The cultivation of medicinal plants for commercial and medicinal purposes depends on various factors. These factors can influence the growth and development of the plants as well as the nature and quality of secondary metabolites.
Such important external factors include altitude, temperature, rainfall, length of day, daylight, type of soil, soil fertility, fertilizers, pests, air pollution, and use of herbicides.
Altitude
Every plant prefers a particular altitude that favors its healthy growth and development. E.g.. Tea, eucalyptus, etc, are cultivated at 1000-2000 m above sea level while cardamom and cinnamon prefer 500-1000 m.Â
Temperature
Temperature influences the growth, metabolism, and the yield of secondary metabolites. Plants can tolerate a particular range of temperatures. At the same time, some plants prefer summer or winter climates and lack resistance to unfavourable temperatures.
Rainfall
The influence of rainfall on medicinal plants depends on the water-holding capacity of the soil and the nature of the plants. Different ranges of rainfall are found to show varying results in the constituent production. In many cases, excessive rainfall causes leaching of water-soluble compounds, leading to reduced amounts of metabolites.Â
Day Length
Day length has a direct impact on metabolite production. Plants kept longer in daylight show either more or less amount of metabolite production, depending on the plant. E.g.. Peppermint produces only menthofuran under short-day conditions. But it produces menthofuran, menthone, and menthol under long-day conditions.Â
Daylight
The intensity of light is found to influence increased production of alkaloids in plants like cinchona, belladonna, and stramonium. Similarly, the amount of radiation also shows its effect on plants.
Soil Type
Each plant prefers a particular type of soil to match its water holding capacity and nutrient composition.
- Nitrogen-rich soil is found to promote increased production of alkaloids in some plants.Â
- Some plants grow better in calcium-rich soil, while others have little response to this nutrient.Â
- pH value of the soil is another influencing factor that also plays a role in the presence or absence of microbes.Â
Soil Fertility
It is an important factor that directly affects the cultivation of medicinal plants. Rainfall, leaching, and erosion often reduce the fertility of soil. Adding manure and nitrogen-fixing bacteria or using fertilizers are common practices to maintain soil fertility.Â
Pests and Pest Control
Pests, moths, etc, need to be controlled to reduce damage to the crop and increase the yield. Common techniques used to control them are sanitation, fumigation, heat, resistant variety, tiling, etc.Â
Air Pollution
Coniferous, deciduous, and other types of plants are sensitive to chemicals in the air. These chemicals can hinder the growth of these plants or cause injuries or burns.Â
Herbicides
Excessive application of herbicides could cause damage to the plant parts or the entire plant. This is influenced by the excess amount or overexposure to herbicides.Â
References
- Shah, Biren N, Avinash Seth. (2010). Textbook of Pharmacognosy and Phytochemistry. Elsevier.
- https://pharmacy.kkwagh.edu.in/uploads/study_material/sy/SY%20-%20Pcog%20I%20-%20Cultivation,%20Collection.pdf
Additional Topics
- Classification of Crude Drugs in Pharmacognosy
- Storage of Crude Drugs
- Therapeutic Drugs from Marine Sources
