Radish (Raphanus sativus L.) Cultivar‐Specific Response to O₃: Patterns of Biochemical and Plant Growth Characteristics

Abstract

The sensitivity of four radish (Raphanus sativus L.) cultivars, Baladey “B,” Cherry Belle “CB,” Prinz Rotin “PR,” and Scarlet Globe “SG” to 80 nL L−1 ozone is assessed in fumigation chambers. O3 visible injury symptoms appears as brown spots to chlorotic areas, but the response is cultivar‐specific. O3 induces higher content of H2O2 and lipid peroxidation (it is estimated as malondialdehyde (MDA) content), leading to drastic visible injury symptoms in B compared to the other cultivars. Root and shoot dry weights, Chlorophyll a, net photosynthetic rates, and chlorophyll fluorescence are reduced in B to a greater extent than the other cultivars. On the other hand, stomatal conductance increased in B and CB (+52 and +24%, respectively) due to O3‐exposure, while it was decreased by 35% in PR and SG. Exposure to O3 generates oxidative stress leading to stimulation of antioxidative defense systems. SG shows the highest induction of catalase (CAT), superoxide dismutase (SOD), and glutathione reductase (GR), while B had the lowest activities of these antioxidative enzymes, but had the highest H2O2 and MDA content. The higher accumulation of H2O2, poor induction of antioxidative enzymes, and increased stomatal conductance led to severe visible injury and drastic inhibition in photosynthetic rates and growth in B than other cultivars depicting its higher sensitivity toward O3. Therefore, it can be used as a bioindicator for O3 pollution worldwide.

Toxicity of Naphthenic Acids on the Chlorophyll Fluorescence Parameters and Antioxidant Enzyme Activity of Heterosigma akashiwo

“…Research has shown that the CAT of Heterosigma erythraea (H. erythraea) also showed stress activity during the early stage of NAs exposure. However, with a continuous increase in exposure time, the CAT activity was significantly reduced and inhibited; hence, it was tolerated [40,41].…”

Effect of Biochar on Chemical Behavior and Radish Plant Uptake of Heavy Metals Grown in ‎Polluted Soils

“…Treatments without biochar (0% biochar) were regarded as the control. The pot experiment was conducted using radish plant (Raphanus sativus) as a bio indicator for environmental pollution (Davies, 1993;Hassan et al, 2018). Five seeds were sown in each pot and water was added to bring the soil moisture to 70% of water holding capacity.…”

The Alleviative Effects of Salicylic Acid on Physiological Indices and Defense Mechanisms of Maize (Zea Mays L. Giza 2) Stressed with Cadmium

“…Net photosynthetic rate (A) and total CO 2 stomatal conductance (g s ) of the second true foliage leaf of each plant/treatment were measured with an open infrared gas exchange system (LI-6400, LICOR, Lincoln, NE, USA (Ismail et al 2014;Basahi et al 2016;Hassan et al 2018). Measurements were taken between 10:00 and 14:00 h (Egyptian local time) and were performed ten times at 7-day intervals in order to cover all growth stages of plant.…”

“…The saturation pulse method was used for analysis of quenching components as described by Hassan (2004;2006a). The light and dark fluorescence parameters were used for calculations of the following: actual quantum yield of PSII [Φ PSII = (F m , − F s ) / F m ] and photochemical [qP = (F m , − F s ) / (F m , − F 0 , )] and non-photochemical [(NPQ) = (F m − F m ) / F m , ] quenching coefficients (Pellegrini et al 2011(Pellegrini et al 2015Bashai et al 2016;Hassan et al 2018;Santos et al 2018).…”

“…The inhibition of the photochemical reduction of nitro blue tetrazolium was determined at 560 nm (Schimadzu UV-1201 spectrophotometer). One unit of SOD activity was defined as the amount of the extract resulting in 50% inhibition of nitro blue tetrazolium reaction (Basahi et al 2014;Hassan et al 2018;Zhao et al 2018).…”