فصلنامه گیاه و زیست بوم
پیاپی 33 (زمستان 1391)

Water reservoirs are considered to be an important element of the environment. Considering their significant role in supplying water for farms and pond-raised fish and providing habitat for non/indigenous migrant and domestic birds, reservoirs need to be further investigated. Furthermore, the identification of the aquatic plants is critical in Mazandaran because of their particular significance in the succession of the aquatic ecosystems, their nutritional value for the aquatic animals and birds, their medical application, and finally their usage as fodder. Given that no prior research has comprehensively investigated the aquatic plants of Mazandaran with a special focus on the water reservoirs, conducting the present study appears essential. The purpose of this study is to identify seed/less aquatic plants within two main regions of Juybar‟s (Larim and Esmailkola) reservoirs. The experiment followed the floristic method and all of the existing plant samples were identified. After collecting plant samples and identifying them by valid keys, they were either dried and attached to herbarium cards or maintained in the reserving solutions. The results indicated that there existed 24 families, 33 genera, and 47 species of Macroscopic Algae, Pteridophytes, and Phanerogames, i.e. "emergent, floating, and submerged plants". Poaceae, Cyperaceae, Potamogetonaceae, and Lemnaceae are important families of plants in this region. Lots of the available types have not been reported in previous studies.

For investigating the impact of the vascular transfer system of the main rachis on the yield and yield-components of Atrak wheat, an experiment was conducted in the Educational-Research site of the IAU, Saveh Branch, during 2008-2009 farming year. The internodes of the spike, the number and the size of the central vascular bundles, and the manner of their distribution were examined in this study. The results indicated a significant relationship between the number of spikelets on the rachis and the number of the central vascular bundles on its lower part. The number of the central vascular bundles decreased toward the upper parts of the rachis. This decrease was averagely about 0.5 vessels in each internode between the first to the fourth internodes in the lower part, 1.2 between the fifth to the fourteenth internodes in the central part, and 0.7 from the fifteenth internode to the terminal spikelet in the upper part. The size of the vascular bundles across the rachis decreased according to a special model. The largest portion of the vascular bundles were observed in the central part of the rachis and then in the lower and upper parts, respectively. There was a positive correlation between the number and weight of the grains and the number and size of the vascular bundles allocated to each spikelet across the rachis, given that the spikelets with the maximum average of grain weight and number, located on the central part of the spike, had the largest number and size of the vascular bundles compared to the spikelets on the other parts of the rachis.

Urtica Diocia L. from the Urticaceae family is a plant with herbal value and of a noticeable distribution in the north of Iran. The growth of different plants in various natural environments and ecosystems seems to be affected by various factors including the height (from the sea level). To investigate the effect of height on the medical compounds of Urtica Diocia L. in its natural habitat, three regions at different heights from the sea level (zero, 800 and 1800 m) were selected. The samples were randomly gathered from each region at three time-intervals and after being dried their essences were extracted with the help of a Clivenger using water-distilling method. For determining the medical compounds of the essences, the GC-MS and GC machines were used. The analysis of variance was carried out in the form of the random-full-block design. The results indicated that there was a significant difference between the percent of the effective materials obtained from the samples in the selected heights; however, such difference was not significant regarding the samples from the same height. From among the eight essences analyzed in the study, the Phytol compound had the highest percentage. It indicated that an increase in the height resulted in a decrease in the percent of the medical compounds. The lower heights could be regarded as the most appropriate height for producing effective medical materials the studied effective materials considering their humid climate and the fertile soil.

Water shortage in Iran and other dry lands is considered as one of obstacles against the expansion of the green fields. In addition, the population growth and the increasing environmental pollutions intensify the essence of finding solutions for water shortage problem. Purified sewage is considered as one of the most economical and available water resources for irrigation in most of the countries which deal with this problem given that this kind of water is rich in the elements required for plants. Considering the aforementioned points, the present study was carried out in an attempt to investigate the application of Roudehen University Sewage Purification Plant and the possibility of using its effluent wastewater for the irrigation of the green fields in the campus. Accordingly, twenty-two parameter values, i.e. pH, CO3, EC, DO, BOD, COD, Ca, Mg, Cl, HCO3, Na, K, TS, TSS, PO4, P, NO2, NO3, NH3, NH4, NH3-N, and MPN were measured in the raw and purified sewage over a 3-month period, using ASTM and single-sample t-test measurement procedures. The obtained results were compared with the criteria and standards of the Organization of the Environmental Protection of Iran for using sewage in irrigation and agriculture. The results indicated that the quality of the purified sewage, except for the MPN and TSS parameters, conformed to the standards. The exclusion of the BOD and COD parameters respectively increased the suitability of Roudehen University Sewage Purification Plant‟s effluent to 71.1 and 69.9 percents. The average amounts of EC and SAR in sewage plant‟s effluent were 1730.8 and 4.41, 49.2 μs/cm respectively. In sum, the results indicated that the purified sewage can be used in small amounts for the irrigation of the plants which are resistant to salinity.

Silicon is a non-essential element with several reported beneficial effects on various crops. For investigating the growth and reproductive yield of the Persian Petunia, a factorial experiment with a completely randomized design was conducted at 4 levels of Si (0, 50, 100 and 150 ppm), during two stages of growth (4-6 and 8-10 leaf) with 4 replications. The experiment was carried out under the greenhouse conditions. Silicon was applied via foliar spray once every two weeks. The application of Si increased the number of the flowers on plants up to 73%. An increase was also observed in the height of the plants under the effects of Silicon and the stage of growth. Although the application of Si foliar spray increased the fresh, dry, and biomass weights during both stages of growth, these weight parameters were generally higher in plants which received Si treatment within 4-6 leaf stage. The fresh and dry weights as well as leaf surface area increased 57, 37 and 52% and leaves‟ evapotranspiration reduced up to 53% using Si, respectively. In conclusion, it can be claimed that the application of Silicon can increase the total biomass weight by reducing plant‟s evapotranspiration and increasing leaf‟s surface area, which in effect results in an increase in the number of the flowers per plant.

In order to study the effects of biofertilizers on the growth properties and the physiological parameters of the Coriander (Coriandrum sativum L.) under salinity stress, a completely-randomized, factorial-design experiment was carried out with three replications under the greenhouse conditions at Sari Agricultural Sciences and Natural Resources University. The factors under treatment included the salinity stress (by sodium chloride) at four levels (control, 30, 60 and 90 mM) and the pretreatment of the commercial biofertilizers, such as Nitroxin (including Azospirillium and Azotobacter) and Supernitroplus (including Aspirillium, Bacillus subtilis, Pseudomonas fluorescens). The results indicated that the interaction effect of the biofertilizers and the salinity was significant on chlorophyll a, chlorophyll b, and a+b contents at P< 0.01. According to the results, the bacterial inoculation had a positive and significant effect on the amount of chlorophyll at all salinity levels under study except for the 60 mM level. The maximum amount of chlorophyll b and a+b contents (6.06 and 20.08 μg/ml, respectively) were obtained from the Supernitroplus treatment at 90 mM salinity level, which increased up to 57.4% and 30% in comparison to the plants under the non-inoculated treatment, respectively. In addition, the interaction effect of salinity and inoculation was significant for all of the traits studied except for the plant height and the dry weight. The highest leaf surface area belonged to the plants under Nitroxin treatment at the control salinity level (with 37.71 cm) which demonstrated a 44.9% increase compared to the plants under the non-inoculated treatment at the same level. Generally speaking, all of the above-mentioned morphological traits significantly decreased by an increase in salinity levels.

The overall increase in the consumption of the cut foliage plants in the recent years is an indication of their aesthetical and job making significance. Cycad is one of the most important cut foliage plants with several decorative uses. In order to increase the vase life of Cycad cut foliages, an experiment was carried out based on the CRD design with three replications. Four different levels of Gibberellins and benzyl adenine (each with 0, 50, 100, & 150 Ppm concentrations) treatments were applied in a mutual experimental statistical design. AgNo3 (with the fixed concentration of 40 Ppm) and sucrose (with the fixed concentration of 3%) were used in all, except for the control, treatments. The parameters analyzed in the present study included: the vase life, the external quality, the total amount of soluble solid, and the fresh and dry weights of Cycad leaf. The results indicated that Gibberellins positively increased the vase life of cut foliages, their external quality, and the total soluble solid. It also delayed the decreasing of the fresh weight. Although it was not anticipated, the application of high concentrations of benzyl adenine decreased the vase life of Cycad's cut foliages. The best treatment was the one with Gibberellins at 50 Ppm without benzyl adenine, which increased the vase life of Cycad‟s cut leaves up to 101 days; a record for cut foliage vase life in Iran. The treatment with Gibberellins at 100 Ppm without benzyl adenine also increased Cycad‟s vase life up to 90 days. The highest amounts of the total soluble solid and fresh weight were obtained during these two treatments. In addition, the external quality of leaves was better kept during preservation time and the demolition of the cut foliage was slower compared to the other treatments.

The agronomic types of the Iranian olives, which are distributed under a similar name, have different varieties. The molecular diversity of 46 olive tree samples of 10 cultivars (derived from two main olive cultivars, i.e. Rowghani and Gelooleh) was investigated in the initial phase of the present study using Random Amplified Polymorphic DNA (RAPD) analysis with 20 markers. The study was carried out at the National Research Center for Genetic Engineering and Biotechnology (NRCGEB). 53.1% of the marker were polymorphic. The obtained results were analyzed using NTSYS and SPSS software. During the second phase of the study, identical samples were omitted and the analysis was repeated using 20 RAPD markers. From among the 20 markers, 18 (79.5%) were polymorphic. Different techniques were applied for measuring the similarity matrix and cluster analysis. The best cluster was obtained from Dice similarity matrix and the UPGMA procedure. The average similarity coefficient obtained from Dice similarity materix indicated that the cultivars were not that much diverse. Analyzing the main characteristics of the olive cultivars differentiated them appropriately. The results of the cluster analysis confirmed the outcome of the morphologic analysis to a great extent. Generally speaking, conducting a molecular experiment along with the morpholic categorization appears essential. The RAPD markers were appropriately applied for the morphological analysis during the initial phase of the study. The obtained results can be further confirmed and analyzed using other markers.

To investigate the effect of different farming procedures and plant density on the quantitative and qualitative characteristics of some varieties of corn, an experiment was conducted in Qarakhyl Agricultural Research Station in Mazandaran in 1389. The study was carried out in 4 replications following the vertical, split-plot factorial and random-full-block designs. The factors analyzed in this study included: the types of the farming procedures applied at three levels (non-plow, minimal-plow, and conventional plow), three levels of density (65,000, 75,000, and 85,000 plants per hectare), and the corn variety at three levels (DC370, SC500, and SC540). The characteristics investigated in the experiment included: the height of the plant, the tassel length, the stem diameter, the grain length, the grain yield, the harvest index, 1000-grain weight, dried-root weight, and the protein. The results indicated that the farming systems significantly influenced dried-root weight, the harvest index, the grain length, and the grain protein at P< 0.05. The highest and lowest dried-root weights were obtained from the minimal plow (rotary) and conventional plow (plow and disk) systems respectively. The maximum grain yield was observed in the plant density of 65,000 per hectare (5.64t/ha) and the minimum yield was obtained from the plant density of 85,000 per hectare (4.58t/ ha). Similarly, the highest and lowest 1000-grain weights were respectively obtained from the plant densities of 65,000 and 85,000 per hectare. The interaction effect of plow and density (plow × density) on all of the characteristics was significant at the probability level of 5%. The highest and lowest grain yields under this interaction effect were respectively obtained from the minimal-plow system with 65,000 per hectare plant density (5.80 t/ha) and the non-plow system with 85,000 per hectare plant density (4.33 t/ha). The interaction effect of plow, density, and variety on all of the characteristics was significant at P< 0.05. The highest and lowest grain yields under this interactive effect were obtained from the minimal plow system with the density of 75,000 plants per hectare and Sc540 (7.54 t/ha) and the non-plow system with the density of 85,000 plants per hectare and Dc370(2.07 t/ha) respectively.