Physiological and chemical changes induced by transparent polythene + green net shed on Pelargonium graveolens L. mother plants during monsoon season

Abstract

Pelargonium graveolens L. or rose scented geranium is an essential oil-bearing plant with extended economic value. It has strong pharmacological and aromatic properties along with its frequent application in perfumery, food, cosmetics, and pharma industries. Seasonal fluctuations in northern India have a detrimental effect on the survival of P. graveolens. Due to its male sterility, the plant is unable to propagate by sexual reproduction, so, vegetative propagation is the only option to grow and protect the mother plant for the next season. To protect the plant in adverse conditions our researchers had developed a protective shed i.e. transparent polythene + green net shed (S) but the reason for the increased survival and growth of the plant in the shed was not well understood. In the present research, approximately 91% of P. graveolens mother plants were protected under the shed compared to open conditions (O). The current study also reported high humidity, increased air temperature and increased microbial infection in open condition, exerting various physiological and chemical changes which further have detrimental effects on plant growth and survival. In shed conditions, a decreased level of antioxidant enzymes, antioxidant metabolites, and elevated level of photosynthetic pigments were observed. Further, an increased density of glandular and non-glandular trichomes and an improved quality and quantity of essential oil were observed in shed conditions. Considering the above observations, polythene + green net shed can be used as an auspicious approach for protecting the P. graveolens mother plant in monsoon season due to its effect on soil moisture, soil microbial biomass carbon (SMBC), trichome morphology/density and yield of essential oil.