Draw the diagram of an open stomatal pore of a leaf and label on it chloroplast and guard cells. Monocot Stem . Stomata occur on both the epidermal layers. Stiff sharply pointed hairs are also present. The leaf of oleander (Nerium oleander of family Apocynaceae) shows some distinct departures so far as the arrangement of tissues is concerned, from the ones described previously, exhibiting clear xerophytic adaptations. Dicot Root . These are composed of files of initials known as marginal initials. A section through a leaf of maize (Zea mays of family Graminaceae) shows the follow­ing structure (Fig. Gravity. In very hot conditions water inside the It as usual forms the main bulk of the leaf, and is composed of iso­diametric cells with intercellular spaces. Chloroplasts are abundantly present, which particularly occur along the radial walls of the cells. The bundles are collateral and closed ones. Chloroplasts are present in the epidermal cells. Syringa (lilac, a dicot) leaf cross section, 100X. Chloroplasts are abundantly present. They are often differentiated into three layers—adaxial, abaxial and middle layers. Collenchyma cells occur next forming hypodermis. how to draw the diagram of cross section of a leaf class x. how to draw the diagram of cross section of a leaf class x. Leaves originate from the promeristem of the shoot apex. 617): Both the adaxial and abaxial epidermal layers are multiseriate. The number of chloroplasts is naturally much smaller here, which explains the pale green colour of the lower surface of the leaf. These are long columnar cells rather tightly arranged with scanty intercellular spaces. They are composed of closely-set cells. They may, however, be regarded as water-storage tissues which do not possess chlorophyll. It is differentiated into palisade and spongy cells. ii) They take up CO2 at night and prepare an intermediate which is acted upon by the energy absorbed by chlorophyll during the day. As already stated, it is formed from an intercalary meristem located at the base of the finger-like protrusion of the shoot apex. Though a monocotyledon, the leaf of banana (Musa sapientum of family Musaceae) is dorsiventral. (c) In certain group of plants, stomata remains closed during day. Xylem occurs on the adaxial and phloem on the abaxial sides. The rest of the ground tissue is made of thin-walled parenchyma with pretty large number of air chambers. Unlike those in the lilac leaf, however, both the upper and lower epidermal layers in the oleander leaf are several cell layers thick. The ground tissue system, as already reported in a preceding chapter, is known as mesophyll tissue. Upper epidermis may be easily identified due to presence of large and empty bulliform cells. There are two clusters of enlarged cells within the upper epidermis. Write. The differentiation of tissues into epider­mal, ground and vascular is clear. Pine Needle. They remain surrounded by parenchymatous bundle sheath. Occurrence of a large mucilage canal at the centre and a few smaller ones here and there is a dis­tinctive character. In extreme cases the phloem may be absent and the veinlet may be made of a single spiral tracheid. It is as usual uniseriate, made of a row of tabular cells with cuticularised outer walls. Which part of the male reproductive system store the sperm? Bundle-ends vary considerably in the leaves, but com­monly it consists of a single tracheid with a single sieve element or specialised paren­chyma representing xylem and phloem respectively, surrounded by a parenchymatous bundle sheath (Fig. It consists of palisade and spongy cells. Tags: Question 10 . Cross Section Of a leaf, functions. It is differentiated into palisade and spongy cells. The xylem vessels usually break down and form lacunae which resemble the air chambers. Learn. Epidermis, stoma, guard cells, palisade & spongy mesophyll. Monocot Root Cross Section . Epidermal layers are uniseriate both on the adaxial and abaxial sides. A good number of trichomes develop from the cells bordering the depression. A section through a succulent leaf with halophytic adaptations reveals the following structure (Fig. control transpiration. Professional leaf cross-section slides. The bundles remain scattered in the lower part of the mesophyll. Anatomy of Dicot Leaf: Mangifera indica-Leaf: Following tissues are visible in the transverse section of the material: Epidermis: 1. A cross section of a leaf shows that it is a complex organ built of several different kinds of specialized tissues. A large vascular bundle practically resembles that of a stem. vein. Vascular bundles are very much reduced with very scanty mechanical elements and occur next to the palisade layer. The leaves of mesophytes possess highly- thickened epidermis and patches of mechanical tissues, either as isolated patches or in association with vascular tissues, as they have to withstand shearing stresses in particular. At the early stage of the development of the blade two strips of meristems, referred to as marginal meristem, occur along the two surfaces of the leaf axis. Lithocysts are frequently present and well-developed calcium carbonate crystals, the cystoliths, occur here and there. Smaller surface area, contain a hypodermis, and have a thick cuticle. 623): It is uniseriate and continuous one, made of small round cells with strongly cuticularised outer walls. of family Graminaceae) would reveal the following internal structure (Fig. Link to detail of vascular tissue . As an aquatic plant it has extremely reduced vascular and supporting tissues and well-formed air chambers. What is the significance of transpiration? 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