Weak microwave can alleviate water deficit induced by osmotic stress in wheat seedlings

Abstract

The aim of the investigation is to determine the effect of microwave pretreatment of wheat seeds on the resistance of seedlings to osmotic stress. Changes in biophysical, physiological and biochemical characters were measured. The results showed: (1) The magnetic field intensity and seeds temperature increased progressively with microwave pretreatments of 5, 10, 15, 20 s and 25 s compared with controls. Although each microwave pretreatment resulted in an increase in alpha-amylase activity and photon emission intensity, the increase of alpha-amylase activity and photon emission intensity was maximal at a microwave pretreatment of 10 s. (2) Osmotic stress induced by PEG treatment enhanced the concentration of malondialdehyde, while decreasing the activities of nitricoxide synthase, catalase, peroxidase, superoxide dismutase and the concentration of nitric oxide, ascorbic acid, glutathione in the seedlings compared with controls. However, compared to osmotic stress alone, in the seedlings treated with microwave irradiation plus osmotic stress the concentration of malondialdehyde decreased, while the activities of nitricoxide synthase, catalase, peroxidase, superoxide dismutase and the concentration of nitric oxide, ascorbic acid and glutathione increased. These results suggest that a suitable dose of microwave radiation can enhance the capability to eliminate free radicals induced by osmotic stress in wheat seedlings resulting in an increase in resistance to osmotic stress.

Microwave Irradiation Enhances the Germination Rate of Tartary Buckwheat and Content of Some Compounds in Its Sprouts

“…The effects of microwave irradiation are based on the effects of temperature and electromagnetism on organisms. Previous studies have illustrated that certain doses of microwave irradiation notably improve the activities of nitric oxide synthase (NOS), CAT, POD, and SOD and increase the concentration of nitric oxide (NO), ascorbic acid (VC) and glutathione (GSH) [Chen et al, 2009a]. Radzevicius et al…”

“…The GR of lentil (Lens culinaris) seeds exposed to the microwave power of 450-730 W for 30 s was improved; however, this rate was inhibited for longer exposure times (60 and 90 s) [Aladjadjiyan, 2010]. A lower power microwave pretreatment increased both POD and SOD activities and increased the GR and growth vigor [Chen et al, 2009a], but a higher power and longer duration caused more negative effects on wheat seeds. Thus, a low power microwave treatment for a short time improved the GR, but a low power for a longer time slightly affected the GR; however, the GR was inhibited when the seeds were incubated for longer times at high power levels.…”

“…These non-thermal effects on seeds and biological objects are due to the direct interaction of the microwaves with molecules or tissue components since particles seek to orient themselves within an electric fi eld and minimize the potential energy [Radzevičius et al, 2013]. Ji et al [2016] reported that the total fl avonoid content in the tartary buckwheat sprouts irradiated with blue light followed by UV-C (BL+UV-C) increased by 10% compared with The results indicated that microwave pretreatment increased some enzyme activities, GR and growth vigor [Chen et al, 2009a]. However, key enzymes (PAL, CHI and rutin degrading enzymes) were revealed to have a signifi cant correlation with total fl avonoids in tartary buckwheat sprouts [Ji et al, 2016].…”

“…Pretreatment with microwaves activates the POD and SOD isozymes at some gene loci and enhances their expression in seedlings [Aladjadjiyan, 2012]; therefore, they can maintain the integrity of the cell membrane and the antioxidant capacity, which enhances plant stress resistance [Chen et al, 2009a]. Seeds irradiated with microwaves followed by salt stress restored plant growth parameters and biochemical parameters related to an oxidative status almost to the levels of non-salt-treated seedlings.…”

“…Seeds irradiated with microwaves followed by salt stress restored plant growth parameters and biochemical parameters related to an oxidative status almost to the levels of non-salt-treated seedlings. The results indicated that irradiating wheat seeds with a suitable dose of microwave radiation could enhance the tolerance of seedlings to salt stress [Chen et al, 2009a;Chen et al, 2009b]. Microwaves improve the activities of some enzymes in Isatis indigotica cotyledons, including amylase, alanine aminotransferase and protease, and they accelerate cell metabolism and signifi cantly increase biophoton emissions [Chen et al, 2005].…”