Alterations in the photosynthetic pigments and antioxidant machineries of red pepper (Capsicum annuum L.) seedlings from gamma-irradiated seeds

Abstract

To characterize the stimulatory effects of low-dose gamma radiation on early plant growth, we investigated alterations in the photosynthesis and antioxidant capacity of red pepper (Capsicum annuum L.) seedlings produced from gamma-irradiated seeds. For two cultivars (Yeomyung and Joheung), three irradiation groups (2, 4, and 8 Gy, but not 16 Gy) showed enhanced development, although Fv/Fm, the maximum photochemical efficiency of Photosystem II (PSII), did not differ significantly among any of the four groups. In contrast, values for 1/Fo -1/Fm, i.e., a measure of functional PSII content, decreased in the irradiated groups of 'Yeomyung' but increased in those of 'Joheung'. Pigment analyses and enzyme activity assays revealed that irradiation altered the compositions of photosynthetic pigments (chlorophylls and carotenoids) as well as the activities of antioxidant enzymes (superoxide dismutase and glutathione reductase). However, these shifts were not directly related to the increase in early growth, although they were cultivar-and developmental stage-dependent. In addition, the effects of irradiation on the enzymatic activities measured here were at opposition between the two cultivars.

Morphological and biochemical responses of Oryza sativa L. (cultivar MR219) to ion beam irradiation

“…This may be due to the hormetic effects of low-dose ionizing radiation on plants that are manifested as accelerated cell proliferation, stimulated germination and growth, improved stress-resistance, or even increased yield (Kim et al, 2004). In many cases, such effects could be characterized as the modulation of photosynthesis and antioxidant machineries (Kim et al, 2004). …”

Studies on the Effect of Gamma, Laser Irradiation and Progesterone Treatments on Gerbera Leaves

“…So [7] reported that, low dose gamma radiation may induce growth stimulation by changing the hormonal signaling net work in plant cells or by increasing the antioxidant capacity of the cell to easily overcome daily stress factors such as fluctuations of light intensity and temperature in the growth condition.…”

“…These radicals can damage or modify important components of plant cells and have been reported to affect differentially the morphology, biochemistry, and physiology of plants depending on the irradiation level. These effects include changes in the plant cellular structure and metabolism, e.g., dilation of thylakoid membranes, alteration in photosynthesis, modulation of the antioxidative system, and accumulation of phenolic compounds [7,8,9]. As for laser rays which belong to unionizing radiation laser is an abbreviation of Light Amplification by Stimulated Emission of Radiation.…”

Improved silymarin content in elicited multiple shoot cultures of Silybum marianum L.

“…Gamma rays belong to ionizing radiation and interact on atoms or molecules to produce free radicals in cells. These radicals can damage or modify important components of plant cells and have been reported to affect differentially the morphology, anatomy, biochemistry and physiology of plants depending on the irradiation level (Kim et al 2004;Wi et al 2005;El Sherif et al 2011). This study builds a foundation for optimization of medium components and conditions as a first step towards further research for commercialization.…”