Use of greenhouse‐covering films with tailored UV‐B transmission dose for growing ‘medicines’ through plants: rocket salad case

Abstract

BACKGROUND The effects of ultraviolet B (UV‐B) radiation on plants are well known and have recently attracted a great deal of attention due to the production of large quantities of secondary metabolites, which are very beneficial for human health. Recent studies have demonstrated the possibility of exploiting UV‐B radiation to induce metabolic changes in fruit, vegetables, and herbs. The role of UV‐B rays in inducing secondary plant metabolites is enhanced by new plastic films, which, as a result of their optical properties, permit the necessary dosage of UV‐B to be transmitted into the greenhouse to stimulate such metabolites without altering the harvest. RESULTS The main goal of the present paper is to demonstrate that, by using a greenhouse plastic film with appropriate transmittance of UV‐B for rocket salad cultivation, it is possible to increase the nutraceutical elements in comparison with the same species grown in absence of such radiation. Tests compared nutritional elements extracted from rocket salad grown under greenhouses covered with several plastic films differing in UV‐B transmittance. We found that rocket salad grown under plastic with 27% UV‐B transmittance exhibited very high luteolin and quercetin content in comparison with rocket salad cultivated under film blocking UV‐B radiation. CONCLUSIONS Our experimental results confirm the possibility of exploiting UV‐B radiation in the correct amounts by appropriate greenhouse plastic covers, to produce natural ‘medicines’ using the plants and to satisfy increasing consumer demand for natural health‐promoting food products. © 2019 Society of Chemical Industry

Plant Responses to UV Blocking Greenhouse Covering Materials: A Review

“…The total amount of phenolic compounds in tomato fruit, as caffeic acid, as well as the content of total phenolics, were reduced by 16% for both cultivars tested, under the UV blocking cover. Lastly, a decreased concentration of total polyphenols including luteolin, quercetin galactoside and quercetin glucoside was detected in rocket salad (Eruca vesicaria L.) plants grown under a UV blocking cover [55].…”

Environmental Sustainability of Greenhouse Covering Materials

“…The loss of light might compromise photosynthetic processes and impact plant growth. Sustainability concerns in crop production and the need for ideal pest control management systems and organic cultivation [15] have informed the development of greenhouse materials with customized properties such as higher photo-selectivity and slow insecticide release capabilities [32,33]. Other properties associated with modern greenhouse materials are limited droplet formation, reduced heat losses, accumulation of dust, and transmission of a particular wavelength of light [14,31,32,34].…”

Environmental Sustainability of Plastic in Agriculture

“…A high level of solar radiation exposure is capable of inducing photodegradation/light-induced damage to plastic materials [30]. Even though the risks associated with photodegradation can be mitigated by the inclusion of photo stabilizers and antioxidants [31], UV damage of plastic shade nets and mulching materials is a common problem in tropical areas. Such areas receive intense sunlight compared to the subtropical/temperate zones.…”