نشریه فیزیولوژی محیطی گیاهی
پیاپی 54 (تابستان 1398)

Today, much attention is paid to the quality of fruits, including those of nuclear origin, with regard to their after-harvest life. The purpose of this research was to evaluate some of the qualitative traits during the final stages of growth and determine the time of harvesting apricot of Shahroodi cultivar according to the time and market of consumption. Apricot fruits were harvested in 3 different time intervals (distance between each harvest and another three days). Experiment was conducted on randomized complete block design in three treatments (different stages of harvesting) and four replications (main tree species). The measured qualitative traits included total soluble solids (TSS), titratable acidity (TA), vitamin C, fruit firmness, pH of fruit extract, phenol, flavonoid, total antioxidant capacity, anthocyanin, antioxidant enzymes (peroxidase, catalase, superoxide dismutase) , Polyphenol oxidase) and total protein. All traits were significant at 5% level and changed during harvesting. Antioxidant enzymes increased during harvesting, except polyphenol oxidase, phenols and flavonoids decreased. According to the results, it seems that the best harvest time for this apricot is the second harvest.

Considering the production of sugarcane compost in some sugarcane companies and the need for using these products as organic fertilizers to reduce the application of chemical fertilizers, this experiment was conducted to investigate the effect of different amounts of sugarcane compost and nitrogen fertilizer on quantitative and qualitative yield of corn. In this study, split plots were used in a randomized complete block design with three replications. The treatments consisted of different amounts of sugarcane compost at three levels of 0, 15, and 30 ton/ha as main plots and nitrogen fertilizer from urea source at three levels of 80, 160, and 240 kg/ha nitrogen as sub plots. Results showed that the effect of sugarcane compost and nitrogen on number of rows per ear, number of seeds per ear, 1000 grain weight, grain yield, and protein yield were significant but the effect of interaction between treatments on all traits were not significant. The maximum grain yield and protein yield were obtaied under 30 ton/ha sugar cane compost and 240 kg/ha nitrogen and the minimum grain yield and protein yield were in non-consuming sugarcane compost and 80 kg/ha nitrogen. In general, the results of experiment showed that increasing the application of sugarcane compost and nitrogen up to 30 ton/ha and 240 kg/ha, had a significant effect on quantitative and qualitative yield of corn and can be considered by farmers and researchers.

Nowadays, carbon nanotubes (CNTs) have a special place in plant science and promising effects have been reported. To study the effects of multi-walled carbon nanotube (MWCNTs), 0 (control), 10, 25, 50, 75 and 100 mg L-1, on rooting of cuttings in Lippia citriodora L., a factorial pot experiment in the form of randomized complete block design was set up in the research field of Shiraz University with 4 replications. Results showed that the application of multi-walled carbon nanotubes (10-50 mg L-1) significantly improved the root morphological traits compared to the control treatment. The highest increase in root weight (around 200% compared with control) was recorded in response to 50 mg L-1 MWCNT treatment. The root volume also increased by 165% under 50 mg L-1 MWCNT treatment while the lowest value was observed in cuttings treated with 100 mg L-1MWCNT. The lowest number of roots in cuttings belonged to 100 mg L-1MWCNT treatment. Application of 50 ppm MWCNT in comparison with control treatment significantly increased the number of roots in cuttings (by 50%). The application of this concentration caused the highest amount of root length which was 65.94% more than the control treatment. Although our finding showed promising effects of MWCNT on root of Lippia citriodora, the further comprehensive studies can are suggested on shoot biomass of the herbal plant.

In order to determine the water requirement of sunflower cultivars, an experiment was conducted during 2015-2016 at Ardestan Station, Isfahan. The experiment was carried out in a factorial randomized complete block design with four replications. Treatments included 3 irrigation regimes (D1: irrigation after 60 mm, D2: irrigation after 120 mm, D3: irrigation after 180 mm evaporation from small tub evaporation) and 5 sunflower cultivars (Azargol, Prograss, Gabur, Hysan 25, and Hysan 36). Results showed that under non-stress and moderate stress, Azargol and Prograss cultivars had the highest rate, in terms of seed filling period, the weight of 1000 grains, stem diameter, and head diameter. Under severe stress, Prograss and Gabur cultivars were remarkable, so that Prograss cultivar had the highest seed filling period, weight of 1000 grains, stem diameter, and Gabur cultivar had the highest number of budding, number of flowering, and stem diameter. In the study of physiological characteristics, results showed that under non-stress and moderate stress chlorophyll a, b, total chlorophyll, and net-photosynthesis in cultivars Progerass and Gabor were significantly increased compared to other cultivars. In severe stress conditions, the Progress and Gabor cultivars in chlorophyll a, b and total chlorophyll content were superior to other cultivars. The results of proline analysis indicated that proline leaf content increased significantly with water stress. Among the cultivars under severe stress conditions, proline leaf content in Progerass and Gabor cultivars was significantly higher than other cultivars. The results of this study showed that Azargol, Gabor, and Progerass cultivars are more tolerant than Hysan 25 and Hysan 36.

Tomato (Solanum lycopersicom L.) a main agricultural crops that is important in most countries including Iran. In this study, we investigated the SlNCED1 gene expression of biosynthetic Abscisic acid pathway by Real Time qRT-PCR and measured some of the physiological characteristics under cold stress. After fruiting, plants were placed under 2° and 4° C temperatures for 12 and 24 hours. Then, the fruits were collected for gene expression and measuring non-enzymatic antioxidant by DPPH and total phenols by Folin Ciocalteo. Results showed that the fruits at 4° C for 24 and 12 hours had more gene expression compared to other treatments. Also, non-enzymatic and total phenols had increased significantly at 2° C for 12 hours. Generally, since tomato Red Cloud cultivar belongs to tropical region, at temperatures below 12° C it is influenced by cold stress and, subsequently, it makes changes in gene expression and antioxidants to protect itself against stress.

In order to investigate the effect of silica and potassium nanoparticles and nitrogen levels in two native and improved rice varieties, a field experiment was conducted in Sari city in 2014. The experiment was split-factorial in a randomized complete block design with three replications. Two native cultivars of local and improved Tarom Hashemi were considered as main factor and nitrogen fertilizer in three levels including 35 and 70 kg of urea per hectare with biological fertilizer nitroxin (without fertilizer nitrogen fertilizer) and nanoparticles in three levels of nanosilicon spraying, Potassium and their lack of use (control) were considered as a sub-factor as factorial. The results indicated that cultivar of Tarom Hashemi produced the maximum grain yield (5000 kg ha-1) with 70 kg of nitrogen and nanopotassium. For local Tarom cultivar, the highest yield of rice (4657 kg ha-1) was obtained by consuming 35 kg of nitrogen and nanopotassium. The highest concentration of silica was obtained by using nanosilica. The highest nitrogen and potassium concentrations were obtained with 70 kg N ha-1. For each cultivar, the highest concentration of potassium potassium was obtained using 70 kg of nitrogen plus nanoparticulate and nano-silica. Therefore, the use of nanoparticles in both cultivars increased the quantitative and qualitative yield of rice.

In order to study the effect of foliar application of chelated nano iron and drought stress on physiological changes and grain yield of purslane cultivars, an experiment was conducted as split plot factorial randomized complete block design with three replications in Ahar Agricultural Research and Natural Resources Station during 2015. The experimental factors included drought stress levels, 90 (control), 70, and 50 field capacity, two levels of chelated nano iron, 0 (control) and 1 lit.hr, and two cultivars (Tehran and Kazeron). Results showed that foliar application of nano iron under drought stress had a significant effect on some traits, so that the highest content of chlorophyll b (4.47 mg/g leaf tissue) was recorded under normal irrigation and foliar application of nano iron chelated, the highest sodium concentration (38.87%) was obtained from 50% filed capacity and non foliar application of chelated nano iron, and the highest potassium content (87.68%) was obtained under drought stress conditions of 50% filed capacity and foliar application of chelated nano iron. Considering the significance of interaction effects, the highest amount of proline (1.22 mg/g fresh weight), soluble sugar (96.92 mg/g fresh weight), and iron (1.11%) was obtained from Kazeron cultivar under drought conditions, 50% filed capacity by non foliar application of chelated nano iron. The highest amounts of chlorophyll a (6.99 mg/g of leaf tissue), carotenoids (1.67 mg/100 ml), and anthocyanins (0.017 mg/100 ml) were recorded by foliar application of chelated nano iron in Kazeron cultivar under normal irrigation. Also under stress conditions, the use of chelated nano iron compared to control increased the grain yield by 32.66% and Kazeron cultivar was superior to Tehran cultivar, so that the seed grain yield of Kazeron was 1.31 more than that of Tehran.

In order to investigate the effects of salinity and vermicompost on the antioxidant enzymes activity and photosynthetic pigments of Borage officinalis L., a factorial experiment was carried out in a completely randomized design with four replications in 2015. The study treatments consist of four vermicompost levels (0, 5, 10, and 15% wt potted soil in dry weight) and four salinity levels 0 (control), 4, 8, and 12 ds/m sodium chloride. The results of analysis of variance showed a considerable influence of salinity stress and vermicompost on the activity level of superoxide dismutase, ascorbate peroxidase, glutathione peroxidase, catalase, and total chlorophyll enzymes. Other results indicated that with increasing salinity, the activity level of antioxidant enzymes and photosynthetic pigments increased and decreased, respectively. Also, use of vermicompost fertilizer raised the levels of chlorophyll a, chlorophyll b, and carotenoids significantly compared to the control. Comparison of means of the interactions between salinity stress and vermicompost showed that the maximum antioxidant enzymes activity was obtained in 15 wt % vermicompost treatment at the salinity level of 12 ds/m NaCl. Therefore, the use of vermicompost as an organic fertilizer, in addition to increasing the activity of antioxidant enzymes and photosynthetic pigments, can be a good way to reduce the negative effects of high levels of sodium and chloride ions in soils on the growth of borage.