Cultivation, Methods of Propagation, Factors Affecting Cultivation and Plant Hormones

Cultivation, Methods of Propagation, Factors Affecting Cultivation and Plant Hormones

Contents

• Cultivation

• Methods of propagation

• Factors affecting cultivation

• Plant hormones

Objectives

At the end of this lecture, student will be able to

• Explain the various methods of propagation, advantages and disadvantages of cultivation

• Discuss the effect of following parameters on cultivation

- Altitude

- Temperature

- Rainfall

- Day length and radiation characteristics

- Soil and soil fertility

- Fertilizers and manures

• Describe pests and pesticides

• Enumerate various plant hormones

• Discuss the role of plant hormones in growth Cultivation

Cultivation

• Cultivation is a process of preparing and use of land for growing crops

• Preparing and Use of land

• Factors from agricultural to pharmaceutical sphere

Advantages

• Purity and Quality

• Good quality

• Better yield and Therapeutic quality

• Regular supply

• Industrialization (Coffee and cocoa cultivation in Kerala)

• Modern technologies

Disadvantages

• High cost

• Prone to loss

Methods of Propagation

• Sexual method (Seed propagation)

• Asexual method (Vegetative propagation)

Sexual Method (Seed Propagation)

• Should be collected from the perfectly ripe fruits

• Should be stored in a dry and cool place

• Must not be over dried

• Long storage of seeds reduces its germinating power

Examples: Cinnamon, Cocoa, Nutmeg etc

• Sometimes immediate sowing of seeds are advised

Cultivation- Seed propagation method

• Slow germinating seeds - soaked in water or 0.2% solution of gibberelic acid for 48 hours before sowing

• More drastic methods are used such as

– Soaking in sulphuric acid eg. henbane seeds

– Partial removal of testa by grind stone. eg. Henbane seeds

– Scarification of seeds. eg. Ipomea, gave 95% germination in 8 days

• Chemical treatments - gibberelic acid, cytokinins, ethylene, thiourea, potassium nitrate or sodium hypochlorite

• Gibberelic acid - dormant seeds & stimulates the seedling growth

• Thiourea - those do not germinate in dark or high temperatures

Methods of Propagating Seeds / Sowing Seeds

Seed Propagation Method - Advantages

• Bear heavily

• Long lived

• Sturdy

• Easy to raise

• Chance seedlings of superior merits

• Where other methods cannot be utilized, this is only method of choice

Seed Propagation Method – Disadvantages

• Cost of harvesting, spraying of pesticides

• Not uniform in growth, yielding capacity

• More time to bear

• Not possible to avail the modern technologies

Asexual Method (Vegetative Propagation)

Vegetative parts of the

• Bulbs (Squill)

• Corms (Colchicum)

• Tubers (Aconite)

• Rhizomes (ginger)

• Division (Rhubarb, Gentian)

• Runners and offsets (Chamomile & Mint)

• Suckers and Stolons (Liquorice & Valerian)

• Cuttings or Portions (Mint, Vanilla)

• Layering (Cascara)

• Grafting and Budding: STOCK and SCION or GRAFT

• Budding - Piece of bark bearing a bud into a suitable cavity or a T shaped slit made in the bark of the stock

• Fermentation

• Inoculation

• Cell culture

Advantages of asexual method (Vegetative propagation)

• No variation

• Seedless varieties

• Bear earlier

• Disease resistant plants

• Modifying influence of root stocks on scion

• Inferior and unsuitable varieties

Disadvantages of asexual method (Vegetative propagation)

• Not vigorous in growth

• Not long lived

• No new varieties can be evolved by this method

Factors affecting cultivation of crude drugs

• Growth and development

• Nature and quantity of secondary metabolites

- Altitude

- Temperature

- Rainfall

- Day length and radiation characteristics

- Soil and soil fertility

- Manures and fertilizers

- Pests

- Important factor

Altitude

• Some plants grow in higher altitude, some in medium altitude and some in sea level

• Cinchona succirubra - low altitude with NO alkaloids

• Bitter principle of Gentiana lutea increases with increase in altitude

• Alkaloids of Aconitum napellus, Lobelia inflata, oil content of thyme decreases with increase in altitude

• Pyrethrum - lower altitude - increased vegetative growth, High altitude - increased flower heads

Cinhona                     1000 – 2000 M

Tea                              1000 – 1500 M

Camphor                   1500 – 2000 M

Cinnamon                 250 – 1000 M

Temperature

• Controls the development and metabolism in plants

• Exist in variable range of temperatures

• Plants in tropical and subtropical places - withstand heat in summer, lack frost resistance in winter

• Optimum temperature for nicotine in Nicotiana rustica is 20OC, less incase at 11-12OC and at 30OC

• Fixed oil produced at lower temperature - more double bonds

Cinchona   60 – 75oF

Coffee        55 – 70oF

Tea             70 - 90oF

Rainfall

• Effect of rain fall should be considered with relation to

- Annual rainfall

- Distribution throughout the year

- Effect on humidity

- Effect coupled with the water holding capacity of the soil

• Continuous rain - Leaching out of water soluble components

• Senna – Leaf bio mass

• Xerophytic plants

Day Length and Radiation Characteristics

• Vary much in their light and radiation requirements

• Wild condition – Shade requirements are met

• Cultivation - Shade should be provided

• Light an important factor - alkaloids and glycosides

- Belladona, Stramonium, C. ledgeriana, full sun shine ↑ses alkaloids

- D. stramonium var. tatula - intense light for long time ↑ses the hyoscine content at the time of flowering

• Catharanthus roseus - irradiated with near UV light - stimulates the synthesis of dimeric alkaloids

• Day and night changes - Nicotiana sylvestris, benzyl alcohol increases in night, no increase in volatiles like linalool, caryophyllene etc

• Flowering plants – day length pattern

• Peppermint leaves –

- Long day, more of menthone, menthal, traces of menthofuran

- Short day, menthofuran is major

• Types of radiation

- Ocimum basillicum - UV-b radiation increases the phenyl propanoids, terpenoids, falvonoids and anthocyanins

Atmospheric conditions

• Digitalis - exposed to 1000 ppm of CO2, digoxin content increased by 3.5 times

 

Pest and Pest Control

Pest

• Undesired plant or animal or microorganisms

Pesticides

• Synthetic and natural sources effective in small concentration against pests

Examples

Virus, fungi, insects, weeds, non-insect pests etc

Virus

• Mosaic virus- necrosis of leaves, stems etc

• Tobacco mosaic virus - tobacco, digitalis etc

• Cucumber mosaic virus - digitalis and Hyocyamus

• Yellow vein mosaic virus, graft transmissible virus etc

Fungi

Fungus affects the plant and decreases the yield

• Eg. Ascophyta atropae - leaf necrosis

• Cercospora atropae – leaf spot

• Pythium spinosa

• Cercospora dioscorea

• Other diseases are damping off (death of seeds), downy mildew (white and grey patch in leaf), powdery mildew (white powdery patch), rust and smuts (in cereals)

Insects

• Causes drastic damage - Agrotis, caterpillar, grass hopper, spiders, ticks, mites etc

• Either by Biting and Chewing or by Piercing and Sucking

Weeds

• Undesired Plants

• Compete for nutrient, sunlight, space and water

• Enhance the effects of other pests

• Even causes allergies to humans

- Parthenium causes hay fever

- Poison ivy causes dermatitis

Non Insect Pests

• Vertebrates – rats, monkeys, birds, rabbits etc

• Non - Vertebrates- snails, mites, crabs etc

• Contaminate the crops with faecal matter

Pest Control Methods

• Mechanical

• Agricultural

• Biological

• Chemical

Mechanical Method of Pest Control Methods

• Collection - Eggs, larvae, pupae, small insects

• Trapping

- Used to capture rats, mice, flying insects etc

- Flavoured attractants were used

- Rose oil / anise oil mixed with saw dust

• Pruning / Cutting

• Burning

- Helps to eradicate both plant pest & animal pest

- Preferred when pruning or cutting is not possible

• Hand picking, Shaking and Beating

Agricultural method of Pest Control Methods

• Advanced plant breeding techniques - genetically manipulated / pest resistant crops

• Systemic insecticides

• Crop rotation

• Deep ploughing - eradicate the weeds / early stages of insects

• Change in environment

Eg. Checking supply of foods, spreading of oil layer in water with mosquito larvae

Biological method of Pest Control Methods

• Combating the pests, mostly the insects, with other living organisms and the latter will be the parasite form

Examples

• Sex phremones

• 7, 8, epoxy 2 methyloctadecane - gypsy moth

• Rabbit destroys certain types of weeds

• Birds eat insects

• Certain flies and wasps lay their eggs on larger insects, which further hatch into smaller larvae and consume the body of the insect

EFFECTIVE - SAFE – ECONOMIC

Chemical method of Pest Control Methods

• Rodenticides - against rodents like rats, mice etc

• Insecticides - against various insects and arthropods

• Ovicides - against egg stage

• Larvicides - against the larva stage of insects

• Acaricides - against ticks and mites (Chlorbenzolate)

• Herbicides / Weedicides

– Used to kill or inhibit the growth of the undesired plant

– Protective or eradicant activity in the form of spray, aerosol, suspension etc

– Stomach poisons - protective in action, Contact poisons - eradicants

– Fumigants and insect repellent

Examples

• Chlorinated hydro carbons: DDT, DDE, BHC, Gammaxine, Aldrin, Eldrin etc

• Organo phosphorous compounds: Dichlorvos, Malathion, Methyl parathion, Carbophenothion, Trichlorophon, Tetra ethyl pyro phosphate etc

• Carbamates: Carbaryl

• Inorganic compounds: Calcium arsenate, Lead arsenate, Zinc phosphite etc

• Fumigants: Aluminium phosphide, Hydrogen cyanide, Ethylene dichloride, Methyl bromide, Phosphine

• Natural Pesticides: Tobacco, Pyrethrum, Derris, Neem, Sabadilla

Ideal Properties of Pesticides

• Nontoxic, non-injurious to medicinal plant and humans

• Selective in action and effective in small concentration

• Stable under normal storage conditions

• Non inflammable

• Non corrosive

• Free from obnoxious odour

• Non-cumulative in soil

Soil and soil fertility

• Fertilizers and manures

• Most important natural resource

• Provides anchorage, water and essential minerals

• Soil Fertility

• Growth depends on the

- Physical arrangement

- Nature of soil particles

- Organic matter

- Living organisms of soil

• Upper shallow layer - friable, plants find foot hold and nourishment

• Clay - finest particle holds the nutrient

• Depending upon the size of the mineral matter it is classified as,

Less than 0.002 mm                 Fine clay

0.002 – 0.02 mm                       Coarse clay or silt

0.02 – 0.2 mm                           Fine sand

0.2 – 2 mm                                 Coarse sand

• If the soil contains less than

0.5 % organic matter            - Poor soil

1.5 – 5 %                       - Rich soil

0.5 – 1.5 %       - Intermediate soil

• Based on the percentage of clay covered,

More than 50 % clay                Clay

30 – 50 % clay                           Loamy

20 – 30 % clay                           Silt loam

10 – 20 % clay                           Sandy loam

More than 70 % sand              Sandy soil

More than 20 % lime               Calcarious soil

• Good Soil - 50 % pore space, water and rest 50 % pore space air

• PH: 6.5 – 7.5 – Optimum range

• Acidic Soil,  Alkaline Soil

• CO2, Water, Sunlight and Minerals

• C, H, O, N, P, K, Ca, Mg, S, Fe, Mn, Zn, Cu, B, M0, Cl; Na, Co, Va , Si

Chemical Fertilizers

• Basic nutrients - C, H, O 96% in plants – present in atmosphere, no need to apply

• Primary nutrients - Large amounts - N, P, K

• Secondary nutrients - Smaller quantity - Mg, Ca, S

• Micro elements - Trace elements - Cu, Mn, Fe, B, Z

• C, O2, N2, H2, Chlorine - air and water

Based on functions performed in plants:

• Basic structure: C, H, O

• Energy storage, bond transfer: N, S, P

• Charge Balance: K, Ca, Mg

• Enzyme activation & electron transport: Fe, MN, Zn, Cu, B, Mo, Cl

Mobility in soil:

• Mobile: Highly soluble, not adsorbed on clay complex; NO₃^-, SO₄⁼, Cl^-

• Less Mobile: Soluble, adsorbed on clay complex; K⁺, NH₄⁺, Ca⁺, Cu⁺⁺

• Immobile: Highly reactive, gets fixed in soil; H₂PO₄^-, HPO₄⁼, Zn⁺⁺

Mobility in Plants

• Helps in finding the deficient nutrient

• Mobile nutrient moves to the growing point in case of deficiency

• N, P, K – Highly mobile

• Zn – Moderatley mobile

• S, Fe, Mn, Cu, Mo, Cl - less mobile

• Ca, B - Immobile

Nutrients based on chemical nature

• Metals: K, Ca, Mg, FE, Mn, Zn, Cu

• Non-metals: N, P, S, B, Mo, Cl

• Cations: K, Ca, Mg, FE, Mn, Zn, Cu

• Anions: NO3, H2PO4, SO4

Fertilizers

• Materials having definite chemical with high analytical value that supply plant nutrients in available form

• Mostly organic, except CaCN2 - Inorganic

- Complete fertilizer – all three major nutrients: N P K

- Incomplete fertilizers - Lacking any one major nutrients

- Straight fertilizers – only one nutrient; murate of potash

- Complex fertilizer – more than one primary/major nutrient produced by chemical reactions

- Mixed fertilizers – 2/ more mixed as dry powders, granules, pellets, bulk blends or liquids

Methods of applications of Fertilizers

Broadcast

• Broadcasting at planting

• Topdressing

Placement

• Plough sole placement

• Deep placement

• Subsoil placement

Localised placement

• Drill placement

• Hill placement

• Pellet placement

In liquid form

• Starter solutions

• Sprays - foliar

• Direct application to soil

• Through irrigation water

Nitrogen fertilizers

Ammonium / nitrate ion

• Ammonical fertilizers – Ammonium sulphate, chloride, phosphate

• Nitrate fertilizers – Sodium nitrate, calcium nitrate, Nitro phosphate

• Ammonium/nitrate ions – Ammonium nitrate, Calcium ammonium nitrate

• Amides – Urea, Urea phosphate, Urea sulphate

• Nitrogen solutions – Aqueous ammonia, anhydrous ammonia, Solution of urea, ammonium nitrate, ammonia

• Slowly available N fertilizers – Urea- formaldehyde compounds, Oxamide

Phosphatic fertilizers

• Phosphorus when burnt gives P2O5; with water its gives meta phosphoric acid, HPO4

• Meta phosphoric acid with water gives ortho phsphoric acid – H3PO4

• H atoms are replaced, 3 salts are formed

- Ca(H₂PO₄)₂ - water soluble – superphospahte, enriched superphosphate, triple superphosphate, ammonium phosphate

- Ca₂(HPO₄)₂  dicalcium phosphate – citric acid soluble – raw and steamed bone meal

- Ca₃(PO₄)₂ (tricalcium phosphate) – mineral acid soluble – rock phosphate, raw bone meal, steamed bone meal

• Plants take P2O5 in the form of H2PO4 – supplies available P2O5 – Superphsphates

Potassic fertilizers

Raw materials for manufacturing K nutrient,

• Carnallite (KCl, MgCl2, 6H2O)

• Kainite (KCl MgSO4, 3H20)

• Langbeinite (K2SO4, 2MgSO4)

• Sylvite (KCl)

Sources of potassium

• Potassium chloride or murate of potash (60-62 % K2O)

• Potassium sulphate or sulphate of potash (48-52 % K2O)

• Potassium magnesium sulphate (20-30 % K2O)

• Potassium nitrate (44 % K2O)

• Bittern potash (7 % K2O)

Manures

• Farm yard manure, compost castor seed cake, poultry waste, neem seed cake, Blood meal, fish meal, bone meal

• 3-6 % nitrogen, 2 % phosphates, and 1-1.5% potash

Biofertilizers

• Micro-organisms or lower organisms

• Examples: Rhizobium, Azotobacter, Azosperillum, Blue green algae Etc

Plant Hormones

• Naturally occurring growth regulators - low concentration controls the physiological processes

• Plant growth regulators - Endogenous & Exogenous (synthetic)

• Growth and development

• Five groups of plant hormones

- Auxins,

- Gibberelins,

- Cytokinins,

- Abscisic acid,

- Ethylene

Use of Plant Hormones

• Regulating cell enlargement

• Cell division & differentiation

• Organogenesis

• Senescence

• Dormancy

Auxins

• In 1931, Dutch workers

– Auxin-a (human urine) and auxin-b (cereals)

• General term - Promote the elongation of coleoptile tissues

• Involved in

- Internode elongation

- Leaf growth

- Initiation of vascular tissues

- Cambial activity

- Fruit setting in the absence of pollination

- Fruit growth

- Apical dominance

- Inhibition of root growth

- Influencing physical, chemical properties in leaf abscission

- Inhibition of lateral buds

• Major auxin - Indole Acetic acid (IAA)

• Other natural auxins

- Indole 3 Acetonitrile,

- 4 chloroindole 3 AA

- Phenyl acetic acid

Synthetic auxins

• Indole 3 butyric acid

• 2 Naphtyloxy acetic acid

• α naphthyl acetic acid

• 1 naphthyl acetamide

• 2, 4 dichloro phenoxy acetic acid

• 2, 4, 5 tri chloro phenoxy acetic acid

• 5 carboxy methyl NN dimethyl carbamate

Practical uses of auxins

• Low concentration - rooting of woody, herbaceous cuttings

• Higher concentration - selective herbicides or weed killers

– 1:500 000 solution of NAA for 24 hrs subsequently develop roots

– 2, 4 Dichloro phenoxy acetic acid - toxic to dicots, little effect against monocots

– Carbamates and urea derivatives - toxic to grass but no effect on dicots

Gibberelins

• In Japan, rice plants affected by a disease - plant grow taller and not support themselves - Gibberella fugikuroi

• Crystalline active material – Gibberelin

• GA1, GA2, GA3

• GA1 is isolated from Phaseolus multiflorus

• GA3 - Gibberelic acid

• By 1980, 58 gibberelins were known; 50% from fungus, 50% from higher plants

• Gibberelins - leaves, accumulate in relatively large quantities in the immature seeds and fruits of some plants

• Cell elongation - sub-apical meristem region where young internodes are developing

Important Actions of Gibberelins

• Initiation of synthesis of various hydrolytic and proteolytic enzymes upon which seed germination and seedling establishment depends

• Used to treat secondary metabolites like volatile oils, terpenoids, alkaloids, glycosides etc

Cytokinins

• Specific effect on cell division (cytokinesis)

• Not confined only to cell division; also regulate the pattern and frequency of organ production; position and shape

• Inhibitory effect on senescence

• Kinetin - autoclaved DNA of herring sperm

• Zeatin - liquid endosperm of coconut and in extracts of maize embryos

• Complex - Cambial region of various woody tissues

• Tissue culture work - promote the formation of adventitious buds and shoots from undifferentiated cells

Growth Inhibitors

• Natural growth inhibitors - affect bud opening, seed germination and development of dormancy

• Abscisic acid (ABA), natural, fungus Cenospoara rosicola

• Carotenoids - Similar to abscisic acid

• Xanthophylls - Violaxanthin produce a germination inhibitor on exposure to light

• Related substances - Vomifoliol (have same activity as abscisic acid in stomatal closure tests)

• Synthetic growth inhibitors - maleic hydrazide, N dimethyl amino succinamic acid

Ethlyene

• Evolved by stored apples; inhibited the growth of potato shoots enclosed with them

• Role in fruit ripening

• Synthesized from S adenosyl methionine

• Stimulation of de novo synthesis

• Secretion of cell wall dissolving enzymes like cellulase during leaf abscission and ripening of fruit

• Ethephon (2 chloroethyl) phosphonic acid is a compound which gives similar response to that of ethylene

Other Growth Regulators

• Aliphatic and aromatic carboxylic acids

• Phenolic and neutral compounds

• Salicylates

• Polyamines

• S and N heterocyclic compounds, including alkaloids and terpenes

• Brassinosteroids - seeds, pollens, galls, leaves, flower buds and shoots

• Other substances stimulate cell enlargement and cell division and influence gene expression and nucleic acid metabolism at the molecular level

Summary

• Cultivation is a process of preparing and use of land for growing crops

• Methods of propagation includes both sexual and asexual method

• Sexual method is by using seeds and the germinating capacity is improved by using physical or chemical treatments

• Asexual method is by using any vegetative part of the plants

• Both sexual and asexual methods has its own advantages and disadvantages

• The factors that affects cultivation includes altitude, temperature, rainfall, day length and radiation characters, atmospheric conditions, fertilizers and manures, pest and pest control etc

• The growth, development and the production of active constituents varies according to the above said factors

• Active constituents varies according to the altitude where the plant grows

• Temperature controls the development and metabolism in plants

• Except xerophytic plants, all other plants require water either in the form of irrigation or rainfall

• Day length and radiation characteristics affects the composition of the constituents

• Pests are undesired plants or animals or microorganisms which causes damage to crops & includes virus, fungi, insects, weeds and non-insect pests

• Pests can be controlled by mechanical method, agricultural method, biological method and chemical method

• Soil fertility is the ability of the soil to provide the nutrients in correct proportion and quantity to the plants

• Soil can be classified based on particle size, % composition of clay, mineral content etc

• Chemical fertilizers includes primary nutrients, secondary nutrients and micro elements

• Manures and bio fertilizers are also used for the proper growth of plants

• Plant hormones are naturally occurring growth regulators and in low concentration controls the physiological processes

• Plant hormones includes auxins, gibberelins, cytokinins, abscisic acid and ethylene

• Generally auxins, gibberelins and cytokinins promotes growth, whereas abscisic acid and ethylene are growth inhibitors