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Background The use of organic nanoparticles to improve drought resistance and water demand characteristics in plants seems to be a promising eco-friendly strategy for water resource management in arid and semi-arid areas. This study aimed to investigate the effect of chitosan nanoparticles (CNPs) (0, 30, 60 and 90 ppm) on some physiological, biochemical, and anatomical responses of Salvia abrotanoides under multiple irrigation regimes (30% (severe), 50% (medium) and 100% (control) field capacity). Results The results showed that drought stress decreases almost all biochemical parameters. However, foliar application of CNPs mitigated the effects caused by drought stress. This elicitor decreased electrolyte conductivity (35%), but improved relative water content (12.65%), total chlorophyll (63%), carotenoids (68%), phenol (23.1%), flavonoid (36.4%), soluble sugar (58%), proline (49%), protein (45.2%) in S. abrotanoides plants compared to the control (CNPs = 0). Furthermore, the activity of antioxidant enzymes superoxide dismutase (86%), polyphenol oxidase (72.8%), and guaiacol peroxidase (75.7%) were enhanced after CNPs treatment to reduce the effects of water deficit. Also, the CNPs led to an increase in stomatal density (5.2 and 6.6%) while decreasing stomatal aperture size (50 and 25%) and semi-closed stomata (26 and 53%) in leaves. Conclusion The findings show that CNPs not only can considerably reduce water requirement of S. abrotanoides but also are able to enhance the drought tolerance ability of this plant particularly in drought-prone areas. Graphical abstract

Various planting designs behave in different ways on microclimate and thermal comfort due to mainly distinct features of vegetation type and ratio. The papers simulated the microclimate behavior and thermal comfort of different planting design scenarios of an urban park using ENVI-met model. We measured temperature, relative humidity and wind velocity during the coldest period of 2016. Seven scenarios of planting design with different types and ratios of vegetation were simulated. In scenario of evergreen trees, humidity was relatively high while temperature and wind velocity were decreased. Simulated grass covered park and deciduous trees showed higher temperature and wind velocity. Scenario of grasses and the scenarios with high ratio of deciduous trees in comparison with other scenarios indicated lower wind speeds. The findings can be seen as a possibility of improvement of winter thermal comfort, considering a proper planting design as an important step in order to achieve Citizen Satisfaction.

Salt stress is a serious problem in urban landscape of arid and semi arid regions. To overcome the adverse impacts of salinity, the application of organic matter and plant nutrients in the growth media for improving of plant growth is essential. An experiment was conducted in order to determine the response of Salvia splendens to salinity levels and also the role of humic acid in the salt stress alleviation. In the current experiment five salinity (0, 20, 40, 60, and 80 mM NaCl) and three humic acid (0, 100, 500 and 1000 mg l−1) treatments were prepared. The effects of these treatments were investigated on some growth parameters, physiological characteristics and also biochemical compounds. The results indicated that the growth parameters decreased in saline-treated plants than control plants. Different salinity levels significantly affected relative water content, evaporation rate and also electrolyte leakage. Salinity caused the increase in proline, malondialdehyde, sugar content, DPPH, total phenol content and decrease in chlorophyll, compare to the control plants. Application of humic acid on Salvia splendens, decrease leaf area and plant height compared to the control plants. Thus, regarding the growth parameters, it is probable that the effect of humic acid on the biochemical compounds is similar to salinity effect. The findings suggest that Sage is a sensitive ornamental plant to salinity and humic acid (in the studied levels) could not alleviate the negative effects of salt stress on this plant.

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Today, one of the most pressing issues confronting the civilized and modern world is air pollution.Particulate matter (PM) is a well-known pollutant that contributes signi cantly to urban air pollution and has numerous short-and long-term adverse effects on human health. One method of reducing air pollution is to create green spaces, mainly green walls, as a short-term solution. The current study investigated the ability of nine plant species to reduce tra c-related PM using a green wall system installed along a busy road in Mashhad, Iran. The main aims were (1) estimate the tolerance level of plant species on green walls to air pollution using the Air pollution tolerance index (APTI); (2) assess the PM capture on the leaves of green wall species using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX) analysis and accumulation of heavy metals using Inductively Coupled Plasma (ICP); (3) select the most tolerance species for reducing air pollution using Anticipated Performance Index (API). The plants' APTI values ranged from 5 to 12. The highest APTI value was found in Carpobrotus edulis and Rosmarinus o cinalis, while Kochia Prostrata had the lowest. Among the APTI constituents, leaf water content (R 2 = 0.29) and ascorbic acid (R 2 = 0.33) had a positive effect on APTI. According to SEM analysis, many PM were adsorbed on the adaxial and abaxial leaf surfaces, as well as near the stomata of Lavandula angustifolia, C. edulis, Vinca minor, and Hylotelephium sp. Based on EDX analysis, carbon and oxygen formed the highest amount (more than 60%) of metals detected in the elemental composition of PM deposited on the leaves of all species. The Sedum re exum had the highest Cr, Fe, Pb, and As accumulation. The concentrations of all heavy metals studied in green wall plants were higher than in the control sample. Furthermore, the C. edulis is the best plant for planting in industrial, urban areas of the city based on APTI, biological, economic, and social characteristics. It concludes that the use of green walls composed primarily of plants with small leaves can signi cantly adsorb PM and accumulation of heavy metal.

Today, one of the most pressing issues confronting the civilized and modern world is air pollution. Particulate matter (PM) is a well-known pollutant that contributes significantly to urban air pollution and has numerous short- and long-term adverse effects on human health. One method of reducing air pollution is to create green spaces, mainly green walls, as a short-term solution. The current study investigated the ability of nine plant species to reduce traffic-related PM using a green wall system installed along a busy road in Mashhad, Iran. The main aims were (1) estimate the tolerance level of plant species on green walls to air pollution using the Air pollution tolerance index (APTI); (2) assess the PM capture on the leaves of green wall species using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX) analysis and accumulation of heavy metals using Inductively Coupled Plasma (ICP); (3) select the most tolerance species for reducing air pollution using Anticipated Performance Index (API). The plants' APTI values ranged from 5 to 12. The highest APTI value was found in Carpobrotus edulis and Rosmarinus officinalis, while Kochia Prostrata had the lowest. Among the APTI constituents, leaf water content (R2 = 0.29) and ascorbic acid (R2 = 0.33) had a positive effect on APTI. According to SEM analysis, many PM were adsorbed on the adaxial and abaxial leaf surfaces, as well as near the stomata of Lavandula angustifolia, C. edulis, Vinca minor, and Hylotelephium sp. Based on EDX analysis, carbon and oxygen formed the highest amount (more than 60%) of metals detected in the elemental composition of PM deposited on the leaves of all species. The Sedum reflexum had the highest Cr, Fe, Pb, and As accumulation. The concentrations of all heavy metals studied in green wall plants were higher than in the control sample. Furthermore, the C. edulis is the best plant for planting in industrial, urban areas of the city based on APTI, biological, economic, and social characteristics. It concludes that the use of green walls composed primarily of plants with small leaves can significantly adsorb PM and accumulation of heavy metal.

To find out the effects of media culture and foliar fertilization on some yield traits including the number of fruits per bush, mean weight of fruit, yield of per bush, long of fruits and diameter of fruits 9 months completely randomized factorial experiment (3 x 5) with four replications was conducted. Media culture treatments include 5 levels namely soil; mixture of soil and vermy compost; mixture of soil and sand; mixture of soil and peat moss and mixture of soil, sand and peat moss. Foliar fertilization treatments include 3 levels namely applying once a week, once a 3 week and no fertilization (control). The results showed that the media culture treatments on the whole of traits and foliar fertilization also on the whole of traits except yield of per bush had a significant difference (p < 0.01). In the foliar fertilization except yield per bush the once a 3 week fertilization caused highest increase than other treatments and in the media culture treatments, the mixture of soil and peat moss showed highest increase than other treatments.