مجله علوم و فنون باغبانی ایران
سال پانزدهم شماره 3 (پاییز 1393)

Nitric Oxide has emerged as an important signaling molecule associated with many biochemical and physiological processes in plants. In this study, the role of SNP (NO donor) in inducing salt tolerance in two grapevine (Vitis vinifera L.) cultivars ‘QarahShani’ and ‘Thompson Seedless’ subjected to NaCl stress was investigated. Well-rooted grape cuttings were treated with four levels of salinity (salinized nutrient solution) 0 (control), 50, 75 and 100 mM NaCl and three levels of SNP (Foliar application) 0 (control), 0.5 and 1.0 mM. Results indicated that with increasing NaCl concentration in nutrient solution, leaf area, shoot and root dry weight decreased. Also decrease in leaf chlorophyll content, stomatal conductance and transpiration in higher level of salinity, resulted in reducing photosynthesis in both cultivars especially in ‘Thompson Seedless’. Our findings suggested that the application of SNP (1 mM) under salt stress could improve the growth and phatosynthesis in both cultivars especially in ‘QarahShani’.

This study was conducted to compare rooting of cutting in Ficus benjamina cv. ‘Comosa’ and cv. ‘Starlight’ and also the effect of different concentrations of IBA and time of taking cutting on rooting of Ficus benjamina in Gorgan University of Agricultural Sciences and Natural Resources, in 2012. The experiment was performed in a randomized complete block design with three replications. Treatments consisted of four levels of IBA (0, 2000, 4000 and 6000 mg l-1 IBA, two time of taking cuttings (late June and early September) and two plant cultivars (F. benjamina cv. ‘Comosa’ and cv. ‘Starlight’). Results showed that maximum of root percentage of cuttings was observed in F. benjamina cv. ‘Comosa’ and cutting time of early September with 4000 and 6000 mg l-1 IBA and also in late June with 4000 mg l-1 IBA. The maximum root length and fresh weight was achieved in cuttings of F. benjamina cv. ‘Comosa’ and cutting time of early September with 6000 mg l-1 IBA. The greatest number of root was obtained in cuttings of F. benjamina cv. ‘Comosa’ with 6000 mg l-1 IBA in both cutting time of late June and early September. The highest survival percentage of plant was recorded in cuttings of F. benjamina cv. ‘Comosa’ and cutting time of early September with 2000, 4000 and 6000 mg l-1 IBA. In general, results showed that F. benjamina cv. ‘Comosa’ had better rooting than F. benjamina cv. ‘Starlight’ and higher concentrations of IBA caused increase in rooting percentage, length and number of roots.

This research was carried out to evaluate the effects of chemical thinners urea and NAA on quantitative and qualitative characteristics of nectarine (cv. Independence and Nectared4) in Horticultural Research Station of Meshkinshar. Experiments were carried out randomized complete block with five treatments and three replications for three years. Application of urea (10, 12%) and NAA (15, 20 mg l-1) and control trees take place at full bloom stage. Characteristics such as flower abscission, fruit weight, fruit size, acidity, TSS and yield were measured. Results showed that effect of different concentrations of urea and NAA on flower abscission, fruit weight, fruit size, acidity, TSS and yield in cultivars were significant. Results showed that different concentrations of urea and NAA increased flower abscission, fruit weight, fruit size and decreased yield in two cultivars compared with the control trees. Application of urea at 12% had the most effect on flower abscission and produced the lowest yield in all cultivars. Urea at 12% increased fruit weight and fruit size in all cultivars compared with other treatments. Urea at 12% treatment decreased TSS content and increased acidity content in cv. Independence nectarine compared with other treatments. Results showed that application of urea 12% had the highest and control trees had the lowest flower abscission in nectarine cv. ‘Nectared4’. NAA at 15 and 20 mg l-1 and urea at 10% treatments had the highest TSS in ‘Nectared4’. The highest amount of yield was obtained from control trees in all cultivars.

Fungal endophytes are microorganisms that associate with healthy plant tissues, persisting without causing diseases symptoms in the host. These fungi improve the plant’s ability to withstand environmental stresses, resistance to pathogens, herbivores and provide increased nutrient absorption and improve plant growth. The main goal of this research was to characterize fungal endophytes in plane trees and study the relationship between presence of endophyte with morphological characteristics of plane trees and nutrient elements of leaves. Healthy tissues of plane tree (shoots, bark and leaves) from 21 young and 19 age-old trees were collected. Approximate age and height were determined and greenness and nutrient elements concentration were also evaluated. Shoots and bark pieces were surface sterilized and placed in Petri dishes containing PDA. The results showed endophytic frequency was greater in age-old trees (60.04%) than young trees (39.96%). Endophytes had positive correlations with Fe and K concentration in leaves and height and circumference of trees. Fungal endophytes may act as plant fertilizers by enhancing nutrient elements assimilation and may affect survival of plane trees.

The intensity of light received by plant affects growth، development and many other quality and quantity indexes including number of flowering stem, lateral shoot number, length and diameter of the flowering stem, changes in the leaves size. Therefore, the effects of shading on growth characteristics of roses was studied under greenhouse conditions. Different levels of shading was achieved by using green meshes to create light intensities of 240, 520, 640 and 1200 (control) μmol m-2s-1 in two rose varieties, ‘Red One’ and ‘Gulmira’. The best performance was achieved for flowering stem number, lateral shoot number, length of flowering stem and flower length, flower diameter and flowering stem diameter and diameter in both cultivars with 520 μmol m-2s-1 whereas, fresh weight and dry weight of leaf and stem increased with 240 μmol m-2s-1. Also there was a direct relation between shading increase and area, length and width of leaf. Thus, 520 μmol m-2s-1 light intensity can be recommended for growing roses under greenhouse conditions.

While nutritional value of edible mushroom is very high, but its short storage life creates limitation for distribution and supply of mushroom. Therefore its postharvest physiology requires more study. It seems that edible chitosan coating should be suitable for mushroom postharvest. Therefore this study was carried out to find the best chitosan concentration and coating film to increase storage life and decrease postharvest losses. A factorial experiment splited in time by using completely randomized design in 3 replications with 4 levels of chitosan (0, 0.5, 1 and 2%) and 5 coating film containing control (packed in selefon), Poly ethylene coating (thickness of 65 microns), Biaxially Oriented Polypropylene coating (thickness of 25 and 35 microns) and Cast Polypropylene (thickness of 25 microns) and duration of 0, 7, 14, 21 and 28 days of storage at 1°C and relative humidity of 90% were carried out. After each storage period, some physiochemical properties of mushroom were measured. The results showed that chitosan demonstrated a significant effect on all traits expect soluble solid content at the 1% level of probability. The higher firmness, titrable acids, pH and lower weight loss and decay was observed when 2% chitosan treatment and packaging with 35 microns Biaxially Oriented Polypropylene coating was used and the lowest firmness value, titrable acids and the highest weight loss and decay was related to control treatment (no chitosan). The coating film 35 microns Biaxially Oriented Polypropylene coating reduced weight loss from 14.56% in control (selefon) to 0.75%.

Physiological and biochemical responses of GF677 rootstock (Prunus persica L × P. amygdalus Batsch) to drought stress induced by polyethylene glycol (PEG-6000) were studied in the solid and liquid medium. This research was conducted using completely randomized design (CRD). Plantlets of GF677 rootstock were subcultured into the Murashige and Skoog (MS) proliferation medium containing 1 mg l-1 BA (6-Benzyladenine) and 0.1 mg l-1 NAA (naphthaline acetic acid) in four drought levels 0 (control), 10, 20 and 30% polyethylene glycol to study the effect of drought stress. After six weeks results showed that drought levels in the solid and liquid medium had a significant effect on all of measured parameters. Antioxidant enzymes activity (catalase and peroxidase), total protein content, proline content and soluble sugars significantly increased in the solid and liquid medium. Increasing of total protein content, proline content and soluble sugars in the liquid medium was more than solid medium. Soluble sugars had non-significant increasing in the different levels of drought in the solid medium. Leaf chlorophyll index was decreased by increasing drought levels. Leaf chlorophyll reduction in the solid medium was more than liquid medium. Generally, drought stress in both medium (solid and liquid), lead to activate defense mechanisms of GF677 rootstock such as antioxidant systems, osmoregulation by proline and soluble sugars and increasing protein synthesis and this increasing was more in liquid medium. Therefore, it concluded that drought stress in the liquid medium is more effective and more accurate in the study of plant tolerance to drought stress.

Drought is one of the most important environmental stresses affecting fruit trees production. A greenhouse experiment was conducted to test whether the foliar application of putrescine can mitigate the deleterious effect of drought stress in date cv. ‘Mazafati’. The lay out was as a 3 × 3 factorial experiment in a complete randomized design. In order to investigate the effect of different levels of drought stress, to determine the tolerance of ‘Mazafati’ offshoots and also to investigate the effects of foliar application of putrescine, the experiment was performed as factorial based on completely randomized design in a controlled greenhouse. The treatments consisting of control (75% FC), moderate stress (45% FC), and severe stress (15% FC) and three doses of putrescine (0, 1, and 2 mM). Results showed that growth parameters of date palm offshoots were decreased under drought stress condition. Application of putrescine in control offshoots (no stress) improved the growth parameters. It was found that 2 mM concentration of putrescine ameliorate. The adverse effects of injury caused by drought reduced the effects of drought stress. Leaf relative water content, the proline content, enzyme activities (ascorbate peroxidase, catalase and guaiacol peroxidase) were increased by application of 2 mM putrescine while the hydrogen peroxide (H2O2) activity was reduced. Also, it was determined that date palm offshoots of ‘Mazafati’ can tolerate the drought stress at 45% FC.

Melon is an important economic crop and Iran is a main center of diversity for Melon. For maintenance and evaluation of some native landraces field experiments were conducted during 2011 and 2012 growing season in Kaboutar-abad Agricultural Research Station of Isfahan. Fifteen selected populations were planted in a randomized complete block design with four replications. Field management was according to commercial practices and necessary notes were taken during growing season. The results showed that highest early harvest was obtained in Khaghani, Dastgerdi and Mashadi. Populations Saberi, Soski and Gaz produced the highest yield at the end of the season. Total yield with 44, 43 and 42 ton per hectare were obtained in Sabz Isfahan, Jalali and Saberi, respectively. The largest fruit size was picking up in Soski, Abbas shouri and Gaz and the smallest fruit size and weight was in Ananasi, Till and Saderati. Abbas shouri, Gaz and Jalali shown maximum frimness and have a relatively thick shell which are suitable for storage. While Till, Ananasi and Mashadi have least frimness and least storability. So regarding many dieases population of melon in Iran, which has good potential of vegetative and reproductive characteristics, it is necessary to study on their purification and selection to introduce for breeding.

Iran is one of the main producers of peach fruit, therefore increasing fruit quality and quantity is important. It has been reported that brassinosteroids are able to improve yield and quality of fruits. In present research, the impact of foliar spray of peach plants cv. ‘Alberta’ with 24- epibrassinolide (0, 0.1, 0.5, 1 μM EBL) at two stages namely; before flower opening, after fruit set and the combination of two stages was studied on fruit number, diameter and weight, stone length, diameter, weight and the ratio of fruit weight to stone weight, leaf chlorophylls, ion leakage and fruit yield. Compared with control, 1 μM EBL applied before flower opening increased leaf chlorophyll, fruit number, length, diameter and also stone length, diameter and weight and fruit yield. All treatments applied reduced leaf ion leakage. However, it is concluded that EBL applied before flowering is able to reduce flower and fruit abscission whenever needed.

Due to chlorosis in leaves of sour orange trees in Eram Botanical Garden of Shiraz University, in a 2-year experiment, the trunk injection of various concentrations of iron and zinc sulfate fertilizers was examined. Experiment was conducted in a randomized complete block design with six treatments and four replications during two successive years of 201 and 2013. Treatments were injections of two concentrations of iron and zinc sulfates (. and 1%) separately, a combination of iron and zinc sulfates (with the concentration of 0.5%) and distilled water as control. In each replication, the amount of 600 ml of fertilizer was injected into each tree. Two and six weeks after injection, leaf area, chlorophyll and carotenoid contents, photosynthesis rate, sugar, starch, catalase and peroxidase activities, iron and zinc contents of leaves and total soluble solid of fruits were measured. The results showed that trunk injection of 1% of iron sulfate significantly increased photosynthesis rate, chlorophyll, starch, iron contents of leaves, catalase and peroxidase activities compared to control. While combination of 0.5% of iron and zinc sulfates had the most effect on leaf area in comparison to control. Iron sulfate injection significantly increased the amount of chlorophyll and corrected the sour orange chlorosis. On the basis of the results of this experiment, trunk injection of iron sulfate at the rate of 1% had the greatest effect on removing chlorosis in sour orange leaves.

Crop nutrition is a practical method against freezing injury which may improves grapevine cold tolerance potential by increasing bud nitrogenous and carbohydrates storages. This study was conducted to evaluate the effect of late- season foliar application of urea 0, 1 and 2%) and potassium sulfate (0, 1.5 and 3%) on cold tolerance, soluble carbohydrates, proteins, proline and water content of grapevine (Vitis vinifera L. cv ‘Bidaneh Sefid’) buds. In summer 2012, urea was sprayed two times at post harvest and potassium sulfate applied two times before and two times after harvest on 14 years old grapevines located in Malayer Grape Research Station using a randomized complete block design. Following exposure of buds to artificial freezing in Nov., Jan. and Apr., cold tolerance was evaluated using electrolyte leakage bioassay. The effect of nutrition treatments was significant on cold hardiness of grapevines. In Jan., the highest cold tolerance (LT50= -25.63 ºC) and the lowest tolerance (LT50= -19.50 ºC) was found in 3% potassium sulfate solely or in combination with different urea levels and 2% urea without potassium sulfate, respectively. Moreover, potassium sulfate solely or in combination with different urea levels resulted in higher increments in soluble carbohydrates, protein and proline. The lowest and highest bud water content was detected after using potassium sulfate (especially in 3% K2SO4) and urea solely, respectively. The combined effect of two nutrients increased membrane stability and decreased electrolyte leakage more strongly via accumulation of osmoregulants and lowering free water which finally resulted in high freezing tolerance of grapevine buds. These results showed that using potassium and nitrogen simultaneously can significantly reduce cold injury in vineyards and may improve bud development through increasing bud nitrogenous and carbohydrates storages.