المناهج الجديدة 2018 / 2019 :

الله أكبر الله أكبر الله أكبر، لا إله إلا الله، الله أكبر الله أكبر، ولله الحمد، الله أكبر كبيرًا، والحمد لله كثيرًا، وسبحان الله بكرةً وأصيلًا، لا إله إلا الله وحدهُ، صدق وعدهُ ونصر عبدهُ وأعز جندهُ وهزم الأحزاب وحدهُ، لا إله إلا الله ولا نعبدُ إلا إياهُ، مُخلصين له الدين ولو كره الكافرون، اللهم صلِ على سيدنا محمدٍ، وعلى آل سيدنا محمدٍ، وعلى أصحاب سيدنا محمدٍ، وعلى أنصار سيدنا محمدٍ، وعلى أزواج سيدنا محمدٍ، وعلى ذرية سيدنا محمدٍ، وسلم تسليمًا كثيرً **** كل عام وجميع الأمة الإسلامية بخير

facebook

النتائج 1 إلى 6 من 6

الموضوع: plant anatomy أجمل شرح وبالصور فقط مع ROTATOTA على ثانوية أون لاين

  1. #1
    VIP الصورة الرمزية ROTATOTA
    تاريخ التسجيل
    Mar 2009
    المشاركات
    1,407

    افتراضي plant anatomy أجمل شرح وبالصور فقط مع ROTATOTA على ثانوية أون لاين

    كما عودناكم دائما على كل ما هو جديد .. مفيد
    اتشرف بالاعلان عن هذا السبق العلمى الرائع و الذى لن اقوم بتقديمه سوى على هذا المنتدى الشامخ
    سأتناول هنا شرح مادة plant anatomy بطريق علمية و مصورة .. و بادق التفاصيل وذلك نقلاً عن اكبر وأشهر المراجع العلمية الأجنبية الحديثة .. لن أطيل عليكم .. اليكموها :
    نبدأ بشرح أجزاء النبات كاملة
    The following is a diagram of the external anatomy of a typical flowering plant:
    axil - the angle between the upper side of the stem and a leaf, branch, or petiole.
    axillary bud - a bud that develops in the axil.
    flower - the reproducti ve unit of
    angiosperm s.
    flower stalk - the structure that supports the
    flower.
    internode - the area of the stem between any two adjacent nodes.
    lateral shoot (branch) - an offshoot of the stem of a plant.
    leaf - an outgrowth of a plant that grows from a node in the stem. Most leaves are flat and contain
    chloroplas ts; their main function is to convert energy from sunlight into chemical energy (food) through photosynth esis.
    node - the part of the stem of a plant from which a leaf, branch, or aerial root grows; each plant has many nodes. Label the two lower nodes (the first and second nodes) on the plant diagram.
    petiole - a leaf stalk; it attaches the leaf to the plant.
    root - a root is a plant structure that obtains food and water from the soil, stores energy, and provides support for the plant. Most roots grow undergroun d.
    root cap - a structure at the ends (tips) of the roots. It covers and protects the apical
    meristem (the actively growing region) of the root.
    stem - (also called the axis) is the main support of the plant.
    tap root - the main root of some plants; the tap root extends straight down under the plant.
    terminal bud - a bud located at the apex (tip) of the stem. Terminal buds have special tissue, called
    apical meristem, consisting of cells that can divide indefinite ly.

    اليكم بعض الصور التوضيحية الأخرى





    و فى المرة القادمة اتناول شرح مفصل و دقيق لأنواع السيقان و الأوراق و المجموع الجذرى .. انتظرونى

  2. #2
    مستشار اللغة الفرنسية القدير الصورة الرمزية leprince
    تاريخ التسجيل
    Mar 2009
    المشاركات
    2,239

    افتراضي رد: plant anatomy أجمل شرح وبالصور فقط مع ROTATOTA على ثانوية أون لاين

    جزاكى الله كل خير

  3. #3
    VIP الصورة الرمزية ROTATOTA
    تاريخ التسجيل
    Mar 2009
    المشاركات
    1,407

    رد: plant anatomy أجمل شرح وبالصور فقط مع ROTATOTA على ثانوية أون لاين

    The Plant Body

    THE ANATOMY OF LEAVES
    Most leaves consist of a stalk, or petiole, and a flattened blade. Veins run from the petiole into the blade. Some leaves, particular ly those of the grass-like plants, lack petioles and the base of the blade is attached directly to the stem. The large veins of dicot leaves usually diverge into the blade from the midrib; this is the pinnate (feather-like) pattern. In some dicot species the major veins diverge from the base of the leaf like fingers from a palm (palmate venation). In all dicots, the smaller veins (the smallest of which can barely be seen with the naked eye) have a reticulate (net-like) pattern, so dicots are said to have net venation. The veins of monocot leaves run parallel to one another; such leaves are said to have parallel venation.
    Leaves of dicots may be either simple (a single blade attached to the stem by a petiole) or compound (a single blade divided into many distinct leaflets). The leaves are arranged on the twig in a manner that is constant for a given species (see figure below). Each leaf is some distance removed from the one immediatel y below it. If only one leaf is attached at a node, the leaves are alternate. If two leaves are formed at the same node, on opposite sides of the twig, the leaves are termed opposite. In a relatively small number of plants more than two leaves arise from the same node in a whorled arrangemen t. These arrangemen ts are found on herbaceous stems as well as on twigs.

    Fig. 1. Arrangemen t of leaves on a shoot: (A) Alternate; (B) Opposite; (C) Whorled

    Almost all legumes have compound leaves; indeed, in some species the leaves are doubly-compound (each leaflet divided again). The soybean has a pinnately compound leaf but in some plant species the leaflets are arranged in a palmate pattern, and others have a whorled arrangemen t. What is the adaptive significan ce of the different leaf types, if any? Lots of debate - no conclusion s.
    How can you tell the difference between a simple leaf and a compound leaf? Leaflets are similar in appearance to simple leaves so it is sometimes difficult to determine whether the structure is a leaflet or a leaf. There are three criteria that you can use to distinguis h leaflets from leaves: (1) Axillary buds are found in the axils of leaves, both simple and compound, but not in the axils of leaflets; (2) Leaves extend from the stem in various planes, whereas the leaflets of a given leaf all lie in the same plane; and (3) Dicot leaves, whether simple or compound, have a petiole that "grasp s" the stem where it attaches. Leaflets do not have such an attachment .



    Leaf Modificati ons
    Bud scales are modified leaves that protect dormant buds in perennial plants.
    In some plants leaves are modified to form spines, which are had, dry, and nonphotosy nthetic. The term “spine” and “thorn” are frequently used interchang eably, but technicall y thorns are modified branches that arise in the axil of leaves. Another term used incorrectl y is prickle. A prickle is neither a stem nor a leave but a small, slender, sharp outgrowth from the cortex and epidermis of a stem. The so-called thorns on rose stems are prickles.
    Tendrils are modified leaves that grow indefinite ly, unlike normal leaves, and coil around objects they touch. This coiling is a growth response: when the tendril touches an object, the side facing the object stops growing while the other side continues to grow.
    Insect traps have evolved from leaves in several families. Passive traps like the pitcher-leaves of several species secrete a watery digestive fluid. Numerous trichomes (hairs) point downward and lead insects to their doom. The sundew is an active trap: when an insect comes in contact with the sticky digestive fluid secreted by a glandular trichome, adjacent trichomes bend toward it and the entire leaf blade curls around the victim. The Venus flytrap is very active: when an insect trips two hairs in quick succession , or one hair twice, motor cells in the midrib quickly lose water causing the two halves of the modified leaf blade to move together. Glands secrete digestive fluid and the digested material is absorbed. Eventually , the motor cells regain water and the trap opens again, ready for a new victim.

    Stems
    The basic body plan of a plant consists of a root-shoot axis. The shoot consists of the stem and the leaves. Leaves are inserted on the stem at the nodes, and the stem regions between nodes are the internodes. The node is not just a surface feature of the stem: at this point the internal vascular tissues diverge into the leaf and bud. Later or axillary buds are formed during primary growth in the axils of the leaves (the axil is the upper angle between the leaf and the stem). Sometimes buds are too small to be easily seen, since they usually stop growth at a very early stage. If and when the bud grows out it produces a branch, i.e., a lateral shoot. Some plants have a single shoot because the axillary buds are suppressed in their growth by the apical meristem (terminal or apical bud). They can usually be forced to branch by removing the apical bud, a common gardening practice called pinching. Other plants may be normally bushy because this apical dominance is naturally limited.
    Tallness in plants is determined largely by degree of expansion of internodes . For plants growing in a dense population , for example a forest, an obvious strategy is to increase internode length and therefore height so that the leaves will be exposed to the light. Some grasses, on the other hand, have extremely short internodes so that the all-important apical meristem hugs the ground and is not damaged by grazing buffalo (or lawn mowers); if the leaves are clipped off they just produce more.
    Stems are variously and sometimes greatly modified in their structure and function in many plant species. Some stems are aerial; these modified stems can function in asexual (vegetativ e) reproducti on and in food storage. The strawberry begonia and the strawberry itself can reproduce by stolons (runners) that produce new shoots periodical ly. Some stems are undergroun d stems. A rhizome, such as found in the ginger plant, is a more or less horizontal undergroun d stem. Rhizomes are used for storage and vegetative reproducti on. The rings around the ginger rhizome are nodes. Tubers are fleshy undergroun d stems used for storage. Sprouts arise from the 'eyes' (nodes). Bulbs (e.g., onions) are large buds consisting of a small conical stem with attached leaves. Food is stored in the thickened bases of the leaves.
    TYPES OF STEM AND LEAF MODIFICATI ONS
    A & B) stem tendrils; (C, F, and G) thorns; (D & E) leaf-like stems)
    External Features of Woody Stems
    Note the buds on the twigs. Buds occur at the tips-the terminal buds-and in the axils of leaves-the axillary, or lateral, buds of the twigs.
    After the leaves fall, leaf scars, with their bundle scars, can be seen beneath the axillary buds. The bundle scars are the severed ends of vascular bundles that extended into the petiole of the leaf prior to abscission .
    Groups of terminal-bid-scale-scars reveal the location of previous terminal buds, and until they are obscured by secondary growth, these groups of scars may be used to determine the age of portions of the stem. The portion of the stem between two groups of such scars represents one year’s growth.
    The lenticels appear as slightly raised areas on the stem.

    External Features of Woody Stems


    Root Systems
    The first root of a plant originates in the embryo and is called the primary root. New cells are constantly being produced in the apical meristem and the root grows downward through the soil. The apical meristem of the root also replaces cells of the root cap that have been sloughed off. In dicots and conifers, the primary root becomes a taproot; it grows directly downward, giving rise to one large vertical root with smaller branch roots or lateral roots produced along the way. The older lateral roots are found near the neck of the root and the youngest near the root tip. This type of root system, one that develops from a taproot and its branches, is called a taproot system. In addition to anchorage and absorption , taproots store food for the plant and many taproots are used as food (e.g., carrots, turnips, radishes).
    In monocots, the primary root is usually short-lived, and the root system develops from multiple adventitio us roots that arise from the stem. Adventitio us roots are roots that arise from anywhere other than from the bottom of the stem, i.e., from the stem above ground or even from leaves. Note the adventitio us roots on the ivy. In the corn plant, a monocot, special adventitio us (prop) roots grow out of the stem and help stabilize the plant against strong winds. The adventitio us roots of monocots and their lateral roots give rise to an extensive fibrous root system, in which no one root is more prominent than the others. The root system of monocots is a fibrous system
    Examine the roots on demonstrat ion in the Study Center and determine whether they are fibrous or taproot systems.

  4. #4
    عضو
    تاريخ التسجيل
    Sep 2014
    المشاركات
    11

    افتراضي رد: plant anatomy أجمل شرح وبالصور فقط مع ROTATOTA على ثانوية أون لاين

    شكرااااااا ااااا

  5. #5
    عضو
    تاريخ التسجيل
    Jun 2012
    المشاركات
    106

    افتراضي رد: plant anatomy أجمل شرح وبالصور فقط مع ROTATOTA على ثانوية أون لاين

    gooooooooo oooooooooo ooooooood

  6. #6

المواضيع المتشابهه

  1. لكل طلبة سنة اولى صور عينات plant anatomy 2008/2009
    بواسطة ROTATOTA في المنتدى منتدى كلية العلوم
    مشاركات: 15
    آخر مشاركة: 03-24-2023, 08:56 AM
  2. مشاركات: 83
    آخر مشاركة: 08-31-2013, 03:44 PM
  3. مشاركات: 0
    آخر مشاركة: 06-17-2010, 04:52 PM

الكلمات الدلالية لهذا الموضوع

المفضلات

المفضلات

ضوابط المشاركة

  • لا تستطيع إضافة مواضيع جديدة
  • لا تستطيع الرد على المواضيع
  • لا تستطيع إرفاق ملفات
  • لا تستطيع تعديل مشاركاتك
  •