نشریه فیزیولوژی محیطی گیاهی
پیاپی 43 (پاییز 1395)

In recent years, increasing attention has been paid by consumers to cornelian cherry fruit, which is rich in antioxidants. This research was carried out based on a randomized complete block design for evaluation of the variations in some quantitative and qualitative properties of cornelian cherry fruits during the last stages of maturation in 2015. Fruits were harvested at 4 different times and from 4 main geographical directions of the tree and were then immediately transferred to the laboratory. Several parameters such as dimension (length and width), weight, firmness, pH, total soluble solids (TSS), total titratable acidity (TA), TSS/TA ratio, ascorbic acid (vitamin C), total phenolic compounds, total flavonoids, total anthocyanins, and total antioxidant capacity of the fruits were investigated. The results showed that the effect of different harvest dates on all traits was significant (P

Since Bromes tomentellus is one of the most important species in natural ecosystems in Iran both quantitatively and qualitatively¡ this research investigated decomposition process of Bromes tomentellus through studying dynamism of the main nutrient elements and decomposition rate of leaves and stems of the plantin a period of one year. The litter bag technique with size of 20×20 cm and 2 mm pores was used in this research. Each bag was filled with 5 g dried plant specimens. A totallof 54 bags with leaf¡ stem¡ and combination of leaf and stem were placed with three replications in Hosein Abad Research Station. Bags were taken at intervals of 60 days (6 times in a year). The amount of nutrients N¡ C¡ K¡ P¡ and C/N in leaves¡ stems¡ and the combination of leaves and stems were measured after each sampling. The results showed that the percentage of N in leaf was 1.02 which was 0.65 and 0.34 more in comparison with the nitrogen content of stem and the combination of leaf and stem¡ respectively. Also¡ annual decomposition constants of leaves¡ stems¡ leaves and stems of this species were 1.22¡ 0.95¡ and 1.88 respectively.

In order to investigate the effect of different levels of plant density and irrigation on some morphologic and physiologic responses and antioxidants activities in chickpea cv. Hashem, an experiment was conducted at Goonbad-e-Kavoos region during 2012-2013 cropping season. Treatments were arranged as split plot in randomized complete block design with four replications. Different irrigation regime levels (rainfed without irrigation, irrigation at flowering stage, and irrigation during pod filling stage) were assigned to main plots and sub-plots comprised of different plant densities (20, 30, 50, and 70 plants/m2). Results showed that different irrigation regimes significantly affected traits except for days to 50% flowering and plant height but plant density factor had significant impacts only on days to 50% flowering, plant height, days to physiologic maturity, seed yield, biologic yield, and leaf chlorophyll index. Results showed that irrigation caused significant increase in leaf relative water content and leaf chlorophyll index while it decreased grain protein content, superoxide dismutase and catalase activities. Maximum and minimum grain protein contents were produced in no-irrigation and irrigation during pod filling stage, respectively. Meanwhile, the maximum and minimum grain yield was gained by irrigation at flowering stage and rainfed without irrigation, respectively. Under plant density levels, the maximum and minimum grain yield was produced in 70 plants/m2 and 20 plants/m2, respectively. Irrigation at flowering stage × 70 plants/m2 had the highest grain yield among all treatments of the study.

The responses of plant roots play an important role in stress tolerance and optimal use of the moisture stored in the soil. Study of the most important morpho-physiological and biochemical parameters of roots can be an appropriate approach for selection of the cultivars tolerant to moisture stress. This study was conducted in pots and as a factorial completely randomized design in three replications.Treatments consisted of lentil cultivars (Gachsaran, Kimiya, Ziba, and Robat) and moisture stress at four levels: 25%, 50%, 75% and 100% field capacity. Results showed that the interactions between lentil cultivars and water stress on all root traits were significant. Under severe moisture stress, Rabat and Gachsaran cultivars were significantly superior to the Kimia and Ziba cultivars in most of the studied traits such as root length, root area, concentration of K, concentration of Ca, proline content, protein content, POX activity, and SOD activity. Kimia cultivar compared to other cultivars in all stress levels had the lowest root morpho-physiological and biochemical characteristics. The findings of this study showed that in comparison with other cultivars, Robat and Gachsaran were affected less under moisture stress, by means of applying effective stress-tolerance mechanisms such as more antioxidant enzyme activity, more root proline and protein contents, increased root length and area, more K and Ca absorption. According to the results of this study, Robat and Gachsaran cultivars are introduced as tolerant cultivars for cultivation under moisture stress.

Olive has a suitable oil, which shows excellent nutritional values. Due to our country's huge need to edible oil and the high quality of olive oil, developing the area under cultivation of olive is an important aim of Iran's agricultural programs. In this study, three cultivars including Mission, Koroneiki and Zard from three regions in Golestan province (Varsan, Ganareh and Minoodasht) were studied in terms of quantity and quality of the oil. Results showed that there were some significant differences among various regions and cultivars. Mission in Varsan and Koroneiki in Minoodasht had the highest and lowest fruit weight, respectively. Cultivars Mission and Zard in Ganareh and Mission in Varsan had the highest percentage of dry matter in fruits. The highest percentages of oil in dry and fresh weights were observed in cultivars Koroneiki and Zard in Ganareh, respectively, though they were not significantly different from the other treatments. In term of oil physicochemical traits, cultivar Mission in Ganareh showed the lowest free fatty acids. Cultivar Koroneiki Minoodasht had the lowest K232 value; while, it had the highest amount of total chlorophyll and carotenoid. The oil produced in Varsan region had the lowest and highest amount of peroxide and K270 value, respectively. In general, the results showed that cultivar Koroneiki is suitable to produce in all three regions of Varsan, Ganareh and Minoodasht.

Plantain (Platanus orientalis L.)is an important tree used in green space in Tehran. Due to severe air pollution in Tehran, these trees experience early fall in recent years. The present study in an attempt to find the causes of this phenomenon, measured leaf area, dry weight, stomata conductance, stomata resistance, relative leaf humidity, relative chlorophyll concentrations, and the values of calcium, magnesium, lead, and cadmium. Leaves were collected from three regions in Tehran: Sadra Park as a clean region, Al-Mahdi Park as the polluted region 1, and Avesta Park as the polluted region 2. Results showed that air pollution causes significant reduction in leaf area and increase in stomatal conductance in Al-Mahdi Park. The highest amounts of magnesium and lead were also observed in Avesta Park plantain leaves. The highest value of cadmium in leaves was recorded in Sadra Park region. No significant differences were observed in the other traits under study at the collection sites. It seems plantain is able to absorb heavy metals.

Thymus daenensis Celak is a native herb in Iran which belongs to Labiatae family. The herb is widely used in traditional medicine and food industry and has contains secondary metabolites (carvacrol and thymol). Drought stress, affects the growth and metabolism of this plant. In this study, the effects of various levels of drought stress including control (100% field capacity), mild stress (25% field capacity) and severe stress (50% field capacity) with two concentrations (0.5 and 1 µmol /L) Paclobutrazol and also two concentrations (2.5 and 5 µmol /L) of 28-Homobrassinolide dissolved in ethanol were investigated on carvacrol and thymol and oil composition of Thymus daenensis in the pot and outdoorcondition. Also gene expression of 1-deoxy xylulose-5-phosphate reductoisomerase was investigated at various levels of irrigation using quantitative RT-PCR method. The results showed that high gene expression level of 1-deoxy xylulose-5-phosphate reductoisomerase was maximum under complete irrigation and imposing draught stress up to 25% field capacity decreased gene expression significantly. Increasing the draught stress to 50% field also decreased gene expression. The concentrations of carvacrol decreased under severe drought stress upto 25% field capacity in comparison with control and increasing the concentration of 28-Homobrassinolide from 2.5 to 5 µM/L led to a significant increase in the concentrations of this compound were increased. Moreover, under severe drought stress, the concentration of thymol was increased in the presence of 28-Homobrassinolide solvent (ethanol) in comparison with the control.

This study aimed to check the effect of drought stress on yield and quality of eight cultivars of soybean in the Natural Resources and Agriculture Research Farm of Zehak during the crop year 2013-2014. The study was conducted based on a split plot randomized complete bock design with tree iterations. The main plot involved two irrigation levels (control) and drought (water stress in reproductive phase) and the subplots included soybean cultivars PE, HT, V292, Sahar, M7, DPX Katool, M9, and Williams. The results showed that the effect of drought stress on all traits including plant height, pod length, number of pods per plant, canopy temperature, grain weight, quantum yield, and grain yield were significant. On the other hand, the number of seeds per pod and harvest index were not significantly affected by draught stress. The effect of cultivar was also significant on all qualitative and quantitative traits so that the highest grain yield was obtained from PE while its impact on phonological traits, pod length, and canopy temperature was not significant. The interaction of draught stress on plant height, number of pods per plant, quantum yield, seed yield, and the rest of the properties under study was not significant. The highest grain yield was observed in full irrigation (control) and PE cultivar.