The impact of short-term UV irradiation on grains of sensitive and tolerant cereal genotypes studied by EPR

Proline accumulation and antioxidant response are crucial for citrus tolerance to UV-B light-induced stress

Plants face a wide range of biotic and abiotic stress conditions, which are further intensified by climate change. Among these stressors, increased irradiation in terms of intensity and wavelength range can lead to detrimental effects, such as chlorophyll degradation, destruction of the PSII reaction center, generation of ROS, alterations to plant metabolism, and even plant death. Here, we investigated the responses of two citrus genotypes, Citrus macrophylla (CM), and Troyer citrange (TC) to UV-B light-induced stress, by growing plants of both genotypes under control and UV-B stress conditions for 5 days to evaluate their tolerance mechanisms. TC seedlings had higher sensitivity to UV-B light than CM seedlings, as they showed more damage and increased levels of oxidative harm (indicated by the accumulation of MDA). In contrast, CM seedlings exhibited specific adaptive mechanisms, including accumulation of higher levels of proline under stressful conditions, and enhanced antioxidant capacity, as evidenced by increased ascorbate peroxidase activity and upregulation of the CsAPX2 gene. Phytohormone accumulation patterns were similar in both genotypes, with a decrease in ABA content in response to UV-B light. Furthermore, expression of genes involved in light perception and response was specifically affected in the tolerant CM seedlings, which exhibited higher expression of CsHYH/CsHY5 and CsRUP1-2 genes. These findings underscore the importance of the antioxidant system in citrus plants subjected to UV-B light-induced stress and suggest that CsHYH/CsHY5 and CsRUP1-2 could be considered genes associated with tolerance to such challenging conditions.

The Role of Reactive Oxygen Species in Plant Response to Radiation

Radiation is widespread in nature, including ultraviolet radiation from the sun, cosmic radiation and radiation emitted by natural radionuclides. Over the years, the increasing industrialization of human beings has brought about more radiation, such as enhanced UV-B radiation due to ground ozone decay, and the emission and contamination of nuclear waste due to the increasing nuclear power plants and radioactive material industry. With additional radiation reaching plants, both negative effects including damage to cell membranes, reduction of photosynthetic rate and premature aging and benefits such as growth promotion and stress resistance enhancement have been observed. ROS (Reactive oxygen species) are reactive oxidants in plant cells, including hydrogen peroxide (H₂O₂), superoxide anions (O₂^•-) and hydroxide anion radicals (·OH), which may stimulate the antioxidant system of plants and act as signaling molecules to regulate downstream reactions. A number of studies have observed the change of ROS in plant cells under radiation, and new technology such as RNA-seq has molecularly revealed the regulation of radiative biological effects by ROS. This review summarized recent progress on the role of ROS in plant response to radiations including UV, ion beam and plasma, and may help to reveal the mechanisms of plant responses to radiation.

The effectiveness of growth processes’ electrostimulation in corn hybrid seeds rodnik 180 sv

The aftereffect’s study of pre-sowing treatment with electric current of 500V, 1000V and 8000V on the sowing qualities and growth processes of corn hybrid seeds Rodnik 180 SV was carried out in laboratory conditions. As a result of the conducted studies, the positive effect of electrical stimulation on the germination and germination energy of corn seeds was revealed. Studies have shown the effectiveness of seeds’ pre-sowing electrical stimulation according to the following traits: growth of roots and seedlings, seed swelling intensity, germination energy and germination. Laboratory germination of seeds increased by 10% compared to the standard, germination energy – by 13-15%. The swelling intensity of treated seeds was 15-17% higher. The weight of raw sprouts in the control option was 32.3g, dry – 10.2 g. The weight of raw sprouts in seeds treated with 8000V was 48.9g, when treated with 500V – 54.0g. The length of roots and seedlings when treated with 8000V ranged from 23.9 mm, at 500V - up to 44.2 mm.