Lecture Number 4 - Plant Structure, Growth, and Differentiation - BADR UNIVERSITY IN CAIRO

Lecture number 4 Week number 4 19 – 24 / 10 / 2024 ‫ صفاء احمد محمد المغازى‬.‫د‬.‫أ‬  Plant Structure, Growth and Differentiation the plant body consists of: A- Root system Its function is to support the plant and absorb water and minerals. B- Shoot system{aerial part} Stem...

Lecture number 4 Week number 4 19 – 24 / 10 / 2024 ‫ صفاء احمد محمد المغازى‬.‫د‬.‫أ‬  Plant Structure, Growth and Differentiation the plant body consists of: A- Root system Its function is to support the plant and absorb water and minerals. B- Shoot system{aerial part} Stem Leaves its function is photosynthesis flowers Fruits It occurs in 2 steps: Light reactions Dark reactions  What are Ergastic Cell Contents? These contents represents either: a)Reserve food material {Primary Metabolites} {carbohydrates, proteins, gums, pectin, lipids, fats and fixed oil} End products {Calcium Oxalates} or b) By-products of metabolism Active constituents {possess medicinal value} Secondary Metabolites  What are metabolites? Metabolites are the products of metabolism, and this term usually restricted to small molecules There are 2 types of metabolites: Primary metabolites Secondary metabolites Directly involved in : Not involved in growth - Normal growth or reproduction - development - reproduction  Process of Metabolism Includes: Anabolism ‫البناء‬ Catabolism ‫الهدم‬  Process of Metabolism Anabolism catabolism It is a set of metabolic A set of metabolic pathways that pathways that construct break down molecules into molecules from smaller units These reactions need energy smaller unites + energy Anabolism is powered by Polysaccharides energy catabolism + monosaccharide Anabolic process tends toward building up organs, Lipid, nucleic acid and proteins tissues and differentiation of nucleotides + energy cells and increase  1- Starches {Amylum} ▪ Starch is a polysaccharide of high molecular weight with the general formula {C6H10O5}n ▪ Starch present in granules vary in size and shape. ▪ Starch granules constitutes the principal form of carbohydrate reserved in the plant. ▪ Algae and fungi do not contain starch granules. N.B:{Green algae only may contain starch}  Chemical composition of starch: It contains 2 carbohydrates amylopectin {α- amylose}, it forms the outer layer of starch molecule, branched, water insoluble, constitutes 80% of most starches, swells giving gelatinized mass. amylose {β- amylose}, it is linear compound and water soluble. It is responsible for the deep blue coloration with dilute Iodine solution  Starch is formed in a special cell called chloroplast It is found more abundantly in roots and rhizomes  Structure of the starch : The hilum: It appears as darker or lighter point according. It is the first part formed in the plastid. The hilum is not always distinguished. The striations: It is concentric ring are fine lines surrounding the hilum. It is successive layers of starch substances deposited as shell- like envelopes about the first formed hilum of the granule General uses of the starch: 1. Nutritive 2. Demulcent 3. Pharmaceutical uses as tablet filler and binder. 4. Antidote in case of poisoning from iodine. 5. Used in case of baby skin irritation due to dipper rash{Zinc Oxide / Starch} 6. Industrial uses in papers and clothes.  Chemical identification of starch: 1- Test with dilute Iodine solution 3- Reduces Fehling's 2- Molisch's tests  Commercial Sources of Starch: ❑ Rice starch: isolated from caryopses of Oryza sativa L. {Family: Graminae}. ❑ Wheat starch: isolated from caryopses of Triticum sativum vulgare {Family: Graminae} ❑ Corn starch {maize starch}: isolated from caryopses of Zea mays L {Family: Graminae}. ❑ Potato starch: isolated from the tubers of Solanum tuberosum L {Family: Solanaceae} Rice starch Maize starch Potato starch  Modified starch Starches are not suitable for most applications, therefore must be modified Modification done chemically or physically to overcome their defects like stability, solubility, to enhance their positive attributes as texture, viscosity and /or minimize their defects Starch modified starch  A- Soluble Starch 1- It is prepared by treating potato starch + 7½% HCL, at room temperature for 7 days, then wash, after washing it forms clear solution {HCL breaks down the amylopectin and gelatinizing property disappears}. 2- Chemical Characters: Little reduction to Fehling’s solution Deep blue colour with dilute I2 solution Gives canary yellow with 5 % KOH. {c.f. from ordinary starch}  B- Pre-gelatinized ▪ By doing mechanical rupture of the grains in the presence of water with or without heat, followed by drying ▪ The product is manipulated to: Improve flow rate and compressibility properties ▪ It is used in tablet and excipient ▪ This is prepared from maize, rice or potato.  C- Dextrin's ▪ It is made from potato starch by simple roasting at 150 - 250 ºC or add small proportions of acid. ▪ Grade is determined according to rate of heat. White dextrin Yellow dextrin Partially soluble in cold water completely soluble in cold {High Grade}, 15% of starch water hydrolyzed completely is soluble + erythrodextrin and form Maltose, reduce Fehling's Give red colour with dilute iodine solution Doesn't reduce Fehling’s solution N.B.: ▪ Commercial white dextrin's prepared by heating starch, moistened with small quantity of HNO3, dried at 110 - 115ºC. ▪ About 15 % is soluble starch and the remainder is erythro-dextrin. Reference page 207 2- Proteins ▪ They are organic nitrogenous compounds, reserve food material of essential nutritive value. ▪ Proteins are large biomolecules, or macromolecules consisting of one or more long chains of amino acid residues Proteins differ from one another primarily in their sequence of amino acids ▪ Present in all living cells ▪ Stored in the plant in the form of aleurone grains {globoids & crystalloids}which seen in oily seeds  Coagulate by heating ▪ Gives red colour with Mellon's reagent. ▪ Gives yellow with picric acid ▪ Gives violet colour with 20 % NaOH + CuSO4 Types of plant protein Structure of aleurone grains  With picric acid with Mellon's reagent  Lipids Simple Complex Fixed oils Lecithin Fats Phosphatides waxes They are widely distributed in plants & animals They are esters of long chain fatty acids + glycerol  Chemical tests Leave permanent stain on filter paper. They + 1% Osmic acid brown or black colour Oils + Sudan III red colour. Oils + alkali saponification Green colour with chlorophyll Differences between Oils and Fats  Methods of Preparation of Fixed Oil Extraction by Pressing Extraction by Solvent using Hydraulic Press Virgin Oil Hot Pressed Oil Pressing is Pressing is carried out carried out using on cold heat