IRANIAN JOURNAL OF PLANT PHYSIOLOGY
Year:2017 | Volume:7 | Issue:4 |Papers Count:8

Seed priming, as a low-cost method, is a technique commonly used to increase germination percentage especially under unfavorable conditions. The objective of this study was to evaluate the effects of bio-priming on the germination of canola (Brassica napus L. ) seeds under saline (NaCl) conditions. Seeds of canola var. Hyola 401 were inoculated with plant growth-promoting microorganism (PGPM) including bacterium Bacillus subtilis strain Ham and fungus Trichoderma harzianum strain bp4. The primed seeds were subsequently exposed to four levels of salinity (0, 5, 7. 5, and 10 dS. m-1). Results showed that application of priming with PGPM significantly improved the percentage of seed germination, root length and seedling vigor index under saline conditions. Results of this study may provide useful information concerning reduction of undesirable effects due to salinity on canola seed germination which leads to increase of the rate of deployment of canola in areas that are facing salinity of soil or irrigation water.

Ficus religiosa has great mythological, religious, and medicinal importance in the culture of India and Nepal since times immemorial. The present paper was done to evaluate the potential of sodium hypochlorite in controlling the contamination of F. religiosa micro-propagation and seed germination of F. religiosa. In this study, a factorial experiment based on a completely randomized design with 18 treatments including six different sodium hypochlorite concentrations (0, 5, 10, 15, 20, and 25 %) and three soaking time of explants (5, 10 and, 15 min) with three replications was conducted. The seeds were inoculated on one-tenth strength of MS (Murashige and Skoog, 1962) medium. The lowest rate of contamination (0%) was obtained in treatments containing 20% Sodium hypochlorite at 10 and 15 min immersion and 25% Sodium hypochlorite at 5, 10 and 15 min immersion. The highest seed germination (63. 33%) was observed in treatments including 10% Sodium hypochlorite at 5 and 10 min immersion.

The aim of this study was to investigate the adaptation of the cyanobacterium Fischerella sp. ISC 107 to combined effects of carbon dioxide concentration, acidic and alkalinity. Axenic strain was incubated in BG0-11 medium. Carbon dioxide treatments were limited and relatively non-limited. Acidic (pH 5), neutral (pH7), and alkaline (pH 9) conditions were employed in each treatment. Survival, growth, chlorophyll, phycocyanin, allophycocyanin, and phycoerythrin contents were evaluated in each treatment along with ammonium liberation, frequency, and biometry of heterocyst. Results showed that like other explored stigonematalean and nostocalean cyanobacteria, this strain cannot grow in acidic condition. Under limited carbon dioxide condition, difference in growth rates were not significant between acidic and alkaline conditions; however, carbon dioxide enrichment caused significant increase in growth rates. Phycobilisome system of this strain lacked phycoerythrin and may complete its structure both at the core and the rod under alkaline condition. Heterocyst frequency and biometry were maximum at alkaline condition showing significant correlation with nitrogenase activity. Heterocyst showed cylindrical and sub-cylindrical morphology on days 4 and 5 after inoculation. Overall, the results showed that this strain may be qualified to be used as a biofertilizer similar to the other cyanobacteria.

The increasing commercial production and the broad usage of engineered nanoparticles (ENPs) have led to concerns over the potential adverse impacts of these ENPs on biota in natural environments. Silver nanoparticles (AgNPs) are one of the most important and widely used ENPs which enter natural ecosystems. In this study we examined the effects of AgNPs on growth and some physiological parameters of Dracocephalum moldavica L. The experiment was conducted hydroponically in a AgNPs spiked solution. The AgNPs toxicity exhibited a decline in growth and chlorophyll content of D. moldavica at elevated concentrations (> 40 mg/L). AgNPs significantly induced oxidative stress by increasing H2O2 production in a concentration dependent manner. The phytotoxicity of AgNPs led to an increase in catalase and peroxidase activities and synthesis of antioxidant compounds such as carotenoids, proline and total soluble carbohydrate. The decline of chlorophyll content at highest AgNPs treatment (80 mg/L) was associated with disturbances in photosynthetic capacity which ultimately results in the reduction of D. moldavica growth. Increase carotenoids, proline and total soluble carbohydrate content suggest that compatible solutes may contribute to osmotic adjustment at the cellular level and enzyme protection stabilizing the structure of macromolecules and organelles. Our results indicate important new avenues of research for understanding the fate of AgNPs in hydroponic media, the interactions between AgNPs and D. moldavica.

The present study aims to assess the effect of Thiobacillus and sulfur on morphological and biochemical properties of medicinal pumpkin properties under deficit irrigation based on a split-plot design. For this purpose, water stress was applied as a main factor in three levels (control, no irrigation in flowering stage, no irrigation in fruiting), and Thiobacillus and sulfur fertilizers as sub-plots (250 kg/ha). The results revealed water stress significantly reduced stem diameter, fruit weight, fruit yield, and 1000-seed weight. In contrast, Thiobacillus + sulfur significantly increased fruit weight, fruit yield, 1000-seed weight, seed yield, and oil content. Furthermore, deficit irrigation and fertilizers influenced fatty acid of medicinal pumpkin. The interaction of fertilizer and deficit irrigation was significant on all seed oil compositions, fruit weight and yield as well as seed weight and yield. The fatty acid profile of the oil showed that it is composed primarily of oleic, linoleic, palmitic, stearic, and linolenic acids.

Knowledge of genetic diversity and relationships between genotypes is mainly important for selection of parental genotypes. Moreover, assessing diversity across and within crop varieties is important to improve the description of collections in gene banks and in on-farm conservation practices. In order to evaluation and study of genetic diversity in the bean in normal condition, forty-five bean genotypes (15 genotypes of each white, red and chiti beans) were planted in a randomized group balanced block design with three replications under the non-stress condition and Twenty-four traits were recorded. The results showed that traits such as R7 (the number of days to stage podding), Bush type, 100 seed weight, bush height, height of internodes and steam diameter in white, red and chiti bean were significantly different (p<0. 01). Furthermore, in the number of days to appearance of first three leaves let, pod/plant, seed/pod and seed/plant there were significant differences (p<0. 05). According to simple correlation analysis of traits, the yield had a positive and significant correlation (p<0. 01) with the length of the highest pod (r= 0. 93). Moreover, in p<0. 05 the correlations between steam diameter (r= 0. 89), height of internodes (r= 0. 85) and height of plant (r= 0. 80) were significantly differences. Yield evaluation, that was carried out by stepwise regression analysis on the basis of yield traits, showed the number of pods/plant, seeds/pod, leaves/plant, and Length of the highest pod were the most important traits for population evaluation regarding yield. Also, the result of factor analysis showed that based on eigenvalues greater than one, seven factors was selected that these factors explained 80. 66% of the total variation. Genotype number KS-41113, KS-41114, KS-31140, KS-31122, KS-41109, KS-31114, KS-41112, KS-41101, KS-41106 and KS-31104 were selected as the better choice.

The objective of this study was to investigate the role of β-aminobutyric acid (BABA) (0, 300μ M) in reduction of oxidative damages in leaves and roots of Brassica napus L. under drought stress (0,-0. 2,-0. 4 MPa). β-aminobutyric acid was investigated as an internal regulator hormone and its role in defense mechanisms against biotic and abiotic stresses. In this study, BABA pretreatment prevented drought induced decrease in K+ content and increase in lipid peroxidation and H2O2 content. Mild and severe drought stress increased leaf and root MDA and other aldehydes content. In BABA pretreated plants under stress, leaf and root MDA and other aldehydes content significantly decreased as compare to drought condition. In addition, in drought stressed plants non-enzymatic antioxidants [GSH] were elevated over the control and BABA pretreatment increased GSH content. The Na+ and Ca++ concentration increased under mild and severe drought stress. On the basis of the results, BABA-treated plants exhibited enhanced drought tolerance.

Plants may show different behaviours during exposure to low temperature stress through various mechanisms. In this study, the chilling responses of ‘ Sultana’ grapevine were investigated during a gradual chilling (2 ° C/h) and also during a shock chilling (5 ° C/h) from 24 ° C to 4 ° C. After artificial chilling stress, electrolyte leakage, lipid peroxidation, hydrogen peroxide production and antioxidant enzymes activities were measured in all plants leaves. Moreover, the potential of plant to accumulate abscisic acid and osmoregulants were compared under both gradual and shock chilling stresses. Based on the results, a significant difference was found between the electrolyte leakage, lipid peroxidation and hydrogen peroxide content of plants under two chilling regimes. These indices were found to be higher in shock chilling stressed plants compared with gradual chilling stressed vines because of the lower catalase, peroxidase and ascorbate peroxidase activities. Moreover, gradual chilling stressed vines exhibited higher accumulation of abscisic acid, proline and total phenolic compounds. The chlorophyll degradation and relative water content were lower in gradual cold stressed plants. Glucose and fructose, unlike sucrose showed higher concentration in gradual cold stressed vines. Totally, under gradual chilling stress grapevine plants showed better cold acclimation by lower oxidative stress and higher accumulation of osmoregulants in compared with shock chilling stressed vines.