مجله علوم و فنون باغبانی ایران
سال نوزدهم شماره 1 (بهار 1397)

One of the most important limiting factors for the postharvest life of many minimally processed fruits is enzymatic browning. In this study to evaluate the effects of heat and some chemical treatments on preventing cut pear browning, different time/hot water (45 ˚C) treatments were used including (40 min (T40), 80 min (T80), and120 min (T120)). Also, slices of pears were dipped in solutions of ascorbic acid 2% with N-acetyl-L-cysteine 0.75% (AA+NAC), ascorbic acid 2% with calcium chloride 1% (AA+CaCl2), ascorbic acid 2% with calcium lactate 1% (AA+CaL) and ascorbic acid 2% with N-acetyl-L-cysteine 0.75% and calcium chloride 1% (AA+NAC+CaCl2) for 15 min prior to storage in air for up to 6 days at 4±2 °C. The results showed that post-cutting dip treatment of AA+NAC+CaCl2 had the highest L*, firmness and total soluble solids and the lowest a* and peroxidase activity compared to the control and the other treatments. The hot water treatments, AA+NAC+CaCl2 or AA+CaCl2 significantly reduced weight losses compared to the control.

In this experiment the photosynthetic water use efficiency and photochemical reaction of pomegranate to deficit and alternate partial root zone drying irrigation were investigated. The experiment was carried out in a randomized complete block design (RCBD) with treatments including 1- full flood irrigation (with regard to crop water requirement) (T1) 2- flood irrigation with 100% of crop water requirement as alternate partial root-zone irrigation (T2) 3- flood irrigation with 50% of crop water requirement as regulated deficit irrigation (T3) 4- full two- side drip irrigation (with regard to crop water requirement) (eight drippers with 2 L/h flow by two different individual network) (T4) 5- alternate partial root-zone drip irrigation with 100% of crop water requirement (T5) 6- regulated deficit drip irrigation with 50% of crop water requirement (T6) in every irrigation period. The highest flower intensity, fruit set, yield and water use efficiency based on statistical analysis were belong to both PRD treatments i.e. alternate partial root-zone drip irrigation with 100% of crop water requirement and alternate partial root-zone flood irrigation with 100% crop water requirement, respectively. Partial root drying irrigation in both traditional flood irrigation and drip irrigation systems caused a significant increment of water use efficiency in pomegranate trees (up to 78.34 and 71.4%) in comparison with control. Increment of vegetative growth under full two-side drip irrigation and full flood irrigation treatments i.e. tree diameter (by 2.64 and 2.21 cm per year) and number of current season shoots (to 4.65 and 4.75 on one-year-old branches), showed the allocation of more photosynthetic material to vegetative growth that could reduce the yield and in consequence water use efficiency in pomegranate. Because of higher photosynthesis efficiency, yield and water use efficiency in alternate partial root-zone drip irrigation, it application is recommended for the region.

Inappropriate nutrition management and environmental stresses reduce the yield per unit area and increase some disruptions, especially sunburn in the apple fruit. Thus, the present study was conducted with aims i) improving the quality and quantity of ‘Red Delicious’ apple, ii) determining the best concentration of micro-elements liquid fertilizer (containing iron, zinc, and manganese), and iii) reducing or eliminating the risk of sunburn using nutrients (calcium and boron). In the first experiment, the effects of micro-elements liquid fertilizer (containing iron, zinc and manganese) on yield and fruit quality of ‘Red Delicious’ apple were examined. The results showed that fruit weight, fruit length, fruit width, TSS and fruit juicy were affected by treatments and there were significant differences between the treatments for these traits. Given that treatments 0.005, 0.004 and 0.003 had better effects than 0.002 and control, application of one of these three treatments is recommended at late-May. In the second experiment, the effects of different treatments of calcium and boron on sunburn and quantitative and qualitative traits of ‘Red Delicious’ apple at two times were investigated. Result showed that the CaCl2 (1.00 %) and boron (0.002) at mid-May had the best effects on reducing sunburn and improving traits in the studied cultivar.

Abiotic stresses are very harmful in plant species due to their extensive presence in agricultural lands and increase in the probability of their severity under climate change conditions. To investigate the effects of salt stress on some morphological and physiological characteristics of miniature rose (Rosa chinensis Jacq. var. minima Rehd.) cultivars a factorial experiment was conducted based on a completely randomized design in greenhouse conditions. Treatments were water with electrical conductivity of 2 and 4 dS m-1 provided by NaCl along with tap water as control and rose cultivars including red (R. chinensis ‘Little Buckaro’), pink (R. chinensis ‘Sourati Local Cultivar’) and yellow (R. chinensis ‘Little Flirt’) flower plants. The results revealed that salinity of 4 dS m-1 decreased the number of leaves and flowers, flower diameter, plant height, dry weights of shoots and roots, leaf area, chlorophyll index, chlorophyll fluorescence and visual quality while leaf ion leakage was increased. ‘Sourati Local Cultivar’ had the lowest plant height, flower diameter, dry weight of roots, visual quality, leaf area, chlorophyll index, and the highest leaf ion leakage in salinity treatments (2 and 4 dS m-1), while in the control treatment this cultivar had the maximum number of leaves and flowers. ‘Little Buckaro’ with the highest plant height, dry weight of roots, visual quality, leaf area, and chlorophyll index was the most tolerant cultivar to salinity stress. Therefore, its cultivation in areas with saline soils can be suggested.

Grape is one of the most important and economic horticultural crops in Iran. One of the problems of grape cultivations is its relative sensitivity to salinity stress. So evaluation of tolerance rate and sensitivity range in grape cultivars has a great importance. This research was conducted to investigate the effects of salinity treatment (NaCl) at different levels (0, 25, 50 and 100 mM) on enzymatic activities, chlorophyll content and morphological changes in four cultivars of grape including 'Sahebi', 'Fakhri', 'Soltani', and 'Khalili'. The experiment was conducted as factorial based on a randomized complete blocks design with three replications. The results showed that under salinity stress conditions and the consequent oxidative stress, 'Fakhri' and 'Khalili' showed the highest tolerance. This higher tolerance is due to more antioxidative enzymes and less accumulation of peroxide hydrogen in 'Fakhri' specially. By increasing in salinity levels, morphological characteristics and chlorophyll content reduced and antioxidative enzymes and free radicle of H2O2 and malondialdehyde enhanced and these changes had variety between different cultivars.

Water deficit is a major limiting factor for turfgrass management in arid and semi-arid regions. This experiment was conducted in order to investigate morphophysiological responses of Bermuda grass (Cynodon dactylon (L.) Pers.) to water deficit stress and application of sodium nitroprusside and salicylic acid. The experiment was carried out based on completely randomized design with four replications. First factor included three water deficit stress levels (40, 70 and 100% of soil available water), and four levels of second factor were salicylic acid (SA) (2 mM), sodium nitroprusside (SNP) (500 µM), 2mM SA + 500 µM SNP and control (distilled water). Water deficit reduced shoot growth and relative water content. Whereas root growth, chlorophyll content, electrolyte leakage, total phenol, leaves antioxidant capacity and proline content increased with decreasing soil available water. Results showed that application of sodium nitroprusside and salicylic acid ameliorate adverse effects of water deficit in Bermuda grass by increasing leaves antioxidant capacity and proline and chlorophyll content as well as reducing electrolyte leakage and this effect was more noticeable in combined application of sodium nitroprusside and salicylic acid.

Proper selection of cultivar and processing method are the main factors intended for production of table olive. Therefore, in the current research, the different processing ability and quality of processed green and black table olives were evaluated during fermentation and storage periods. Evaluations were carried out on selected cultivars including Shiraz, Manzanilla, Zard, Direh, Meshkat, Tokhm Kabki, and genotypes including KH15, BN5, QG18, TMN2 and GW1. Evaluation of qualitative parameters during fermentation and storage periods showed the highest amount of acidity in Shiraz cultivar and TMN2 genotype, which decreased with increasing fruit maturity. Also, in terms of oleic acid, there was a significant difference between cultivars at harvest time, which reduced with increasing fruit maturity and changing fruit skin color to black. According to the sensory analysis results unscratched fruit treated with NaOH with a profit compared to the scratched fruit have a higher rating in terms of overall acceptance and texture hardness; however, the scratched samples also had a remarkable superiority in traits such as the pit detachment and fruit color compared to unscratched fruits. According to results of the processed black olive, Manzanilla, Meshkat, BN5 and GW1 had higher potential for production of black table olives due to uniform color, appropriate firmness and optimal overall acceptance.

There are many medicinal plants that could be found in fields, hill sides, and specific natural habitats. Myrtus communis is one of the most valuable medicinal plants that widely extended in Iran. In this research, we studied the changes in the essential oil yield and chemical composition of Myrtle during 2013 to 2014 seasons. Samples of plants were collected from the Mian Jangal Fasa area. Essential oils were obtained by hydro distillation and were analyzed by GC and GC/MS. The highest and the lowest essential oil yields were found in autumn (1.28%) and winter (0.41%), respectively. Major compounds were 1,8-cineol (22.9% in summer), α-Pinene (25.5% in spring), Limonene (26.8% in winter) and Linalool (18.5% in summer(.

In order to improve post-harvest life and increase the quality of post-harvest quality of strawberry cv. Selva, a completely randomized design with three replications was carried out. The treatments consisted of immersion of fruits in Aloe vera gel at two levels of zero (control) and 100% for 10 minutes, acetic acid 0 and 1%, and UV-B radiation for 0 and 10 minutes. The results showed that treated fruits with Aloe vera + UVB radiation showed the lowest weight loss during storage compared to other treatments. Fruits treated with Aloe vera + Acetic acid + UV-B radiation showed the highest amount of tissue firmness at the end of the experiment. Low levels of decay were observed in fruits treated with acetic acid and combined treatments of Aloe vera + acetic acid + UV-B radiation. Aloe vera + Acetic Acid + UVB could maintained the amount of anthocyanin, total phenol, and vitamin C at the end of the storage period. Finally, the post-harvest application of Aloe vera gel, along with acetic acid and UVB, can be useful in improving the post-harvest quality of strawberry fruit.

To evaluate the chilling and heat requirements of Iranian wild blackberry genotypes, dormant canes of 15 genotypes representing 4 species were collected and placed in refrigerator at 2.5ºC. Chilling treatments were 0 (control), 100, 200, 300, 400, 500 and 600 hours. Chilled canes were placed in distilled water under continuous light at 24ºC. Days to first bud break, days to 50% bud break and the percentage of total bud break of each genotype in each treatment were calculated. Heat requirement was also calculated by Growth Degree Hours model. Results showed that chilling requirement ranged from 300 to 500 h. Also, heat requirement was varied from 4824 (Abidar) to 7668 (Kazerun) GDH. Results also showed that chilling and heat requirements had a negative correlation (r=-0.3) with increasing altitude and total precipitation of original habitats of the genotypes, the amount of heat requirement is reduced (r=-0.21 and -0.48 respectively). Chilling requirement also had a negative correlation with mean temperature and wind speed(r=-0.4 and -0.16 respectively).