نشریه فیزیولوژی محیطی گیاهی
پیاپی 41 (بهار 1395)

The aim of this study was determining the physiological and morphological responses of two-year-old common ash (Fraxinus excelsior L.) seedlings to flooding stress. For this purpose¡ seedlings of common ash were examined in a completely randomized design for 102 days under continuous flooding¡ temporary flooding treatment (for 60 and 42 days drainage¡ respectively) and control. Stomatal conductance¡ transpiration¡ and photosynthesis rate were progressively decreased by flooding while all seedlings survived at the end of flooding. Also¡ flooded plants were able to adequately recover their physiological activities. In addition¡ height¡ root length¡ leaf area¡ and biomass accumulation of seedlings decreased under flooding conditions (particularly in continuous flooding). Diameter growth on the other hand¡ increased in seedlings subjected to temporary flooding. Overall¡ the results showed that two-year-old seedlings of F. excelsior had a suitable response to flooding stress until day 60. After 42 days drainage¡ the physiological characteristics of the seedlings were recovered. Generally¡ on the basis of the findings in this research¡ it is expected that F. excelsior can be used for the purpose of restoration of lowlands and wood production in areas subjected to periodic flooding.

This study was designed in order to investigate the effect of foliar spraying of brown seaweed water extract (Nizamuddinia zanardinii) at different levels of nitrogen on some physiological, biochemical, parameters and yield of wheat (Triticum aestivum cv. Chamran 2). The experiment was based on a factorial study with completely randomized design and three replications at five levels (0, 5, 10, 15, and 20 percent) of brown seaweed water extract and three levels of nitrogen (0, 34.5 and 69 kg.hec-1). Leaf area, photosynthetic pigments, soluble carbohydrates, protein, and proline content at seedling stage and plant height, spike length, and total harvest index of plant at complete mature stage were measured. The results showed that application of brown seaweed extract led to a significant increase in the studied growth parameters in comparison with the control. Application of brown seaweed extract at concentration of 10% along with 34.5 kg.hec-1 nitrogen resulted in the highest leaf area, photosynthetic pigment content, carbohydrates, protein, plant height, spike length, and total harvest index. The maximum amount of proline was observed at concentration 20% of brown seaweed extract. According to the results, using brown seaweed extract at 10% concentration along with 34.5 kg.hec-1 nitrogen led to the maximum quality and yield of wheat.

Increasing salinity of soil and water is the most important concern for agriculture in dry lands. In this research the effect of Azospirillum inoculation alone and in co-inoculation with phosphate solubilizing bacteria was investigated in alleviating the adverse effect of salinity on mung bean Vigna radiata L. cv Gohar) for 2-year under field condition. The study was a factorial experiment based on a randomized complete block design with three replicates. The main factors were application of various serovars of Azospirillum, phosphate solubilizing bacteria Bacillus megaterium, co-inoculation of both bacteria, non-inoculated treatment as control and two levels of salinity irrigation (0.2 and 12 dS m-1). Analysis of variance indicated significant effect of salinity and microbial inoculation on mung bean seed yield. Salinity resulted in reduction of seed yield by 88%. Under salinity and non-salinity conditions, the highest amount of grain yield, seed weight, and seed number was observed in plants with seeds inoculated with Azospirillum. The minimum Na and K and maximum P contents of seeds were observed in Azospirillum inoculated plants. Co-inoculation with Azospirillum and Bacillus megaterium resulted in no further beneficial effect under saline and non-saline conditions. Overall, Azospirillum appeared to be effective in mitigation of the adverse effect of NaCl and its co-inoculation with phosphate solubilizing bacteria gained no more additives benefit.

Stachys lavandulifolia is one of the medicinal plants from genus of Stachys and Labiatae with different medicinal properties that is widely found in Iran. This research was based on a completely randomized design with three replications to investigate the morphological characteristics and phytochemical properties in four habitats in Semnan, Razavi and North Khorasan provinces in 2014. Morphological characteristics such as plant height, wet and dry root and shoot weights, root length, number of total flowers, number of open flowers and leaf, leaf area, and chlorophyll content were measured at the time of flowering. Also, essential oil yield and percentage, total phenols, total flavonoids, and antioxidant activity were measured in flowering time. Morphological characteristics did not show any significant difference but essential oil yield and percentage showed a significant difference in different habits. The highes total phenol and antioxidant content were recorded for Shahrud and Mashhad, respectively. The amount of total phenol and flavonoid were determined in the leaves and the highest amount of antioxidant was recorded in flowers. Finally, the highest level of essential oil yield and percentage were recorded for Mashhad and decrease in the altitude and rainfall could be attributed increase in essential oil in Stachys lavandulifolia.

In order to study the response of nitrogen physiological efficiency of safflower to animal and chemical fertilizers in Kashan region, this study was carried out in 2014. A factorial arrangement of treatments in a randomized complete block design with three replications was used. Chemical fertilizer treatment (F1= Control, F2= 50 kg ha-1 of nitrogen 25 kg ha-1 of P2O5, F3= 100 kg ha-1 of nitrogen 50 kg ha-1 of P2O5, F4= 150 kg ha-1 of nitrogen 75 kg ha-1 of P2O5) and animal manure treatment (M1= Control, M2= 20 ton ha-1, M3= 40 ton ha-1) were assigned in plots. Each plot consisted of 4 rows, 5 m long with 50 cm between rows space and 5 cm between plants on the row was used. Stem height, number of boll per m2, harvest index, oil yield, weight of boll, protein yield, phosphorus percentage, nitrogen absorption amount, nitrogen superficial recovery, nitrogen physiologic efficiency, and phosphorus use efficiency were assessed. Results indicated that the interaction effects of chemical fertilizer and animal manure on the characteristics such as oil yield, weight of boll, protein yield, phosphorus percent, nitrogen absorption amount, nitrogen appear recovery, nitrogen physiologic efficiency, and phosphorus use efficiency were significant. The maximum and minimum oil yield (254.3 and 75.33 kg ha-1) were obtained with the treatment (150 kg ha-1 of nitrogen 75 kg ha-1 of P2O5 20 ton ha-1 of animal manure) and (no application of the chemical and animal manure),respectively.

In order to study the effect of phosphate solubilizing bacteria in combination with phosphorus fertilizer on yield of corn hybrids, the experiment was carried out in the north of Khuzestan province during the summer of 2013-2014 by a split plot design in the form of randomized complete block with four replications. Combining biological and chemical fertilizers as main factors at four levels (100% chemical fertilizer, 75%, 50% and 25% chemical fertilizer combined with 100% bio-fertilizer) were used in the main plots and corn hybrids pellets with three levels (S.C 704, S.C Mobin, S.C Karoon) were used in sub plots. In this study the combination of chemical fertilizer with biofertilizer had a significant effect on biological yield at 5% level while the other traits were not significant. Also, the hybrid type had a significant effect on yield components; however, the harvest index was not significant. It seems that combination of chemical fertilizer with biofertilizer was able to increase the performance of single cross hybrids and cross hybrids 704 and Karun while Mobin hybrid showed a lower capability for fertilizer.

This study examines the variability in soluble carbohydrate reserves of Halocnemum strobilaceum and Halostachys caspica at various harvesting intensities (no harvesting (as control), 25%, 50%, and 75%) and different growth stages (vegetative, flowering, and seeding) in the aerial (stems) and underground (root) parts. The results showed that different harvesting intensities had significant effects on soluble carbohydrate reserves in the two species (P≤0.05). In both species no harvesting (control) had maximum soluble carbohydrate reserves and with increasing of harvesting intensity, the soluble carbohydrate reserves significantly decreased so, due to the negative effects of 50% and 75% harvesting levels on soluble carbohydrate reserves, more than 25% harvesting level must be avoided as it damages the soluble carbohydrate reserves of the species. Also the results showed that plant growth stage and plant part type had significant effects on soluble carbohydrate reserves in the two species. In terms of the total amount of soluble carbohydrate (stem root), there was significant difference between two species. With the growth progresses, the amount of soluble carbohydrates significantly increased in both species. Therefore, we can consider the seeding stage as the best time for grazing in the studied species.

The issue of salinity stress caused by oil extraction has been one of the major environmental issues of the country in the last decade. Biological agents in oil-contaminated areas can be considered the most efficient methods. The aim of this study was to reduce salinity by cyanobacteria isolated from oil contaminated areas. Soil cyanobacterium Anabaena sp. FS 76 were collected from oil polluted areas of southern Iran (Khuzestan province) and were studied ecophysiologically for acclimation ability at combination of different salinities (up to 1%) and extremely limited irradiances (2 μmol quanta.m-2S-1) at laboratory conditions. Samples were collected from oil polluted soils at different stations of Khuzestan province (Khark) for one year. Anabaena sp.FS 76 showed common strain and was selected for next steps after preliminary identification. Salinity treatments included Salt-free medium and BG011 medium with 0.25, 0. 5, 0.75, and 1% sodium chloride which were applied before and after limited irradiance treatments. Analysis involved growth analysis, Pigments (phycocyanin, allophycocyanin, phycoerythrin) and protein and sugar content assays. Results showed that the maximum growth rate may be observed at 1% salinity. At this range of salinity. 1% NaCl not only may not decrease total sugar and protein content but also cause significant increase. In vivo absorption spectra support the presence of central and rod sections of phycobilisome. This strain has salinity amelioration ability at the laboratory conditions. This potentiality reaches to highest degrees of salinity especially at 1% probability level. The results showed examples of environmental physiology and biotechnology powerful is for future studies.