Medicinal Plants Lecture 2 2023/2024 PDF

Medicinal plants 2023/2024 Lecture 2 Dr. Amal F. Soliman Associate Professors of Pharmacognosy Try to remember the pervious lecture Study the opposite figure and complete the following table: Layer name Chemical...

Medicinal plants 2023/2024 Lecture 2 Dr. Amal F. Soliman Associate Professors of Pharmacognosy Try to remember the pervious lecture Study the opposite figure and complete the following table: Layer name Chemical composition Black layer ……………………… ……………………… Red layer ………………………. ………………………… Grey layer ………………………… …………………………. Complete the following: 1-The opposite figure represent …………………. Which composed of …………………………….. 2- The cytoplasm like fluid inside the opposite structure called ……………. 3- The function of the opposite organelle is ………………………………….  Ergastic substances (Cell inclusions) ❑ The materials present in the vacuoles are known as ergastic. ❑ They are either reserve substances that may be utilized by the protoplast, for vital activities or they are by-products of metabolism. ❑ Ergastic substances occur in the vacuoles and in the cell wall. 1- Starch cleft pointed 2- Protein ▪ Proteins are stored as aleurone grains. ▪ Proteins are polypeptide of amino acids. ▪ Aleurone grains are stained red with Millon reagent, yellowish brown with iodine solution and yellow with picric acid, leaving the globoids unstained. 3- Crystals ‫البلورات‬ 4- Fats o Esters of fatty acids with glycerol. o They widely in the plant body. Present at high precent in seeds. o Wax, suberin and cutin are fatty in nature. They act as a protective substance in and on the cell wall.  The cell theory ❑ In plants with well defined tissues, the production of new cells is performed by certain growing regions called meristems. ❑ Tissues are generally divided into: ✓ Meristematic (have the ability to divide). ‫ا ألنسجة الانشائية‬ ✓ Permanent types. ‫ا ألنسجة ادلامئة‬ Classification of meristems They are classified, as regards their position in the plant body, into : Apical: located at the apices of main and lateral shoots and roots. Intercalary: lie at the internodes of monocot plants.. Lateral: arranged parallel with the sides of the organ such as the vascular cambium, cork cambium and interfascicular cambium.  The primary permanent structure of the plant ▪ Those which lost their power of division. ▪ They may be classified according to their function, structure and position in the plant body. ▪ They may be pictured as composed of four systems of tissues: A- The dermal B- The ground C- The vascular D- The secretory tissues A) The dermal or protective tissue ❑ This is the system forming and the outer protective covering the plant (the epidermis). ❑ The epidermal cells are living. ❑ There are no intercellular spaces between the epidermal cells forming a continuous layer except in certain regions, especially on leaves and green stems, there stomal pores are found. Isodiametric cells in Elongated in dicot leaves monocot leaves Stomata ‫الثغور‬ ❑ Openings in the epidermis mainly on the lower surface of the leaf that regulate gas exchange in the plants. ❑ Stomata consists of: 1- Guard cells ✓ Kidney-shaped in dicots ✓ Dumbbell-shaped in monocots 2- Subsidiary cells (2 or more cells) Dicot stomata Monocot stomata Epidermal modification and appendages ❑ The are commonly known as hairs or trichomes. ❑ According to their function, they may be classified into glandular and non-glandular epidermal appendages.  Trichomes Non- Glandular glandular Unicellular Multicellular Unbranched Branched Uniserriate simple Biserriate Stellate Multiserriate Candelabra  Cannabis trichome Solanaceous leaves What is the type of stomata ? A B C D ‫‪B) The ground or fundamental tissue‬‬ ‫اخلالاي الكولنش ميية‬ ‫اخلالاي الربنش ميية‬ ‫اخلالاي الاسلكرنش ميية‬ ▪ They are living cells, having large ▪ They are living cells, more elongated vacuoles and thin wall consists of and narrower than parenchyma cells cellulose. with non-lignified walls. ▪ Parenchyma cells perform ▪ They act as a supporting tissue in several functions as storage of young growing organs as stems and water and food such as starch, fat leaves. and protein.  Parenchyma Chlorenchyma ▪ If chloroplasts are present, these cells can carry photosynthesis and usually known as chlorenchyma. Aerenchyma cells ▪ Modified parenchyma consisting of chains of small cells enclosing very wide intercellular spaces. ▪ Parenchyma tissue with extensive connected air spaces. ▪ Aerenchyma is widespread in aquatic plants. Sclerenchyma ▪ They are non-living cells with thick often lignified secondary wall. ▪ Made up of a primary wall (cellulose) and a secondary wall (lignin). ▪ They are classified into a) Fibers b) Sclereids ▪ Function of Sclerenchyma: support Sclerides are usually isodiametric to rectangular or elongated cells, but not much longer than they are broad. Fibers are elongate sclerenchyma cells with usually pointed ends. * Match the following statements (write only the numbers next to the matched sentence). Item Sentence 1 Rough Endoplasmic Outgrowth of the cell arises and becomes Reticulum impregnated with calcium carbonate 2 Plasmodesmata Powerhouse of cell 3 Cystolith Small strands of cytoplasm connecting to adjacent cells. 4 Mitochondria Attached by ribosomes * Mention the name, tissue and the function. A B * Mention the name, tissue and the function. A B Give only the term corresponding to the following sentences: - A type of modified parenchyma tissue with large air lacunae (spaces). Outermost structure of plant cells surrounding the protoplast. A modified type of parenchyma cells with an abundance of chloroplasts. Needle-like crystals of calcium oxalate; often occur in groups.