Iranian Journal of Plant Physiology
Volume:5 Issue: 4, Summer 2015

The present study is focused on the importance of SNP, a NO donor, as Cd stress modulator on seedlings of cabbage. The exogenously applied Cd induced stress in cabbage seedlings to explore the protective role of SNP. 21-day-old seedlings were grown in Hoagland solution and Cd at 0.5 and 0.7 mM concentration with and without SNP. The biophysical and biochemical parameters were analyzed. Cd exhibited inhibitory effects on growth and metabolism of cabbage seedlings. SNP enhanced growth viz. root and shoot length and fresh and dry weight of the seedlings. The pigment content, sugar, and protein contents decreased in seedlings treated with Cd while increased in SNP with and without Cd. The graded concentration of Cd significantly enhanced the antioxidative enzyme viz. superoxide dismutase (SOD), catalase (CAT), and peroxidase (POX) to avoid the oxidative damage caused by heavy metal stress. SNP reduced the oxidative damage and provided protection against heavy metal toxicity.

Fresh peaches are highly perishable and they deteriorate quickly during low temperature storage which results in losses in nutritional quality. To prevent these adverse effects, peach fruits were treated by dipping with γ-aminobutyric acid (GABA; 2, 4 and 6 mM) immediately after harvest and then stored at 1 °C for 7, 14, 21, and 28 days. Peach fruits treated with GABA exhibited higher flesh firmness and TSS. In addition, GABA treatments were effective in maintaining higher contents of healthpromoting molecules such as ascorbic acid, total phenols and flavonoids as well as DPPH scavenging capacity. These results suggest that GABA could have promising postharvest effect for maintaining quality and enhancing the health benefits of peach fruit consumption by increasing the antioxidant capacity.

In this research, the effects of electromagnetic fields of various strengths (0, 1 and 2mT) have been investigated on antioxidant enzymes activity in Valerian (Valeriana officinalis L.). The dry and wet (soaked for 30 min) Valerian seeds were exposed to electromagnetic fields 30 min per day for 3 days. Each treatment and control groups had 3 replicates and 10 seeds were employed for each replicate. Results showed that electromagnetic field treatment increased significantly root length, fresh and dry weight, ascorbate peroxidase, guaiacol peroxidase, superoxide dismutase, polyphenol oxidase and lipoxygenase activity compared to control for most treatment groups especially in the groups of dry treated seeds. These results showed that electromagnetic fields probably enhanced oxidative stress and treated Valerian seeds probably increased antioxidant enzymes activity to inhibit overproduction of free radicals against electromagnetic fields tension.

The present study was carried out to evaluate the effects of light and plant growth regulators on callus induction and explant browning in date palm cultivar, Estameran in in vitro condition. The explants were pretreated by an antioxidant combination (100 mgl-1 citric acid and 150 mgl-1 ascorbic acid) for 3 days in 5 °C. Then, the leaf explants were cultured in Murashige and Skoog medium (MS) with 3 gL-1 of activated charcoal, 75 mgl-1 citric acid and 75 mgl-1 ascorbic acid, for 14 days. After that, explants cultured in callogenesis medium were supplemented with 12 different levels of plant growth regulators including 2,4-D (0 and 5 mgl-1), TDZ (0 and 5 mgl-1), and BAP at three concentrations (0, 5, and 10 mgl-1), and two incubation conditions (light condition and absolute darkness). The number of explants that induced callus and browning was recorded after six months. Results indicated that 2,4-D and BAP increased browning and this was exacerbated under light condition. Highest callus induction was achieved in medium supplemented with 5 mgl-1 BAP or with 5 mgl-1 TDZ. This experiment showed that low concentrations of cytokinin induced callus in date palm in vitro leave culture and callus induction increased in darkness.

Hydroponically grown ten grape genotypes (Vitis vinifera L.) were treated with different concentrations of NaCl. Chawga genotype accumulated K+ in its root and shoot even at high salinity. The correlation between Na+ and K+ concentrations in root and lamina of all genotypes was negative (P<0.05, r2=-0.841) except for Chawga (P<0.01, r2=0.998). Km calculated for K+ and Na+ uptake into root and shoot of Chawga showed that K+ and Na+ compete to enter the plant, especially through roots. Chawga accumulated K+ in plant parts in spite of external higher Na+ due to increasing salinity. Two KUP/KT/HAK-type potassium transporters are expressed highly in the grapevine during stress. VvK1.1 could play a major role in K+ loading into grape tissues. Under salinity stress the expression of VvKUP1 and VvKUP2 transporter and VvK1.1 channel increased significantly (P<0.05) in roots and leaves of Chawga genotype, but that increase was higher in roots than in leaves.

In order to survey effect of salinity and cadmium on catalase and peroxidase enzymes activity, proline accumulation, Malondialdehyde and protein content variation in Brassica oleracea an experiment was conducted in green house condition factorial design based on completely random block in 2014 year. The first factor was cadmium at four levels (0, 50, 100 and 200 ppm) and second factor was salinity at three levels (0, 50, 100 ppm). According to result of this experiment, catalase and peroxidase enzymes activity and proline and Malondialdehyde accumulation increased with Cd accumulation and protein content decreased. Under salinity stress peroxidase enzymes activity and Malondialdehyde accumulation increased. Interaction effect of cadmium and salinity cause to decrease Malondialdehyde accumulation, decrease protein content and decrease peroxidase and catalase enzyme activity.

This study involves in vitro androgenesis of Zea mays L. via anther culture. In the first experiment, three embryo induction media were tested in ETH-M82 genotype of maize. The results showed that the embryo structures were established 2 to 3 weeks after culturing the anthers. The effect of induction medium was significant for embryo frequencies. The obtained results confirm that the induction medium is one of the major supplements that support the development of anthers finalized either to embryo. IMSS medium with 22.4 embryo like structure (ELs)/replication was better than other medium and N6 medium had low production of embryos. In the second experiment, the analysis of variance showed that the percentage of normal regenerated plants was remarkably influenced by using whatman filter paper on regeneration medium (YPNAS).The use of whatman filter paper on the surface of regeneration medium had substantial increased normal plant production. In fact, the percentage of normal plants was 38% more in the presence of whatman paper on plant regeneration medium. In general, considering the morphology, such in vitro normal regenerated plants were very similar to maize seedlings. Such success in producing normal plants in maize anther culture by using whatman paper has not been reported yet.

Phytoremediation is a relatively new method in agricultural science for removing soil contaminants to some extent through cultivating some plants with the least cost. This research was conducted to examine the role of nickel as a heavy metal in catalase and peroxidase activities and also to study uptake and transfer ability of nickel in the organs of Persian clover. Experiment was done as randomized complete blocks design with four treatments. Treatments were consumption of Ni (NO3)2 at four levels of 0, 100, 200, 300 ppm. The plants were treated for 10 days. The results of research showed that the increase in nickel concentration reduced LWCA and the fresh weights of shoot and root; however, it had no effect on the dry weight of shoots, RGR, and leaf area. Moreover, nickel concentration in aerial organ was higher than in roots. The results showed that catalase and peroxidase activity increased by increase of nickel in the nutrient solution. The results of this research indicated that protein content decreased as nickel increased. TF was greater than 1 but BCA and BCF were less than 1 and with increase in soil Ni so did ratios value. Therefore, Persian clover is not suggested as a suitable plant for phytoremediation.