فصلنامه زیست شناسی گیاهی ایران
سال دوازدهم شماره 4 (پیاپی 46، زمستان 1399)

In order to study the effect of Sodium Selenate, Titanium dioxide and Growth regulator (Hamon Green®) on some physiological traits, yield and oil content of Goldasht cultivar of safflower under drought stress, a split plot experiment was conducted in a randomized complete block design with three replications in Agricultural Research Center of Zabol University (Chah-e-Nime). The main factor included irrigation cut off levels based on the phenological stages of growth in three levels: I1 = control (complete irrigation), I2= irrigation up to stage R2 (flowering) and I3= irrigation up to stage R1 (branching) and sub-factor including control(not spraying), Sodium selenate (2 mM), Titanium dioxide (0.03%), Growth regulator (0.1 L). Drought stress reduced biological yield, seed yield, 1000 seed weight, relative water content and chlorophyll content (SPAD), but seed and biological yield did not differ significantly between two levels of I1 and I2. The highest amounts of catalase(I2+not spraying),and proline, ascorbate and guaiacol peroxidase was obtained from the interaction of stress(I3) and not spraying. The highest amount of soluble carbohydrates was observed in irrigation + Hamon Green® spraying. The treatments applied did not have a significant effect on seed oil percentage. In general, treatment in order to observe water consumption in the production of safflower in Goldsch cultivar seems appropriate.

In order to induction of hairy roots, the leaf and petiole explants from seedlings grown under in vitro condition were inoculated with A4 strain of Agrobacterium rhizogenesis. Transgenic hairy roots were confirmed by PCR. Transgenic hairy roots were treated with different concentrations of iron and nickel nano-oxides and methyl jasmonate alone and in combination with L-leucine. Then hairy roots were sampled at 24 and 72 hours after treatment and the biochemical properties and expression of VoTPS1 and VoTPS6 genes were evaluated. The gene expression level was measured using real-time PCR technique and specific primers for each gene. The results showed that the combined application of 100 μM methyl jasmonat and 1 mM L-leucine was increased the activity of catalase enzymes and proline content in Valerian hairy root compared to the control. Among the different concentrations of nickel nano-oxide, the treatment containing 30 mg/l nickel nano-oxide with 1 mM L-leucine increased the activity of peroxidase enzyme and containing 60 mg/l nickel nano-oxide increased the total protein content in hairy roots. In addition, Among the different concentrations of iron nano-oxide, 30 mg/l of this nano-oxide increased the activity of peroxidase enzyme and the amount of flavonoid content, and combination of 90 mg/l of this nano-oxide with 1 mM of L-leucine amino acid was led to the an increase in proline content. The highest expression for VoTPS1 gene was observed in treatment containing 60 mg/l iron Nano-oxide at 24 hours after elicitation. The highest expression for VoTPS6 gene was observed in treatment containing methyl-jasmonate (100µM) and L-leucine (1mM) at 72 hours after elicitation.

AbstractCalotropis procera (Aiton) W.T belonging to family Apocynaceae (subfamily Asclepiadoideae) is a xerophytic, perennial and evergreen shrub highly tolerant to drought and salt stresses with remarkable distribution ability in dry and hot areas of southern of Kerman province, Iran. Due to its pharmacognostic features, this shrub is used in traditional medicine for the treatment of various diseases. In addition, due to its importance in phytoremediation, this species is a useful bio-indicator for monitoring pollution in urban and suburban areas. In this research, the structure of ovary and fruit, structure and ultrastructure of seed and its hairs (fibers) were studied with stereo, light and scanning electron microscopy (SEM (.Gynoecium has two free and superior ovaries with numerous anatropous ovules and marginal placentation. The fruits are oval shaped follicles, which their pericarp become swollen during maturity and split and invert to release hundreds of flat and brown seeds. The seeds have a tuft of silky white hairs at one end. These white fibers attached to the seeds serve to wind dispersal. The seed coat has reticulated ornamentation at early developmental stages and then during maturation, the leaf-like ornamentations differentiate among which the small prominent structures are developed.

This study aimed to investigate the effect of mild salinity on cadmium (Cd)-induced toxicity in Malva parviflora. Forty days after sowing the seeds in trays containing Peat Moss soil, the plants were transferred to nutrient solutions under controlled light and temperature conditions. After one week, the plants were transferred to complete nutrient solutions with four treatments including 50 µM Cd, two levels of NaCl (25 and 50 mM) along with 50 µM Cd and control. Six days after the treatments, the plants were harvested and some biochemical and growth indices were evaluated. Both levels of salinity, especially 25 mM, resulted in increased length, weight and chlorophyll content in the plants exposed to Cd. In leaves and roots, the salinity reduced levels of lipid peroxidation, proline and soluble proteins contents, as well as activity of catalase, guaiacol peroxidase (GPX) and superoxide dismutase (SOD) in the plants treated with Cd. In addition, both salinity treatments reduced Cd content in roots and shoots. Investigation of electrophoretic pattern of enzyme extract in all studied plants revealed two isoenzymes of GPX. For SOD, three isoenzymes were observed in the leaves for all treatments. In the roots, five isoenzymes were detected for all plants exposed to Cd. Based on the results of this study, it seems that both levels of salinity can modulate the toxic effects of Cd and induction of oxidative stress and improve plant tolerance to Cd stress by reducing metal accumulation in M. parviflora.

Plants life has been affected by carbon cycle. The discovery of new forms of carbon in recent years has raised the question of how these forms affect plants. One of these new forms of graphene is the nanosized form caused by the mechanical breakdown of graphite materials. In this study, the effect of different concentrations of nanographene oxide (NGO) on plant growth, photosynthesis and antioxidant enzymes activity of cucumber plants in hydroponic culture was investigated. The seedlings root were treated with different concentrations of NGO including 0.4, 0.8, 1.2, 1.6 and 2 mg ml-1 graphene oxide for 30 and 60 minutes before transferring to culture medium. The results showed that NGO at lower concentrations (1.2 mg ml-1) can increase plant growth characteristics such as root and shoot dry weight as well as increase chlorophyll content and maximum photosynthetic yield. Maximum chlorophyll content (41.18) and photosynthetic efficiency (0.42) were observed at 1.2 mg ml-1. The maximum activity of peroxidase and superoxide dismutase enzymes was observed at concentrations of 1.2 and 1.6 mg ml-1 respectively. Malondialdehyde content decreased by 58 (30 min) and 23 (60 min) percent at 1.2 mg ml-1 concentration compared to control. The NGO also increased the concentration of nitrogen, potassium and iron and decreased the concentration of calcium compared to the control, but no significant difference was observed in the concentration of phosphorus and zinc. In fact, optimal concentrations of NGO can be used as a regulator and stimulant of cucumber plants growth. However, further studies are needed to investigate the effect of these emerging nanoparticles on plants.

Due to the drying trend of Urmia Lake, climate change and frequent occurrence of droughts in the region, verification of photosynthetic flexibility in the floral elements of Lake Urmia is important. In this work, the ability of Rosularia elymaitica and Zygophyllum fabago species to shift from C3 to Crassulacean acid metabolism (CAM) as well as survival and productivity of these plants were studied in both salty and dry soils of Lake Urmia. While salinity alone was not able to induce functional CAM expression in both species, we showed that drought alone induced low level of nocturnal acid accumulation in both species, which were similar to acid fluctuations in CAM-cycling pathway, as an initial stage of CAM. We indicated that Z. fabago species have a high tolerance to combined drought (30 days water dificit) and salt (7±0.42 dSm-1) stresses in salty and dry soils of the Lake Urmia, as compared to R. elymaitica plants. This higher tolerance was correlated with up-regulation of phosphoenolpyruvate-carboxylase (PEPC) activity and maintenance of higher photochemical functioning. As a result, this research introduces Z. fabago as an important climate-resilient crop, which can switch from C3 to CAM in salty and dry soils of the Lake Urmia.