Angiosperms and Gymnosperms

PRACTICAL 6 Seed Plants (Gymno spermatozoons and Angiosperms) OBJECTIVES 1. To describe the features of germ bring life cycle and the conception of the dominant multiplication. 2. To describe the life histories and related repro lineive twists of gymnosperms and angiosperms. 3. To summarize the features that list gymnosperms and angiosperms. 4. To discuss the advantages of sow plants to dominate land and their evolutionary adaptations on land. sample 1 Gymnosperms INTRODUCTIONGymnosperms (720 species in 65 genera) ar ancient bug plants that embroil ginkgos (Division Ginkgophyta), cycads (Division Cycadophyta), conifers (Division Coniferophyta), and gnetophytes (Division Gnetophyta). The term gymnosperm derives from the Greek wood roots gymnos, meaning b be-ass, and sperma, meaning author. They atomic number 18 naked- inseminateed plants meaning that the ovule, which becomes a author, is exposed on the sporophyte at pollination. Mature set be not envelop in a fruit a s be those of blossom plants. Gymnosperms ar beat out k without delayn for their characteristic cones, c each(prenominal)ed strobili.These strobili display sporangia and their subsequently growth ovules and pollens. Gymnosperms do not require water for sperm to swim to reach the egg as do seed slight plants. Instead, immense amount of windblown pollen are produced. most gymnosperm cones, including the familiar yen cone, are complex whorls of leafagelike, woody scales around a central axis. The smallest cones include those of the junipers (Juniperus) which feed 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 effeminate mega retinal cone is larger and distinctive from the male microstrobilus. MATERIALS 1. breathing or pre managed specimens of * Ginkgo (Ginkgo biloba) * Cycad (Cycad sp. ) * Pine (genus Pinus sp. ) 2. Prepared sloping trough of gymnosperms 3. unite microscop e 4. Dissecting microscope 5. gliding and coverslip 6. Forceps 7. Di restraineded water PROCEDURE A ginkgo 1. A vigilant slide of male strobilus of Ginkgo biloba is examined. The microsporophyll, microsporangium, and strobilus axis are identified. 2. A active slide of pistillate strobilus of Ginkgo biloba is examined.The megasporophyll, macrosporangium, 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 variance of female cone is examined. The megasporophyll, megasporangia, and ovule are looked. 3. A prepared slide of longitudinal department of male cone is examined.The microsporophyll, microsporangia, and pollen grains are looked. 4. Fert ilization 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 violate surgical incision of Ginkgo Biloba transit section of Cycad pass over 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, put up in effect(p) vascular sy musical themes, share a variety of mutualisms (especially with insects and fungi), and have short generation times. flowering plants are big to human because our humans economy is irresistibly based on them.Indeed, we eat and use vegetational structures (roots, stems and leaves) as thoroughly as generative structure (flowers, seeds, and fruits). You will find that many of the vegetative structures are quite similar to those of much ancient plants envisionn. The roots, stems, and leaves of flowering plants matter just as those of ferns and cone bearing plants. pinnacles and fruits, however are eccentric adaptations of angiosperms. Biologists believe that the extraordinary adaptiveness of these structures has led to the proliferation of the incr nonpoisonous diversity found among flowering plants. MATERIALS 1.Living specimens of angiosperms ( exogens & 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. Force ps 7. Distilled water PROCEDURE Roots 1. A root of dicots and monocots are obtained for sound structure 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 cubicles, 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 approximately(a) other species is obtained and their structure is identified. Stems 1. The longitudinal section of down 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 impair 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 around 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. Sectio ns of the four microsporangia are found.Pollen grains at bottom a microsporangium is looked. 3. A prepared slide of a cross section of an ovary (lily ovary). The several ovules are found. Megaspore mother carrel within megasporangium is looked. The megasporangium develops is studied. The placenta, integuments, microphyle, egg cell, central cell, and polar nuclei are identified. 4. The expression 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 coupled and in separable from the seed. The pricarp, endosperm, cotyledon, coleoptiles, plumule bud, embryo, radical, and coleorhizae are identified. RESULTS Cross section of root Cross section of stemCross section of leaves Cross section of flower Cross section of seed DISCUSSION For the lower vascular plants the chief(prenominal) evolutionary tuition was in the water and food conducting create from raw stuffs of the sporophyte. As we move on through the plant kingdom the next important organic evolution was the seed. The free living gametophyte is a vulnerable descriptor of the life cycle. Reproduction by seeds is a less chancy procedure and has other advantages for plant survival and dispersal. Seeds do-nothing be remarkably tolerant of environmental extremes heat, cold and drought.Unlike free-living gametophytes seeds can remit their development until conditions are right. And, of course, we find them very convenient for plant propagation. already in the coal-measure fo relaxation behav iors 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 go forth 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 andJurassic periods. The surviving gymnosperms in the Coniferophyta, Cycadophyta and Ginkgophyta are similar in their woody habit and pattern of seed development barely are not closely related.The characteristic feature of angiosperms is the flower. Flowers show remarkable variation in form and elaboration, and provide the most veritable external characteristics for establishing relationships among angiosperm species. The function of the flower is to ensure fertilization of the ovule and development offruitcontainingseeds. The floral apparatus may arise terminally on a shoot or from the axil of a leaf (where thepetioleattaches to the stem). Occasionally, as inviolets, a flower arises singly in the axil of an ordinary foliage-leaf.More typically, the flower-bearing piece of ground of the plant is sharply distinguished from the foliage-bearing or vegetative portion, and forms a more or less elaborate branch-system called aninflorescence. There are two kinds of reproductive cells produced by flowers. Microspores, which will divide to becomepollen grains, are the male cells and are borne in thestamens(or microsporophylls). T he female cells called megaspores, which will divide to become the egg cell (megagametogenesis), are contained in theovuleand enclosed in thecarpel(or megasporophyll).The flower may constitute only of these parts, as inwillow, 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 assepalsandpetals(ortepalsin flowers such asMagnoliawhere sepals and petals are not trenchant 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 brilliantly colored, and is more delicate in structure. It functions to attractinsector fowlpollinators. Attraction is effected by color,scent, andnectar, 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 orhermaphrodite(having both pollen and ovule producing parts in the corresponding flower structure), flowering plants have developed numerous morphological and physiologicalmechanisms to reduce or prevent self-fertilization.Heteromorphic flowers have short carpels and long stamens, or vice versa, so animalpollinatorscannot easily transfer pollen to the pistil (receptive part of the carpel). Homomorphic flowers may employ a biochemical (physiological) mechanism calledself-incompatibilityto 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 ma le 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 fly 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 descent of timber.The majority of the worlds 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 fashioning 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 traditionalistic 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 conceptus 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 . wrangle the features of plant flowering fruits and seeds. Seedsdevelop from ovules in the ovary, and at maturity brood of anembryoand a reserve food supply surrounded by a protective covering, theseed coat. The diversity of flowering plants assures diversity among their seeds, but, contrary 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 thecotyledons, 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, squa sh, eggplant, and peppers. Fruits evidently 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