Iranian Journal of Plant Physiology
Volume:6 Issue: 1, Autumn 2015

Elicitors could be used as the enhancer of plant secondary-metabolite synthesis and could play an important role in biosynthetic pathways of important medicinal compounds. The present study investigated the effect of abiotic elicitor (fungal extract of Fusarium graminearum) and two abiotic elicitors (methyl jasmonate and salicylic acid) at different concentrations in 18- and 30-day-old cultures of hairy roots infected with two strains of Agrobacterium rhizogenes, A13 and 9534. The hairy roots were harvested 48 and 96 h after inoculation. Polymerase chain reaction analysis (PCR) with specific primers rolB and virD genes was performed to confirm the transgenic hairy roots production. Detection and identification of lignan was carried out by high performance liquid chromatography (HPLC) method. The results of PCR analysis showed diagnostic bands 780 bp in size related to specific reproduction of rolB gene. Also maximum lignan production for each elicitor was as follow: fungal extract at 1% v/v (12.87 ± 0.66 and 89.65 ± 3.9 mg/gr DW ± SD podophyllotoxin and 6-methoxypodophyllotoxin, respectively for), methyl jasmonat at 100 μm (11.37± 0.65 and 75.65 ± 3.9 mg/gr DW± SD for podophyllotoxin and 6-methoxypodophyllotoxin, respectively), and salicylic acid at 200 μm (7.97 ± 0.33 and 51.68 ±2.1 mg/gr DW ± SD for podophyllotoxin and 6-methoxypodophyllotoxin, respectively). Important factors such as strain of agrobacterium (A13), duration of exposure time (48 h), and age of culture (18-day-old culture) affected lignan accumulation.

objective of this study was to evaluate total phenolic content and antioxidant activity of leaf and different parts of fruit (hull, shell, and kernel) of Bene in Ilam province. Total phenolic content was determined with the Folin- Ciocalteu Reagent (FCR); antioxidant activity of methanolic extracts were examined by DPPH (2,2-diphenyl- 1- picrylhydrazyl), FRAP (ferric reducing antioxidant power) and nitric oxide radical scavenging methods. Among all the samples tested, leaf contained the highest total phenolic content followed by hull, kernel, and shell. There was a positive correlation between total phenol content and FRAP, Nitric oxide radical scavenging activity, and DPPH radical scavenging activity (r= 0.993, r= 0.972, and r= 0.969, respectively). The results indicated that antioxidant activity of leaf and hull extracts were significantly higher than kernel and shell extracts and this is attributed to their higher total phenolic and flavonoid contents. The FRAP, nitric oxide radical scavenging activity, and DPPH radical scavenging activity assay showed that leaf and hull extracts with potent activity can be introduced as a source of natural antioxidant. Compared with BHA, the extracts of leaf and hull revealed a remarkable DPPH free radical scavenging activity but shell and kernel extracts with higher EC50 had a weak activity.

The increase of environmental pollutants especially heavy metals derives from human industrial communities. Zinc is one of the natural elements that exist in biotic environment, plants body, and animals in different forms. Zinc has toxic and lethal effects in high concentrations on plants. Also some plants are introduced as accumulators of this element. Therefore, an investigation was carried out to consider different concentrations of Zn on Plantago major in completely random form and with three replications. The ZnSO4.7H2O was included at 0, 50, 100, 250, 500, and 700 μmolar concentrations that were applied to the plants during 8 days. The results indicated that catalase enzyme activity increased significantly in comparison with control in root and shoot except at 50 μmolar concentration. Ascorbate peroxidase enzyme activity increased significantly only at 50 and 500 μmolar concentrations in comparison with control in shoots but it increased significantly in root with increasing metal concentration. Peroxidase enzyme activity increased significantly only at 50 and 700 μmolar concentration in shoot; however, this enzyme increased significantly in root with increasing metal concentration except at 500 μmolar concentration. The amount of proline increased significantly with increasing of zinc concentration. Soluble carbohydrates decreased significantly in comparison with control in root and aerial organs except at 700 μmolar concentration. These results derive from plant resistance against high concentrations of Zn.

The impact of three levels of sea salt (0.0, 8.0, and 16.0 mS/cm2) on six varieties of soybean (Crawford, G21, G22, G35, G82, and G83) was studied. Growth criteria, photosynthetic pigments, soluble sugars, soluble protein, free amino acids, free proline, and protein profile of soybean varieties were investigated under sea salt stress. Results of this study showed a considerable decrease in growth criteria (shoot height, root depth, and leaflet area), photosynthetic pigments (Chl a, Chl b and carotenoids), soluble sugars, and soluble proteins with the increase in salinity level. The total free amino acids and free proline contents were increased with the increase in sea salt level. SDS-PAGE of the seedling proteins showed a significant variation in the protein profile of soybean and the variation is a function of varieties and sea salt level.

Jasmonate compounds are known as new plant hormones that play important roles in the regulation of plant growth and development. Mints have been used and valued as aromatic herbs for thousands of years. Peppermint (Mentha piperita L.) is used for medicinal and food purposes and its essential oil is considered industrially important. Peppermint plants were grown in a greenhouse in pots. At flowering phase, the plants were treated with different concentrations of MeJA (0, 0.1, 0.5 mM) and after 24 h were evaluated for their carotenoid, anthocyanin, phenol, flavonol, flavonoid, H2O2, and proline. Analysis of variance indicated that different concentrations of MeJA caused significant variation in all measured traits except proline. As the latest studies indicated that components such as polyphenols, carotenoids, and flavonoids are natural antioxidants, the results of this experiment showed a significant increase in the antioxidant potential of Mentha piperita treated with 0.1 mM MeJA.

Trees can improve air quality, but at the same time, pollution might put them at risk. Plane(Platanus orientalis L) and willow trees (Salix babylonicaL) are important trees in the green space of Tehran. Plane trees in Tehran have experienced early autumn in recent years due to severe air pollution. The present study, investigated some physiological traits of these trees under study to determine the cause of early autumn phenomenon. Three regions in Tehran were chosen for the study: Sadra Park as a clean region, Al-Mahdi Park as the polluted region 1, and Avesta Park as the polluted region 2. The results showed that the highest levels of chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, and anthocyanins were observed in the leaves of the plane trees of Sadra Park and the leaves of the willow trees of the Avesta Park and Sadra Park. The average concentration of lead (Pb) in the plane leaves was observed in the Avesta Park and the highest cadmium concentration was recorded for the Sadra Park while the concentration of these two metals in the leaves of willow trees in the three regions were not significantly different. This may suggest that the willow trees, by an increase in the amount of anthocyanins of their leaves, prevent the reduction of the amount of photosynthetic pigments under the influence of air pollution. By late spring, the two plants could relatively preserve similar amounts of lead and cadmium in their leaves.

ROS detoxification is an essential process in protecting plant cells and their organelles, which is caused by ROS generated in stress condition. Peroxidase (POD) isozyme, Malondialdehyde (MDA) content, and Ascorbate peroxidase (APX) activity are the indicators of plants for measuring pollution effects. The purpose of the present study was to investigate Cd-induced stress on POD isozymes, MDA content, and APX activity in seedlings of Berberis integerrima and Cercis siliquastrum. 100 seedlings were treated with cadmium chloride separately at concentrations of 0, 1000, 2000, 4000, 6000 mg/kg three times at intervals of 15 days. POD activity varied at different levels of Cd stress Cercis siliquastrum, while this was not the case with Berberis integerrima. MDA was slightly increased up to 6000 mg/kg from 5% to 27%, but a sharp increase (41%) was found at 6000 mg/kg compared with 4000 mg/kg Cd treatment in Cercis siliquastrum. The highest MDA content (10.5 μM/ g FW) was recorded at 6000 mg/kg trearment in Berberis integerrima, while the lowest value (2.3 μM/ g FW)was found in control Cercis siliquastrum plants. The maximum and minimum APX activity were found in the treatments of 6000 mg/kg (0.13 unit/mg protein) and control (0.02 unit/mg protein), respectively, for both Cercis siliquastrum and Berberis integerrima. In control Berberis integerrima, APX activity (0.02 unit/mg protein) was higher than that of Cercis siliquastrum (0.006 unit/mg protein) (p 0.05). Overall, the findings suggest that Berberis integerrima is less tolerant than Cercis siliquastrum under Cd-induced stress.

The effects of UV-B radiation on the amount of chlorophyll a, b, carotenoids, flavonoids, anthocyanins, and polyphenols of three soybean cultivars was studied. After germination in the incubator, plants were put in pots of soil and during 3 weeks and irrigated with Hoagland solution every day. After 3 weeks, plants were exposed to UV-B for 20 min every day for a week. In each cultivar, UV-B reduced chlorophyll a, b, and carotenoids and increased anthocyanins, flavonoids, and polyphenols. The reduction of chlorophyll a and b content was significant between two cultivars Williames, Linfored and L17, Linfored. Carotenoids content showed significant decrease between cultivars Linfored, Williames and Linfored, L17. The anthocyanin and flavonoid contents were affected by UV-B and there was a significant difference in the increase between Williames and L17 and also between L17 and Linfored cultivars. Also increase in phenol content was significantly different between Williames and L17 and also between Williames and Linfored cultivars.