Effects of UV-C Radiation on Common Dandelion and Purple Coneflower: First Results

Abstract

Ultraviolet-C (UV-C) light (100 ≤ λ ≤ 280 nm) is a ionizing radiation that can damage living organisms. An experiment was conducted on plants of common dandelion (Taraxacum officinale Weber, T. Densleonis Desf.) and purple coneflower [Echinacea purpurea, (L.) Moench] irradiated with UV-C at different exposition times, under controlled conditions and grown in self-produced characterized compost, to assess the effect of different doses UV-C radiation on some physiological parameters. Trials have been carried out using a black chamber equipped with an UV-C lamp in which plants were divided in four groups on the basis of UV-C irradiation period (10, 30, 60, and 120 min). Non-irradiated plants were kept as controls. Plant photosynthetic performance, chlorophyll content (SPAD) and some morphologic traits were recorded before, immediately after irradiations and 20 days weeks later. The effects on photosynthetic performances and chlorophyll contents (SPAD) were evaluated and compared with data obtained in similar experiments where tomato plants were irradiated at different times with UV-C light. In both species, SPAD values decreased as the irradiation period became longer. The two species showed different gas exchange dynamics, depending on the UV-C exposure time. Two months after the UV-C irradiation, plant dry weight measured at 120-min UV-C exposure was significantly lower than the control.

Mechanistic Insight of Allantoin in Protecting Tomato Plants Against Ultraviolet C Stress

“…In recent decades, UV-induced damage has augmented due to the depletion of the ozone layer by excess chlorofluorocarbons, which has a long half-life (50 to 150 years) and is being discharged excessively from the earth due to the anthropogenic causes [ 1 , 3 ]. Despite the filtration of natural UVC via the ozone layer, it has become a point of concern due to its future impact on natural ecosystems and agricultural productions due to atmospheric pollutant-induced ozone layer depletion [ 7 , 17 , 18 ].…”

Ionizing Radiation as a Source of Oxidative Stress—The Protective Role of Melatonin and Vitamin D

“…IR is a form of energy transfer that is able to cause ionization of a material medium while interacting with it [7]. This energy can be transferred by means of electromagnetic waves, including X radiation, gamma radiation and a small range of ultraviolet (UV) radiation with short wavelength and high energy, or through alpha and beta particles [27,28]. Each type of radiation differs in its energy, penetration and biological effects of the exposure.…”

“…Both X and gamma rays are characterized by high penetration and a plate made of lead is needed as an effective shield against them [ 31 ]. UV radiation capable of causing ionization has a wavelength in the range of 100–280 nm (UVC) and is absorbed by the atmosphere [ 28 , 32 ].…”

UV-C Rays to Simulate the Exposition of Photosynthetic Organisms to Solar Radiation in Space Environments

“…16,22 Finally, a few papers were focused on the positive and promoting effects of UV-C radiation on germination, sprouting, growth and flowering. 23,24 According to two recent studies from our research group, 25,26 wild plants (common dandelion and purple coneflower) seem to be more tolerant to UV-C radiation compared to cultivated ones (e.g., tomato), even if, at high exposure times (30, 60 and 120 min with an irradiation of 3.8 J m -2 and plants at 1-m distance from the UV-C source), significantly short-term and longterm (up to 120 days) negative effects have been observed for gas exchange, chlorophyll content and fresh weight in all the species examined.…”