ovaries otherwise being involved. An embryo may develop, for example, from a 2n nutritive cell or other diploid cell of an ovule, instead of from a zygote. After germination, this makes the plant that develops from such a seed the equivalent of a vegetatively propagated plant. Fruits that develop from ovaries having unfertilized eggs are said to be...

Human Relevance of the Archaebacteria

Methane Digester Facts

Archaebacteria are significant to humans in several ways. In the future, methane bacteria may be used on a large scale to furnish energy for engine fuels and for heating, cooking, and light, since the methane gas they produce can be used to replace the methane in natural gas. Methane has an octane number of 130 and has been used as a motor fuel in Italy for over 40 years. It is clean, nonpolluting, safe, nontoxic, and prolongs the life of automobile engines, also making them easier to start....

What Do Pine Resin Mint Oil Rubber And Opium Have In Common

Transverse Section Lilium Leaf

Figure 4.8 How water flow is controlled in adjacent pairs of bordered pits. The pits are separated by a pit membrane consisting of the middle lamella and two thin layers of primary walls. A. Water moves relatively freely through the pit openings and pit membrane when the torus a thickened region of the pit membrane is in the center. B. If the flexible pit membrane swings to one side so that the torus blocks an opening, water movement through the pit pair is restricted. increase absorptive parts...

Where Are Seeds Developed In Figure 8.1

Coleoptile And Cotyledon

The concave side of an ordinary kidney bean a dicot has a small white scar called the hilum. The hilum marks the point at which the ovule was attached to the ovary wall. A tiny pore called the micropyle is located right next to the hilum. If this bean is placed in water for an hour or two, it may swell enough to split the seed coat. Once the seed coat is removed, the two halves, called cotyledons, can be distinguished Fig. 8.28 . The cotyledons, which have a tiny immature plantlet along one...

Phylum Dinophyta The Dinoflagellates

Cryptomonas Eyespot

Occasionally, visitors to an ocean beach in midsummer may notice a distinctly reddish tint to the water, usually as a result of a phenomenon known as a red tide. Red tides are caused by the sudden and not fully understood multiplication of unicellular organisms called dinoflagellates Fig. 18.24 . There are over 3,000 species of dinoflagellates, with 300 of them known to be capable of producing red tides. When a red tide appears, some biologists dip a cup of sea water and save it for examination...

Tissues Produced By Meristems

Parenchyma Transfer Cells

After cells are produced by meristems, the cells assume various shapes and sizes related to their functions as they develop and mature. Some tissues consist of only one kind of cell, while others may have two to several kinds of cells. Simpler, basic types of such tissues are discussed first, followed by those that are more complex. Parenchyma tissue is composed of parenchyma cells Fig. 4.2 , which are the most abundant of the cell types and are found in almost all major parts of higher plants....

Diversification Of Plant Study

Anatomy Flowering Plants Animation

Plant anatomy, which is concerned chiefly with the internal structure of plants, was established through the efforts of several scientific pioneers. Early plant anatomists of note included Marcello Malpighi 1628-1694 of Italy, who discovered various tissues in stems and roots, and Nehemiah Grew 1628-1711 of England, who described the structure of wood more precisely than any of his predecessors Fig. 1.10 . Today, a knowledge of plant anatomy is used to help us find clues to the past, as well as...

Human and Ecological Relevance of the Imperfect Fungi

Imperfect Fungi

Among the best known of the medically important fungi are the Penicillium molds Fig. 19.32 , which secrete penicillin, the well-known and widely used antibiotic a substance produced by a living organism that interferes with the normal metabolism of another living organism . In 1929, Sir Alexander Fleming of England noticed that certain bacteria would not grow in the vicinity of the mycelium of a Penicillium mold and gave the name penicillin to the element in the mold that prevented the...

Intergeneric Peyote

Depending on which authorities are followed, the number of known orchid species all in the family Orchidaceae may exceed 30,000. Popularly cultivated orchids include species of Cattleya, Cymbidium, Dendrobium, Odontoglossum, Oncidium, Paphiopedilum, Phalaenopsis, Vanda, and both interspecific and intergeneric hybrids. 20. The original producer of penicillin discovered by Sir Alexander Fleming was Penicillium notatum current commercially used producers of penicillin are strains of...

Other Conifers

Megasporangium And Female Gametophyte

Some conifers don't produce woody seed cones with conspicuous scales, nor do all produce both pollen and seed cones on the same plant. For example, yew Taxus and California nutmeg Torreya produce ovules singly at the tips of short axillary micropyle pollen chamber integument 2n Figure 22.7 A longitudinal section through part of a pine ovule, x100. Introduction to See d Plants Gymnosperms 427 microsporocytes undergo meiosis, producing zygote develops into the embryo of a seed zygote develops...

Polypodium Life Cycle

Polypodium Young Sporophyte

Figure 21.16 Common ferns with typically dissected fronds. A. Cinnamon fern. The cinnamon-colored fertile fronds in the center are nonphotosynthetic and produce large numbers of sporangia. B. Holly fern. C. A maidenhair fern. D. 'Ama'uma'u, a small Hawaiian tree fern. A, B Courtesy Perry J. Reynolds that they are actually clusters of sporangia Fig. 21.19 . The sporangia may be scattered evenly over the lower surfaces of the fronds, but they are often confined to the margins. The sporangia are...

Breeding Methods Using Sexually Compatible Germplasm

Breeding High Yielding Plants

A plant breeder tends to divide crop plant species into two groups self-pollinating and cross-pollinating. A self-pollinating plant is capable of fertilizing itself, while a cross-pollinating one cannot. Breeding methods for self-pollinating plants are radically different from those for cross-pollinating ones. A self-pollinating plant tends to be highly homozygous because all of its genes came from the same parent. The plant's mother was also its father As you might expect, these plants have...

The Carbon Cycle

Co2 Fixation Photosynthesis

In the process of feeding acquiring the energy they need to maintain themselves and grow, i.e., respire , bacteria process carbon and nitrogen in a way that allows these elements to be recycled Fig. 25.7 . Bacteria eat organic matter carbohydrates , obtaining the energy present in the molecules. As a result of this activity respiration , they convert carbohydrates to carbon dioxide. One of the two raw materials of photosynthesis, carbon dioxide constitutes 0.03 of our atmosphere. The combined...

Transport Of Food Substances Organic Solutes In Solution

Water And Sugar Movement Plants

One of the most important functions of water in the plant involves the translocation transportation of food substances in solution by the phloem, a process that has only recently come to be better understood. Many of the studies that led to our present knowledge of the subject used aphids small, sucking insects and organic compounds designed as radioactive tracers. Most aphids feed on phloem by inserting their tiny tubelike mouthparts stylets through the leaf or stem tissues until a sieve tube...

Abscission

Abscission Zone Leaf

Plants whose leaves drop seasonally are said to be deciduous. In temperate climates, new leaves are produced in the spring and are shed in the fall, but in the tropics, the cycles coincide with wet and dry seasons rather than with temperature changes. Even evergreen trees shed their leaves they do so a few at a time, however, so that they never have the bare look of deciduous trees in their winter condition. The process by which the leaves are shed is called abscission. Abscission occurs as a...

Human and Ecological Relevance of the Water Molds

Two important members of Phylum Oomycota cause serious diseases of higher plants. Although dew or rain water is needed for their reproduction, neither grows under water. One, called downy mildew of grapes, completes its life cycle on grape leaves, usually killing the leaves and, if not controlled, the vine. This disease seriously threatened the French wine industry toward the end of the 19th century, after it reached the vineyards on imported American cuttings. Within a few years, it was...

Trends of Specialization and Classification in Flowering Plants

Simple Pistil

Various classifications of plants have been proposed ever since the 4th century B.C. when Theophrastus grouped plants into trees, shrubs, and herbs. The first classifications were merely for convenience and did not necessarily reflect natural relationships. Even today, plants may be lumped together in unnatural groupings in order to make them easier to identify. For example, some wildflower books arrange together all white-flowered species or all yellow-flowered species. There is nothing wrong...

External Form Of A Woody Twig

Stipules Buds Bud Scales Scars

A woody twig consists of an axis with attached leaves Fig. 6.1 . If the leaves are attached to the twig alternately or in a spiral around the stem, they are said to be alternate, or alternately arranged. If the leaves are attached in pairs, they are said to be opposite, or oppositely arranged, or if they are in whorls groups of three or more , their arrangement is whorled. The area, or region not structure , of a stem where a leaf or leaves are attached is called a node, and a stem region...

Specialized Roots

Potato Storage Roots

As mentioned earlier, most plants produce either a fibrous root system, a taproot system, or, more commonly, combinations of the two types. Some plants, however, have roots with modifications that adapt them for performing specific functions as well as the absorption of water and minerals in solution. Most roots and stems store some food, but in certain plants, the roots are enlarged and store large quantities of starch and other carbohydrates Fig. 5.8 , which may later be used for extensive...

Fruit And Seed Dispersal

Seed Dispersal

Why are so many species of orchids rare, while dandelions, shepherd's purse, and other weeds occur all over the world Why are some plants confined to single continents, mountain ranges, or small niches occupying less than a hectare 2.47 acres of land The answers to these questions involve many different factors, including climate, soil, the adaptability of the plant, and its means of seed dispersal. How fruits and seeds are transported from one place to another is the subject of the following...

Specialized Stems

Cladophylls

Although most higher plants have an erect shoot system, many species have specialized stems that are modified for various functions Fig. 6.14 . The overall appearance of specialized stems may differ markedly from that of the stems discussed so far, but all stems have nodes, inter-nodes, and axillary buds these features distinguish them from roots and leaves, which do not have them. The leaves at the nodes of these specialized stems are often small and scalelike. They are seldom green, but...

Flowering Plants and Civilization

Selected Families of Flowering Plants Stern-Jansky-Bidlack I 24. Flowering Plants and I Text I I The McGraw-Hill Introductory Plant Biology, Civilization Companies, 2003 This chapter begins with comments on some of the problems involved in distinguishing between fact and fancy in reported past uses of plants. It continues with a brief discussion of Vavilov's centers of origin of cultivated plants and subsequent modifications of Vavilov's theories. A survey of 16 well-known flowering plant...

True Bacteria Useful to Humans

Bacillus Thuringiensis Spray

For many years, we controlled insect pests of food plants mostly through the use of toxic sprays. Residues of the sprays remaining on the fruits and vegetables have accumulated in human tissues, often with adverse effects, while at the same time, many organisms have become immune or resistant to the toxins. In addition, the sprays kill useful organisms, and precipitation runoff washes the toxins into streams, lakes, and oceans, harming or killing aquatic organisms. As we have become aware of...

Development of Gametophytes

Development Flowering Plants

While the flower is developing in the bud, a diploid megasporocyte cell differentiates from all the other cells in the ovule Fig. 23.3 . This megasporocyte undergoes meiosis, producing four haploid megaspores. Soon after they are produced, three of these megaspores degenerate and disappear, but the nucleus of the fourth undergoes mitosis, and the cell enlarges. While the cell is growing larger, its two haploid nuclei divide once more. The resulting four nuclei then divide yet another time....

Lateral Root Origin

Vascular Cylinder Buttercup Plant

Of a dicot buttercup Ranunculus root. A. Complete view, x100. The cells of the cortex, a tissue composed of parenchyma cells lying between the epidermis and inner tissues, mostly store food. This tissue, which may be many cells thick, is similar to the cortex of stems except for the presence of an endodermis at its inner boundary Fig. 5.6 . The endodermis consists of a single-layered cylinder of compactly arranged cells whose primary walls are impregnated with suberin. The suberin bands, called...

Other Significant Processes That Occur in Chloroplasts

Photosynthesis

In addition to photosynthesis, there are two very important sets of biochemical reactions that take place in chloroplasts and also in the proplastids of roots . 1. Sulfates are reduced to sulfide via several steps involving ATP and enzymes. The sulfide is rapidly converted into important sulfur-containing amino acids, such as methionine and cysteine, which are part of the building blocks for proteins, anthocyanin pigments, chlorophylls, and several other cellular components. Figure 10.13...

Fossil Whisk Fern Look Alikes

Rhynia Major Pteridophytes

Fossil plants that somewhat resemble whisk ferns have been found in Silurian geological formations Table 21.1 . These formations are estimated to be as much as 400 million years old. One group of these fossil plants, of which Cooksonia and Rhynia are examples see Fig. 21.22 , had naked stems Figure 21.1 Psilotum sporophytes. The small yellowish objects are three-lobed sporangia. Figure 21.1 Psilotum sporophytes. The small yellowish objects are three-lobed sporangia. and terminal sporangia....

Root Structure

Zone Elongation Maturation

Close examination of developing young roots usually reveals four regions or zones. Three of the regions are not sharply defined at their boundaries. The cells of each region gradually develop the form of those of the next region, and the extent of each region varies considerably, depending on the species involved. These regions are called 1 the root cap, 2 the region of cell division, 3 the region of elongation, and 4 the region of maturation Fig. 5.2 . The root cap is composed of a...

Specialized Leaves

Parts Stomata Upper Epidermis

If the leaves of all plants could function normally under any environmental condition, various leaf modifications would provide no special benefits to a plant. But the form and structure of tropical rain-forest plants do not adapt them to thrive in a desert, and cacti soon die if planted in a creek because their structure, form, and life cycles are attuned to specific combinations of environmental factors, such as temperature, humidity, light, water, and soil conditions. The modifications of...

Phylum Rhodophyta The Red Algae

Life Cycle Fucus

Like the brown algae, most of the more than 5,000 species of red algae are seaweeds Fig. 18.21 that tend, however, to occur in warmer and deeper waters than their brown counterparts. Some grow attached to rocks in intertidal zones, where they may be exposed at low tide. Others grow at depths of up to 200 meters 656 feet where light barely reaches them, and in 1984, a new species of red algae was discovered at a depth of 269 meters 884 feet , where the light is only 0.0005 of peak surface...

Vascular Cambium And Cork Cambium

Pine Stem Labeled

The evolution of seeds by the seed plants, including the gymnosperms, facilitated their invasion of land. Encased in a seed, the embryo of seed plants can withstand the extremes of the terrestrial environment such as freezing weather, drought, and even fire. Other characteristics, such as a thick cuticle on the epidermis, sunken stomata, and a hypodermis, consisting of one to several layers of thick-walled cells, also enable gymnosperms to withstand harsh environmental conditions from the...

Human Relevance of Viruses

Nuclear Polyhedrosis Virus

The economic impact of viruses in both third-world and industrialized countries is enormous. The annual loss in work time due to common cold and influenza viruses alone amounts to millions of hours. While discomfort, adverse effects on employment, and even deaths due to viral diseases, such as chicken pox, measles, German measles, mumps, and yellow fever, have declined dramatically since immunizations against the diseases became widespread, they still take their toll. Another viral disease,...

Quillwort Life Cycle

Isoetes Levenscyclus

Figure 21.8 Life cycle of a quillwort Isoetes , a heterosporous member of the phylum. Figure 21.8 Life cycle of a quillwort Isoetes , a heterosporous member of the phylum. exploited to the extent that they are now on rare and endangered or threatened species lists they should no longer be collected. Quillwort corms have been eaten by domestic and wild animals, waterfowl, and humans.

Chlamydomonas

Ulothrix Life Cycle

A small, actively moving little alga, Chlamydomonas Fig. 18.3 is a common inhabitant of quiet freshwater pools. It has an ancient history among eukaryotic organisms, with Stern-Jansky-Bidlack Introductory Plant Biology, Ninth Edition Figure 18.2 Representative green algae. A. Volvox. The cells form hollow, spherical colonies that spin on their axes as the flagella of each cell beat in such a way that the motion is coordinated. New colonies are produced within the older ones, x 800. B....

Corn Root Cortex

Primary Xylem

Figure 5.2 A longitudinal section through a dicot root tip. A. Regions of the root. B. Locations of the primary meristems of the root. the edges of this inverted cup-shaped zone, located a short distance behind the actual base of the meristem. Here the cells divide every 12 to 36 hours, while at the base of the meristem, they may divide only once in every 200 to 500 hours. The divisions are often rhythmic, reaching a peak once or twice each day, usually toward noon and midnight, with relatively...

Thalloid Liverworts

Liverwort Rhizoids

The best-known species of thalloid liverworts are in the genus Marchant a named in honor of French botanist N. Marchant see Fig. 20.4 . The most widespread Marchant a species is often found on damp soil after a fire. The thallus, which is about 30 cells thick in the center and 10 cells thick at the margin, forks dichotomously as it grows. Each branch has a notch at the apex and a central groove that extends back lengthwise behind the notch. The thalli grow as meristematic cells at the notches...

Selaginella Spike Mosses Structure and Form

Fertilization Moss

The sporophytes of Selaginella, the larger of the two major genera of living club mosses, are sometimes called spike mosses Fig. 21.5 . The approximately 700 species are widely scattered around the world in wetter areas, but they are especially abundant in the tropics. A few are common weeds in greenhouses. They tend to branch more freely than ground pines, from which they differ in several respects. The two most obvious differences are 1 their leaves each have a tiny extra appendage, or...

Prochlorobacteriae The Prochlorobacteria

Prochloron

Lewin of the Scripps Institute of Oceanography announced the discovery of unicellular, prokaryotic organisms with bright green cells that were living on marine animals called sea squirts found in shallow marine waters of Baja California. These organisms, which were given the name Prochloron, have the chlorophylls a and b of higher plants but no trace of the phycobilin accessory pigments associated with cyanobacteria. Instead, their accessory pigments were confined to the...

The Laurel Family Lauraceae

Fruit Lauraceae Family

The Laurel Family's primitive flowers have no petals but have six sepals that are sometimes petal-like. The stamens, which occur in three or four whorls of three each, are a curiosity because the anthers open by flaps that lift up. The ovary is superior. Most of the approximately 1,000 species in this family are tropical evergreen shrubs and trees, many with aromatic leaves. The family received its name from the famous laurel cultivated for centuries in Europe. Its foliage was used by the...

Lichens

Foliose Lichens

A student who was interested in natural dyeing came to me a number of years ago and asked if she could experiment with the dye potential of local plants as a special project. In the course of her experimentation, she obtained beautiful shades of yellow, brown, and green from two dozen common local plants, using simple recipes.1 During the following summer, she extended the project to include lichens growing on the trees and rocks at a camp where she served as a counselor. The rich colors she...

Oedogonium

Sexual Reproduction Inspirogyra

In colonies of Spirogyra, the filaments usually are produced so close to each other that they may actually be touching. When sexual reproduction begins, the individual cells of adjacent filaments form little dome-shaped bumps, or papillae singular papilla , opposite each other. As these papillae grow, they force the filaments apart slightly, and then the papillae fuse at their tips, forming small cylindrical conjugation tubes between each pair of cells. The condensed protoplasts then function...

Location Of Light Independent Reactions In A Flowering Plant

Bundle Sheath

Figure 10.10 The Calvin cycle light-independent reactions of photosynthesis. The cycle takes place in the stroma of chloroplasts where each step is mediated by an enzyme. Carbon dioxide molecules from the air enter the cycle one at a time, making six turns of the cycle necessary to produce one molecule of a 6-carbon sugar such as glucose C6H12O6 . 5. This leaves a net gain of two GA3P molecules, which can contribute either to an increase in the carbohydrate content of the plant glucose, starch,...

Flowering Hormone

Cocklebur Photoperiodism Graft

After photoperiodism was discovered, many scientists, including M. H. Chailakhyan, a Russian botanist, conducted experiments to determine which part of a plant was sensitive to day length. They soon found it was mainly the leaf, although they also noted that buds of long-day plants exhibited similar responses. If they completely enclosed the leaf of a short-day plant in black paper for all but 8 hours of a 24hour day while exposing the rest of the plant to long days, flowering was initiated,...

Size and Structure

Ebola Protein Coat

We know now that smallpox was caused by something considerably smaller in size than bacteria. During Pasteur's time, virtually all infectious agents, including bacteria, protozoans, and yeast, were called viruses. One of Pasteur's associates, Charles Chamberland, discovered that porcelain filters would block out bacteria but would not keep an unseen agent from passing through. The agent caused rabies, another serious disease of both animals and humans. Agents of disease that could pass through...

What Is Plant Biology

Harvesting Opium From Poppy Plants

The Relationship of Humans to Their Environment Human and Animal Dependence on Plants Botany as a Science Hypotheses Microscopes Diversification of Plant Study Summary This chapter introduces you to botany what it is, how it developed, how it relates to our everyday lives, and what its potential is for the future. The discussion includes a brief introduction to some common questions about plants and their functions, an examination of the scientific method, and a brief look at botany after the...