Cultivation, Collection, Processing and Storage of Crude Drugs CULTIVATION OF CRUDE DRUGS Cultivation of medicinal plants requires intensive care and management. The conditions and duration of cultivation required vary depending on the quality of medicinal plant materials required. METHODS OF PROPAGATION: A. Vegetative propagation (Asexual propagation): Vegetative propagation can be defined as regeneration or formation of a new individual from any vegetative part of the plant body. The method of vegetative propagation involves separation of a part of plant body which develops into a new plant. Methods of vegetative propagation: They are two types: 1, Methods of natural vegetative propagation: 2. Methods of artificial vegetative propagation. 1, Methods of natural vegetative propagation: . (a) Vegetative propagation by stem : Following examples: Runner: peppermint. Bulb: Allium, Squill. Corms: Colchicum. Tuber: Potato, aconite. Offset: valerian. Rhizome: Ginger and haldi. (b) Vegetative propagation by root : Examples: asparagus. 2. Methods of artificial vegetative propagation: various parts developed for natural vegetative propagation have also been used for artificial vegetative propagation. Following methods are used: * Cutting: These are the parts of the plant (stem, root or leaf) which, if grown under suitable conditions, develop new plants. Stem cutting are generally used to obtained new plants. Examples: Sugarcane and rose, ete.56 Textbook of Pharmacognosy and Phytochemistry1 « Layering: Roots are induced on the stem while it is still attached to the parent plant. This part of stem is later detached from the parent plant and grown into a new plant. * Grafting: New variety is produced by joining parts of two different plants. The rooted shoot of one plant, called stock, is joined with a piece of shoot of another plant known as scion. Examples: Rose, citrus and rubber, etc. * Micro propagation: This method consists of growing cell, tissue and organ in culture. Small pieces of plant organs or tissues are grown in a container with suitable nutrient medium, under sterilized conditions. The tissue grows into a mass of undifferentiated cells called callus which later differentiates into plantlets. These are then transferred into pots or nursery beds and allowed to grow into full plants. Importance of asexual propagation: 1. It is a cheaper, easier and rapid method of multiplication. Many fruit trees usually require 4-5 years to bear the fruits when developed from seeds. The plants developed by vegetative methods, take only a year to bear fruits. 2. Plants like roses and chrysanthemum, etc do not form viable seeds. Thus, vegetative propagation is the only method of propagation is the only method of reproduction and continuation of species in such plants. 3. All the plants developed by these methods will be generally similar to the parent plant. 4. Micropropagation is useful in raising disease free plants, homozygous diploids, and those without viable seeds. B. SEED PROPAGATION (SEXUAL PROPAGATION): ‘The process of sexual propagation: () Microsporogenesis : Microspores are formed from microspore mother cells inside the anther. (ii) Pollination : This is the tranefer of pollen grains from the anther to the stigma. (iii) Microgametogenesis : This involves the formation of male gametes from microspore. (iv) Megasporogenesis : This process leads to the formation of megaspores from megaspore mother cell, inside the ovule. (v) Megagametogenesis : The events involving the formation of embryo sac from megaspore are included in this process. (vi) Fertilization : Fusion of male and female gametes takes place, resulting in the formation of zygote.1 (vii) Embryogeny : The process involves development of embryo from zygote.Cutivation, Collection, Processing and Storage of Crude Drugs 87 COLLECTION OF DRUGS Medicinal plant materials should be collected during the appropriate season or time period to ensure the best possible quality of both source materials and finished products. It is well known that the quantitative concentration of biologically active constituents varies with the stage of plant growth and development. This also applies to non-targeted toxic or poisonous indigenous plant ingredients. The best time for collection (quality peak season or time of day) should be determined according to the quality and quantity of biologically active constituents rather than the total vegetative yield of the targeted medicinal plant parts. In general, the collected raw medicinal plant materials should not come into direct contact with the soil. If underground parts (such as the roots) are used, any adhering soil should be removed from the plants as soon as they are collected. Collected material should be placed in clean baskets, mesh bags, other well aerated containers or drop cloths that are free from foreign matter, including plant remnants from previous collecting activities. After collection, the raw medicinal plant materials may be subjected to appropriate preliminary processing, including elimination of undesirable materials and contaminants, washing (to remove excess soil), sorting and cutting. The collected medicinal plant materials should be protected from insects, rodents, birds and other pests, and from livestock and domestic animals. If the collection site is located some distance from processing facilities, it may be necessary to air or sun-dry the raw medicinal plant materials prior to transport. If more than one medicinal plant part is to be collected, the different plant species orplant materials should be gathered separately and transported in separate containers. Cross- contamination should be avoided at all times. Collecting implements, such as machetes, shears, saws and mechanical tools, should be kept clean and maintained in proper condition. Those parts that come into direct contact with the collected medicinal plant. materials should be free from excess oil and other contamination. Time of collection: The period of growth or development at which medicinal activity is highest has been carefully determined for many plants. The proportion of alkaloid in the leaves of Hyocyamusniger and of belladonna is largest at the beginning of flowering, whilst with Stromonium the peak coincides with full bloom. Example: Stromonium leaves, gathered in the morning, contain a higher proportion of alkaloids than those collected in the evening.58 Textbook of Pharmacognosy and Phytochemistry S.] Plant parts Time of collection No. 1 Bulbs Late autumn, long after the plant has flowered and fruited is usually best. 2 Barks Autumn (after leaf fall) or spring (before development of the leaves) is generally selected. 3 Root and From annuals: Shortly before flowering. rhizomes | From Biennials: during “the autumn or winter following the first year growth. From. perennials: During the autumn or winter following the second or third year’s growth. 4 Leaves Collection should be affected in dry weather whilst the plant is flowering. It is often preferable to collect the stems bearing the leaves, and then separate them; collection in the morning is important in some cases, eg.-Solanaceous leaves, 5 Flowers Collection should be affected in dry weather and towards the middle of the day, after dew has dissipated. 6 Seeds and | Collection should be affected when fully grown and fruits ripe, or nearly ripe. Weather active dispersal of the seeds occurs on the completion of ripping; it is advantageous to collect slightly earlier, eg. Cardamom and Strophanthus. HARVESTING Medicinal plants should be harvested during the optimal season or time period to ensure the production of medicinal plant materials and finished herbal products of the best possible quality. The time of harvest depends on the plant part to be used. Detailed information concerning the appropriate timing of harvest is often available in national pharmacopoeias, published standards, official monographs and major reference books. However, it is well known that the concentration of biologically active constituents varies with the stage of plant growth and development. This also applies to non-targeted toxic or poison. 's indigenous’ plant ingredients. The best time for harvest (quality pe. k season/time of day) should be determined according to the quality and quantity of biologically active constituents rather than the total vegetative yield of the targeted medicinal plant parts. During harvest, care should be taken to ensure that no foreign matter, weeds or toxic plants are mixed with the harvested medicinal plant materials. Medicinal plants should be harvested under the best possible conditions, avoiding dew, rain or exceptionally high humidity. If harvesting occurs in wet conditions, the harvested material should be transported immediately to an indoor drying facility to expedite drying soCultivation, Collection, Processing and Storage of Crude Drugs 59 as to prevent any possible deleterious effects due to increased moisture leveis, which promote microbial fermentation and mould. Cutting devices, harvesters, and other machines should be kept clean and adjusted to reduce damage and contamination from soil and other materials. They should be stored in an uncontaminated, dry place or facility free from insects, rodents, birds and other pests, and inaccessible to livestock and domestic animals. Contact with soil should be avoided to the extent possible so as to minimize the microbial load of harvested medicinal plant materials. Where necessary, large drop cloths, preferably made of clean muslin, may be used as an interface between the harvested plants and the soil. If the underground parts (such as the roots) are used, any adhering soil should be removed from the medicinal plant materials as soon as they are harvested. The harvested raw medicinal plant materials should be transported, promptly in clean, dry conditions. They may be placed in clean baskets, dry sacks, trailers, hoppers or other well-aerated containers and carried to a central point for transport to the processing facility. All containers used at harvest should be kept clean and free from contamination by previously harvested medicinal plants and other foreign matter. If plastic containers are used, particular attention should be paid to any possible retention of moisture that could lead to the growth of mould. When containers are not in use, they should be kept in dry conditions, in an area that is protected from insects, rodents, birds and other pests, and inaccessible to livestock and domestic animals. Any mechanical damage or compacting of the raw medicinal plant materials, as a consequence, for example, of overfilling or stacking of sacks or bags that may result in composting or otherwise diminish quality should be avoided. Decomposed medicinal plant materials should be identified and discarded during harvest, post-harvest inspections and processing, in order to avoid microbial contamination and loss of product quality. As Per Who Guidelines : Medicinal plants/herbal drugs should be harvested when they are at the best possible quality for the proposed use. ¢ Damaged plants or parts plants need to be excluded. © Medicinal plants/herbal drugs should be harvested under the best possible conditions avoiding wet soil, dew, rain or exceptionally high air humidity. If harvesting occurs in wet conditions possible adverse effects on the medicinal plant/herbal drug due to increased moisture levels should be counteracted. * Cutting devices or harvesters must be adjusted such that contamination from soil particles is reduced to a minimum.60 Textbook of Pharmacognosy and Phytochemistry—1 « The harvested medicinal plant/herbal drug should not come into direct contact with the soil. It must be promptly collected and transported in dry, clean conditions. * During harvesting, care should be taken to ensure that no toxic weeds mix with harvested medicinal plants/herbal drugs. * All containers used during harvesting must be clean and free of contamination from previous harvests. When containers are not in use, they must be kept in dry conditions free of pests and inaccessible to mice/rodents, livestock and domestic animals. * Mechanical damage and compacting of the harvested medicinal plant/herbal drug that’ would result in undesirable quality changes must be avoided. In this respect, attention must be paid to - Overfilling of the sacks, - Stacking up of sacks. « Freshly harvested medicinal plants/herbal drugs must be delivered as quickly as possible to the processing facility in order to prevent thermal degradation. * The harvested crop must be protected from pests, mice/rodents, livestock and domestic animals. Any pest control measures taken should be documented. PRIMARY PROCESSING Harvested or collected raw medicinal plant materials should be promptly unloaded and unpacked upon arrival at the processing facility. Prior to processing, the medicinal plant materials should be protected from rain, moisture and any other conditions that might cause deterioration. Medicinal plant materials should be exposed to direct sunlight only where there is a specific need for this mode of drying. Medicinal plant materials that are to be used in the fresh state should be harvested/collected and delivered as quickly as possible to the processing facility in order to prevent microbial fermentation and thermal degradation. The materials may be stored under refrigeration, in jars, in sandboxes, or using enzymatic and other appropriate conservation measures immediately following harvest/collection and during transit to the end-user. The use of preservatives should be avoided. If used, they should conform to national and/or regional regulations for growers/collectors and end-users. Medicinal plant materials that are to be employed fresh should be stored under refrigeration, in jars, in sandboxes, or using enzymatic or other appropriate conservation measures, and transported to the end- user in the most expeditious manner possible. These of preservatives should be avoided. If used, this should be documented and they shouldCultivation, Collection, Processing and Storage of Crude Drugs 61 conform to national and/or regional regulatory requirements in both the source country and the end-user country. All medicinal plant materials should be inspected during the primary-processing stages of production, and any substandard products or foreign matter should be eliminated mechanically or by hand. For example, dried medicinal plant materials should be inspected, sieved or winnowed to remove discolored, moldy or damaged materials, as well as soil, stones and other foreign matter. Mechanical devices such as sieves should be regularly cleaned and maintained. All processed medicinal plant materials should be protected from contamination and decomposition as well as from insects, rodents, birds and other pests, and from livestock and domestic animals. DRYING When medicinal plant materials are prepared for use in dry form, the moisture content of the material should be kept as low as possible in order to reduce damage from mould and other microbial infestation. Medicinal plants can be dried in a number of ways: 1. In the open air (shaded from direct sunlight); 2. Placed in thin layers on drying frames, wire-screened rooms or buildings. 3. By direct sunlight, if appropriate. 4. In drying ovens/rooms and solar dryers. 5. By indirect fire; baking; lyophilization; microwave; or infrared devices. . Vacuum drying Spray dryer: Examples: Papaya latex and pectins, etc. When possible, temperature and humidity should be controlled to avoid damage to the active chemical constituents. The method and temperature used for drying may have a considerable impact on the quality of the resulting medicinal plant materials. For example, shade drying is preferred to maintain or minimize loss of colour of leaves and flowers; and lower temperatures should be employed in the case of medicinal plant materials containing volatile substances. The drying conditions should be recorded. In the case of natural drying in the open air, medicinal plant materials should be spread out in thin layers on drying frames and stirred or turned frequently. In order to secure adequate air circulation, the drying frames should be located at a sufficient height above the ground. Efforts should be made to achieve uniform drying of medicinal plantmaterials and so avoid mould formation. Drying medicinal plant material directly on bare ground should be avoided. If a concrete or cement surface is used, medicinal plant materials should be laid on a tarpaulin or other appropriate cloth or aoe62 ‘Textbook of Pharmacognosy and Phytochemistry sheeting. Insects, rodents, birds and other pests, and livestock and domestic animals should be kept away from drying sites. For indoor drying, the duration of drying, drying temperature, humidity and other conditions should be determined on the basis of the plant part concerned (root, leaf, stem, bark, flower, etc.) and any volatile natural constituents, such as essential oils. If possible, the source of heat for direct drying (fire) should be limited to butane, propane or natural gas, and temperatures should be kept below 60°C. If other sources of fire are used, contact between those materials, smoke and medicinal plant material should be avoided. Vacuum drying: This is conducted in steam- heated ovens with perfect closure, and a pump is used to exhaust the air. The low pressure maintained within the oven ensures rapid and complete drying. Example: digitalis. Advantages of vacuum drying : Rapid drying. Relatively low temperature. Cleanliness and freedom from odour and dust. Independence of climate conditions. Control of temperature. Elimination of risk of fire. Compactness. SPECIFIC PROCESSING Some medicinal plant materials require specific processing to: improve the purity of the plant part being employed; reduce drying time; prevent damage from mould, other microorganisms and insects; detoxify indigenous toxic ingredients; and enhance therapeutic efficacy. Common specifie processing practices include pre-selection, peeling the skins of roots and rhizomes, boiling in water, steaming, soaking, pickling, distillation, fumigation, roasting, natural fermentation, treatment with lime and chopping. Processing procedures involving the formation of certain shapes, bundling and special drying may also have an impact on the quality of the medicinal plant materials. Antimicrobial treatments of medicinal plant materials (raw or processed) by various methods, including irradiation, must be declared and the materials must be labeled as required. Only suitably trained staff using approved equipment should carry out such applications, and they should be conducted in accordance with standard operating procedures and national and/or regional regulations in both the grower/collector country and the end-user country. Maximum residue limits, as stipulated by national and/or regional authorities, should be respected.Cultivation, Collection, Processing and Storage of Crude Drugs 63 STORAGE ¢ Storage facilities for medicinal material should be well aerated, dry and protected from light, and, when necessary, be supplied with air-conditioning and humidity control equipment as well as facilities to protect against rodents, insects and livestock. The floor should be tidy, without cracks and easy to clean. Medicinal material should be stored on shelves which keep the material a sufficient distance from the walls; measures should be taken to prevent the occurrence of pest infestation, mould formation, rotting or loss of oil; and inspections should be carried out at regular intervals. © Continuous in-process quality control measures should be implemented to eliminate substandard materials, contaminants and foreign matter prior to and during the final stages of packaging. Processed medicinal plant materials should be packaged in clean, dry boxes, sacks, bags or other containers in accordance with standard operating procedures and national and/or regional regulations of the producer and the end-user countries, Materials used for packaging should be non-polluting, clean, dry and in undamaged condition and should conform to the quality requirements for the medicinal plant materials concerned. Fragile medicinal plant materials should be packaged in rigid containers. « Dried medicinal plants/herbal drugs, including essential oils, should be stored in a dry, well-aerated building, in which daily temperature fluctuations are limited and good aeration is ensured. « Fresh medicinal plant materials should be stored at appropriate low temperatures, ideally at 2-8°C; frozen products should be stored at less than — 20°C. Small quantity of crude drugs could be readily stored in air tight, moisture proof and light proof container such as tin, cans, covered metal tins or amber glass containers. * Wooden boxes and paper bags should not be used for storage of crude drugs. FACTORS INFLUENCING CULTIVATION OF MEDICINAL PLANTS The following factors are influencing of cultivation: Light ‘Temperature. . Atmosphere humidity . Altitude. pope64 Textbook of Pharmacognosy and Phytochemistry-I Rain fall Soil Fertilizer Pest and pest management ). Plant hormones 10. Mutation 11. Polyploidy 12. Hybridization 13. Green house effect. OMAIHHK LIGHT Light is the only external source of energy for the continuation of life of the plant, It influences photosynthesis, opening and closing of stomata, plant movements, seed germination, flowering and vegetative growth like tuber formation, Dry sunny weather increases the proportion of glycosides in digitalis and of alkaloids in belladonna. TEMPERATURE Temperature is the major factor influencing the cultivation of the medicinal plant. The sudden decrease in temperature caused the formation of the ice crystals in intercellular spaces of the plant. As a result, water comes out of the cells and ultimately plants die due to drought and desiccation. The ice crystals also mechanical injury to the cells. Temperature stimulates the growth of seedlings. Water absorption decreases at low temperatures. The rate of photosynthesis is affected by change in temperature. The rate of respiration increases with increase in temperature. Examples: Cinchona- 58-73°F; Tea- 75-90°F and coffee- 55- TOR. ATMOSPHERE HUMIDITY It is present in the form of water vapours. This is called atmospheric humidity. Clouds and fog are the visible forms of humidity. The major sources of water vapours in the atmosphere are evaporation of water from earth surface and transpiration from plants. The major effect of humidity én plant life and climate. Evaporation of water, its condensation and precipitation depends upon relative humidity and humidity affects structure, form and transpiration in plants. ALTITUDE ‘The altitude is the most important factor influencing of cultivation of medicinal plants. The increase the altitude, the temperature and atmospheric pressure decreases while the wind velocity, relative humidity and light intensity increases. Thus, as the climatic conditions change with height, they also produce change in the vegetational pattern. ‘The bitter constituents of Gentianalutea increase with altitude, whereas the alkaloids of Aconitum napellus and lobelia inflate and oil content of thyme and peppermint decrease. Pyrethrum gives the best yield andCuttvation, Collection, Processing and Storage of Crude Drugs 65 Pyrenthrin at high altitude. Examples: Tea-9500-1500 metres; cinnamon- 300-1000 metres and saffron- upto 1250 metres. . RAINFALL ‘The rainfalls are most important factor influencing of cultivation of medicinal plants. The main source of water for the soil is rain water. Rainfall and snowfall have a large effect the climate condition. The water from rainfall flows into the rivers and lakes, percolates into the soil to form ground water and remaining is evaporated. The minerals in the soil get dissolved in water and are then absorbed by plants. Water influences morphological and physiology of plant. Examples: continuous rain can lead to a loss of water- soluble substance from leaves and root by leaching; this is known to apply to some plants producing glycoside and alkaloids. SOIL Soil is defined as surface layer of the earth, formed by weathering of rocks. The soil is formed as a result of combined action of climate factors like plants and micro-organisms. The soil should contain appropriate amounts of nutrients, organic matter and other elements to ensure optimal medicinal plant growth and quality. Optimal soil conditions, including soil type, drainage, moisture retention, fertility and pH, will be dictated by the selected medicinal plant species and/or target medicinal plant part. The soil made of five components: - Mineral matter. - Soil air. - Soil water. - Organic matter or humus. - Soil organisms Plants depend on soil for nutrients, water supply and anchorage. Soil influences seed germination, capacity of plant to remain erect, form, vigour and woodiness of the stem, depth of root system, number of flowers on a plant, drought, frost, etc. Classification of soil particles: S.No._| ‘Type of particle Size (mm in diameter) 1 Clay Less than 0.002 2 Silt 0.002-0.02 3 Fine sand 0.02-0.2 4 __| Coarse sand 0.2-2.0 5 Stone or gravel 2.0 and more ‘Type of soil: (i) Clay (ii) Loamy.ae ‘Textbook of Pharmacognosy and Phytochemistry cu m wast i) Silt loam (iy) Sandy loam ehRaneyard ind) Oy Sandy scl remaining uous (vi) Calcareous soil. & Gon peatteaal Clay soil : Clay particle are very small. These fit together very eed closely and therefore, leave very less pore space. These spaces get filled - sOnaeh inane up with water very easily. Hence, the clay soil becomes quickly and mixed with waterlogged. Such soil have practically no air, therefore, the plants ‘The plants used growing in these soil are not able to absorb water. This soil known as These add both physiologically dry soil. Clay soil is plastic and forms a colloid when alfo forme a'pr moist. It cracks and shrinks when condition are dry. The soil rich in and leaching, TI nutrient elements and therefore, acts as a negatively charged colloidal Gi) Biofertilizer: It system. products or bacterit Sandy soil : Sand particles are large sized. These leave large pore about soil nutrie spaces which do not have capillary action and therefore, water is not nitrogen fixing mic retained by ‘them. Most of the water is quickly drained off and reaches as follows: deep into the soil. As a result, roots spread and also reach a great depth. = Legume-Rhizoi The sandy coil is poor in nutrient elements; it is less fertile and plants ~ Aaolla-Anabaei growing in this soil have less dry weight. - Free-living bac Loam soil : The mixture of clay, silt and sand is known as loam. - Loose associati Toam is very useful for growth. Tt is fertile soil because it contains ~ Cyanobacteria available nutrient elements in sufficient amounts. It has a high water - Mycorrhiza. retention capacity and appropriate amount of soil air is also present. The 1. Eetomycorr plants growing in loam are vigorous and have very high weight. between pl Sandy loam : the amount of sand particles is more than other types state matry of loams. 2, Endomycor Silt loam : Silt loam is considered to be the most fertile as it contains meee ‘more amount of organic substances than others. Nitrogen FERTILIZER > Phosphorous ‘The fertilizers are two types : ~ Potassium 1. Biological origin fertilizer. + Calcium 2. Synthetic fertilizers: ~ Magnesium 3. Chemical fertilizer = Sulpher. 1. Biological origin fertilizer : Soil is generally poor in organic Gi) Micronutrients: matter and nitrogen. The substances of biological origin used as + fron fertilizer are thus selected if these could provide the elements + Magnese required. These are two type: =. Zine (Green manures ; Manure is material, which are mixed - Boron with soil. These supply almost all the nutrients required by + Copper the crop plants. This results in the increase in crop ~ Molybdenum productivity. Manures are three types: Carbon, oxygen, hydrogen air. Examples : Urea, Potash.Cultivation, Collection, Progessing and Storage of Crude Drugs 67 - Farmyard manure: This is a mixture of cattle dung and remaining unused parts of straw and plants stalks fed to cattle. Composited manure: This consists of a mixture of rotted or decomposed and useless parts of plants and animals. - Green manure; It is a herbaceous crop ploughed under and mixed with the soil while still green to enrich the soil. The plants used as green manure are often quick growing. ‘These add both organic as well as nitrogen to the soil. It is also forms a protective soil cover that checks soil erosion and leaching. Thus, the crop yield increases by 80-50%. (ii) Biofertilizer: It can be defined as biologically active products or bacteria, algae and fungi which useful in bringing about soil nutrient enrichment. These mostly include nitrogen fixing microorganisms. Some of the Biofertilizer are as follows: - Legume-Rhizobium symbiosis - Azolla-Anabaena symbiosis. - Free-living bacteria. = Loose association of nitrogen fixing bacteria. - Cyanobacteria (blue green algae). - Mycorrhiza. 1. Ectomycorrhizae: Increase the interface surface between plant root and soil. Mycorrhizae absorb and store nitrogen, phosphorous, potassium and calcium. 2, Endomycorrhizae 2. Chemical fertilizers : @ Macronutrients: : - Nitrogen - Phosphorous - Potassium - Calcium - Magnesium Sulpher. (i) Micronutrients: - Tron - Magnese -. Zine - Boron - Copper - Molybdenum Carbon, oxygen, hydrogen and chorine are provided from water and air. Examples : Urea, Potash.63 Textbook of Pharmacognosy and Phytochemistry-1 PLANT HORMONES AND THEIR APPLICATIONS The plant growth regulators are small, simple molecules of diverse chemical composition. Classification of Growth regulators : 1. Plant growth promoter : (a) Auxins: (i) Natural Auxins: - Indole-3 — acetic acid ~ Indole -3-acetaldehyde - Indoleacetonitrile. - Indole- 3-pyruvic acid. (ii) Synthetic Auxins. _ > 1mnaphthalene acetic acid - 2, 4- dichlorophenoxyacetic acid (2, 4-D) - Indole- 3- butyric acid - 2,4, 5- trichlorophenoxyacetic acid (2, 4, 5- T). - 2. Naphthyloxyacetic acid. (>) Cytokinins: (i) 6- Benzyl aminopurine or 6- benzyl adenine. (ii) 6- Dimethylaminopurine. (iii) Kinetin. (iv) Zeatin. (v) N, N- diphenylurea. (vi) Thidiaziron. (©) Gibberellins: GA1, GA2, GAs 2. Plant growth Inhibitors: (a) Ethylene (b) Abscisic acid. PLANT GROWTH PROMOTORS A, AUXINS Auxin (From Greek ‘auxein: to grow) was first isolated from human urine. ‘They are classifying as follows: G) Natural Auxins: ¢ Indole-3 — acetic acid Indole 3- acetaldehyde Indoleacetonitrile. Indole 3- pyruvic acid. IndoleethanolCultivation, Collection, Processing and Storage of Crude Drugs 69 Gi) Synthetic Auxins. * I-naphthalene acetic acid 2, 4- dichlorophenoxyacetic acid (2, 4-D) Indole- 3- butyric acid 2, 4, 5- trichlorophenoxyacetic acid (2, 4, 5- T). 2- Naphthyloxyacetic acid. ‘CH;-COOH — CH COOH a 2 NH 13 a Indole-3- acetic acid 2,4- Dichlorophenoxyacetic acid CHy-COOH cl Ce a Naphthyl acetic acid 2, 4, 5- trichlorophenoxyacetic acid (2, 4, 5-T). CH)CH;CH,COOH NH Indole butyric acid Applications of Auxins: 1. Cell division: Auxins induce cell division underfollowing conditions: © During injury for healing of wound. ¢ During grafting for producing graft union. e During secondary growth by initiating cell divisions in the cambium. ¢ Inculture tissue. Root initiation: Application of Indole acetic acid and some other Auxins to cut end of the stem stimulates the rate of formation and number of root initiated. Shortening of internodes. »70 Textbook of Pharmacognosy and Phytochemistry! 4. Preventing of lodging: Application of naphthylacetamide, induces cell divisions in the cambium. This increases the amount of xylem in the basal part of the stem. It results in thickening and strengthening of the lower plant part, and thus prevents lodging. Dormancy. Initiation of flowering: spraying of dilute solution of Auxins like 2,4-D, and NAA, initiates flowering almost simultaneously. Flowering can be inhibited by spraying high concentration of Auxins. 7. Parthenocarpy: Fruit development in the absence of pollination and fertilization is called parthenocarpic development and the fruits thus formed are called parthenocarpic fruits. 8, Eradication of weeds: Few synthetic Auxins also act as herbicides and are used to kill weeds. 9. Apical dominance: apical meristem suppresses the growth of lateral buds. This condition is known as apical dominance. 10. Abscission and senescence: Auxins influence the development of abscission or separation layer. Application of Auxins to leaves and fruits can thus prevent their premature falling. . Cell elongation: Auxins promote elongations and growth of stems and roots and enlargement of many fruits by stimulating elongation of cells in all directions. Sugars << Starch —————— Sugars om 1 Salt Inceased t . “a — Hespiration Amylase Increased synthesis Increased Greater osmotic 1AA——> membrane ——P Pressure | permeability ‘Water Loosening of cell wall microfibrils, Endosmosis More cell wall materials Call elongation ‘Action of IAA (Indole-3-acetic acid) in cell clongation B. CYTOKININS Cytokinins have specific effects on cytokinesis. Zeatin has effect on cell division and leaf senescence and synthetic Cytokinins, kinetin, areCultivation, Collection, Processing and Storage of Crude Drugs nm useful in promoting lateral bud development and inhibition of senescence. Other examples: 6-Benzyl aminopurine or 6-benzyl adenine; 6- Dimethyl aminopurine; N- diphenylurea and Thidiaziron. «o> Chy-CI X oe 0 CHLOH n~ ‘NH nZ N LI? L I> N’ N N ‘NH Kinetin Zeatin Applications of Cytokinins: Cell division : They promote cell division, however, only in the presence of auxins. The balance of these two hormones determines the growth of root and shoots systems. With high concentration of both Cytokinins and auxins, the tissue continues to grow as a callus. If the concentration of auxins is higher as compared to the cytokinin concentration, root develops in the cultured tissue. 2, Breaking of dormancy : Cytokinins break the dormancy of seeds and thus help in their germination. 3. Counteraction of apical dominance: Auxins and cytokinins act opposite to one another in the relation to apical dominance the auxins allow dominance of apical bud while cytokinins stimulate the growth of lateral buds. Application of cytokinins to lateral buds relieves them from apical inhibition. 4, Delay in senescence : Cytokinins is their ability to delay normal process of senescence in leave. Disappearance of chlorophyll and degradation of proteins are the two important symptoms of senescence. 5. Sex expression: It promote formation of female flowers in some plants. 6. Parthenocarpy : Development of parthenocarpic fruits through cytokinin treatment. 7. Accumulation and Translocation of solutes :Cytokinins induce accumulation of salts inside the cells. They also help solute translocation in phloem. C. GIBBERELLINS Gibberellins are endogenous plant growth regulators and were originally discovered as the phytotoxic metabolites of a rice pathogen,72 Textbook of Pharmacognosy and Phytochemistry1 Gibberellafugikuroi. There are more than 100 gibberellins reported from widely different organism such as fungi and higher plants. They are denoted as Gi, Gz, and Gs and so on. They are acidic in nature. They are producing a wide range of physiological response in plants. Their ability to cause an increase in length of axil is used to increase the length of grapes stalks. Gibberellins cause fruits like apple to elongate and improve its shape. They also delay the senescence. Gs is used to speed up the malting process in brewing industry. P oc’ HO’ Coon ° Gibberellic acid Avgilieattons of Gibberellins : . Elongation of genetically dwarf plants: In higher plant is to stimulate the elongation of internodal cells. Dwart and miniature varieties of plants are often genetic mutants, which do not produce gibberellins. They can be made to grow to normal size by application of gibberellins. . Bolting and flowering in long- day plants: They controlling a balance between internodes growth and leaf development. . Substitution of cold treatment: Biennial plants flower only when they receive low temperature during winter season. Such plants would, however, flower after gibberellins treatment even if they do not receive suitable low temperature. Thus biennial plants can be made to flower in a single year by gibberellins treatment. . Breaking of dormancy: They can effectively break the dormancy of potato tubers and winter buds of many trees. They also act as an antagonist to abscisic acid. . Parthenocarpy: they are more effective than auxins in inducing parthenocarpy. . The hormone tried with leaf and root culture of digitalis, showed higher production of digoxin. . Spraying juvenile conifers with gibberellins hastens the maturity period, the leading to early seed production . Spraying sugarcane crop with gibberellins increase the length of the stem. . Delayed ripening: Ripening of citrus fruits can be delayed with the help of gibberellins. It is useful in safe and prolongs storage of fruits.Cultivation, Collection, Processing and Storage of Crude Drugs 73 PLANT GROWTH INHIBITORS I. ETHYLENE Ethylene is a gaseous hormone which stimulates transverse growth but retards the longitudinal one. Ethylene is a simple gaseous plant growth regulator. It is synthesized in large amount by tissues undergoing senescence and ripening fruits. Influences of ethylene on plants include horizontal growth of seedlings, swelling of the axis and apical hook formation in dicot seedlings. Ethylene promotes senescence and abscission of plant organs especially of leaves and flowers. Ethylene is highly effective in fruit ripening. It enhances the respiration rate during the ripening of the fruits. They break seed and bud dormancy, initiate germination in seeds. Ethylene promotes rapid internodes elongation in deep water rice plants. At low concentration of ethylene has been shown to increase the Sennoside concentration in Cassia angustifolia, and applied to tobacco leaves it stimulates production of the stress compounds phytuberin and phytuberol. IL, ABSCISIC ACID They are natural occurring plant growth inhibitors and have been isolated from the fungus, Cenosporarosicola. Abscisic acids inhibit seed germination. CH; CH SY AK coon o ‘CH3 Abscisic acid Role of abscisic acid in plant growth are as follows: 1. It stimulates the closure of stomata in the epidermis and increases the tolerance of plants to various kinds of stresses. Therefore, it is also called the stress hormone. 2. It hastens the formation of abscission layer and senescence. 3. Abscisic acid plays an important role in seed development, maturation and dormancy. 4. They suppress the growth promoting effects of gibberellins and hence, is also known as antigibberellins. . It maintains dormant condition of twigs. . Suppresses the germination of seeds. Dormant seeds germinate, when abscisic acid is overcome by gibberellins. 7. Hardness: Abscisic acid promotes cold hardiness and inhibits growth of pathogens.14 ‘Textbook of Pharmacognosy and Phytochemistry—1 8 Rooting: Abscisic acid can be used to promote rooting in many stem cutting. 9. Abscission: Abscisic acid promotes the abscission of leaves, flowers and fruits in plants. POLYPLOIDY Plants whose cells contain two sets of chromosomes, derived at fertilization from the union of one set from the pollen and one set from the egg cells, are described as diploids and denoted by “2n”. The term polyploidy is applied to plants with more than two sets of chromosomes in the cells; when four sets are present the plants are described as tetraploids and denoted by “4n”, Tetraploidy is induced by treatment with colchicine, which inhibits spindle formation during cell division, so that the divided chromosomes are unable to separate and pass to the daughter cells. The two sets of chromosomes remain in one cell and this develops to give tetraploids plant. Treatment with colchicine may be applied in various ways, but all depend on the effects produced in the meristem. The seeds may be soaked in a dilute solution of colchicine, or the seedlings, the soil around the seedling or the young shoot treated with colchicine solution. Fertile seed and robust, healthy tetraploid plants were obtained, the tetraploid condition being indicated by the increased size of the pollen grains and stomata; chromosome counts in root-tip preparations confirm the tetraploid condition. The average increase in alkaloids content compared with diploid plants of Daturastromonium and Daturatatula was 68%, with a maximum increase of 211.6%. Similar results were obtained with Atropa belladonna and Hyoscyamusniger, the average increase in belladonna being 93%. Increased Alkaloidal content of tetraploids plants has been confirmed for Daturastromonium and Daturatatula. The diploid of Acoruscalamus is 2.1% of volatile oil content but they are converted into tetraploid, they produce 6.8% of volatile oil contents. MUTATION Define; Sudden heritable change in the structure of a gene or chromosome or change the chromosome number. TYPE OF MUTATIONS: Spontaneous and induced mutations. Recessive and dominant mutations. . Somatic and germinal mutations. . Forward, back and suppressor mutation. Chromosomal, genomic and point mutations. gpepe