Solar UV‐B radiation limits seedborne anthracnose infection and induces physiological and biochemical responses in Lupinus mutabilis

Abstract

The aim of this study was to test whether solar UV‐B radiation and temperature have an effect on infection of lupin seeds by Colletotrichum acutatum. Samples of infected seed were placed in a solar oven and exposed on sunny days for 15, 30, 45, 60, 75, 90 and 120 min. The degree of reduction in disease incidence and seed germination was dependent on the exposure time. Exposure times of 75 min (UV‐B 4.41 kJ m−2, ≈76 °C) and higher reduced incidence from 5% to undetectable levels, but also reduced seed germination by around 10% compared with untreated seed. Therefore, in a second experiment, infected seeds were exposed for 45 or 60 min in the solar oven (UV‐B 2.83 or 3.75 kJ m−2, respectively, ≈76 °C), for 60 min at ambient temperature (UV‐B 3.75 kJ m−2, ≈21 °C) or to dry heat for 60 min at 75 °C. Exposure for 60 min in the solar oven reduced seed infection by 99%, while UV‐B‐radiated seed at ambient temperature or dry‐heat reduced infection by 60% or 32%, respectively. To evaluate the effect of UV‐B plus high temperature on seedlings, lupin seed exposed for 45 or 60 min (UV‐B 2.83 or 3.75 kJ m−2, respectively, at ≈76 °C) were grown and physiological and biochemical responses of the seedlings were assessed. Seedlings from exposed seed had higher total concentrations of chlorophyll, protein and peroxidase activity than those grown from unexposed infected seed.

Solar Cookers and Dryers: Environmental Sustainability and Nutraceutical Content in Food Processing

“…The use of direct solar irradiation on food together with heating, could further modify food nutraceutical properties. UV light is helpful in preventing bacterial spoilage and fungal infection [80] but it can activate photolytic radical reactions that can further decrease the content of antioxidants, vitamins and other nutraceuticals that are fundamental for the beneficial impact of food on our diet. A few studies have analyzed the effect of direct solar irradiation on cooked food; however, many research groups have studied the effect of the sun on food, seeds and vegetables dried using SDs and these studies can give us an idea of the possible effects of UV light in direct solar cooking.…”

Cellulose-Based Photothermal Coating: A Sustainable Solution for Seed Protection and Long-Term Grain Storage

“…Other state-of-the-art physical sterilization methods for seed protection, e.g. , UV irradiation, , pulsed electric field, nonthermal plasma, ozone, and ultrasonic treatment, are still at the experimental stage and not ready yet for large-scale commercial applications.…”

Native Bacillus subtilis Strains Efficiently Control Lupin Anthracnose Both under Greenhouse and in Field Conditions

“…However, no fungicides eradicate the pathogen because they do not completely reach its survival site [9]. For this reason, the application of dry heat in convection ovens [10], ultraviolet-C radiation [3] UV-B solar radiation converted into thermal energy plus 50% of accumulated radiation in a solar oven for the disinfection of seed [11], and biological treatments such as Bacillus subtilis for reducing infection on seed [11] constitute sustainable alternatives to reduce anthracnose infections in seed without causing damage to the environment and human health, including animal health.…”