Plants

Blueberry Blueberries are perennial flowering plants of the genus Vaccinium, and are native to North America. The genus is very diverse, containing 150 to 450 species, mostly found in the tropics at high elevation, but also in temperate and boreal regions. Most are shrubs, but again, a diverse range of growth forms from epiphytes to trees exists. The leaves can be either deciduous or evergreen, ovate to lanceolate. The flowers are bell-shaped; white, pale pink or red, sometimes tinged greenish.

The fruit is a berry 5-16 millimeters in diameter with a flared crown at the end; they are pale green at first, then reddish purple, and finally dark blue when ripe. Three commercially important blueberry species are recognized, along with two interspecific hybrids: Northern Highbush blueberry, Rabbiteye blueberry, Lowbush blueberry, Southern highbush, and half- high highbush. The blueberry plant’s reproduction was designed specifically for pollination. The flowers of blueberries need to be pollinated by insects. There are special characteristics in a blueberry flower that make pollination easier.

The flowers are fused, having only one end opened. The nectarines, which cause the blueberry to become pollinated, are at the base of the ovary and have a sweet-smelling aroma, attracting the insect far into the flower. Its stamens are shorter than normal, and the pollen is unable to fall on the stigma. The plant is designed to not self-pollinate. Blueberries have many different uses. They are sold fresh or processed, puree, juice, or dried. They may be turned into a variety of consumer goods such as jellies, jams, pies, muffins, and cereal.

Especially in wild species, blueberries contain phytochemicals, which possibly have a role in reducing risks of some diseases, including inflammation and certain cancers. A 2007 symposium on berry health benefits, reports showed consumption of blueberries may alleviate the cognitive decline occurring in Alzheimer’s disease and other conditions of aging. Feeding blueberries to animals reduced brain damage in experimental stroke. Research has also shown the blueberries may help prevent urinary tract infections.

After many laboratory- based animal and cell studies show that anthocyanins, found in blueberries cause blood vessels to relax and increase production of nitric oxide, which helps in maintaining normal blood pressure. Other animal studies found blueberry consumption lowered cholesterol and total blood lipid levels, possibly affecting symptoms of heart disease. Another study also found supplementation of diets with wild blueberry juice enhanced memory and learning in older adults, while reducing blood sugar and symptoms of depression. Also the blueberry plant is excellent for people who are diabetic or have heart problems.

They can eat the berries and make teas from the plant. Blueberries were also used to dye fabrics, textiles, and baskets. Early colonists made gray paint out of the blueberries by boiling them in milk. A blueberry extract diet improves balance, coordination, and short-term memory. Studies have also showed that because blueberries are high in bioflavonoids, which are used by the rods in the eye for night vision, that blueberries can improve night vision. Since blueberries are so high in antioxidants signs of aging such as wrinkles and sagging skin are prevented.

The Aloe Vera Barbadensis plant has been used for thousands of years to heal a variety of conditions, including wounds, skin irritations, and constipation. Originally Aloe Vera is native to arid regions of north-eastern and southern parts of Africa and Madagascar. Aloe is a member of the Lily family often referred to as “the desert Lilly”. The plant stores the limited rainwater it gets in its leaves and forms a gel. The Gel is used both internally and externally on humans, and is claimed to have some medicinal effects.

For that reason it is grown commercially in the United States, the Caribbean, and Mexico. There are around two hundred and forty species growing in other dry regions around the world, but only a few are recognized as being of value to humans and animals. Aloe barbadensis is significantly at the top of the aloe species. The earliest reference to its use can be found in the famous Egyptian Ebers Papyrus, which dates back to 1500 BC and is widely regarded as one of the earliest documents, the western Materia Medica.

The Egyptians referred to it as “the plant of immortality”. However, it is more than likely its been commonly used for centuries before it was recorded. There is reference made to it in the New Testament, when Nicodemus comes by night and brings a mixture of Myrrh and Aloe to embalm the body of Jesus. If you believe in Christianity this is the first documented use of Aloe vera. Galen was a physician to a Roman emperor (AD 131-201), he used Aloe vera as a healing agent and authored over 100 books on conventional and herbal medicine.

He gained his knowledge from doctoring the Roman gladiators. Galen was a follower of the works of Hippocrates and Aristotle. Also Christopher Colombus had documented the medical use and value of the plant on his ship logs, many believe he introduced it to the “New World”. World War II military manuals suggested that servicemen could use it as a remedy for burns, insect bites, or other skin ailments. Aloe would lose potency when transported due to oxidation. The pulp was most effective when fresh.

Aloes Vera’s reputation as a miracle plant declined in places were the plant could not be grown, until the mid 1900’s. In 1950’s America, many processing techniques were attempted, but they ended in failure. Over heating the Aloe can cause it to loose its medicinal value. By the 1970’s there was a breakthrough in the processing techniques leading to the successful stabilization of the leaf gel. This success was found by using natural ingredients and cold pressing. They also found a way to separate the aloin form the rind.

The aloin is a compound found in Aloe that is used internally for digestive health. It worked as a laxative and was found as a main ingredient in most OTC laxative medications until the millennium. These new found processing techniques created a new market for Aloe vera. In modern day America Aloe vera is used for the same reasons it was thousands of years ago in ancient civilizations. Externally used for the treatment of burns, cuts, insect bites, and rashes and it is still rarely internally used as a natural dietary supplement that regulates digestion.

Today it can be found in many different forms such as dried powders, capsules, extracts, juices, gels, and lotions. When looking for quality Aloe products to use on your skin you must read labels to ensure that Aloe is the first or second ingredient listed. A lot of the gels and lotions can be extremely diluted with other ingredients. If you are looking for the soothing effects of pure aloe on the shelves of your local drugstore you must see that the product is free of artificial colors and stabilizing ingredients.

When looking for a quality Aloe product to apply to your skin, look for a gel that is 98-100% Aloe. There is much debate to whether benefits exist from ingesting the aloin compound. In 2002, the FDA required that all OTC aloe laxative products be removed from the U. S. market or reformulated because the companies that manufactured them did not provide the necessary safety data. Externally Aloe is still a treasured remedy used for osteoarthritis, burns, sunburns, and psoriasis. Because Aloe Vera plants are very succulent and consist of 95% water, they are tender to frost.

If they are grown outdoors in warm climates, they should be planted in full sun, or light shade. Aloe vera’s roots like to be crowded so they must be planted clustered or potted. In a temperate American climate they thrive as potted houseplants. Due to their vulnerability to frost most of the year they must be kept inside next to a south or westward facing window to receive sunlight but regulate temperature. They thrive in pots and make great indoor plants. Aloe Vera is a succulent meaning it stores a large quantity of water within its leaves and root system.

The plant will become dormant-like in the winter season utilizing very little moisture, watering at this time should be minimal. During the summer months the plant needs to be saturated with water. After watering the plant allow the soil to dry before re-watering. The soil needs to have a sandy base in a way to emulate an arid climates soil. A quality commercial potting mix with extra perlite, granite grit, or coarse sand added will work perfectly. The plant has a very wide root base so a deep pot is not necessary however the width of the pot is very important.

When it is time to repot an aloe vera plant look for a wider pot than before, focus on width rather than depth. Aloe Vera plants are propogated by removing the offsets, which are produced around the base of mature plants, it can also be planted by seed. The Aloe Vera plants scientific relevance is debated widely for its different remedies. I believe it is obviously a miracle plant and the human race is blessed to have it for burns, cuts, and infection. It appears people have been using aloe vera since the dawn of humanity and do not appear to be stopping anytime soon.

Hydroponics Mentality

In an of all time altering universe, aquicultures has proven its significance to agribusiness and specifically gardening in infinite different states, every bit good as its benefits to the environment ( Mason, n.d. ). From Brooke’s ( 1995 ) reappraisal of aquicultural turning activities, topographic points that were even believed as infertile for cultivation are now able through these new systems, such as Australia and Alaska. In ( 2003 ) Devries spoke about the credence of the soilless turning medium that is realized as a solemn system. This was mentioned by Wilcox ( 1980 ) when composing “High Hopes of Hydroponics”, in which he predicted that the nursery industry would necessitate more productive harvests closer to the metropolis. The rapid growth of the aquicultures industry and its importance towards agribusiness was underlined at the “South Pacific Soilless Culture Conference ” by Alexander ( 2003 ). Therefore, aquicultures is thought to be the remedy for intensive harvest production throughout the universe ( Resh, 2013 ). On the other manus, Jones and Gibson ( 2002 ) argue that “the hereafter of the continued enlargement of aquicultures for the commercial production of works is non-encouraging unless major discovery occurs in the manner the technique is designed and used ”. This is derived from the fact that aquicultures is viewed by some as excessively expensive and excessively proficient, something simple husbands/men can non understand ( Schmitz, 2004 ).

Jensen ( 1995 ) argued that nowadays the industry of aquicultures seems more optimistic and the hereafter for aquicultural developments will depend on the advancement of systems that can be cost-efficient and supply net incomes. Resh ( 2013 ) discussed that the adaptation from out-of-door field cultivation to indoor nursery shows a bright hereafter for the industry, in which the lone drawbacks would be H2O and alimentary deficit. Yet the key to guaranteeing our hereafter is sustainability, vouching that this planet will be able to provide natural stuff, H2O, and birthrate. Hydroponics uses minimal H2O, merely nutrients the work’s demands, and does non do dirt depletion. However, earlier Garnaud ( 1985 ) and Wittwer ( 1993 ) disputed the importance factor impacting aquicultural systems the most is plastic, which is included in all greenhouse/hydroponic activities, from turning vane, irrigation tubings, sheets, adjustments, all indispensable constituents. Prospectively, the usage of technological promotions for aquicultural systems, as computing machines and control panels can revolutionize every facet of the operations and processes ( BENTON, 2014 ).

Types of Hydroponic Systems

Hydroponics are classified in many different systems, one classification is the unfastened and closed systems. Resh ( 1995 ) defined aquicultures to be the scientific discipline of cultivating works, by replacing dirt with an inert medium ( substrates ), which could be sand, crushed rock, Rockwool, perlite, clay pellets, vermiculite, sawdust, pumice, or peat, where we adjoin the solution of the indispensable works foods.

Sing the unfastened type of aquicultures systems, we refer to the method of providing a harvest continuously with H2O and the solution of foods needed, which are non recycled. Many states that use unfastened systems have polluted their ecosystem, as H2O with fertilizers and all foods are abandoned in nature, the dirt, air, and H2O ( Mason, n.d. ). In closed systems, H2O and alimentary solution are collected and reused, after they pass through the roots. After go through through the rooting medium or roots mass, in a closed system, the alimentary solution is collected and recirculated ( Mason, n.d. ). So, obscuring with many fertilizers is reduced, H2O and alimentary wastage are decreased and the impact on the environment is at a lesser sum.

Another categorization of aquicultures systems refers to the methods that use substrates or non. A medium-less civilization merely uses an alimentary solution with no solid medium. One renowned system since the 1970s is the NFT Nutrient Film Technique, which caused huge alterations in aquicultural techniques all around the universe ( Cooper, 1976 ). In order to properly program and use the NFT system, a right PVC channel incline must be used, the flow of foods, and proper channel length. For illustration, tomatoes turning in channels need the width to suit its big root system, but strawberries, which have less than 1/3 lesser root system will equivalently necessitate smaller channels. The advantages of this system are expounding of the work’s roots to sufficient supplies of O, H2O, and foods, which subsist of the basic demands for vigorous works growing and its easiness and simpleness. On the other manus, this simplistic design, brings uncertainness on breaks of the flow, by contaminated armored combat vehicles, diseases, power outages, and costs are elevated when pumps are continuously used. The image below shows a simple illustration of an NFT system.

( pnchydroponics.com/type/4-Hydroponics.html ) n.d.

Another “substrate-less ” aquicultural system that recirculates H2O, is the NGS System ( New Growing System ), one of the most modern techniques used, peculiarly planned for horticultural harvests of any size, either indoors or out-of-doors ( Kriel, 2015 ). After personal communicating with Mr. Samantouros, an agronomist and representative of NGS in Greece, he analyzed how the system works. Basically, this system provides the optimal environment for the harvests, by supplying the accurate sum of H2O, running for 1 minute and resting for 4 supplying O and foods needed ( NGS, 2015 ). The image below shows the NGS system’s alone design. It is made by three interrelated beds of polyethylene sets based on a triangular “steel fretwork ” ( channel ), making a circuit at multiple degrees that favors oxygenation of the works and its alimentary solutions. The chief advantage of this system is the maximization of the works possible, sing strong rooting systems, disease opposition, and productiveness ( Kriel, 2015 ).

hypertext transfer protocol: //ngsystem.com/en/ngs/multibanda

Alternatively, one of the systems that use substrates in their techniques is the ‘Ebb and Flow ” system, which operates by the inundation of the grow tray provisionally with the solution of foods, and following drains it into a reservoir, with the assistance of a submerged pump ( Makehydroponics.com, 2015 ) . This happens legion planned times twenty-four hours, depending on the type of the works, its size, the substrate used, and the irrigation needs from the clime. The trays can be filled with Rockwool, crushed rock, Grow Rocks, or perlite turn outing its versatility ( Mason, n.d. ). The major failing of this system is that when there is a break in the rhythm of the H2O, roots may dry rapidly.

( hypertext transfer protocol: //diy.1woodworks.com/tag/diy-ebb-and-flow-table ) 2015

Another type of aquicultural cultivation is the drifting system, which could be characterized as the easiest and most cheap manner of production without the usage of dirt. This was the method used to research and prove the inquiry of the thesis. In the nursery float-system, there is a drifting phonograph record made out of Styrofoam or polystyrene that floats on top of the solution of foods, as seen in the image below ( Cornell, n.d. ). The indoor cultivation was chosen to guarantee that the method can bring forth homogenous root extensions and the quality of the grafts at a specific clip line. Yet, the conditions can still hold a consequence on the indoor nursery production, as ice chest conditions may do a reverse on the sprouting phase and excessively much heat between February – March could hike the growing of the works, doing diseases to the root and root ( Reed, 2009 ). Typically, there is an air pump that provides O to the air rock, which supplies through bubbles air to the roots of the works ( Pearce, et.all. , 1999 ). However, in this thesis survey, there is no aeration supply, as it was chosen to analyze if the riddance of air could do a difference in the production of hydroponically grown baccy seedlings. Issues can be faced when seeking to cultivate big works or long-run works, as the Styrofoam can non pull off. In the instance of the baccy seedlings, the roots are pruned each hebdomad in the first stage, in order for the stork to turn bigger and stronger, to reassure that the grafts are physically powerful plenty to last in the field ( Reed, 2009 ).

Pros These Photos Apo Float System Kai Tobacco

Mentions:

1. Brooke, L. L. 1995. A universe in front: The leaders in aquicultural engineering. Turning Edge6 ( 4 ) pp. 34–39, 70–71.
2. Devriess, J. 2003. Hydroponics. In Ball Redbook: Greenhouses and equipment, vol. 1, 17th ed. , erectile dysfunction. C. Beytes, 103–114. Batavia, IL: Ball Publishing.
3. Wilcox, G. E. 1980. High hopes for aquicultures. American Vegetable Grower28: pp.11–14.
4. Alexander, T. 2003. The 2003 South Pacific Soilless Culture Conference.Turning Edge14 ( 5 ) pp.14–19.
5. Resh, H. 2013 Aquicultural Food Production. Boca Raton, FL: CRC Press
6. Jones, J.B. & A; Gibson, P.A. 2002 A turning position: Hydroponics, yesterday, today, and tomor­row. Turning Edge13 ( 3 ) pp.50–56.
7. Garnaud, J-C. 1985, Plastics and plastic merchandises. In Hydroponics worldwide: State of the art in soilless harvest production, erectile dysfunction. A. J. Savage, Honolulu, HI: International Center for Particular Surveys pp.31-35
8. Wittwer, S. H. 1993, Worldwide usage of plastics in horticultural harvests.HortTechnology3 pp.6–19.
9. Complete usher for works hydroponically Benton 1.
10. Resh, H 1995, Hydroponic nutrient production, Woodbridge Press Pub. Co., Santa Barbara, Calif.
11. Mason, J. n.d. Commercial Hydroponics, ACS Distance Education, 3rd Ed, p. 5-9. ISBN: 978-0-9871022-2-5
12. Cooper, A. 1976.Nutrient movie technique for turning harvests.London: Grower Books

13. Makehydroponics.com, 2015, ‘How To Hydroponics – Flood and Drain Hydroponics ‘ , accessed May 2, 2015, from & lt ; hypertext transfer protocol: //www.makehydroponics.com/whatsystem/flood-and-drain.htm & gt ; .
14. Personal Communication with Konstantinos Samantouros on 15th of May 2015
15. Kriel, G 2015, ‘Farmer ‘s Weekly | No sterilization needed with this turning system ‘ , Farmersweekly.co.za, accessed April 3, 2015, from & lt ; hypertext transfer protocol: //www.farmersweekly.co.za/article.aspx? id=71191 & A ; h=No-sterilisation-needed-with-this-growing-system & gt ; .
16. NGS, 2015, ‘Sistema | New Turning System ‘ ,Ngsystem.com, accessed April 5, 2015, from & lt ; hypertext transfer protocol: //ngsystem.com/en/ngs/descripcion & gt ; .
17. Pearce, R, Li, Y & A; Bush, L 1999, ‘Calcium and bicarbonate effects on the growing and alimentary consumption of burley baccy seedlings: Float system 1 ‘, Journal of Plant Nutrition, vol. 22, no. 7, pp. 1079-1090.
18. Reed, D 2009, ‘Float Greenhouse Tobacco: Transplant Production Guide ‘, Virginia Cooperative Extention, vol. 436, no. 051, pp. 1-11.

PRACTICAL 6 Seed Plants (Gymnosperms and Angiosperms) OBJECTIVES: 1. To describe the features of seed plant life cycle and the concept of the dominant generation. 2. To describe the life histories and related reproductive structures of gymnosperms and angiosperms. 3. To summarize the features that distinguish gymnosperms and angiosperms. 4. To discuss the advantages of seed plants to dominate land and their evolutionary adaptations on land. EXPERIMENT 1: Gymnosperms INTRODUCTION:

Gymnosperms (720 species in 65 genera) are ancient seed plants that include ginkgos (Division Ginkgophyta), cycads (Division Cycadophyta), conifers (Division Coniferophyta), and gnetophytes (Division Gnetophyta). The term gymnosperm derives from the Greek wood roots gymnos, meaning “naked”, and sperma, meaning “seed”. They are naked-seeded plants meaning that the ovule, which becomes a seed, is exposed on the sporophyte at pollination. Mature seed are not enclosed in a fruit as are those of flowering plants. Gymnosperms are best known for their characteristic cones, called strobili.

These strobili display sporangia and their subsequently developing ovules and pollens. Gymnosperms do not require water for sperm to swim to reach the egg as do seedless plants. Instead, immense amount of windblown pollen are produced. Most gymnosperm cones, including the familiar pine cone, are complex whorls of leaflike, woody scales around a central axis. The smallest cones include those of the junipers (Juniperus) which have flesh scales fused into a structure resembling a berry. The larger cones may weigh 45 kg and are produced by cycads.

In most gymnosperm species, the female megastrobilus is larger and distinctive from the male microstrobilus. MATERIALS: 1. Living or preserved specimens of * Ginkgo (Ginkgo biloba) * Cycad (Cycad sp. ) * Pine (Pinus sp. ) 2. Prepared slide of gymnosperms 3. Compound microscope 4. Dissecting microscope 5. Slide and coverslip 6. Forceps 7. Distilled water PROCEDURE: A ginkgo: 1. A prepared slide of male strobilus of Ginkgo biloba is examined. The microsporophyll, microsporangium, and strobilus axis are identified. 2. A prepared slide of female strobilus of Ginkgo biloba is examined.

The megasporophyll, megasporangium, and strobilus axis are identified. A cycad: 1. A female cycad is examined. The leaves, megasporophylls, megasporangia and developing seed are identified. 2. The pollen cone bears on male cycad. Pollinated cone is examined and microsporophyll, microsporangia, and pollen grains are identified. A pine: 1. A male cone and female cone of Pinus sp. are obtained. 2. A prepared slide of longitudinal section of female cone is examined. The megasporophyll, megasporangia, and ovule are looked. 3. A prepared slide of longitudinal section of male cone is examined.

The microsporophyll, microsporangia, and pollen grains are looked. 4. Fertilization occurs after the pollen tube penetrates the megasporangium and allows sperm to enter the archegonium and fuses with the egg. The zygote will form after fertilization. A prepared slide of the developing embryo of Pinus sp. is examined. 5. Mature seed cone is obtained. The seed with wing attached to the ovuliferous scale is found. 6. The anatomy of pine leaf one needle is examined. The following: epidermis, stoma, photosynthetic mesophyll, endodermis, phloem, xylem, and resin duct are identified.

RESULTS Cross section of Ginkgo Biloba Cross section of Cycad Cross section of female pine Cross section of male pine EXPERIMENT 2: Angiosperms INTRODUCTION: Angiosperms are the most abundant, diverse, and widespread of all land plants. They are successful because they are structurally diverse, have efficient vascular systems, share a variety of mutualisms (especially with insects and fungi), and have short generation times. Flowering plants are important to human because our world economy is overwhelmingly based on them.

Indeed, we eat and use vegetative structures (roots, stems and leaves) as well as reproductive structure (flowers, seeds, and fruits). You will find that many of the vegetative structures are quite similar to those of more ancient plants shown. The roots, stems, and leaves of flowering plants function just as those of ferns and cone bearing plants. Flowers and fruits, however are unique adaptations of angiosperms. Biologists believe that the extraordinary adaptiveness of these structures has led to the proliferation of the incredible diversity found among flowering plants. MATERIALS: 1.

Living specimens of angiosperms (dicots & monocots) with roots, stems, leaves, flowers, fruits and seeds. (Imperata cylindrical, zea mays, Carica papaya, Phaseolus sp. ) 2. Prepared slide of angiosperms (dicots & monocots) 3. Compound microscope 4. Dissecting microscope 5. Slide and coverslip 6. Forceps 7. Distilled water PROCEDURE: Roots: 1. A root of dicots and monocots are obtained for morphology and anatomy study. 2. The root systems of representative dicot and monocot are looked. 3. Cross section of dicot root shows the central stele is surrounded by a thick cortex and epidermis.

The following: epidermis, cortex, parenchyma cells, starch grains, pericycle, endodermis, phloem, and xylem are identified. 4. Cross section of monocot roor shows this root has a vascular cylinder of xylem and phloem that surrounds a central pith. The following: epidermis, cortex, endodermis, Casparian strip, pith, phloem, and xylem are identified. 5. A prepared slide of the roots for some other species is obtained and their structure is identified. Stems: 1. The longitudinal section of shoot tip of representative dicot and monocot is studied.

The following: leaf, leaf primordium, apical meristem, ground meristem, axillary bud, vascular bundle, and pith are identified. 2. A dicot and monocot is obtained and a cross section of the stems is made and the arrangement of vascular bundles is examined. The anatomy between this dicot and monocot is compared. 3. For both type of plants, epidermis, cortex, phloem, xylem, cambium, pith, and vascular bundle are identified. Leaves: 1. Fresh specimen provided in lab is looked. Flowering plants show a variety of morphology to identify, such as, leaf arrangements and leaf venation. 2.

Using fresh prepared slide or prepared slide of some flowering plants, the structure of the leaves is studied. The leaves have common features: cuticle, air space, lower epidermis, upper epidermis, palisade mesophyll, spongy mesophyll, and vascular bundle are noticed. Flowers: 1. The longitudinal section of some flowers is looked. The parts of a flower: stigma, pistil, style, ovary, sepal, receptacle, peduncle, petal, filament, stamen, and anther are named. 2. A prepared slide of a cross section of mature anther (lily anther) is examined. Sections of the four microsporangia are found.

Pollen grains within a microsporangium is looked. 3. A prepared slide of a cross section of an ovary (lily ovary). The several ovules are found. Megaspore mother cell within megasporangium is looked. The megasporangium develops is studied. The placenta, integuments, microphyle, egg cell, central cell, and polar nuclei are identified. 4. The demonstration slide of double fertilization is observed and the zygote, primary endosperm nucleus, and central cell of the female gametophyte are identified. Fruits and seeds 1. A sample of dry, dehiscent fruits (peanuts) is obtained.

The fruit wall, cotyledon, plumule of embryo, embryo, radical, cotyledon, and seed coat are identified. 2. A sample of simple flesy fruits (tomato, a berry) is obtained. Pericarp, mesocarp, endocarp, locule, seed and placenta are identified. 3. A prepared slide of corn grain (Zea mays), a caryopsis fruit is examined. The pericarp of a corn grains is tightly united and inseparable from the seed. The pricarp, endosperm, cotyledon, coleoptiles, plumule bud, embryo, radical, and coleorhizae are identified. RESULTS Cross section of root Cross section of stem

Cross section of leaves Cross section of flower Cross section of seed DISCUSSION For the lower vascular plants the important evolutionary development was in the water and food conducting tissues of the sporophyte. As we move on through the plant kingdom the next important development was the seed. The free living gametophyte is a vulnerable phase of the life cycle. Reproduction by seeds is a less chancy procedure and has other advantages for plant survival and dispersal. Seeds can be remarkably tolerant of environmental extremes heat, cold and drought.

Unlike free-living gametophytes seeds can postpone their development until conditions are right. And, of course, we find them very convenient for plant propagation. Already in the coal-measure forests there were plants that reproduced by seeds. Some were the so-called “seed ferns”. Others were the ancestors of the plants we now know collectively as “gymnosperms”. In these plants the seeds are not enclosed in an ovary, as in the flowering plants; they grow on the surface of a modified leaf in a strobilus or cone. “Gymnosperm” means naked seed. Alternation of generations is still involved in the reproduction of these plants.

They are all heterosporous: the microspores are shed as pollen, whereas the megaspore germinates in the strobilus to produce the female gametophyte. The archegonia in this gametophyte get fertilized by sperm from the male gametophyte and the zygote grows to produce an embryo which is enclosed in a seed coat of tissue from the parent plant. Gymnosperms were the dominant land plants in the age of dinosaurs, the Cretaceous and Jurassic periods. The surviving gymnosperms in the Coniferophyta, Cycadophyta and Ginkgophyta are similar in their woody habit and pattern of seed development but are not closely related.

The characteristic feature of angiosperms is the flower. Flowers show remarkable variation in form and elaboration, and provide the most trustworthy external characteristics for establishing relationships among angiosperm species. The function of the flower is to ensure fertilization of the ovule and development of fruit containing seeds. The floral apparatus may arise terminally on a shoot or from the axil of a leaf (where the petiole attaches to the stem). Occasionally, as in violets, a flower arises singly in the axil of an ordinary foliage-leaf.

More typically, the flower-bearing portion of the plant is sharply distinguished from the foliage-bearing or vegetative portion, and forms a more or less elaborate branch-system called an inflorescence. There are two kinds of reproductive cells produced by flowers. Microspores, which will divide to become pollen grains, are the “male” cells and are borne in the stamens (or microsporophylls). The “female” cells called megaspores, which will divide to become the egg cell (megagametogenesis), are contained in the ovule and enclosed in thecarpel (or megasporophyll).

The flower may consist only of these parts, as in willow, where each flower comprises only a few stamens or two carpels. Usually, other structures are present and serve to protect the sporophylls and to form an envelope attractive to pollinators. The individual members of these surrounding structures are known as sepals and petals (or tepalsin flowers such as Magnolia where sepals and petals are not distinguishable from each other). The outer series (calyx of sepals) is usually green and leaf-like, and functions to protect the rest of the flower, especially the bud.

The inner series (corolla of petals) is, in general, white or brightly colored, and is more delicate in structure. It functions to attract insect or bird pollinators. Attraction is effected by color, scent, and nectar, which may be secreted in some part of the flower. The characteristics that attract pollinators account for the popularity of flowers and flowering plants among humans. While the majority of flowers are perfect or hermaphrodite (having both pollen and ovule producing parts in the same flower structure), flowering plants have developed numerous morphological and physiological mechanisms to reduce or prevent self-fertilization.

Heteromorphic flowers have short carpels and long stamens, or vice versa, so animal pollinators cannot easily transfer pollen to the pistil (receptive part of the carpel). Homomorphic flowers may employ a biochemical (physiological) mechanism calledself-incompatibility to discriminate between self- and non-self pollen grains. In other species, the male and female parts are morphologically separated, developing on different flowers. POST-LAB QUESTIONS: 1. How to distinguish between a male and female cone of pine?

The male cone will form at the bottom of the tree and it is much smaller than the female and the male produces the pollen grains and the female produces the ovule and forms at the top of the tree. 2. Explain the characteristics of gymnosperm seeds to aid in dispersal. Many gymnosperms have winged seeds that aid in dispersal. Generally, gymnosperms have heavy seeds so the wings only assist in moving the seed a short distance from the parent plant. 3. List some uses for conifers. Economically, conifers are very important as they are a major source of timber.

The majority of the world’s sawn timbers come from conifers. Exploitation of this resource from wild growing forests is still going on in many parts of the world, but there is an obvious trend especially in the developed world to phase this out and use more sustainable planted or seeded resources. There are many species with highly different wood properties, some of these are extremely valuable and used for fine cabinet making or expensive applications in construction. Wood from conifers is also an important source of pulp for paper and cellulose fibres such as rayon.

Conifers also very important in horticulture, especially in regions with a temperate climate. Several species have yielded hundreds of different cultivars and new ones are constantly appearing on the market. In some countries conifers have a role to play in traditional medicine and in religious ceremonies and, of course, our Christmas trees can be seen as a form of this kind of use. A few conifers even have edible seeds; well known are those of certain pines. 4. Lists the common characteristics of seeds plants. i. They have vascular tissue ii.

They use seeds to reproduce iii. They all have body plans that include leaves, stems, and roots. 5. Contrast between dicots and monocots, the two classes of flowering plants. Monocots| Dicots| Herbaceous| May be woody or herbaceous| Embryo with single cotyledon| Embryo with 2 cotyledons| Flower parts in multiple of three| Flower parts with multiple of 4 or 5| Parallel-veined leaves| Net-veined leaves| Bundles of vascular tissue are scattred throughout the stem| Vascular bundle in the stem forms rings| Roots are adventitious| Root develop from radicle| . Discuss the features of plant flowering fruits and seeds. Seeds develop from ovules in the ovary, and at maturity consist of an embryo and a reserve food supply surrounded by a protective covering, the seed coat. The diversity of flowering plants assures diversity among their seeds, but, unlike fruits, which have numerous variations, structural plans for seeds are few. The reserve food can be stored either in or out of the embryo and the cotyledons, the seed leaves can remain either below ground or be elevated above the surface when germination occurs.

Fruits are ripened ovaries containing seeds with sometimes additional flower or inflorescence tissues associated with them. Only angiosperms produce flowers and fruits. From a botanical viewpoint, many of the foods we eat as vegetables are fruits, for examples, tomatoes, green beans, squash, eggplant, and peppers. Fruits apparently arose as a means not only of protecting the seeds, but as a way to ensure their dispersal. REFERENCES 1. http://faculty. unlv. edu/landau/gymnosperms. htm 2. http://www. kew. org/plants/conifers/uses. html 3. http://edhelper. com/ReadingComprehension_37_251. html

The time that a seed germinates, and whether or not it actually does germinate, depends on many factors. These factors include; the chemical environment, which must be the right conditions; oxygen must be present, and inhibitory chemicals must not be present. Germination also depends on the physical environment. Temperatures must be suited to the seed, and light quality and quantity must also be suited to the needs of the seed. In some cases, all these conditions are met, and still, the seed fails to germinate. This is because the seed is said to be dormant (Bewley and Black 1985).

Seed dormancy is a short-lived deficiency, or block of an able seed to complete germination under suitable conditions. There are two different types of dormancy, embryo, and coat dormancy (Kucera et al.2005). Embryo dormancy is mostly common in woody species, but can also be found in blossoming plants as well. Coat dormancy is when the tissues that enclose the seed are too tight and the seed cannot overcome the constraint. Seeds can be released from dormancy through being chilled, sometimes for several weeks, or sometimes even months, at temperatures of one to five degrees Celsius. This means that seeds that rely on such ways of dormancy must wait for the cold seasons to pass before they can germinate (Bewley and Black 1985).

Many seeds can germinate with, or without light, but the plants that require light, are called photoblastic, and are controlled by the phytochrome (Kendrick and Russell 1975). Phytochrome has two descriptions, the first one, Phytochrome red (Pr), is transformed by red light, to the second form, phytochrome far red (Pfr). Far red radiation can reverse the whole process. Phytochrome far red absorbs far red light (730nm), and phytochrome red absorbs red light (660nm) (Toyomasu et al. 1997).

Seeds that are grown in darkness don’t germinate unless they are exposed to red light for a short period of time. For a red light to be effective, water content in the seed must be at 15%, because dry seeds do not respond to red light. In lettuce seeds that are matured naturally, phytochrome is most commonly in the form of phytochrome red, and in the dehydrated form, the conversion to phytochrome for red light is not possible (Kendrick and Russell 1975).

Lettuce is an important vegetable cultivated worldwide, and requires high quality seeds. Lettuce seeds are unable to germinate in the dark, and are unable to germinate at high temperatures. These characteristics affect the rates that new seeds are developed (Metzger et al. 2009). Light is a very important factor in releasing seeds from dormancy. Seeds can be affected by being exposed to white light from just a few seconds, to or even minutes, others require intermittent light. The light frequency that is required depends on the temperature. Lettuce seeds that are bought in stores are usually treated to improve the germination process, even when lots of light is unavailable. Although, light sensitive leaves need a lot higher levels of phytochrome far red light to bring the seed out of dormancy (Kendrick and Russell 1975).

Using all the information I have gathered, I hypothesised that the red light and white light would cause a greater percentage of germination than the other lights, because they produced more far red light.

Methods The lettuce seeds that we used (Lactuca sativa L.cv Tango), were dried and stored at 22oC until we used them. We used gibberellin acid (GA3) of ≥ 90% purity, at the following concentrations; 10-3, 10-4, 10-5, and 10-6. The red light source we used was gathered by filtering white light that came from a twenty-five watt fluorescent bulb, through two layers of dark red cellophane paper. We got the far red light by a forty watt incandescent bulb. The light was then filtered through a container containing 10cm of water, which was placed above the two layers or red and blue cellophane. The white light we obtained was taken from a sixty watt . Twenty to thirty-five lettuce seeds were placed on two layers of whatman No. 1 filter paper, and all seeds were equally controlled in a room with a green light bulb.

In each dish, 5ml of distilled water was added, along with 5ml of its appropriate GA3 solution. The dishes were wrapped in one layer of tin foil, and put in a darkened box. A control was also prepared. The seeds were added to a dish with distilled water. All the experiments were conducted at the same temperature, 24oC. When everything was ready, to figure out how many seeds were germinating, we counted how many seeds in each petri dish had a white radical coming out if it. When we were done, we recorded our results, and pooled them with the rest of the class (Migabo 2011).