فصلنامه گیاه و زیست بوم
پیاپی 59 (تابستان 1398)

Awareness regarding the plant distribution pattern in each region is considered to be a requirement and prerequisite for studying the vegetation. The distribution pattern indicates the position of populations in an environment and how they are arranged relative to each other. In this study, the fixed-area-plots sampling method was used. A total of 76 circular plots were harvested in two closed and grazed areas, and inside each plot, in addition to species type, large and small crown diameters, the distance between the center of the plot to the nearest person, and the nearest person to the nearest first neighbor were measured and recorded. To determine the spatial pattern, distance indicators such as Johnson and Zimmer, Eberhardt, C index, Hopkins, Hines and Pielou were used.The Johnson and Zimmer, Eberhardt and Hines indicators showed a clumped pattern for pistachio trees in both regions. The Hopkins and C indicators, respectively, showed a random and a uniform pattern for the pistachio trees in both regions. Additionally, the Pielou index demonstrated a clumped and a uniform pattern for pistachio trees in both closed and grazed areas, respectively.

In order to investigate the effect of different proportions of seaweed extract and vermicompost on yield and yield components of bean, a factorial experiment in a completely randomized block design with four replications was carried out in spring and summer of 2018 in Arak. The experimental treatments included the administration of vermicompost (A) in four levels (control (a1), 5 t/ha (a2), 10 t/ha (a3) and 15 t/ha (a4)); and the seaweed (B) spray spread in four levels of control (b1), 1% (b2), 2% (b3) and 3 percent (b4). The results showed that vermicompost application had a significant effect on all of the studied traits. Furthermore, the main effect of spray application of seaweed extract on the number of pods per plant, number of seeds per pod, number of seeds per plant, 100 seed weight, yield Grain, biological yield, harvest index, plant height, leaf area, relative humidity, chlorophyll b, stomatal conductance and protein function was significant. Regarding the interaction between vermicompost application and marigold algae extraction, only grain yield, biological yield, and harvest index were significant. The results of mean comparisons of the above-mentioned traits showed that the highest values were obtained from the application of 15 t/ha vermicompost and spray application of seaweed extract with 3% casting. The results of the mean comparisons of the interaction effect of vermicompost application in algae application indicated that the highest grain yield with an average of 500 g/m2 was related to the application of 15 t/ha of vermicompost and 3% algae, and the lowest (156.55 g/m2) related to the control consumption of vermicompost and intense consumption of algae. Therefore, it can be concluded that the application of high levels of vermicompost and spray application of seaweed extract can have a significant effect on the yield and yield components of bean.

Some species of Heteroptera and Hymenoptera are powerful natural enemies in most of the agroecosystems especially paddy fields. These biological control agents can play an efficient role in controling agricultural pests and thus decreasing pesticides application in rice fields. Considering this along with the significance of growing rice in Iran and also due to the presence of different pests in the rice fields of the north of Iran, the species diversity of these beneficial insects was studied during 2016-2017 in the rice fields of the central parts of Mazandaran. In total, 16 species of predator bugs including Anthocoridae (four species), Reduviidae (two species), Lygaeidae (three species), Pentatomidae (single species), Nabidae (three species) and Miridae (three species); and 11 species of parasitoid wasps including:Chalcididae (one species), Encyrtidae (two species), Eulophidae (three species), Mymaridae (one species) and Pteromalidae (four species) were collected and identified. Additionally, the population fluctuation of predator bugs was studied in rice growing seasons and the maximum density observed belogned to June.

Livestock graze is one of the significant factors affecting the structure and dynamicity of rangeland ecosystems. That is why analyzing the impact of grazing on the species diveristy indice of the vegetation appears essential. Species diversity is composed of two interrelated indices: species richness and species evenness. Evenness relates to the distribution of the species in the environment and richness stands for the number of species in the sampling plots. Considering the critical role of both indices in determining the species diversity, the ecologists are interested in analyzing the diversity indice in a way that the contribution of each of these two indices in determining the species diversity is identified. The new approach designed for so doing is called SHE Analysis. To determine the role of richness and evenness indices in diversity index in the rangelands of Nodooshan region in Yazd Province, a total of 108 random- systematic plots of 2 m2 were laid out in line with the grazing gradient. In each plot, the percentage of canopy cover by species was estimated and then the richness and evenness were counted in grazing gradient (i.e., light, moderate and heavy grazing). The results revealed that, in all three grazing intensities in the gradient, the richness indice (LnS) played a more significant role in determining the diversity compared to the evenness indice (LnE).

Floristic studies are like birth certificates that reflect the past and present status of a region and also play a significant role in future predictions. The basis for sustainable development and logical use of natural resources is conservation and safeguarding of plant species. In order to carry out this research, after several visits and field navigations during different seasons of 2016 and 2017, plant samples were collected and identified in the Herbarium of Isfahan Jihad Agriculture Research Center. A total of 364 plant species belonging to 257 genera and 57 dams were identified. Asteraceae family with 67 species and Apiaceae with 38 species constitute the largest families, respectively. The results of the classification of the biological form of plants showed that the most abundant biological forms were the hemicritophyte (50%), trophyte (23%) and camphyte plants (10%). Additionally, the geographic dispersion of the plants in the region indicated that the elements belonging to the Irano-Turanian region (IT) had the highest frequency with 58.88%. Eleven vulnerable and four going extinct species were identified in this region. This highlights the great diversity of species in this genetic reservior in Iran, which sould be carefully preserved.

Drought increases the salinity of agricultural lands. Recognizing some physiological mechanisms in strawberry plants is essential for facing the salinity.Methyl jasmonate is a plant growth regulator that affects many biochemical and physiological processes in a plant. Salicylic acid, as one of the hormones, plays an important role in increasing plant resistance to environmental stress. Growth regulators play a vital role during the growth stages of plants and their application can increase the quantitative and qualitative yields of plants. The present facotrial experiment followed arandomized complete block design with three replications andexplored the effect of different concentrations of methyl jasmonate (0, 1 and 2 micromolar) and Salicylic acid (0.2 and 4 mM) under conditions of salinity stress (0, 5 and 10 dS) on some morphological responses (plant height and leaf area), physiological traits (soluble solids, vitamin C and acidity), and function (fruit number, fruit weight and fruit yield) of strawberry plants. In the year 2018-2019, in Azad Shahr city of Golestan province, two strawberry cultivars (Silva and Camaroso (Fragaria × ananassa Duch, Selva and Camarosa)) were examined. The results of this study showed that salinity stress significantly reduced the morphological and physiological properties of two strawberry cultivars Silva and Camarrowso. Quantitative properties of plant height and leaf area, and the qualitative properties of soluble material, vitamin C, and acidity decreased with increasing salinity. Methyl jasmonate and salicylic acid significantly increased vegetative and reproductive growth. This result also correlates with the performance of two cultivars. In examining the effect of these two treatments under the same conditions of salinity, the salicylic acid in comparison with methyl jasmonate was shown to increase the quantitative and qualitative properties under salinity conditions.

In developing countries, fungal infections are considered as a major problem and commonly used antifungal drugs are usually toxic and expensive or have side effects. Hence, nowadays, attempts for identifying the antifungal plant compounds for the treatment of some fungal diseases such as dermatophytosis are increasing. The present study was carried out to investigate the effect of methanolic extract of Ferula persica on Trichophyton rubrum (PTCC 5143), Trichophyton mentagrophytes (PTCC 5054) and Microsporum gypseum (PTCC 5070). The alcoholic extract of the aerial part of this plant was prepared following Soxhlet method. Two methods of disc diffusion and agar dilution in two forms of macrodilution and microdilution were used, and inhibition zone diameter, MIC80 (minimum inhibitory concentration required to inhibit 80% of fungi) and MFC (minimum fungicidal concentration) in the presence of extracts, and terbinafine were determined. Based on the obtained results, the highest inhibition zone diameter and the maximum sensitivity to extract related to Trichophyton rubrum, and Trichophyton mentagrophytes and Microsporum gypseum were in the second and third positions in this regard.