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One of the major abiotic stresses that negatively affects plants is the presence of heavy metals. Soil pollution with heavy metals, resulting from the industrial development and use of fertilizers containing heavy metals, has become a major environmental concern in human societies. Mercury is a toxic heavy metal that causes pollution in agricultural lands. Accumulation of Hg by plants may disrupt many cellular functions and block growth and development. Under such conditions, the enzymatic and non-enzymatic defense systems of plants are activated. Several defense systems are cooperating together in plants to cope with stressful situations. In this study, the effect of different concentrations of mercury on the photosynthetic pigments content and non-enzymatic defence systems in Nicotiana tabacum was studied. After planting the plants under the same conditions in the hydroponic medium and feeding the plants with Hoagland solution, treatments with different concentrations of mercury nitrate (0.5, 1 and 3 mM and a control group) were applied to the seedlings in three replications. Ten days after the application of the treatments, the plants were harvested and examined. The results showed that tobacco plants which had been exposed to heavy metal used the accumulation of osmolytes such as proline and soluble sugars in order to balance their osmotic pressure. The decrease in the amounts of photosynthetic pigments and increase in the levels of malondialdehyde in the leaves indicated the elevation of oxidative damage. Increased activity of non-enzymatic antioxidants in tobacco leaves, including anthocyanins, phenol, flavonols and flavonoids, can be interpreted as the mechanisms of resistance to heavy metal stress induced by mercury.
 

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Tamarix is the largest genus in the family Tamaricaceae with about 54 species. T. tetragyna var. meyeri and T. tetragyna var. deserti were previously reported from Iran. Due to the presence of overlapping features in the previously designed identification keys for the separation of these two varieties, it could be helpful to use other characters and character states derived from other sources, such as anatomical and molecular studies, in addition to find more effective morphological features for the separation of the two varieties. Therefore, the present study aimed to differentiate these two presumed varieties by multiple approaches using morphological, anatomical and molecular data. For morphological study, 6 quantitative and qualitative characters were examined in 12 samples of the two varieties. ANOVA analysis showed a significant difference between the studied characters. For anatomical study, 10 traits were examined in 4 samples of the two varieties, which also showed a significant difference. AMOVA analysis based on molecular studies using Scot marker showed a significant difference between the two varieties. The PCA biplot show the most variable traits in morphological and anatomical studies. For varieties delimitation, different clustering methods were drawn in all three studies. The results of this study showed that the use of appropriate diagnostic traits in morphological and anatomical studies as well as the use of molecular markers can be effective in showing the separated boundaries of the two varieties studied.
 

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Tomato (Solanum lycopersicum) is one of the most important crops and a known host of broomrapes. The species of genus Orobanche are biotic stress factors restricting plant growth and crop production. Some natural compounds and chemicals affect this biological relationship. Therefore, in the present study, the effect of gallic acid and kiwi fruit extract on the biological relationship between broomrape and tomato plant was investigated. To this end, first, the symbiotic effect of the broomrape species, Orobanche aegytica, on growth parameters of tomato plant and the amount of soluble sugar and photosynthetic pigments were evaluated. Then, the effect of concentrations of gallic acid and kiwi fruit extract at different levels on this biological relationship was investigated by measuring the growth parameters of tomato and broomrape, photosynthetic pigments and the amount of soluble sugar in tomatoes. The results demonstrated that the broomrapes reduced the fresh weight and dry weight of the stem, leaves and roots of tomato, diminished the leaf area of the host plant, and decreased the amount of photosynthetic pigments and its soluble sugar content. Gallic acid treatment and kiwi fruit extract lessened the growth parameters of the broomrape species and its overall growth, in addition to increasing the growth of tomato plants. This process could be associated with the constraint of the biological relationship between the parasite and the host, as the soluble sugar content as well as the amount of the photosynthetic pigments of tomato plants were increased and the tomato plants remained highly resistant.

 

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Seaweed extract can improve the physicochemical properties of the soil and has a favorable effect on the plant growth and development due to having high nutrient content, high water holding capacity, plant growth regulators and beneficial microorganisms. The aim of this experiment was to investigate the effect of Ascophyllum nodosum extract, a brown alga, on the morphophysiological characteristics of bean plant (Phaseolus vulgaris) under water stress. The experiment was performed in a Completely Randomized Factorial Design with three replications. Experimental treatments included 4 concentrations of foliar application of seaweed extract (0, 0.2, 0.4 and 0.6%) and 3 levels of water stress including no stress, mild stress and severe stress (irrigation at 75, 50 and 25% of field capacity, respectively). The results showed that the interaction effects of stress and algal extract on the evaluated traits were not significant. However, the seaweed extract significantly increased the leaf area, number of the leaves, leaf length, surface and length of the roots, root dry weight, the content of chlorophyll a and b and the total chlorophyll content. Application of algal extract at levels of 0.2 and 0.4% caused a significant increase in the evaluated parameters as compared with the control plants. The evaluation of water scarcity stress effects showed a significant reduction in the all studied characteristics in accordance with increasing water stress level from 75% to 25% of field capacity. The results of this study showed that foliar application of seaweed extract significantly increased some morphological and photosynthetic properties, while water stress significantly reduced the investigated parameters.

 

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In the present study, two regulatory phytohormones, abscisic acid and auxin, were extracted from two different macroalgae, Sargassum muticum and Gracilaria corticata, for the first time. Sampling was performed each month with three replicates, from Bushehr Province shores located in the north region of Persian Gulf for six alternative months. The alteration of seaweeds biomass and the probable impacts of some environmental factors were measured. The extracted phytohormones were isolated employing HPLC method and identified by injection of standards. The highest amount of ABA phytohormone in the two species, occurred in November. Also, the highest amount of Auxin in Sargassum muticum was reported in May, while the highest amount of this hormone in Gracilaria corticata was observed in January. In January, the maximum mean biomass in Sargassum muticum was 679gr/m², while the minimum mean of 20.66gr/m² was observed in September. Moreover, the highest average biomass in Gracilaria corticata was 423/33gr/m² in March and the lowest mean of 158g/m² was reported in November. ANOVA and Chi-squared test results showed a significant difference in all samples. These phytohormones could be applied in preparing algae liquid fertilizer in future studies.
 

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 Piptatherum ferganense is recorded as a new grass species for the flora of Iran collected from Ghorkhod Protected Area and Aladagh Mountains in North Khorassan province. The core distribution range of the species is Eastern Irano-Turanian with a disjunction in northeastern Iran. The morphological characters of P. ferganense are illustrated and compared with the closely related P. latifolium. It can be distinguished from P. latifolium by its evenly arranged spikelets in the panicle, lanceolate fertile lemma, and shorter lemma awns. Notes on taxonomy, ecology, phytogeography, and conservation status of the recorded species are provided.

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Pollen respiratory allergies have been increasing in prevalence over the last two decades, partly as the result of the impact of climate change. For many allergenic trees, grass and weed species, increased pollen production and prolonged pollination period result in long-term increased abundance of pollen allergens in the atmosphere; earlier shifts of airborne pollen grains and prolonged exposure to respiratory allergens with important health effects on allergic individuals. The aim of this review paper was to investigate the impact of climate change and meteorological factors on pollen season indicators with a special focus on the main allergenic taxa worldwide. Main variables influencing flowering phenology such as location, climatic and meteorological parameters were identified, discussed and substantiated by published literature. Temperature, solar radiation, humidity, rainfall, wind speed and direction were identified among the most important meteorological parameters affecting the fluctuations of annual concentrations of allergenic airborne pollen grains. Although notable variations were observed according to allergenic species and studied geographical areas, temperature appeared to be the most important climatic parameter affecting flowering phenology and pollen season indicators, especially in tree species. Rising carbon dioxide levels also result in increased plant biomass, increased flowering intensity and pollen production in several tree, grass and weed allergenic species. In the light of this review, there is a growing body of evidence supporting the effect of climate change on the flowering phenology and pollen season indicators of a substantial number of allergenic ornamental and invasive plant species.
 

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Halimocnemis commixta is recorded as a new species for the flora of Iran from Pistacia vera woodland remnants in NE Iran. It grows on open salty soils with several typical halophytic plants. The new species record is illustrated and compared with the closely related species. It can be distinguished from H. gamocarpa by its clustered flowers and irregularly horned fruits and differs from H. pilosa by its entirely short and adpressed hairs. We provide some additional notes on the distribution, ecology, and conservation status of the newly recorded species.

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Two new species of Cousinia are described from Iran. Cousinia bornmulleriana from the west that can be placed in sect. Haussknechtii based on some key characters such as flower numbers, phyllary numbers and the inflorescence form traits. This species can be also compared with its closest relative C. haussknechtii. and C. karkasensis. The second new species, C. semnanensis, from North East of Iran, belongs to the sect. Stenocephalae for its flower numbers, winged stem, and phyllaries shape, and is compared to C. alexeenkoana and C. glaucopsis as its close relative. Natural photos and distribution maps are presented.

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High-quality DNA extraction plays an important role to make sharp bands in the gel electrophoresis and also produces clean chromatograms. Usually, DNA extract is delivered using the modified CTAB method but this method cannot obtain high-quality DNA for molecular analysis from old dried leaves of Bellevalia due to having different chemical compounds which inhibit to obtain a clear DNA extraction. To solve the problem, in different phases of a modified CTAB protocol, activated carbon, phenol, potassium acetate, RNase and deionized water (instead of TE) were applied to eliminate contaminants and improve obtained high-quality DNA. The DNA absorption data from the modified method were compared with CTAB method in 260 and 280 nm wavelengths. The results showed a 15-80-fold change in the DNA concentration. This study suggests the modified method of extraction is more efficient in the quality of DNA obtained from the little amount of herbarium old leaves of Bellevalia than that of the CTAB method.

 

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The genus Ulva L. (Sea lettuce), one of the most valuable marine macroalgae, is found in shallow coastal areas and in brackish and fresh water around the world. Ulva species have nutritional and medicinal values in addition to other applications, and contain various compounds such as lipids, proteins and carotenoids. These species have high phenotypic plasticity and varied in response to different environmental conditions. In this study, 38 populations of 10 species of Ulva from the coastal areas of the Persian Gulf and Oman Sea, from different areas of Bushehr, Hormozgan and Sistan and Baluchestan provinces, were studied and identified on the basis of morphological and anatomical traits. Different populations showed variations in characteristics such as height, shape and color of thallus, number of pyrenoids and cell dimensions. Metabolites such as total protein, total oil, chlorophyll a, b and carotenoids contents were measured and compared among the different populations. The results should that the percentage of protein was highest in U. prolifera of Shif Island from Bushehr province as compared with the Ulva species studied, with about 26.5% of dry weight, and the percentage of total oil was lowest in U. flexuosa of Hakhamanesh region from Hormozgan province as compared with the species studied, with about 4.8% of dry weight. These results show that different environmental conditions affect the morphological and anatomical structure of species and the content of their metabolites. Due to the high-protein and low-calorie content of the Ulva genus and the importance of finding new and sustainable resources for food and pharmaceutical industries, the species of this genus have valuable potentials.
 

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Basil is an important medicinal plant, belonging to the Lamiaceae family. Basil is used for the treatment of different diseases such as stomachache, headache, constipation, fever and infections, as well as to reduce and regulate the blood sugar. Moreover, Basil is known for its antibacterial, antifungal and antioxidant properties. In this study, the impact of drought stress on phenols and flavonoids concentrations, as well as the antioxidant activities of leaf extract of three basil cultivars were investigated. Seeds of basil cultivars (mikhak, green, purple) were cultivated in sand-loamy soil and drought stresses (75%, 50% and 25% of the field capacity) were applied on six-leave plants. Experiments were conducted in a completely randomized design and three repeats. Total phenols, total flavonoids and flavonols concentrations of basil leaf extracts and their antioxidant activities were measured. The maximum values (with significant differences) of three groups of non-enzymatic antioxidants and the highest levels of antioxidant activities were observed for green cultivars under mild stresses (75% of the field capacity). It was observed that antioxidant activities were elevated by the increase of the concentration of the plant extract. Drought stress results in oxidative stress in basil plants. Phenols, flavonoids and flavonols are well-known as strong antioxidants have a role in the plant’s protection against the oxidative stress. In thrice cultivars of basil which were investigated, concentrations and abilities of these compounds to inhibit free radicals were decreased by the increase of the levels of drought stresses. It seems that both basil genotypes and drought stress levels affected the production of antioxidants studied and, consequently, have impacts on the plant inhibitory abilities against the oxidative stress.

 

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The seed micromorphological characters of 15 taxa of Iranian Pyrus comprising 22 individuals were examined by Scanning Electron Microscopy (SEM) and Digital Microscopy (DM) for the first time in this survey. For the assessment of probable ecological effects, several individuals of some widespread species were studied. After collecting several samples of each wild taxa of Pyrus from different localities in a ten-year period, the specimens were identified by means of the examination of type specimens and different Floras. After the examination of the seeds surface, qualitative (e.g., shape and ornamentation of seeds including areolate, foveate, reticulate, colliculate, striate and undulate types) and quantitative characters (e.g., size of seeds, size of surface cells and thickness of cell walls) were assessed. Statistical analyses were performed on the data using SPSS software. According to these observations, seed morphological characters showed to have a considerable variation even among the different individuals of the same species, verifying complexity of the genus as revealed by the different approaches which were previously reported. However, some descriptive characters of seeds such as shape, size, surface ornamentation type, cell size and cell wall thickness are presented for the first time for the genus.

 

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Successful germination is the main factor in proper establishment and seedling yield. Information on seed germination, in the face of temperature changes at the time of planting, is a way to identify more suitable cultivars for cultivation at the planting site. For this purpose, a factorial experiment was performed based on completely randomized design with 3 replications. This experiment was conducted to investigate the temperature changes on the germination and growth indicators of lentil cultivars at Khatam Al-Anbia University of Behbahan. The studied treatments included five lentil cultivars of Gachsaran, Kimia, Robat, Ziba and Bilehsevar, and the temperature levels were 20, 25 and 30 °C, similar to the autumn conditions of Khuzestan Province. The results showed that all the seedlings of investigated cultivars cultivated at temperatures of 20 and 30 °C had a significant decrease in all the investigated traits, i.e., germination percent, germination rate, germination vigor, seed vigor index, endosperm consumption, plumule length, radicle length, seedling length, plumule dry weight and radicle dry weight, in comparison with those seedlings cultivated in 25 °C. The study of the interaction of cultivar-temperature effects showed that Bilehsevar cultivar had the highest germination and growth indices at 25°C compared to other investigated cultivars. This increase in traits such as germination rate, germination vigor, seed vigor index, plumule dry weight and radicle length was more significant in Bilehsevar cultivar compared to other cultivars. The second rank of the highest germination and growth indices was assigned to Gachsaran cultivar under 25°C conditions, which had a significant increase compared to other cultivars (Kimia, Robat and Ziba). Considering the autumn cultivation of lentils and the changes of temperature in that season (temperature range of 20 to 30 °C) in the studied area, the use of Bilehsevar and Gachsaran cultivars under the temperature of 25 °C, due to their higher germination indicators compared to the other cultivars, i.e., Ziba, Kimia and Robat, could be recommended.


 

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Selenium, a non-essential element for plants, is essential for animals as well as human beings. Although the role of selenium in plants is yet to be properly understood, previous researches have shown that this element can affect plant growth and metabolism. In this study, the effect of foliar application of selenium nanoparticles (0, 5, 10, and 20 mg/L) and sodium selenate (0, 5, 10, and 20 mg/L) on the physiological and biochemical responses of bell pepper (Capsicum anumm L.) was investigated. The potential changes in various growth and biochemical indices were evaluated in response to the treatments. According to the results, selenium treatments at concentrations of 10 and 20 mg/L reduced the biomass accumulation in both roots and shoots. These treatments also increased the content of hydrogen peroxide and malondialdehyde. The foliar application of selenium led to the increase of the concentrations of soluble phenols, proline and thiols. The activity of antioxidant enzymes including catalase, peroxidase, ascorbate peroxidase, and polyphenol oxidase were increased in response to the selenium treatments. The protease activity displayed a similar upward trend following the selenium treatments.

 

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Wheat (Triticum aestivum L.), as one of the most important cultivated crops in the world and Iran, is constantly threatened by many diseases, including Fusarium contamination. Due to the unique characteristics of nanoparticles, copper oxide nanoparticles show high antibacterial and antifungal properties. The purpose of this research was to comparatively investigate the antifungal effects of copper oxide nanoparticles and its bulk form on the suppression of Fusarium calmorum in wheat. For this purpose, a pot experiment was done with four levels (10, 250, 500, and 1000 mg L^-1) of nanoparticles and bulk form of copper oxide treatments in wheat (Roshan cultivar). The results showed that the maximum inhibition of root pathogenicity was observed in a high concentration of nanoparticles as compared to bulk form. The 250 and 500 mg L^-1 concentrations of copper oxide nanoparticles caused the highest stem and root length and the highest dry weight of the aerial part and root, respectively. Treatment with 10 and 250 mg L^-1 nanoparticles also increased the content of chlorophyll a, total chlorophyll, carotenoid, chlorophyll stability index, membrane stability coefficient, and relative leaf water content. While the content of chlorophyll b, malondialdehyde, hydrogen peroxide, and proline increased with the increasing concentration of both nanoparticle and bulk forms. The results of this research showed that the low and medium concentrations of nanoparticles were more successful in inhibiting the aforementioned fungus than the bulk form.
 

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The increase of the entry of industrial effluents containing various types of heavy metals into water and soil leads to the ever-increasing spread of environmental problems. Therefore, it is necessary to find less expensive solutions to reduce the pollution. In this regard, in order to compare the effect of the removal of heavy elements on some of the morphological and physiological characteristics of C. alternifolius, Ch. zizanioides and Aloe vera plants, an experiment was conducted in the form of a randomized complete block design with three replications for 14 months at the University of Guilan. The results showed that under the treatment of industrial wastewater, the metal accumulation indices (MAI) of zinc, chromium, lead, copper, manganese, nickel, magnesium were higher in Ch. zizanioides and Aloe vera than those in C. alternifolius. In all three studied plants, the indices of root length, shoot length, total biomass and tolerance index (TI) had a significant decrease compared with those in the control plants, and Ch. zizanioides and A. vera plants had the lowest percentage of decrease. In addition, other investigated components including absorption index (UI), total soluble sugar, total phenol content, total flavonoid, total anthocyanin, total tannin, and DPPH free radical inhibition percentage increased in all three plants under industrial wastewater treatment. The highest percentage of increase in all investigated components, except DPPH free radical inhibition percentage, was observed in Ch. zizanioides. In general, it can be said that in terms of MAI and morphological and physiological characteristics, Ch. zizanioides and A. vera were more successful than the C. alternifolius. Therefore, it is recommended to plant the studied plants in the order of priority (Ch. zizanioides ˃ A. vera ˃ C. alternifolius) in soils contaminated with industrial effluents, in order to remediate the soil.


 

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