مجله علوم باغبانی ایران
سال پنجاه و یکم شماره 1 (بهار 1399)

To investigate the effect of NaCl salinity (0, 4, 8 and 12 dS m-1) on some morpho-physiological indices of Rosa damascenea Kashan genotype, a factorial pot experiment was designed based on randomized complete block design with four replications and three pots per replication (with total of 48 pots) on open air countineued for two years, and results of the second year data are reported. The results showed that salinity stress reduced fresh and dry weight of leaves and shoots. Also, the relative water content (RWC) of leaf and shoot decreased under salinity stress. Mean comparison showed that chlorophylls and carotenoids content were inversely associated with increasing salinity levels. The lowest levels of chlorophyll and carotenoids were observed in 12 dS m-1 treatment. Antioxidant enzymes activity such as superoxide dismutase (SOD), catalase (CAT) and guaiacolytic peroxidase (GPX) increased by increasing salt stress, although the lowest activity was observed in control treatment. Total phenol content of the leaves was also affected by increased salinity stress, but there was no significant difference between treatments. In addition, the results showed that by increasing salinity stress, the amount of soluble proteins decreased and its lowest amount was observed with 12 dS m-1 treatment. According to the results, salinity stress reduced plant growth by its effects on physiological and biochemical characteristics of Rosa damascena. Thus, it seems that the Damask Rose can tolerate a salinity level of up to 8 dS m-1, without detrimental effects on plant growth.

Allium jesdianum is an important and endangered medicinal plant that main habitats are located in the Zagros Mountains of Iran. In this study, onion of three ecotypes including Kakareza, Zalaghi and Meleh, which are grown in different geographical and climate conditions in Lorestan province, were collected. The collected onions were cultivated in a randomized complete block design with four replications. In the spring of the next year, plants are grown on the field and natural habitats were sampled to determine the physical and chemical properties of soil, soil samples were taken from 0-30 cm depth in each of the habitats and the farm, with three replications. The characteristics included quantitative and qualitative of essential oils, antioxidant activity total protein, vitamin C, non-structural sugars, and nutritional elements (nitrogen, potassium, phosphorus, iron, manganese, copper and zinc) of the shoots. The results showed that Dimethyl Trisulfide, Dipropyl trisulfide, Di-2-propenyl tetrasulfide, Hexadecanoic acid, and Pentacosane are the major components of the Allium jesdianum essential oil. The percentage of essential oil components was a significant difference (p<0.01) between wild and cultivated ecotypes. The maximum yield of essential oil (0.22%) was observed in wild plants from Mela habitat, and the minimume yield of essential oil (12.2%) was recorded in wild plants from Zalaghi habitat. Although the essential oil yield was significantly different between wild ecotypes, but there are no significant differences between these ecotypes at the farm. The highest amount of phosphorus (4.5 mg/g DW), zinc (2.3 μg/g DW), manganese (2.46 μg/g DW), non-structural sugars (45.66 mg/g DW), and total protein (8.83 mg/g DW) was observed in the cultivated ecotype of Meleh. Kakareza ecotype in habitat had the highest amount of vitamin C (80.66 mg/100 g FW) and antioxidant activity (IC50=42 μg/mL).

To evaluate the effect of different levels of irrigation as well as different types of mulches on some physiological and morphological traits of greenhouse cucumbers an experiment was conducted as split plot based on randomized complete blocks design with three replications. Irrigation were considered as the main plot in three levels (100, 80 and 60 percent of water requirement) and mulch levels were considered as subplot in four levels (no mulch, black plastic, transparency plastic and wood chips). Plant height, stem diameter, percent of dry weight of shoot and leaf, chlorophylls a and b as well as total chlorophyll, early yield, yield of cucumber grade1 and 2, total yield and water use efficiency were evaluated. The results showed the most levels of most features were attained at 100 percent level of irrigation. Some traits such as plant height, shoot diameter, chlorophylls a and b as well as total chlorophyll, and yield were decreased by applying 1evels of irrigation (100, 80 and 60 percent of water requirement). The highest yield of cucumber grade1 and total (3514 and 3684 g/plant, respectively) were recorded for 100 percent level of irrigation with adoption of wood chips mulch. The results of this research represented that applying wood chips mulch was completely efficient and beneficial in most studied physiological and morphological features of cucumber because of maintaining soil moisture and optimizing application of that in irrigation management that can increase productivity of greenhouse crops especially in arid and semiarid areas.

Epipactis veratrifolia is a terrestrialorchid that belongs to thetemperate zones of Iran with great breeding potentials for ornamental usages. Although in vitro propagation of this orchid has been previously performedbut investigation on factors influencing its in-vitro growth and photosynthesis is still needed. In the current study, three-leaflet seedlings were cultured in closed vessels containing modified Fast liquid medium together with sterilized perlite (for sample establishment). To remove CO2, vials containing saturated KOH solution as CO2 absorbent and to increase CO2 concentrations, vials containing 3 mL CO2-releasing solutions (3 M sodium bicarbonate and sodium carbonate) were placed into the culture vessels. The experiment was carried out based on a completely randomized design with three replications and three samples per each replicate. Growth parameters including fresh and dry weights of shoot, stem height and root length together with transpiration rate and maximum quantum yield of photosystem II efficiency (QYmax) of the samples were measured. The highest values for shoot height, shoot dry and fresh weights and root length were observed in CO2-increased treatments. Removing CO2 from the atmosphere of culture vessels caused a dramatic decrease in QYmax of plantlets in vitro. Meanwhile, following desiccation, higher transpiration rate was detected in control and CO2-increased treatments, while removing CO2 decelerate transpiration rate of the plantlets. In conclusion, with increasing CO2 in vitro we can promote photosynthetic efficiency of Epipactis veratrifolia and as a result enhance growth of plantlets in vitro.

In this study, the effects of six citrus rootstocks: Swingle citromelo; Troyer citrange; Carizo citrange, C-35 citrange; Smooth flat sevill and Gou tou) on reproductive reactions of Miyagawa Satsuma mandarin was investigated during 5 years (2013-2017). Experiment was done in randomized complete block design with 96 trees. Results showed that trees on Swingle citromelo at the beginning of fruiting phase (2013 and 2014) was more productive (58 and 48 kg/tree respectively) than other rootstocks and they had the most annual mean yield (52 kg/tree), cumulative yield during 5 years (261 kg/tree) and minimum alternate bearing index (22.1%), statistically. Also, cold tolerance in this rootstock was more than others due to maintaining the flower and fruit and high final yield in the year after the frost (2014). Annual mean yield and cumulative yield during five years on Citranges (Troyer, Carizo and C-35) and Smooth flat sevill was statistically similar. But, the highest yield efficiency was obtained on C-35 (6.72 kg/m3). Fruits on Swingle citromelo, were more spherical (length/width: 0.953) and juicy (46.22%), on Carizo were more oblate (length/width: 0.939) and thinned peel (2.21 mm) and on C-35 were heavier (150.2 g) and more premature (harvest index: 11.21) than fruits on other rootstocks. Gou tou significantly increased the thickness of the peel (2.83 mm), reduced fruit juice (41.65%) and extended fruit ripening time (harvest index: 8.52). Also, trees on Gou tou had the highest alternate bearing index (42.4%) during five years.

In this study, effect of deficit irrigation from olive fruit set to ripening stage was investigated. Treatments were control (100ETc), the first one regulated deficit irrigation (RDI1); 100% ETc from fruit set to beginning of fruit ripening and 50% ETc after that to harvesting, the second one regulated deficit irrigation (RDI2); 100% ETc from fruit set to pit hardening and 50% ETc thereafter to harvest, the third one (RDI3); 100% ETc during fruit set to the pit hardening and the beginning of ripening to harvest and 50% ETc at pit hardening, and no irrigation (rainfed). Fruit and oil yield and oil quality characteristics were evaluated. Results showed that the highest yield of fruit (30.41 kg per tree) and olive oil (5.86 kg in dry weight), the least peroxide value (8.33 meq O2/kg) andK270 (0.164), alsothe highest water use efficiency for fruit and oil production (24.24 and 64.4 kg/m3 , respectively) were in RDI3. The least yield of fruit (8.96 kg per tree) and oil (18.1 kg dry weight) and the highest peroxide value (23 meq O2/kg) was observed in rainfed. Overall, results showed that RDI during fruit pit hardening could increase water use efficiency, whitout reducing fruit yield, quality and oil percentage.

Drought and salinity are among the most important factors limiting plant growth in many parts of the world. The purpose of this study was to investigate the interaction effects of drought and salinity stresses on some morphological and physiological factors of Narcissus tazetta L. This pot experiment was conducted as a factorial based on completely randomized design with three replications at the Faculty of Agriculture, University of Birjand in 2017.The treatments included sodium chloride (NaCl) in four levels 0 (control), 20, 40 and 60 mM and drought stress in four levels 30, 50, 70 and 90% of field capacity.The results showed that salinity and drought stresses decreased length and width of leaf, dry weight of shoot and bulb, relative water content and chlorophyll content. However, the effects of salinity and drought stress and their interaction on reducing the number of flowers in flowering stem were not significant. In contrast, electrolyte leakage and proline content were increased under these two stresses. In general, the results showed that in the range of applied treatments, the destructive effects of salinity stress on growth, ornamental and physiological traits of N. tazetta flower were more than drought stress.

In the present research, the antioxidant property of 15 barberry genotypes was assessed by four various methods namely; DPPH, ferric reducing antioxidant power (FRAP), beta-carotene linoleic acid and total antioxidant activity based on TFPL method in Gorgan University of Agricultural Siences and Natural Resources at 2017. The plant materials were 14 seeded berrbery genotypes and a seedless one that already collected from northeastern provinces of Iran. The results of analysis variance showed that the effect of genotype was significant on phenol, flavonoid, anthocyanin, antioxidant capacity of barberry genotypes measured by DPPH, FRAP, beta-carotene linoleic acid and TFPL methods. In this experiment the highest and lowest levels of phenol (169 and 149 mg/g DW) were obtained in Daregaz1 and seedless Birjand genotypes, respectively. Also, Golestan1 and Shirvan5 genotypes had the highest flavonoid (88.6 mg/g) and anthocyanin (619 μmol/g), respectively. The results also showed that the antioxidant properties of barberry fruits were different in all measurement methods. The measured antioxidant capacity by various methods such as DPPH, FRAP, beta-carotene Linoleic acid were the highest in Shirvan4 (63.7 mg/g), seedless Birjand (54.5 μmol/g) and Dargas2 (78%) respectively. The total antioxidant activity based on TFPL method in Golestan3 genotype (29.9 μg/ml) was higher than other genotypes. The results showed that the total antioxidant activity in different barberry genotypes was directly related to phenolic compounds, and genotypes with the higher phenolic compounds, especially total phenols, had higher antioxidant properties. In this study, results of antioxidant activity comparison in different methods for berbery genotypes showed that it was finally determined that the total antioxidant activity based on TFPL method was a better technique for measuring the antioxidant activity in barberry genotypes due to its greater association with antioxidant compounds such as phenols. Furthermore, Daregaz1 genotype had the thigher phenols and therefore showed a high total antioxidant activity, which may be used in clinical studies.

To determaine th effect of root inoculation of Rasha grape cultivar with three species of arbuscular mycorrhizal fungus(G.versiforme, G. etunicatum, G. intraradices) on shoot growth, macro nutrient elements, chlorophyll content, leaf temperature, RWC, soluble sugars and drought symptoms rate under deficiet irrigation condition (75%, 50% and 35% water requirment) a factorial experiment based on RBCD was conducted in Kahriz Horticultural Research Station, Urmia, Iran. Results showed that increasing deficiet irrigation level, reduced shoot growthand fungus inoculation did not have a posetive effect on this trait in comparision with control. Leaf temperature and dry symptoms on leaves was lowest in vines that inoculated with G. versiforme under 35% deficiet irrigation condition. Leaves of vines with this fungus showed the high RWCin all stress tretments, too. By increasing deficiet irrigation level, soluble sugars were decreased in 55% water requirement and then increased in 35% water requirement. Among macro nutrient elements, the highest amount of P (0.14%) was measured in leaves of vines inoculated by G. versiforme.

Vegetative traits, chlorophyll content, water use efficiency, nitrogen, potassium and nitrate reductase activity of leaves and root tip were investigated in composition of the melon 'Khatooni' on squash cultivars Ace and Shintozwa under greenhouse conditions. Treatments consisted of melon grafted on squash, melon on melon, squash on melon, squash on squash, melon and squash own-rooted. Results showed that melon grafted on Shintozwa  had stem length (408.3 cm), leaf number (38.56), total leaves fresh weight (156.7 g), total shoot fresh weight (132.7 g), leaf area (18517.6 cm2), biomass (247.5 g), leaf dry matter (14.19%), shoot dry matter (7.96%) and root dry matter (17.46%) more than Ace. Grafted melons on both rootstocks were increased water, nitrogen and potassium use efficiency. The amount of total nitrogen and leaf nitrate on Ace rootstock was more than Shintozwa. The leaf ammonium on Shintozwa rootstock was more than Ace. A high nitrate reductase activity of leaves was obtained on melons grafted on Ace rootstock. Nitrate reductase activity in roots was higher than the leaves especially in the case of grafting. Root nitrate reductase activity was demonstrated a negative correlation with shoot length, biomass, leaf fresh weight, shoot fresh weight, leaf total area and root dry matter. Grafted melons totally contain large amount of organic nitrogen were compared to non-grafted, which it related to nitrate reduction and high nitrate consumption.

In this project, the processing ability and quality of green table olives during storage period on six selected cultivars and five genotypes were investigated. After harvesting, debittering carried out using NaOH (2%). The fruits were then placed in a solution of water and salt for fermentation and storage. During the fermentation and storage period, quality parameters such as ash, glucose, fatty acids, acidity, pH, mineral elements and sensory properties wereevaluated. At harvesting time, Direh, Tokhm kabki and KH15 genotypes had the highest fruit weight in comparison to the other selected cultivars and genotypes. During the processing and storage period, there was an increase trend for sodium, while a decrease trend in the amount of calcium and potassium in the fruit flesh compared to the harvest time. However, there was not a distinct trend in the acidity changes during the processing period. According to the sensory analysis, Zard, QG18, GW1, Direh, Meshkat, Manzanilla, TMN2and BN5, acquired the high score of total acceptance index among panelists (between 7.5 and 9), respectively.

This research was conducted in two stages to optimize in vitro propagation of Persian wild paeony. Stage 1: effect of BAP (0, 0.5, 1 and 2 mg.l-1), NAA (0, 0.1, 0.2 and 0.3 mg.l-1) and GA3 (0 and 0.5 mg.l-1) on apical bud ofPaeonia mascula and stage 2: effect of BAP (0, 0.5, 1 and 2 mg.l-1) and NAA (0, 0.25, 0.5 and 1 mg.l-1) were studied on embryonic callus induction on young leaves of Paonia mascula. At stage 1: the highest shoots number (5.38) was obtained on media containing 1 mg.l-1 BAP + 0.1 mg.l-1 NAA+ 0.5 mg.l-1 GA3. The results showed that increasing BAP level caused decreasing of shoot length. At stage 2: maximum of compact embryonic callus (17.93%) and somatic embryo number per explant (7.11) were obtained on 2 mg.l-1 BAP and 0.5mg.l-1 NAA. For callus proliferation, calli were maintained on MS medium containing 2 mg.l-1 BAP, 0.1 mg.l-1 NAA and 0.5 mg.l-1 GA3. Maximum rooting percentage (70.51%) and root number (0.0.02) were obtained with 0.25 mg.l-1 NAA.

This research was carried out with the aim of improving fruit sugar content in cantaloupe, accession Saveh. The ‘Saveh’ was crossed with ‘Galia’ and the F2 population was generated. The sugar content in fruits of parental generations and F2 population was measured using a refractometer. In F2 population 42 plants out of 2100 plants were selected and evaluated. HRM technique was used to determine the genotype of three candidate SNP markers which previously had been reported strongly associated with sugar content in fruit. The HRM analysis was carried out using Real Time PCR. Among the three SNP markers, one of them (SlE1-HRM) showed polymorphism. ‘Galia’ and ‘Saveh’ genotypes had A1A1 and A2A2 genotypes, respectively. After determining the genotypes, 13, 23 and 6 plants were obtained for three genotypes of A1A1, A1A2 and A2A2 , respectively. Unbalanced completely randomized design analysis of variance showed that these three groups had a significant difference in sugar content. The average of sugar content in brix unit (%) for A1A1, A1A2 and A2A2 genotypes was 11.75, 10.85 and 6.68, respectively. The mean comparison with Duncan's method showed that the difference of these average values was significant at the probability level of p <0.01. These results indicate that the marker can well select the plants that have higher sugar content than the parent of Saveh.

In order to study the effects of biochar and chicken manure tea compost on the nutrition responses and growth characteristics of tomato plants (Lycopersicon esculentum), a greenhouse experiment was carried out. The experiment was designed as factorial based on randomized completeblock design with three replications. Factors included biochar in two levels (including 0 and 10 t/ha) and organic and chemical nutrition in six levels (including fresh chicken manure 30 t/ha, three levels of chicken manure compost tea 1:4, 1:8, and 1:12 chicken manure-to-water ratio by w/w, Macromix and Polymicro chemical fertilizer 1 lit/ha and water as control). The results showed there were significant differences among different treatments in regard to soil total N, Fe, Mn, Zn and Cu. The highest leaf N, shoot dry weight and yield were obtained in T1B1 treatment(biochar and chemical ferlilizer) and the maximum manganese, zinc, copper and iron were obtained in T3B1 (compost tea 1:4 and biochar) and T4B1 (compost tea 1:8 and biochar) treatments. T3B1 (compost tea 1:8 and biochar) treatment contained the highest value of DPPH IC50 (3.75 mg), vitamin C (29.03 mg/100g), however, no significant differences were observed between biochar and biochar plus nutrition on soluble solids and titratable acidity compared with control.

Satureja sahandica is one of the endemic Iranian medicinal plants which, has application in pharmaceutical, food, cosmetic and sanitary industries and has high agricultural importance due to its high tolerance to drought stress and production capacity in rainfed areas. In order to investigate the changes in the physiological traits of Satureja sahandica, this research was carried out in two years under field conditions with split plot design in three replications. Drought stress considered as main slot at four levels (full irrigation and interupted irrigation at shoot, budding and 50% flowering stages) and inoculation with mycorhiza as sub plot  at four levels ( non-use of bio fertilizer (control), Glomus intraradices, Glomus mosseae, and Glomus mosseae + Glomus intraradices). The results showed iteraction effect of year * drought stress * mycorrhiza at 1% level on peroxidase and polyphenol oxidase and percentage of essential oil was significant. Mean comparison of traits showed that catalase, superoxide dismutase, peroxidase and total phenol were the highest in the second year. The highest amount of chlorophyll b, total chlorophyll, malondialdehyde, soluble sugar was obtained in drought stress at stem elongation. The highest superoxide dismutase, proline, and total phenol belonged todrought stress at 50% flowering. The highest percentage of essential oil (1.87%) obtained in use of both species of mycorrhiza. So using bio fertilizers can reduced effects of drought stress.

Jujube (Ziziphus jujuba Mill.) is cultivated for a long time in Iran, which has medicinal and economic value. In order to effective management of genetic sources, identifying species and determination on the genetic relationships between them, knowledge of genetic diversity will be helpful. To evaluate genetic diversity of 25 trees collected from South Khorasan Agricultural and Natural Resources Research and Education Center Collection, 16 RAPD and 22 SSR primers were used. Both the markers showed highly polymorphic. Distinctive power of two markers were compared using percent of polymorphism, polymorphic information content (PIC), resolving power (RP), marker index (MI) and effective multiplex ratio (EMR). RAPDs produced 108 polymorphic bands, while SSRs amplified 118 polymorphic bands. SSRs showed higher PIC, EMR and MI (0.47, 5.36, 2.58, respectively) than RAPDs (0.19, 3.55, 0.76, respectively). However, RP of RAPDs (9.92) higher than to SSRs (2.10). The dendrogram drawn with UPGMA cluster analysis showed that root-suckers of the same rootstock were separated from each other, which is indicative of the occurrence of somatic mutation among them. Dendrogram derived from the combination of SSR and RAPD datas, divided most of root-suckers from the same rootstock into same clusters.

In this study diversity of 10 populations belong to Achillea biebersteinii Afan and Achillea wilhelmsii C. Koch in natural habits of West-Azerbaijan province including (Urmia-Nazlu, Oshnaviyeh-Shahraksanati, Naghadeh Mohammadshahsofla, Mahabad-Esakandi, Miandoab-Chalkhamaz, Simineh-Khorojishahr, Bukan-Aliabad, Mahmoodabad-Hosseinabad, Shahindezh-Sarojeh and Sardasht-Nalas) were evaluated. Essential oil composition of the aerial parts of plant was identified by (GC/MS) gas chromatography. Cluster analysis divided the populations into three distinct groups. In general 23 and 27 components were identified in the essential oil ofA. biebersteinii and A. wilhelmsii, respectively. The essential oil percentage of the A. biebersteinii was 0.56 to 1.10 and the essential oil percentage of the A. wilhelmsiiwas 0.49 to 0.68%. The population of Naghadeh belongs to A. biebersteinii had the highest essential oil percentage and the population of Bukan belongs to A. wilhelmsii had the highest amount of 1,8-cineole (72.88%), the population of Miandoab (A. wilhelmsii) was high in camphor (57.98%) and camphon (58.5%) and the Shahindezh population belongs to (A. wilhelmsii) had the high levels of piperiton (32%). Populations of Naghadeh belongs to (A. biebersteinii), Bukan (A. wilhelmsii), Miandoab (A. wilhelmsii) and Shahindezh (A. wilhelmsii) were superior in terms of performance and efficacy that can be used for the pharmaceutical industry and breeding programs.

Due to decreasing in precipitation and under-ground water resources and increasing the chance of drought stress, it is necessary to select drought resistant or tolerant cultivars and genotypes. Hazelnut is one of the most important nut trees. In order to study responses of six hazelnut cultivars (‘Fertile’, ‘Ronde’, ‘Longue’, ‘Segorbe’, ‘Gerd’ and ‘Merville’) to drought stress, a RCBD based factorial experiment was carried out on three-year-old outdoor potted saplings. Irrigation treatments included control (regular watering), and drought stress (withdraw watering). Rewatering after drought stress period was performed and recovery of plants after one day and after one week were studied. Results of variance analysis showed significant differences between irrigation treatments as well as the cultivars. Photosynthetic pigments and the quantum efficiency decreased under drought stress, whereas, MDA and proline contents increased. The highest quantum efficiency of photosystem II was observed in control treatment (0.731) and the lowest was in stress treatment before rewatering, but one week after rewatering it returned to the control level. Gerd cultivar with highest amount of photosynthetic pigments had also the highest amounts of antioxidant compounds (phenolic compounds and flavonoids). Proline content had negative correlations with most of the studied characters except MDA. Under drought stress, ‘Longue’ and ‘Ronde’ expressed the lowest and the highest leaf injury (necrosis %), respectively. ‘Longue’, ‘Fertile’ and ‘Gerd’ cultivars were more tolerant to drought than other cultivars.

The present study was conducted to evaluate some of the morphological and physiological traits of four basil cultivars under drought stress condition in greenhouse. The experiment was conducted as a factorial based on a completely randomized design. Four commercial basil cultivars (including Iranian green and violet basils, Genovese and Amethyst) were used as the first factor and drought stress at four levels (including irrigation at 100, 85, 70 and 55% FC) was used as second factor. The results showed that drought stress increased root length, but decreased dry weight of the plant. Plant height, leaf area, RWC and transpiration were reduced under drought stress treatments. The rate of membrane stability index increased although the reduction was different among the cultivars. Genovese and Iranian green cultivars showed the highest fresh and dry weights. The highest root dry weight and fresh and dry weights of plant were obtained in Genovese cultivar. Finally, Genovese cultivar showed the highest potential to introduce as tolerant cultivar in order to cultivation in drought condition.

One of the major problems with commercial production of micro-propagated plants is low survival and poor growth after transplanting. In order to investigation the effect of arbuscular mycorrhizal symbiosis on establishment, survival, growth, as well as nutrients absorption on Pyrodwarf micropropagated rootstock in drought stress conditions, a factorial experiment was conducted in a completely randomized design with two factors including mycorrhizae in two levels (with and without) and drought stress in three levels (three, five and seven days irrigation intervals) in three replications in greenhouse conditions. The plants harvested two months after drought stress. The results of variance analysis showed that mycorrhizal symbiosis significantly increased vegetative indices at all levels of drought stress. The total leaf area, stem height, total leaf fresh weight and root dry weight of mycorrhizal seedlings were 3.6, 1.3, 3.1 and 1.9 times higher than non-mycorrhizal plants, respectively. The content of P, Mn, Cu, Zn and K and in root and shoot tissues increased significantly in mycorrhizal treatments than control. Generally, the results of this study showed that pear seedlings treated by arbuscular mycorrhizal fungi had better acclimatization, growth and more tolerance at normal and drought stress condition.