نشریه علوم و تحقیقات بذر ایران
سال دهم شماره 3 (پاییز 1402)

Potato (Solanum tubersum) is an important economic crop in the world. In order to investigate the effect of potassium (Potabarvar Bioferrtilizer) and Phosphorus (Barvar 2 Biofertilizer) biofertilizers on the yield and quality of two families of true potato seeds, including Fanta free pollinators and Savalan × Agria hybrids, an experiment was conducted in the form of a completely randomized block design with 8 treatments and three repetitions were done. The results showed that the use of Potabarvar Bioferrtilizer and Barvar 2 Biofertilizer affected plant height, leaf area and the dry matter percentage of tuber and leaf and led to an increase in yield compared to the control plants and the application of a mixture of biological fertilizers at the probability level of 1%. So that the highest yield in the treatment of Potabarvar biofertilizer was obtained on the free-pollinating Fanta family. Also, the application of these fertilizers led to an increase in the leaf chlorophyll index at the five percent probability level. The use of these biofertilizers led to an increase in the concentration of potassium, nitrogen and phosphorus elements in the plant at the level of 1% probability. The application of these fertilizers had a greater effect on the free-pollinating Fanta family. Also, the application of the mixture of these biofertilizers did not lead to an increase in the desired indicators.

Plant growth promoting rhizobacteria are a group of bacteria that can actively colonize plant roots and can stimulate plant growth. This study was executed to evaluate of four strains of Pseudomonas fluorescens Migula (PF1-4) and six strains of Pseudomonas putida (Trevisan) Migula (PP 1-6) on seed germination characteristics including germination percentage, germination rate, root and shoot length and dry weight, seed and seedling vigor index and α-amylase activity of pot marigold (Calendula officinalis L.). In vitro production of siderophore, hydrogen cyanide, indole-acetic acid (IAA) and volatile and non-volatile metabolites of bacteria were also determined. The bacterial suspension (109 CFU/ml) was used to inoculate the seeds under aseptic conditions. Results revealed that the metabolites concentrations were significantly different between bacterial strains. Different strains of rhizobacteria had also variable effects on germination parameters and the effect of plant-rhizobacteria interactions on germination characteristics could be positive or neutral. Maximum effects of bacterial strains were recorded for PP-1, PP-2, PP-5, PF-1 and PF-2 strains. The effects of bacterial strains on studied characteristics were significantly correlated with IAA production by bacteria. As a conclusion, the role of biopriming with growth promoting rhizobacteria on germination characteristics and seedling growth were dependent on bacterial species and strains. These results also suggest that the amont of bacterial IAA produced plays a major role in seed germination and may stimulate germination features.

Salinity is one of the abiotic stresses that has a major role in limiting the development and cultivation of plants in the green space. One of the most sensitive periods in life cycle of plants is the stage of germination and establishment of the plant in the soil. The application of priming has been effective in improving the germination of many plants. The present study was conducted with the aim of investigating the effect of priming on the germination of the periwinkle seeds under salt stress. The experiment was conducted based on a factorial in a completely randomized design with three replications. The factors include four salinity levels using sodium chloride (0, 4, 8 and 12 dS/m) and five priming levels (potassium nitrate 100 and 200 mg/l and ascorbic acid 100 and 200 mg/l and distilled water). The results showed that salinity reduced all investigated traits, but seed priming was effective in modulating the effect of stress at all salinity levels. Potassium nitrate priming was more effective than ascorbic acid. In treatment without salt stress, the application of priming in some levels, parameters such as seedling length, seedling fresh and dry weight, tissue water content increased compared to the control. According to the results obtained from this experiment, it is suggested that more research be done to reach the appropriate level of potassium nitrate priming for germination of periwinkle plant under salinity stress.

The propagation of Gundelia tournefortii L. via seed faces certain problems due to the strongly lignified disseminule from secondary capitulum. Therefore, in this study, in first, the interaction of chemical and mechanical scarification (Control, sodium hypochlorite, H2O2, scalpel and sand paper for 10 min) with cold stratification (0, 1, 2, 3 weeks) or nitrogenous compounds (control, thiourea, nitrate, sodium nitroprusside) on seed dormancy breaking were investigated in two separate factorial experiments. Results showed that all scarification methods significantly increased emergence percentage and growth of seedlings and the interaction of scarification methods with stratification or nitrogenous compounds on these attributes was significant. In the first experiment, the highest emergence percentage (75.6 %) and length of seedlings (22.4 cm) was gathered in treatment of seed scarification by scalpel + 3 weeks cold stratification. In the second experiment, the maximum emergence percentage (65.6 %) and length of root (10.2 cm) and shoot (8.1 cm), and minimum mean time of emergence (11.5 days) of seedlings, was obtained in treatment of seed scarification by scalpel and applying sodium nitroprussid (SNP). In third experiment, the impact of combined application of SNP and cold stratification was assessed on dormancy breaking of seeds scarified with scalpel. Results showed that the application of SNP reduced duration of cold stratification required for obtaining the best emergence indices and maximum dry weight of seedlings. These results indicate that Gundelia tournefortii seeds have physical and physiological dormancy and can achieve the highest percentage of emergence (85%) and the lowest average emergence time (8.5 days) by treatments of scarification with scalpel and then cold stratification or SNP treatment.

To investigate the effect of different levels of Mycort fungus, nitrogen fertilizer and cytokinin hormone on yield and yield components of wheat, an experiment was conducted in 2018-19 crop year. The experimental design was a factorial based on randomized complete block with three replications. The first factor was organic fertilizer of mycorrhizal fungus (2, 4 and 6 kg/100 kg seeds), the second factor was nitrogen fertilizer (zero, 25 and 50 kg/ha) and the third factor was cytokinin foliar application (control, foliar application at flowering and grain filling). The results of mean comparisons showed that levels of 25 and 50 kg/ha of nitrogen fertilizer increased the number of grains compared to the control treatment by 44.23 and 32.69%, respectively.resultsshowed that inoculation with 2 and 4 kg/100 kg of seeds along with the application of 25 kg / ha of nitrogen had the highest spike length and number of fertile spikes. The highest number of fertile spikes, number of grains per spike, 1000-kernal weight, grain yield and harvest index were assigned to seed inoculation treatment with 4 kg of mycorta and cytokinin foliar application at grainclosure stage. Also, foliar application of cytokinin in the graining stage along with the application of 25 kg / ha of nitrogenfertilizer had the highest number of spikes, 1000-kernal weight, biological yield and grain yield.

To evaluate the effect of seed priming with ascorbic acid to increase salt tolerance in Chenopodium quinoa var. Giza 1 during the vegetative growth period, the current research was conducted in the form of a factorial experiment (ascorbic acid at three levels of 0, 20 and 60 mM and NaCl at two levels of 0 and 400 mM) and based on a completely randomized design. The traits measured in the experiment were fresh and dry weight, concentration of photosynthetic pigments, hydrogen peroxide (H2O2) and malondialdehyde, and the activity of antioxidant enzymes. Data analysis showed salinity resulted in a significant decrease in the amount of dry weight (51.4%), fresh weight (65.6%) and total chlorophyll (55.8%). In addition, salinity increased the content of malondialdehyde (2.3 folds), hydrogen peroxide (2.5 folds) and the activity of antioxidant enzymes (catalase, ascorbate peroxidase and guaiacol peroxidase). However, seed priming with ascorbic acid at the best level (20 mM) alleviated the adverse effects of NaCl in this variety by increasing the fresh weight (44.7%), dry weight (51.4%), and protecting membrane integrity and photosynthesis activity. Also, the use of ascorbic acid by changing the activity of antioxidant enzymes and reducing the content of hydrogen peroxide caused a reduction in oxidative stress in in this variety. It can be concluded that seed priming of this variety with 20 mM ascorbic acid can be effective on its successful cultivation in high salinity levels.