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In a completely randomized design, the effect of the extract from Trifolium alexandrium (0, 0.2 and 0.4%) on the germination, some morphological characteristics, photosynthetic pigments, and nutrients uptake of Prosopis cineraria was evaluated. The highest germination rate and percentage (9.16 and 21%, respectively) were recorded in the 0.2% treatment. The maximum and minimum lengths of radicle (6.58 and 3.16 cm) and pedicel (6.56 and 14.23 cm), and dry weight were recorded in the control and 0.4% treatments, respectively. The highest level of chlorophyll a (16.80 mg g^-1 fresh weight) was found in the control. The highest and lowest chlorophyll b (9.65 and 7.96 mg g^-1 fresh weight) were measured in the 0.2%and control, respectively. The extract adversely affected the nutrient uptake by P. cineraria, the minimum and maximum of which were recorded at the 0.4%and control treatments, respectively. In general, although the extract of T. alexandrium increased the P. cineraria germination in the 0.2% treatment, the increased concentrations led to its reduced growth and nutrient uptake. Therefore, the simultaneous cultivation of these two species in the dry lands is not recommended.

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Aims: Salt stress is one of the most important environmental stresses that cause to reduce biological function in plants. In this context, appropriate biotech is needed that would not only improve the productivity of the product but also improve the soil. Regarding the problem, the use of humic acid in addition to the positive effects on soil properties, it is useful in terms of economic, environmental, and social aspects and can be an appropriate alternative to chemical fertilizers.
Materials & Methods: The present research was conducted as a factorial experiment in a completely randomized design. The first factor was humic acid (0, 0.009 mg Li⁻¹). The second factor was salt stress, which was applied at three levels of 2, 6, and 12 dS m⁻¹. In each treatment, seed germination, seed vigor index, growth traits (allometric coefficient, radicle and pedicle length, total dry, and fresh weight), and photosynthetic contents of Medicago sativa L. were measured.
Findings: The findings showed that under salt stress, humic acid increased the seed germination of M. sativa L. Humic acid was effective in increasing the plant growth. In connection with the photosynthetic contents, the humic acid showed positive effects, especially in terms of 2 and 12 dS m⁻¹ salinity levels, respectively.
Conclusion: In general, humic acid had high impact on reducing the negative impacts of saltstress. Due to the fact that majority of the world’s rangelands are in arid and semi-arid areas, and salt stress is one of the most important factors in reduced plant growth, more comprehensive and accurate survey in the field is recommended.

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Endophytic and epiphytic bacteria have been reported as agents of bio-control of diseases and plant growth promotors. Here, in vitro and greenhouse experiments were conducted to evaluate the action of two microbial strains; Aureobasidium pullulans and Pantoea agglomerans, on biocontrol of bacterial canker and growth promotion of tomato (Lycopersicon esculentum cv. Campbell 33). Two frequencies of treatment were used to assess their potential effect (15 and 30 days between two subsequent treatments). The two strains were able to inhibit, in vitro, the growth of Clavibacter michiganensis subsp. michiganensis the causative agent of tomato canker. Also, their antagonistic effects were confirmed in greenhouse conditions. Indeed, bacterial canker incidence in tomato plants treated with A. pullulans and P. agglomerans separately or in mixture was significantly less severe (16%) compared to the positive control (83%). The treatment frequency (intervals of 15 or 30 days) and the choice of strains to inoculate (separated or combined strains) appear to be essential for obtaining significant results. Consequently, both A. pullulans and P. agglomerans strains highly reduced incidence of bacterial canker particularly when tomato plants were treated at a frequency of fifteen days

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  In order to study the effects of different nutrition systems (organic, chemical, integrated) and plant growth promoting rhizobacteria (PGPR) on on the grain yield, seed oil content and fatty acid composition in Sunflower (Helianthus annuus L. . cv. Alestar) an experiment was conducted using Alestar cultivar at the research farm of college of agriculture, Tarbiat modares university of in 2007. Five levels of nutrition systems including F1(100% organic), F2(75% organic+25% chemical), F3(50% organic+50% chemical), F4(25% organic+75% chemicaL), F5(100% chemical) in main plot and two levels of biofertilizer I1(inoculation) and I0 (control) as subplot were used in a split plot arranged in a randomized complete block design with three replications. Results showed that the integrated fertilizer system had higher grain yield than the other fertilizer systems (F3›F4›F2›F5›F1). Maximum and minimum oil content were obtained with the F3 treatment and F1 respectively. The oil saturated fatty acids(acid palmitic and acid stearic) decreased significantly, while insaturated fatty acids( linoleic acid and oleic acid) increased significantly in response to raising the FYM-rate. The highest linolenic acid and oleic acid were observed in F3 and F1 treatments respectively. The results revealed that PGPR improved plant productivity and quality in sunflower seed. The inoculation of PGPR (I1) increased, grain yield, oil content and unsaturated fatty acids and decreased saturated fatty acids compared with untreated plants I0.

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Biocontrol of Fusarium oxysporum f. sp. ciceris by six Bacillus species was evaluated. Also plant growth promoting potential of the bacteria was assessed. Results showed that four bacterial strains produced the chitinase and cellulase enzymes and all isolates produced indole acetic acid. Bacillus licheniformis proved to be the most productive of hydrogen cyanide and particularly, Bacillus firmus solubilized phosphorus on Pikovskaya solid and liquid media. The majority of strains were able to produce siderophore and three produced NH₃. Results showed that the Flip05-156C chickpea variety was less susceptible to Foc isolates compared to Flip93-93C and there was a clear difference in pathogenicity of the Foc isolates. Thus, Foc1 and Foc2 isolates caused 31.25% and 41.66%, plant mortality, respectively. As regards PGPR effect, results showed that B. licheniformis gave the best branching number, stem length and root weight of both chickpea varieties. However, Bacillus lentus distinctly improved the root length while Bacillus amyloliquefaciens improved weight of the vegetative parts.

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This study investigated the variation between two sugar beet (Beta vulgaris L.) cultivars with respect to growth parameters and photosynthetic rates of individual attached leaves during salinization. Sugar beet plants grown in sand culture were gradually exposed to different levels of salinity (0, 50, 150 , 250, and 350 mM, NaCl+CaCl2 in 5:1 ratio). Salt concentrations significantly decreased all growth traits. At the highest level of salinity (350 mM), cv 7233- P29 showed a significantly higher leaf area and total dry matter than Madison after eight weeks of salt treatment commencment. Net photosynthesis (ACO2) and stomatal conductance (gs) were strongly affected by salinity. The Na+ and Cl- concentrations in shoots significantly increased as salt concentration increased. Net photosynthesis (ACO2) was plotted against computed leaf internal CO2 concentration (Ci), and the initial slope of this ACO2-Ci curve was used as a measure of photosynthetic ability. Leaves from plants exposed to 50 mM salinity showed little change in photosynthesis, whereas those treated by high levels of salinity had up to 91.5% inhibition in photosynthetic rates and an increase in CO2 compensation point. Leaf chlorophyll content increased with increasing salinity. Although partial stomatal closure occurred with salinization, reductions in photosynthesis were partly non-stomatal at high levels of salt treatment.

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The present study was conducted to determine the plant growth-promoting activities of Bradyrhizobium sp. (vigna) strain MRM6 grown in the presence and absence of the selected herbicides, quizalafop-p-ethyl and clodinafop. The herbicide tolerant Bradyrhizobium sp. (vigna) strain MRM6 was further tested for bioremediation and plant growth promoting potential using greengram as a test crop, grown in soils treated with quizalafop-p-ethyl and clodinafop, at both recommended and higher dose rates. The quizalafop-p-ethyl and clodinafop tolerant Bradyrhizobium sp. (vigna) strain MRM6 recovered from the nodules of greengram plants produced a substantial amount of indole acetic acid, siderophores, hydrogen cyanide and ammonia, both in the presence and absence of technical grade quizalafop-p-ethyl and clodinafop under in vitro conditions. Both quizalafop-p-ethyl [40 (recommended dose), 80, and 120 µg kg-1 soil] and clodinafop [400 (recommended dose), 800, and 1200 µg kg-1 soil] decreased the growth of Bradyrhizobium sp. MRM6-inoculated and un-inoculated plants. Quizalafop-p-ethyl at all concentrations showed more phytotoxicity and affected the growth in terms of nodulation, total dry biomass, nutrients (nitrogen and phosphorus) uptake and seed yield compared to clodinafop or un-inoculated control. When the inoculant strain MRM6 was used with any concentration of the two herbicides, the growth and nodulation parameters of the plants were relatively better compared to the plants grown in soils treated solely (without inoculant) with the same concentration of each herbicide. For example, when strain MRM6 was used with 1200 µg clodinafop kg-1 soil, it increased the symbiotic attributes (nodule number, nodule dry mass, leghaemoglobin), whole biomass, root N, shoot N, root P, shoot P, seed yield, and grain protein by 14%, 62%, 60%, 102%, 23%, 31%, 9%, 10%, 72% and 4%, respectively, compared to the un-inoculated treatment having the same concentration of clodinafop. The present findings suggest that the bradyrhizobial strain MRM6 endowed with multiple properties could be used to facilitate the productivity of greengram under herbicide-stressed soils.

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Individual grain weight of wheat kernels differs with their positions on a spike. Cultivation practices (such as fertilizer nitrogen and plant growth regulators application) can be used to improve weight of basal and distal kernels. For this purpose, two experiments based on randomized complete block design were carried out with three replications. The aim of this research was to study the mechanisms related to sink strength as well as the regulatory factors affecting sink activity. One cultivar of a facultative wheat, cv Yangmai15, was used. Treatments of the experiments included application of nitrogen (two levels) and plant growth regulators [abscisic acid (ABA) and Fluridone (inhibitor ofABA synthesis)] in basal and distal kernels, respectively. Results showed that nitrogen application increased grain yield and its components. Grain filling in basal kernels started earlier and its rate was higher than that of the distal kernels. Nitrogen fertilizer increased the individual kernel weight both in basal and distal kernels, and the rate of increment was higher than the control, even in distal kernels. The application ofABA resulted in increase in grain weight, whereas a considerable decrease in grain weight was observed in response to Fluridone compared to the control. Nitrogen application together withABA application enhanced the activity of SuSase, AGPase, SSS, and SBE in basal and distal kernels and the increment in the activity was higher in distal kernels. It is concluded that simultaneous application of nitrogen andABA enhanced grain weight by regulating the activity of key enzymes involved in starch synthesis. 

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The effects of the plant growth promoter gibberellic acid (GA₃) and plant growth retardant chlormequat chloride (CCC) on biomass and quality of Angelica dahurica var.formosana plants were investigated employing physiological and biochemical methods. Plants were sprayed with GA₃ or CCC at rosette stage and coumarin content was analyzed by high performance liquid chromatography (HPLC) after harvest. Two coumarins in root were detected: isoimperatorin and imperatorin. The root content of imperatorin was not affected by application either GA₃ or CCC, while isoimperatorin was increased to 127% after treatment with CCC (400 mg L^-1). The lowest concentrations of GA₃ (50 mg L^-1) and CCC (400 mg L^-1) increased root yield to 157 and 139%, respectively. We note here that GA₃ and CCC might be used in improving the yield of A. dahurica var. formosanaandmaintaining the coumarin content.

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The effects of rootstocks such as 'sour orange' (Citrus aurantium L. var. ‘Yerli’), 'Carrizo' and 'Troyer citranges' (Citrus sinensis Osb. x Poncirus trifoliata Raf), 'Smooth Flat Seville sour orange' (Citrus spp. hybrid of uncertain origin), 'Brazilian sour orange' (Citrus aurantiam L. var. ‘Brasilian’), 'Volkameriana' (Citrus volkameriana Tan. and Pasq.) and 'Calamondin' (possibly Citrus reticulate var. austere×Fortunella hybrid, Swingle) on plant growth, fruit yield, and quality of ‘Rio Red’ grapefruit were investigated from 2008 to 2012. Rootstocks were found to have significant effects on plant growth, fruit yield, and quality. ‘Rio Red’ grapefruit trees budded on 'Carrizo' and 'Troyer citranges' showed higher vegetative growth parameters (canopy height, diameter, and volume) than the trees on the other rootstocks. The trees on 'Volkameriana' and 'Carrizo citrange' produced higher percentage of cumulative yield of about 55.1 and 34.3%, respectively, than the trees on 'sour orange'. ‘Rio Red’ grapefruit budded on 'Carrizo citrange' had higher fruit quality such as thin rind, high juice content, and more color development than the other rootstocks. 'Carrizo citrange' was the most promising rootstock for ‘Rio Red’ grapefruit in Dörtyol, Eastern Mediterranean region of Turkey.

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The objective of this work was to study the responses of two baby lettuce (Lactuca sativa L.) cultivars, namely, green Paris Island and red Sanguine, to different NaCl concentrations (0, 5, 10, and 20 mM). The study was conducted in a floating system and plants were harvested at the stage of 5-6 leaves, outside leaf 6-10 cm in length (25 and 31 days after sowing for green and red lettuce, respectively). Photosynthetic parameters (photosynthesis rate, stomatal conductance, transpiration rate, and intercellular CO₂ concentration) and yield (leaf fresh weight) as well as color [L* (lightness), C* (saturation), Hº (object’s color)], pigments (Chla, Chlb, total chlorophyll, carotenoids and anthocyanins) and quality indices (appearance, freshness, taste and texture) were determined. The results indicated that, in both cultivars, leaf fresh weight was reduced at 20 mM NaCl; the reduction depended on the limited water accessibility and photosynthetic rate was suppressed in high salt concentration through stomatal limitations aiming at the retention of water but resulting in restricted availability of CO₂. Nevertheless, no limitations were observed in photosynthetic pigments and, thus, stomatal closure was the dominant factor limiting photosynthesis. On the other hand, salinity improved anthocyanin content and coloration in red lettuce and enhanced freshness in green lettuce.

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The present work developed an efficient plant regeneration and propagation system via direct organogenesis for Morinda officinalis How., a valuable endangered medicinal plant. The effects of explant types on shoot induction, plant growth regulators on shoot proliferationand elongation and the subsequent rooting ability of shoots were examined. Among the various types of explant, direct shoot proliferationwas successfully achieved from shoot tips and nodal stem segments with around 95% of the explants producing approximately 5 shoots per explant after 8 weeks of culture on optimal medium. On the other hand, leaf and internodal explants did not produce any shoots. The most effective cytokinin on shoot proliferation was 6-benzyladenine. When the concentration of 6-benzyladenine was at 1.0-2.0 mg L^-1, a high mean shoot number (about 5 shoots per explant) was achieved. Shoot elongation was obtained satisfactorily by transferring the shoots to Murashige and Skoog basal media containing 2.0-3.0 mg L^-1 gibberellic acid-3 within 2 weeks. Rooting was 100% on half-strength Murashige and Skoog medium containing 0.2 mg L^-1 indole-3-butyric acid after 3 weeks of culture. The plantlets were acclimatized in the greenhouse and subsequently transferred to the field with 90% survival rate.

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In the present study, the effect of two species of AMF, Glomus mosseae and Glomus intraradices, alone and in combination, was evaluated on the growth criteria, chlorophyll content, and root rot disease caused by Fusarium solani f. sp. pisi, on chickpea (Cicer arietinum L.) under greenhouse conditions. Chickpea seeds were sown into pots containing 100 g of AMF inoculum (more than 1,000 propagules g^-1) and, after four weeks, root of seedlings were inoculated with conidia suspension (10⁶ conidia mL^-1) of F. solani f. sp. pisi. Six weeks after pathogen inoculation, shoot and root dry weight, shoot height, chlorophyll content and mycorrhizal and Fusarium colonization were measured. Results showed that inoculation of G. mosseae was more effective than G. intraradices and dual inoculations (G. intraradices+G. mosseae) on the above criteria. Inoculation of F. solani f. sp. pisi without AMF treatments reduced shoot height, shoot and root dry weight, and chlorophyll content significantly compared with the control. In the presence of AMF, root colonization by F. solani f. sp. pisi and disease severity decreased and individual inoculation with G. mosseae was more effective than the other treatments. Inoculation of G. mosseae and G. intraradices caused a significant increase in plant height, shoot and root dry weight, and chlorophyll content of pathogen-inoculated plants compared with inoculated chickpea plants with F. solani f. sp. pisi. Based on the results, application of G. mosseae was found to be the best for reducing the root rot disease and improving plant growth parameters of chickpea, followed by G. intraradices and dual inoculations.

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Endophytic bacteria colonize in plant tissues and enhance plant growth by a wide variety of mechanisms. The objectives of this study were to examine the population of root endophytic bacteria in soybean and corn, and to identify IAA-producing endophytic bacterial strains and their growth promoting effect. The density of endophytic bacteria varied irrespective of crops, sampling times and soil amendments. A total of 119 and 277 bacterial isolates were isolated from soybean and corn roots, respectively. 39.6% of the total isolates showed IAA production in the range of 1~23 μg mL^-1 in culture medium supplemented with tryptophan. Fourteen isolates, designated as S1-S4 from soybean roots and C1-C10 from corn roots, had the capacity of producing IAA over 10 mg L^-1. Based on 16S rRNA gene sequence analysis, the fourteen isolates were closely related to Psychrobacillus, Microbacterium, Lysinibacillus and Bacillus. Pot experiment indicated that the growth-promoting effects varied among these 14 bacterial strains and not all of the strains were able to promote growth of the tested soybean and wheat plants. Strains Microbacterium sp. C4 and Lysinibacillus sp. C7 showed better performances in promoting soybean and wheat seedling growth.

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Studies on determination of the effect of herbicides on survivability of Plant Growth Promoting Bacteria have a strategic usefulness in determination of plant health and the fate of applied agrochemicals in agroecosystem. Antimicrobial potential was assessed using estimation of a minimum inhibitory concentration of the Roundup 360 SL against Pseudomonas sp. A quantitative analysis of bacteria was performed, and the tendency of physicochemical changes in the mineral medium was evaluated during long-term exposure to the herbicide. Furthermore, the antagonism of the SP0113 strain against F. culmorum and F. oxysporum under stress conditions caused by Roundup® 360 SL was verified. It was demonstrated that use of the undiluted and 2.6-fold diluted product resulted in the inhibition of growth of the investigated strain. Pseudomonas sp. SP0113 showed survivability and resistance to near recommended dose concentration of Roundup® 360 SL. The possibility of bacterial development on the Tryptic Soy Agar (TSA) medium at contact concentrations of 14.4 and 5.4 mg mL^-1, as per the diluents quantity declared by the producer, indicates the role of cofactors such as: adiuvant or pH, redox potential (mV) or salinity. They comprise pH change, oxidation and salinity that may be due to the reaction of the active substance of the herbicide with mineral nutrient ingredients. The high salinity of environment, as a result of the reactions with the ingredients contained in the medium, is characteristic for concentrations higher than those recommended in practice. Furthermore, it was found that glyphosate limits the growth of fungi of the Fusarium genus, which support plant protection using strain SP0113.

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Possibility of improving physiological traits and minituber yield of potato cultivars (cvs. Agria and Fontane) was investigated by application of plant growth regulators (BAP, ABA and BAP+ABA) at tuber initiation stage. Regardless of the cultivars, Net photosynthesis rate (Np), actual quantum yield (Φ), stomatal conductance (g_s) and Transpiration rate (T_r) of BAP-treated leaves were superior to those of the control. For Agria, the greatest Chlorophyll content (Chl) was observed in BAP-treated plants, while the highest Chl for Fontane was observed in ABA-treated plants. Increasing Np and Chl content were associated with higher Soluble Carbohydrate content (SC). BAP+ABA application increased SC of leaflets in both cultivars compared with the control. Tuber Yield per Plant (Y/P), Mean Tuber Weight (MTW), and Tuber Number (TN) were stimulated by foliar treatment of plants with PGRs compared with the untreated ones, but there were significant interactions between cultivar and hormone type. Positive correlation between SC and Y/P (r= 0.97*) and MTW (r= 0.97*) were observed in Agria. Leaf area as well as dry and fresh weight of aerial parts of the BAP+ABA-treated plants were more than the untreated plants and other PGR treatments. These results indicate that either of BAP, ABA, or their combination could be effectively used to improve physiological traits and tuber yield of these cultivars, although, Agria responded more prominently to PGRs than Fontane.

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The scarcity of water, along with the concern of safe production of food, emphasizes the need for new agricultural techniques. Increasing dissolved oxygen concentration in water promotes the growth of plants in many ways. The aim of the present research was to investigate how cucumbers (Cucumis sativus L.) morphologically and physiologically respond to water enriched with air Micro-NanoBubbles (MNBs) as an oxygen saturating measure. The plants from early stage of seed planting (two groups, 32 plants in each) were cultured either with air-nanobubbles water or with tap water for 12 weeks, and the steric stability of MNBs in water was confirmed through zeta potential measurements (-20.47 mV). The number of blossoms in the plants irrigated by air MNBs water was almost 3.8 times more than the number of blossoms in those that were irrigated by tap water. MNBs water increased leaf area up to an average of 77%. Physiological indices such as chlorophylls a, b, and carotenoids were, respectively, 1.34, 1.44, and 1.35 times greater in the plants watered with MNBs than those with tap water. Overall, this study demonstrated that water with air micro-nanobubble had a positive effect on cucumber plants and is potentially an effective tool for the environmental friendly, economical, and profitable production of the plant.
 

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Using immature embryos that undergo somatic embryogenesis, we studied the effects of different hormonal compounds and media on controlling secondary somatic embryogenesis (SSE) in Persian oak (Quercus brantii L.). To this end, we focused on the immature embryos that were subjected to several treatments including chilling (at 4 ℃) period and SH, MS, 2,4-D, IBA, BAP, and glutamine concentrations in 5 separate sequential experiments. The results showed that, by extending chilling period to 8-weeks, SSE induction was reduced (68.75%). In different MS concentrations or MS containing PGRs, the lowest globular embryo (66%) and the secondary embryo induction (87.5%) were observed in embryos treated with MS+IBA+BA. Adding 0.75 mg L^-1 glutamine to MS resulted in a decrease in the secondary somatic embryogenesis (56.25%). Among MS and SH media, 1/2 SH almost entirely controlled this phenomenon (6.25%). The highest maturation progression was obtained in the SH+glutamine treatment, which had the highest conversion to plantlet percentage (100%) and vigor index of plantlets (51.93) compared to the use of SH alone. We found that nutrient and PGR concentration were critical in embryo maturation and conversion percentage and stop the embryo induction cycle that plays a major role in secondary embryogenesis.
 

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Two endophytic fungi, namely, Curvularia lunata and Nigrospora sphaerica, were isolated from Melia azedarach, an exotic tree introduced in Egypt from Asia. The fungal endophytes were identified by microscopic examination and molecular identification of nucleotide sequence by DNA sequencing of the purified PCR product. Their antagonistic activities against phytopathogenic fungi and their ability to produce important growth hormone and providing some necessary nutrients for plant growth were also evaluated. Both endophytes exhibited antagonistic activities: C. lunata caused 56% and 50% growth inhibition of Alternaria solani and Fusarium oxysporum, while N. sphaerica suppressed both pathogenic fungi by 63.4% and 56.6%, respectively. N. sphaerica was able to dissolve insoluble phosphorus, produce ammonia, and secrete 40 µg mL^-1 of IAA. In contrast, C. lunata failed to dissolve phosphorus, secreted less amount of IAA (3 µg mL^-1), but produced ammonia. A greenhouse pot experiment was conducted using phosphorus deficient soil to find out the ability of both endophytes to improve growth of tomato plants. N. sphaerica significantly increased shoot fresh weight by 13% and 22% over C. lunata and the control, respectively. Concerning the nutritional status of tomato plants, both endophytes led to significant increase in nitrogen concentration in shoots when applying 50% of the recommended mineral fertilizer. N. sphaerica enhanced phosphorus concentration in shoots by 13% over the control. Finally, the antifungal activities of both endophytes against F. oxysporum in tomato plants were tested under glasshouse conditions. N. sphaerica was more potent than C. lunata in suppressing 40% of F. oxysporum infection and had positive impact on tomato plant growth. Our study results highlight the potential use of N. sphaerica endophytic fungi as plant biofertilizers and bio-control agent under glasshouse conditions.