Factors affecting cultivation of crude drugs
Answers
The following factors are influencing of cultivation:
1. 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.
2. 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- 55-70°F
3. 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 on plant life and climate. Evaporation of water, its condensation and precipitation depends upon relative humidity and humidity affects structure, form and transpiration in plants.
4. 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 vegetation pattern. The bitter constituents of Gentiana lutea increase with altitude, whereas the alkaloids of Aconitum nacelles and lobelia inflate and oil content of thyme and peppermint decrease. Pyrethrum gives the best yield and Pyrethrum at high altitude. Examples: Tea- 9500-1500 meters; cinnamon- 300-1000 meters and saffron- up to 1250 meters
5. 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.
6. 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 microorganisms. 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.
Factors affecting cultivation of crude drugs,are as follows -
• Necessary resources :
The cultivation of the crude drugs is more complex than any other harvesting process. The necessary environmental conditions and intense care are needed to successfully cultivate these crude drugs. (Eg. Proper climate, Soil minerals, Altitude etc.)
• Market demand :
In the markets like India,where the Ayurvedic herbal medicines are very popular,the cultivation of crude drugs is performed in huge amount. So,the market demand plays a significant role here.
• Government rules :
Even the crude drugs are beneficial for us, the government of many nations had already established many limitations on the amount of cultivation which is a major factor behind the yield of the crude drugs in many countries.