Microclimatic buffering on medicinal and aromatic plants: A review

In recent years, the demand for herbs and aromatic products has increased worldwide in the herbal, flavor, and fragrance industry. Studies suggest that rapidly increasing anthropogenic activities have put a lot of pressure on energy and water use, especially in the dry land areas. To meet the burgeoning demand of medicinal and aromatic plants (MAPs), long-term use of agrochemicals and poor farming techniques reduced the quality of produce as per industrialist grade and can cause public health challenges and environmental pollution. Sustainable crops, higher productivity, and quality are typically assured by microclimate modification, which in turn contributes to sustainability and livelihood generation for people. Modification of climatic conditions in a relatively small area, at a height of 3-6 m over the surface of the earth, affect the growth and development of plants by altering different physical parameters such as light intensity and wavelength. Morphology, growth, yield, and secondary metabolites production in MAPs are affected by microclimate modification. These parameters influence plant photosynthesis which plays an important role in plant vegetative, reproductive, and developmental stages, yield, and secondary metabolite accumulation. Different crops behave differently to microclimate modifications. In some crops, shade levels significantly reduce the yield and quality of seed, while in some others, higher amount of light is required to enhance productivity and quality. Therefore, it is indispensable to evaluate the threshold light intensity to ensure the sustainable production of MAPs. This study provides an understanding of plant acclimation to light intensity from the vegetative phase to the reproductive phase of the MAPs. So, from the current study we have concluded that in the climate change era and as per the need of the herbs, aromatic products and perfumery industry, substitution of synthetic fertilizers and poor agronomic techniques with microclimate modification can be considered to enhance the quality of products. This technique can be recommended to industrialist and farmers as sustainable culture techniques by eliminating the additional need of chemical fertilizers, however, more studies are required to fill the information gaps with morphology, physiology, quality and soil properties of MAPs in different light conditions along with other agronomic techniques.