Cell inclusions / Ergastic substances
• Non-protoplasmic, non-living, metabolically inactive substance formed due to activity of protoplasm.
3 types
1. Reserve/storage food material:
• Carbohydrate, protein and lipid are reserve material.
Carbohydrate:
• Most abundant monosaccharide is glucose.
• Most sweetest carbohydrate is fructose, also present in honey, semen.
• Sugar present in fruits, honey and nectar is fructose
• Galactose is called nerve sugar.
• Inulin is the fructose units, present in Dahlia. Also, called Dahlia starch.
• Starch = Amylose + Amylopectin
• Aleurone grains are found in the endosoperm of cereals.
• Glycogen: in animal cells and fungi.
Note: Largest starch grain is found in Canna and smallest in rice.
Lipid:
• Cells contain unsaturated fattyacids like oleic acid (C17H33COOH), linoleic acid (C17H31COOH) and linolenic acid (C17H29COOH)
• Phospholipids are amphipathic in nature
• Waxes are esters of monohydric alcohol and fatty acids.
Protein:
• The building block of protein is amino acid.
• Simplest amino acid is Glycine, most complex Tryptophan, first amino acid to be discovered is Asparagine.
• Sulphur contaning amino acids are cystein, cystine and methionine.
• Proteins are amphoteric in nature oxidized by putrefaction process.
• Most abundant protein is RUBISCO (RUBP-Carboxylase)
• Smallest protein is Adrenocorticotropic hormone (ACTH)
• Zeatin of Maize, Oryzenin of rice, Glutelin and Gliadin of wheat are protein.
2. Secretary products: enzyme, pigment and nectar are the secretary products.
Enzymes
• Term enzymes was coined by 'Kuhne'.
• Buchner reported zymase in yeast.
• Apoenzyme + cofactor = Holoenzyme (Conjugated enzyme)
• Enzymes have cavity known as active site, where specific substrate is attached during reaction.
Nectar
• Mixture of sucrose, glucose and fructose.
• Attracts insects for pollination.
Pigments
• Yellow colour-xanthophyll, orange colour carotene
• Anthocyanin for purple and pink colours of flower, fruits etc.
3. Excretory products: These are waste of different metabolism and accumulated in
old leaves, bark, etc. These includes.
A. Alkaloids:
• Nitrogen containing substances, found in storage organ in combination with organic acids.
• Waste of protein metabolism
• Insoluble in water, sour in taste and poisonous.
• Sometimes, used in medicine as well.
Examples:
Name of Alkaloid | Obtained From |
Atropine | From roots of Atropa belladona |
Quinine | From bark of Cinchona |
Morphine | From latex of Papaver somniferum (opium or poppy) |
Nicotine
| From leaves of Nicotiana tabaccum (tobacco leaves) |
Reserpine | From Roots of Rauwolfia serpentina [@ R = R] Useful in cure of snakebite |
Ephedrine | From shoots of Ephedra (gymnosperm)
→ Found in sub–alpine climate.
→ Yaks take it as food |
Ergotine | From fungi Claviceps purpurea (Ergot fungi): source of LSD. |
Thein | From leaves of Tea (Thea sinensis) |
Caffeine | From seeds of coffee (Coffia arabica). |
Vasine | From leaves of Adhatoda vasica |
Colchicine (is a mutagen) | From corm of Colchicum autumnale (Family- Liliaceae) |
Note:
• Colchicine is also called as mitotic poison.
• Inhibits formation of spindle fibres.
• Disturb metaphase stage of cell division.
• Quinine, reserpine and atropine are used for treatment of malaria, high blood pressure and heart disease respectively.
B. Tannins:
• Degradation product of carbohydrates.
• Bitter in taste.
• Found in cell sap.
• Its percentage is high in young fruits.
• Obtained from heartwood of Acacia catechu, leaves of tea, fruits of Emblica officinalis (amla).
• At maturity, tannin changes to sugar.
C. Latex:
• Yellow/white viscous fluid made of suspensions of main source of proteins, gums, etc.
• Main source of commercial rubber production
• Latex of papaya contains enzyme papain.
• Papain helps in protein digestion.
• Latex of banana contains Tannins.
D. Glucosides:
• Degradation products of carbohydrates.
• Control acidity and alkalinity of cell.
Eg: Digitoxin (useful in cure of heart diseases) → source plant → Digitalis purpurea, Saponin (from fruits of Sapindus)
E. Gums: Degradation products of cell wall or cellulose.
• Source of gum Acacia Senegal (Gum tree).
• Process of gum formation is called gumosis.
F. Essential oils:
• These oils evaporate in contact with air. Eg: Leaves of Ocimum, citrus.
G. Resin: Oxidation product of essential oils.
Types:
(i) Oleoresin: eg. Canada balsam → used as a mounting medium for preparation of permanent slide.
• Source plant of Canada balsam → Abies balsamea.
(ii) Gum Resin: Eg: Assafoetida (Hing)
• From roots of Ferula assafoetida.
H. Organic acids:
• Citric acid (in fruits of citrus)
• Malic acid (from apples)
• Oxalic acid (oxalis)
• Tartaric acid (fruit of Tamarindus).
I. Mineral crystals:
• Aggregate crystals of calcium oxalate
(i) Raphids: are needle shaped.
eg. Pistia, Eicchornia.
(ii) Sphaeroraphides/Druses: are star shaped.
eg. Colocasia, Dioscorea.
• Aggregate crystals of calcium carbonate (CaCO3) are called cystoliths → found in leaf cells of Ficus (Banyan tree).
• Crystals of silica → in leaf cells of grasses.
→ Petiole of Atropa belladona (Solanaceae)
→ Equisetum (Horse tail plant) is a pteridophyte.
Note:
• Chloroplast containing spores are found in Funaria, Equisetum.
• Cell walls of grasses and Equisetum are impregnated with silicon.