مجله پژوهشهای گیاهی (زیست شناسی ایران)
سال سی و ششم شماره 1 (بهار 1402)

Since the ultimate goal in the cultivation of medicinal plants is to achieve secondary metabolites, Phosphorus is one of the macro nutrients and plays an important role in plant growth and essential oil biosynthesis that its deficiency reduces the growth and function of the plant. In order to evaluate the effect of phosphorus deficiency on growth factors and essential oil quality of Salvia officinalis L. and Mentha aquatica L. an experiment was conducted in a completely randomized design with three replications including phosphorus treatment at two levels of control and phosphorus deficiency on Salvia officinalis L. and Mentha aquatica L. plants. Phosphorous deficiency caused decrease in growth factors in both plants. Mean comparisons showed that phosphorus deficiency decreased root and shoot length and dry weights in Salvia and Mentha. There was a significant positive correlation between shoot dry weight and shoot length (P<0.01, r= 0.875) and leaf area (P<0.01, r= 0.914). Therefore, according to the results it seems that P deficiency in a controlled way can increase the essential oil content by increasing the content of some essential oil components in Salvia and Mentha.

The current research is conducted to investigate the effect of application of mycorrhiza treated soil under water deficit stress on some morphophysiological and biochemical traits of stevia plants obtained from tissue culture. The experiment was done in a greenhouse condition with treatments of two mycorrhiza species at four levels (M1: without mycorrhiza, M2: Glomus mosseae, M3: Glomus intraradices, M4: mixed of both species) and application of water deficit. The irrigation was applied at four levels as follows: I1: maintaining soil moisture at 100% of field capacity, I2: irrigation after reaching 75% of field capacity, I3: irrigation after reaching 50% of field capacity, I4: irrigation after reaching 25% of field capacity. The statistical model was factorial experiment using completely randomized design with 6 replications. Application of mycorrhiza species in water deficit stress conditions dued to 1.70, 4.11, 1.73 and 4.32 fold increase in leaf greenness index, total plant dry weight, main stem height and leaf area parameters, respectively. In addition, these treatments caused to 1.66, 6.13, 29.6 and 1.30 fold increase of potassium, glucose, fructose and total soluble sugars in stevia plants. Under moderate and severe water deficit stress, the use of a mixture of mycorrhiza species in treatments M4I4 and M4I3 compared to treatments M1I4 and M1I3 (without mycorrhiza fungus) increased more than threefold the leaf area of stevia tissue culture plants that positive root symbiosis stevia plants were well clarified by mixing two species of mycorrhizal fungi under water deficit stress and irrigation restrictions.

Important monoterpenes such as camphor and fenchol are components of lavender (Lavandula angustifolia) essential oil. Monoterpene synthases are suitable target genes for metabolic engineering in Lavender. This study was performed to analyze the expression and induction of the two key genes (borneol synthase and fenchol synthase) involved in monoterpenes biosynthetic pathway in lavender after elicitation by methyl jasmonate and salicylic acid. First, plants in the pre-flowering and post-flowering stages were treated separately by methyl jasmonate and salicylic acid, each at a concentration of 1 mM. Then, plant leaves were harvested 0 (control), 24, 48 and 72 hours after treatments for gene expression analysis. The results showed that the expression of these genes was affected by salicylic acid and methyl jasmonate treatment. In general, the expression of both genes in the pre-flowering stage was higher than that of post-flowering. Moreover, the expression of borneol synthase was more affected by methyl jasmonate, so that its expression trend was completely increased up to 72 hours. Given the increased expression of borneol synthase and fenchol synthase in plants treated with salicylic acid, and methyl jasmonate it could be expected that the content of valuable monoterpenes such as camphor and fenchol increase in lavender.

Numerous factors limit the plant propagation under in vitro conditions. Tissue browning is a serious problem in the establishment of explants in woody perennials and complicates the successful implementation of in vitro techniques. To solve this problem, application of activated charcoal resources was used, hence by controlling the effect on browning of plant tissue culture media the concentration of phenolic compounds was reduced. Furthermore, some easy methods were followed to solve the problem of oxidative browning, especially in Paulownia and Grapevine explants. The present study was conducted in Tissue Culture Laboratory, Dep. of Horticulture, Faculty of Plant Production, Gorgan University of Agricultural Sciences and Natural Resources. The basal MS medium supplemented with IBA (2 and 4 mg / l, for Grapevine and Paulownia, respectively), was fortified with different concentrations of activated charcoal and carbon nanotubes (0, 50, 100, 200, 400 mg/l). The estimation of phenolic compounds was performed with the calorimetric Folin-Ciocaltea method at 760 nm. The experiment was undertaken as completely randomized design. The results showed that both activated charcoal and carbon nanotubes had positive and significant effects on the absorption of phenol in the culture medium and the propagation of in vitro explants. The results of this study indicated that concentrations of 400 mg/l activated charcoal and 200 mg/l carbon nanotubes can be used as phenol-absorbing carbon sources in the culture media of these plants. Also, after minor modifications, the results of the present may be utilized in commercial propagation of other crops and plant species.

Alfalfa (Medicago sativa L.) is the most cultivated forage legume in Iran that productivity and quality of that are limited by salt stress. Melatonin as an indole amine was used for this study, with different concentrations of melatonin (0.1, 10 and 15 μM) under in vitro salt stress (150 and 200 mM NaCl) of alfalfa seedlings which by increasing salinity, growth rate as well as antioxidant power and synthesis of antioxidant compounds decreased. Growth parameters and defense system such as antioxidant enzymes were reduced in plants under salt stress. Exogenous utilization of melatonin in alfalfa significantly elevated fresh and dry weight, shoot length, photosynthetic pigments and carotenoid content. Melatonin application was augmented phenolic compounds such as total phenol, flavonoids and also antioxidant enzymes, phenylalanine ammonia-lyase (PAL) and tyrosine ammonia-lyase (TAL). According to our findings, Melatonin could be an excellent candidate for increasing salt resistance, by antioxidant capacity, scavenging ROS, reducing oxidative damage, augmented of non-enzymatic antioxidant such as phenolic compounds and on the other hand increasing the photosynthetic capacity of the plant by preserving photosynthetic pigments in alfalfa seedlings.

To conduct this research, first by preparing the land use map using Landsat 8 OLI sensor images and its combination with geological map, homogeneous units were determined and sampling was done in randomly-systematically in the representative areas of each plant community. Sampling was done along 3 transects of 500m which were vertical, in each site. In each transect placed 10 plots of 3×3m2 at a distance of 50 meters from each other And characteristics related to any plant including vegetative form, scientific name, genus, canopy percentage were harvested. Also, 48 soil samples were taken from a depth of 0-20cm and properties such as soil texture, organic matter, salinity, pH and adsorption ratio sodium were measured. To classification plant communities and investigate the relationships between these communities and soil properties using cluster analysis and principal components analysis respectively in Rstudio software. According to the cluster analysis results, four plant communities were identified and tamarix stricta and Suaeda fruticosa plant species with shrub-shrub vegetative form had the highest frequency with 37.2% and 26.5%, respectively. Results of ANOVA indicated that there were significant differences between some soil properties in identified plant communities. There is also a relationship between the plant communities distribution and environmental factors (p<0.05). The results also showed that the most important factors affecting the establishment and distribution of plant communities in the study area are the percentage of sand, electrical conductivity, sodium absorption ratio and percentage of organic matter

One of the basic requirements before starting any breeding program is to identify the relationships and genetic diversity in the population and to recognition the target traits. This study was conducted to investigate the genetic diversity among some European pear cultivars using fruit's key traits of these cultivars. Eleven European pear cultivars were used for this study along with two control cultivars Shahmiveh and Sardrodi. Thirteen cultivars were planted in a randomized complete block design with three replications and during three crop years ten key traits including fruit weight, fruit length, fruit diameter, fruit texture firmness, fruit length to diameter ratio, TSS, pH, acidity, fruit set and fruit yield were recorded for each tree. Combined variance analysis of the data showed that the cultivar component was significant for all studied traits at the level of 1% probability. The highest fruit weight among the cultivars belonged to Nart cultivar with an average fruit weight of 374.38 g and the highest fruit yield belonged to Mellina cultivar with a yield of 10.07 kg per tree. With the principal component analysis, the studied traits in the first four components explained 87.66% of the total variance. With cluster analysis, Nart cultivar was placed in a cluster alone due to the high differences in its traits and appearance, and Decandel, Pacham's Triumph, Abate fetel and Mellina cultivars were distinguished as superior from the two control cultivars due to their favorable fruit characteristics.