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This study of selected fruits of the Oleaceae and Solanaceae families quantified the contents of free and bound phenolics (FP and BP) and their in vitro antioxidant activity and inhibitory potential towards enzymes relevant for hypertension and hyperglycemia management. For all the fruits considered, FP extracted at 30 °C (FP-30 °C) were the predominant fraction of the total phenolics and had higher antioxidant activities. The highest inhibition (100%) towards angiotensin I-converting enzyme (ACE), α-amylase and α-glucosidase was obtained respectively with extracts from tomato (FP-30 °C extract) and red pickled olive (BP-acid extract), red hot pepper (BP-base extract), and green and red pickled olives and yellow sweet pepper (BP-base extracts). Significant positive correlations existed between ACE inhibitory activity and total phenolics for Solanaceae fruits, and between the α-amylase and α-glucosidase inhibitory activities of phenolics from olives, tomato and yellow sweet pepper. Distinct phenolic profiles were evidenced for each fruit, with p-coumaric acid detected in appreciable amounts in BP extracts from all fruits.

Drought stress has a negative impact on crop growth and productivity worldwide. Plant symbionts such as arbuscular mycorrhizal fungi (AMF) can enhance plant growth and improve plant resistance to drought stress. AMF mixture inocula and plant responses to drought still require further study. The objective of this study was to investigate the effects of non-inoculation (NM) or inoculation with three commercial AMF inocula containing a single or mixtures comprising different numbers of AMF species: M1 (Rhizophagus intraradices), M2 (Rhizophagus clarus, R. intraradices, Septoglomus deserticola, Funneliformis mosseae), and M3 (Rhizophagus intraradices, R. aggregatum, Funneliformis mosseae, Olaroideoglomus etunicatum) on growth, nutritional, and physiological responses of soybean (Glycine max L. cv. Hutcheson) grown in a greenhouse under different water stress levels [WW = well watered (90% FC), MS = medium (60% FC) and SS = severe stressed (30% FC)]. The AMF-inoculated plants had significantly higher plant biomass, chlorophyll content, stomatal conductance, leaf water relations, and mineral contents in comparison to NM plants. Applied mycorrhizal inocula differed in their response to water-deficit conditions. M2 inoculant generally supported greater plant biomass, stomatal conductance, leaf water content, and leaf N, P, K, S, Mn, and Cu contents than M1 and M3 inocula, especially under MS and SS treatments. These results indicated that all mycorrhizal inocula supported plant growth both generally and with soil water deficit; however, M2-inoculated plants performed better than M1 and M3 under drought stress. Therefore, mycorrhizal inocula are effective for supporting soybean growth and offsetting the effects of drought and AMF technology that can support sustainable crop cultivation under soil water-deficit conditions. Different types of inocula have different effects, however, and thus require testing for individual crops.

This study quantified the free and conjugated phenolic content of extracts from selected Liliaceae (white and red onion), Punicaceae (red and pink pomegranate), Vitaceae (zini, red globe, and baladi grape), and Rosaceae (yellow and red apple) cultivated family plants and evaluated their antioxidant activities and beneficial properties toward diabetes and hypertension. Free and bound phenolics were extracted from plants, and total phenolic contents were evaluated. Antioxidant activities were assessed, as well as the inhibitory effects of angiotensin I-converting enzyme (ACE) and α-amylase and α-glucosidase activities. Liquid chromatography–mass spectrometry/mass spectrometry (LC–MS/MS) measured the individual phenolic content in both free and bound extracts. The free phenolic contents in the selected plants were higher than bound phenolic contents, except for in zini and red globe grapes. In onion, the highest antioxidant activity was observed in the bound phenolic extract (49.6–56.9%). In pomegran...

Turf grasses are considered an integral part of landscape ecological systems worldwide which provide functional, recreational and aesthetic benefits to society and the environment. In arid and semiarid regions (e.g., Mediterranean region), turf grass is usually grown under harsh and unfavorable growing conditions with low rainfall and high rates of evapotranspiration as well as in soils with nutrient deficiencies. Hence, growing turf grass in these regions becomes dependent on application of high levels of fertilizers as well as on excessive use of irrigation water, resulting in an environmental pollution. Therefore, it is important that turf grass plantations are managed in a sustainable way to reduce the impact of turf grass cultivation on ecosystems while maintaining healthy and productive turf through using such practices as mycorrhizal fungi technology. The application of mycorrhizal fungi technology is an option that can benefit both agronomic plant health and ecosystems. Mycorrhizae confer numerous benefits to host plants including improved plant growth, mineral nutrition, water uptake, tolerance to diseases and stresses such as drought and salinity. The aims of this paper were to review how mycorrhizal fungi might play a role in enhancing landscape turf establishment and productivity in arid and semiarid regions and to evaluate the effectiveness of application of commercial mycorrhizal inoculum to enhance plant growth and survival under field conditions. Field experiment was conducted to study the effects of arbuscular mycorrhiza (AM) fungi inoculation on water use efficiency and establishment of a landscape turf. The results showed that turf grass inoculated with AM fungi used water more efficiently, established lawn more quickly and had more biomass than uninoculated turf grass. The conclusions of this paper indicated the potential of mycorrhiza inoculation in improving the fast establishment of turf landscape plants under arid and semiarid environments.

A field study was carried out under rainfed conditions during the growing season 2008/2009 in Maru (Northern Jordan) to evaluate the phenological variation using heat-accumulated system and its relation with yield in sixteen durum wheat genotypes. Grain yield was negatively correlated with growing degree days (GDDs) to maturity, while positively correlated with GDD to heading. Increasing GDD to heading resulted in higher grain yield, while increasing grain fill duration had little effect. Rapid grain fill rate was positively correlated with grain weight and negatively correlated with grain fill duration. Waha-1, Omrabi-5, and Massara-1 genotypes had the highest grain yields among genotypes studied. These three genotypes tended to have relatively longer preheading periods with early maturity. The results of this study indicate that Mediterranean-adapted cultivars would have long preheading periods, followed by short periods and high rates of grain fill and mature early to avoid late-season drought and high-temperature stress and to attain high yields. Therefore, it is recommended for the development of high yielding wheat cultivars adapted to semiarid environments to select the genotypes with early maturity and a relatively long time to heading.

Protected horticultural crops as well as those planted in open fields particularly in the Mediterranean region have to cope with increasing salinization ofirrigation water. High salinity of the supply water has detrimental effects on soil fertility and plant nutrition and reduces crop growth and yield. This study was conducted to determine if pre-inoculation of transplants with arbuscular mycorrhizal (AM) fungi alleviates salt effects on growth and yield of tomato (Lycopersicon esculentum Mill. Cv. Marriha) when irrigated with saline water. Tomato seeds were sown in polystyrene trays with 20 cm 3 cells and treated with AM fungi (AM) or without (nonAM) Glomus mosseae. Once the seedlings were reached appropriate size, they were transplanted into nonsterile soil in concrete blocks (1.6 m 3m 0.75 m) under greenhouse conditions. The soil electrical conductivity (ECe) was 1.4 dS m 1 . Plants were irrigated with nonsaline water (ECw = 0.5 dS m 1 ) or saline water (ECw = 2.4 dS m 1 ) until harvest. These treatments resulted with soil EC at harvest 1.7 and 4.4 dS m 1 for nonsaline and saline water treatments, respectively. Root colonization with AM fungi at flowering was lower under saline than nonsaline conditions. Pre-inoculated tomato plants with AM fungi irrigated with both saline and nonsalinewater had greater shoot and root dry matter (DM) yield and fruitfresh yield than nonAM plants. The enhancement in fruit fresh yield due to AM fungi inoculation was 29% under nonsaline and 60% under saline water conditions. Shoot contents of P, K, Zn, Cu, and Fe were higher in AM compared with nonAM plants grown under nonsaline and saline water conditions. Shoot Na concentrations were lower in AM than nonAM plants grown under saline water conditions. Results indicate that pre-inoculation of tomato transplants with AM fungi improved yield and can help alleviate deleterious effects of salt stress on crop yield. # 2006 Elsevier B.V. All rights reserved.

Plants grown in alkaline soils often have reduced productivity because of limited mineral nutrients. For plants to obtain adequate nutrients under these conditions, some source of fertilizer is commonly added or a method to make nutrients more "available to plants, such as mycorrhiza, is needed. Durum wheat (Triticum turgidum var. durum cv. Petra) was grown in alkaline soil (pH = 8.1) with added phosphogypsum (PG) at different rates [0 (control), 15, 30, 45, and 60 g PG kg−1 dry soil] and the arbuscular mycorrhizal fungus (AMF) Glomus mosseae to determine the effects of these treatments on plant yield and acquisition of phosphorus (P), zinc (Zn), copper (Cu) and iron (Fe). Plants were grown in a greenhouse and harvested at maturity. Colonization of roots with AMF was highest for plants grown without added PG or added at 15 g PG kg−1 dry soil and decreased as added PG to soil increased. Total plant dry matter and grain yields were enhanced by PG and even more so when roots were colonized with AMF, especial...

Several studies have demonstrated improved growth of plants infected with arbuscular mycorrhizal fungi (AMF) compared to non-AMF plants. The growth responses of garlic (Allium sativum" L.) to an AMF in soil fertilized with different levels of phosphorus (P) were studied under field conditions. Garlic cloves were planted in furrows after treatment with different P levels (0, 20, 40, and 60 Kg P ha−1), and with or without the AMF Glomus fasciculatum. Roots were sampled at three growth stages to quantify AMF. AMF colonization occurred at all samplings and the root colonization by AMF increased gradually with time, peaking at mid-bulb filling stage in the AMF-inoculated treatments. The AMF-inoculated plants had higher fresh bulb yield and mean bulb weight than uninoculated plants regardless of P level. This increase in yield and mean bulb weight was associated with a significant increase in the bulb P total accumulation of AMF inoculated plants. The enhancement in fresh bulb yield and mean bulb weight due to ...

The seed chemical composition and mineral element concentration were investigated in three improved (Jubeiha-1, Jubeiha-2, Jubeiha-3) and a local Jordanian chickpea cultivars. Seed protein, fat, glucose, sucrose, starch, P, Mg, Na, Mn, Fe, Cu, and Zn concentrations varied significantly among cultivars. Higher concentrations of fiber, starch, P, Na, Fe, Cu, and Zn in Jubeiha-1 seeds; while higher concentrations of protein, fat, fructose, K, Mg, and Mn, in Jubeiha-3 seeds in comparison with other cultivars were noted. The concentrations of seed protein, fat, fiber, ash, glucose, fructose, P, Ca, Mg, Na, and Cu were significantly affected by growing season. The cultivar x growing season interaction found to influence significantly all measured traits except seed starch and Na concentrations in the investigated chickpea cultivars. The investigated chickpea cultivars have different genetic backgrounds for almost all the chemical traits tested.

Tomato (Lycopersicon esculentum Mill.) yields are known to decrease for plants grown in saline soils. This study was conducted to determine the effects of arbuscular mycorrhizal fungi (AMF) inoculation on fruit yield and mineral content of salt-tolerant and salt-sensitive tomato cultivars grown with varied levels of salt. NaCl and CaCl2were added to soil in the irrigation water in equal molar ratios to give ECe values of 1.4 (nonstressed) and 4.9 dS m−1 (salt stressed). Plants were grown in a greenhouse using unsterilized, low phosphorus (P) (silty clay) soil-sand mix. Mycorrhizal root colonization occurred whether cultivars were salt stressed or nonstressed, but the extent of AMF root colonization was higher in AMF inoculated than uninoculated plants. The salt tolerant cultivar ‘Pello’ generally had higher AMF root colonization than the salt sensitive cultivar ‘Marriha’. Shoot dry matter (DM) yield, fruit fresh yield, and AMF colonization were higher for plants grown under nonstressed than for plants gro...

Effects of arbuscular mycorrhizal fungi (AMF) and salt stress on nutrient acquisition and growth of two tomato cultivars exhibiting differences in salt tolerance were investigated. Plants were grown in a sterilized, low-P (silty clay) soil-sand mix. Salt was applied at saturation extract (ECe) values of 1.4 (control), 4.9 (medium) and 7.1 dS m–1 (high salt stress). Mycorrhizal colonization occurred irrespective of salt stress in both cultivars, but AMF colonization was higher under control than under saline soil conditions. The salt-tolerant cultivar Pello showed higher mycorrhizal colonization than the salt-sensitive cultivar Marriha. Shoot dry matter (DM) yield and leaf area were higher in mycorrhizal than nonmycorrhizal plants of both cultivars. Shoot DM and leaf area but not root DM were higher in Pello than Marriha. The enhancement in shoot DM due to AMF inoculation was 22% and 21% under control, 31% and 58% under medium, and 18% and 59% under high salinity for Pello and Marriha, respectively. For both cultivars, the contents of P, K, Zn, Cu, and Fe were higher in mycorrhizal than nonmycorrhizal plants under control and medium saline soil conditions. The enhancement in P, K, Zn, Cu, and Fe acquisition due to AMF inoculation was more pronounced in Marriha than in the Pello cultivar under saline conditions. The results suggest that Marriha benefited more from AMF colonization than Pello under saline soil conditions, despite the fact that Pello roots were highly infected with the AMF. Thus, it appears that Marriha is more dependent on AMF symbiosis than Pello.

Seed germination is a major factor limiting the establishment of plants under saline conditions. Six barley (Hordeum vulgare L.) cultivars were screened for salt tolerance (using NaCl) during seed germination. The uptake of water, and levels of Na+ and K+ of salt sensitive and salt tolerant cultivars, before and after imbibition, were measured to determine the contributions of ionic and osmotic factors to seed different response to salt stress. Imbibition of seeds incubated with NaCl solutions was reduced by approximately 5% for each 100mM increase in NaCl concentration once the level of 100mM NaCl was reached. The Na+ concentration of seeds after imbibition did not differ significantly among cultivars and selective uptake or exclusion of Na+ were not associated with the differences in salinity tolerance. No differences between the two tested cultivars were noted for initial K+ concentration, but the salt tolerant cultivar lost less K+ relative to Na+ uptake than did the salt sensitive cultivar. The adver...

High salt levels in soil and water can limit agricultural production and land development in arid and semiarid regions. Arbuscular mycorrhizal fungi (AMF) have been shown to decrease plant yield losses in saline soils. The objective of this study was to examine the growth and mineral acquisition responses of greenhouse-grown tomato to colonization by the AMF Glomus mosseae [(Nicol. And Gerd.) Gerd. and Trappe] under varied levels of salt. NaCl was added to soil in the irrigation water to give an ECe of 1.4 (control), 4.7 (medium) and 7.4 dS m–1 (high salt stress). Plants were grown in a sterilized, low P (silty clay) soil-sand mix. Mycorrhizal colonization was higher in the control than in saline soil conditions. Shoot and root dry matter yields and leaf area were higher in mycorrhizal than in nonmycorrhizal plants. Total accumulation of P, Zn, Cu, and Fe was higher in mycorrhizal than in nonmycorrhizal plants under both control and medium salt stress conditions. Shoot Na concentrations were lower in mycorrhizal than in nonmycorrhizal plants grown under saline soil conditions. The improved growth and nutrient acquisition in tomato demonstrate the potential of AMF colonization for protecting plants against salt stress in arid and semiarid areas.

Through the process of domestication, cultivated crops have been selected from their wild ancestors for various anthropocentrically important characteristics. Tetragonolobus palaestinus Bioss is a wild grain legume species which grows naturally on the plains and hilly areas of north Jordan and neighbouring countries. In a study of agronomic and morphological traits of wild populations of T. palaestinus at two locations, the following variables were evaluated: number and dry weight of nodules per plant, plant height, number of branches and pods per plant, pod length, number of seeds per pod, 100-seed weight, and seed weight per plant. Positive and significant correlations between 14 pairs of variables were noted, including number and dry weight of nodules per plant, plant height, number of branches and pods per plant, pod length, and seed weight per plant. The wild populations of T. palaestinus studied here appeared to be homogenous, although some of the observed variation could have arisen from variation of the environmental conditions among locations.

Salinity tolerance in some plant species has been related to characteristics of potassium (K) and sodium (Na) uptake and transport. Tomato (Lycopersicon esculentum Mill., cv. Rossel) plants were grown in nutrient solution to determine effects of two K levels [0.2 (low) and 2 mmol (high)] combined with 0, 100, and 200 mmol NaCl on growth, and on Na and K uptake and translocation. Net uptake rates of Na and K were determined by disappearance in the growth medium and by plant accumulation. At the low level of K in solution, salinity decreased shoot and root dry weight and leaf area. Addition of 2 mmol K ameliorated of the added NaCl effects and improved growth parameters. Salinity reduced net K uptake rates and to a lesser extent K translocation from root to shoot, which resulted in higher K shoot concentration and a lower K root concentration. The inhibitory effect of salinity on K translocation was greater with low K level in nutrient solution. Net uptake of K was dependent on K level in the growt...

Effectiveness of arbuscular mycorrhizal fungi (AMF) is crucial for maximum plant growth and acquisition of mineral nutrients under drought. The objective of this research was to determine effects of varied rates of AMF inoculum on plant growth and acquisition of phosphorus (P), zinc (Zn), copper (Cu), and manganese (Mn) by barley (Hordeum vulgare L. cv. SLB‐6) grown with and without drought stress (WS and nonWS). Plants inoculated with four inoculum rates [control (M0), 120 (M1), 240 (M2), and360 (M3) spores per 100 g dry soil] of Glomus mosseae were grown in a low P silty clay (Typic Xerochrept) soil (pH=8.0) mix in a greenhouse for 45 days. Root AMF colonization increased as inoculum rate increased in plants grown with WS and nonWS. Leaf area and shoot and root dry matter (DM) increased as inoculum rate increased up to M2 regardless of soil moisture. Shoot concentrations of P, Cu, and Mn were generally higher for mycorrhizal (AMF) than for nonmycorrhizal (nonAMF) plants grown with both WS and n...

Root colonization by arbuscular mycorrhizal fungi (AMF) may affect protein and lipid composition of plants by altering P nutrition or by eliciting other metabolic responses in the host plant. This study was conducted to determine the effects of an AMF and soil P on seed protein and lipid contents and yield of two genotypes of durum wheat (Triticum durum L.). Plants were grown in a greenhouse using soil: sand mixes with different levels of P, and with or without the AMF Glomus mosseae [(Nicol. and Gerd.) Gerd. and Trappe]. Percentage AMF root colonization decreased as P added to soil increased. The wheat genotype CR057 had higher AMF root colonization but lower seed P and protein concentrations than CR006. Without added soil P, protein concentration was significantly lower and lipid concentration and seed dry weight higher in arbuscular mycorrhizal (AM) than in nonAM plants. Seed lipid and protein contents were highly correlated with P content of plants. In nonAM plants, seed lipid and protein contents were low with no added soil P and did not differ with added soil P. Seed protein/lipid (Pro/L) concentration ratios of AM plants were higher than those of nonAM plants only when no P was added to the soil. The data indicate different patterns of seed P accumulation and different relationships between seed P and protein and lipid in AM and nonAM plants. Thus, both the presence and degree of AMF root colonization affected seed lipid metabolism in these durum wheat genotypes.

Relationships between seed protein, lipid, starch and sugar concentrations and seed yield of 14 pea (Pisum sativum L.) cultivars were examined under rain-fed conditions in northern Jordan. Significant differences amongst cultivars for each character were noted. The cultivar-by-environment interaction was significant for each character except lipid and starch concentrations. A negative correlation was noted between seed yield and seed protein and fructose concentrations. Positive non-significant correlations between seed yield and seed lipid and starch concentrations were noted. The cultivars DMR-8, P 350-1 and 88P022-6 had similar seed yields, but varied seed chemical components. Seeds of the Praire No. 11 cultivar had the highest protein concentration amongst cultivars, although it produced the lowest seed yield. These results indicate that factors other than seed yield are important for determining the chemical composition of seeds, and that one-sided selection for high seed yield tends to reduce the nutritional quality of the pea seed.

Dry pea (Pisum sativum L.) growers in the semiarid Mediterranean region require cultivars that are both early maturing and high yielding. However, negative relationships between these two characteristics limit their simultaneous improvement. A better understanding of the relative importance of the developmental stages in determining yield would assist in pea improvement. Sixteen dry pea cultivars were grown for 2 years under semiarid Mediterranean conditions (Maru, north Jordan) in order to see if differences in growing degree days (GDD) to flowering and GDD from planting to physiological maturity exist and to study their relationships with seed yield. Seed yield was negatively correlated with GDD to maturity, but not significantly correlated with GDD to flowering. Increasing GDD to flowering resulted in higher seed yield, while increasing seed fill duration had little effect. Rapid seed fill rate was positively correlated with seed weight and negatively correlated with seed fill duration. These results indicate that Mediterranean-adapted cultivars would have preflowering periods lasting as long as possible, followed by short seedfill periods. Simultaneous selection for early maturity and a relatively long time to flowering is recommended for the development of early-maturing, high-yielding cultivars adapted to semiarid Mediterranean environments.

Root nodulation by rhizobial bacteria and P fertilization may affect seed protein and lipid composition in plants by altering nitrogen (N) and phosphorus (P) nutrition or by eliciting metabolic responses by the host plant. This study was conducted to determine the effects of rhizobium and P fertilization on seed protein and lipid contents and yield of lentil (Lens culinaris Medik). Lentil was grown to maturity in a greenhouse with P levels of 0 (low) and 50 (high) mg kg‐1 soil with or without inoculation with Rhizobium bacteria. At the low level of P, protein and lipid concentrations and protein contents were significantly higher in inoculated than in uninoculated plants. Seed dry weight and protein concentrations and contents were higher in inoculated than in uninoculated plants at the high level of P. Seed protein/lipid (Pro/L) concentration ratios varied between inoculated and uninoculated plants at both P levels, and was related to the intensity of root nodulation. Lipid and protein contents ...

Pre-sowing osmotic seed treatments were evaluated as a means of improving water uptake and germination performance of wheat (Triticum durum L. cv. Hourani-27) and barley (Hordeum vulgare L. cv. ACSAD 176) under four levels of water potential (0, -0.4, -0.8 and -1.2 MPa) created by using polyethylene glycol 8000. Seeds were osmoprimed in aerated solutions of 0.0, 0.2, 0.4 or 0.6 M KCl at 24 ± 2°C overnight and then rinsed and dried. Rate of water uptake by seeds was higher in osmoprimed than untreated seeds of both crops regardless of the water potential level. Decreasing water potential (more stress) adversely affected rate of water uptake in seeds of both crops. Seeds osmopriming increased germination percentage and decreased time to 50 % germination at high water potentials (low stress), whereas the germination at low water potentials (more stress) was not affected by osmopriming treatments. The effect of osmopriming on rate of water uptake, germination percentage, and time to 50 % germination was more pronounced in wheat than in barley. Reduction in the lag time of imbibition may be accounted for in part by some germination rate enhancement in the osmopriming treatments. Fresh weight and length of shoots (plumules) and roots (radicles) were enhanced in osmoprimed seeds in comparison to untreated seeds, in both crops at high water potentials (0 and - 0.4 MPa). As water potential in the medium decreased, these traits were inversely affected regardless of osmopriming treatment. Longer roots in wheat compared to barley were noted in the positive osmopriming treatments at high water potentials (0 and -0.4). These results might indicate that wheat is more responsive than barley at relatively high water potentials to osmopriming through rapid penetrating root system.

Seed size is an important parameter for plant growth andyield. The eifects of seed size and water potential on seedwater uptake, germination and early growth of lentil(Lens culinaris Medik. cvs. Jor-1 and Jor-2) were inves-tigated. Rate of water uptake by seed size (small, mediumand large) from solutions containing different waterpotentials (0, —0.5 and — 1.0 MPa, as polyethylene gly-col-8000) was higher in large than in medium or smallseeds of both cultivars, regardless of water potential. Rateof water taken into seeds was higher in Jor-2 than in Jor-1. Decreasing water potential (more stress) had adverseeffects on rate of water uptake by seeds in both cultivars.In another experiment, with lentils grown in a greenhouseat different soil metric potentials (—0.03, —0.15 and— 0.30 MPa), seed size or cultivar had no effects on ger-mination percentage (GP), but GP was reduced as soilwater potential decreased (more stress), in greenhousesoil, shoot dry matter (SDM), root dry matter (RDM),plant height, total root length (TRL) and number ofprimary branches per plant of 35-day-old plants fromlarge seeds were larger than those of plants from mediumand small seeds of both cultivars. Increasing soil waterdeficit progressively decreased each of these traits. Plantsfrom large seeds had higher SDM, RDM and TRL thanthose from small seeds at intermediate soil water potential( — 0.15 MPa) in comparison with the control (—0.03MPa) or severe (—0.30 MPa) soil water potentials.Larger seeds produced larger plants than smaller seeds,and this appeared to be more pronounced under inter-mediate than well-watered or more severe water-stressedconditions. Faster early growth of plants from largerseeds may be advantageous in establishing plants undersemiarid conditions.Key words: Imbibition — Lens culinaris — metricpotential — water stress

Arbuscular mycorrhizal fungi (AMF) living symbiotically with host plants enhance plant growth by improving the acquisition of mineral nutrients and water relations. This study determined the effects of AMF inoculation on growth, benefit/cost and water-use efficiency (grams dry matter produced per kilogram water evapotranspired) in two durum wheat genotypes (drought sensitive and drought tolerant) under water-stressed and well-watered conditions. Plants were grown in a low-P silty clay (Typic Xerochrept) soil mix in a greenhouse. Shoot and root dry matter (DM) and root AMF colonization were higher for well-watered than for water-stressed plants. The mycorrhizal plants were more water-use efficient than nonmycorrhizal plants. Shoot DM differences between mycorrhizal and nonmycorrhizal plants represent the benefit derived by plants from AMF-root associations. Shoot DM differences between mycorrhizal and nonmycorrhizal plants under similar conditions of water treatment represent the cost to the plant of AMF-root associations. Values of benefit/cost for AMF-root associations were highest when plants were water-stressed and decreased under well-watered conditions. Genotypic differences in calculated costs and benefits were pronounced. Benefit/cost analysis may be helpful in evaluating host plant genotypes in order to optimize efficiencies of AMF symbiosis under different environmental conditions.

Increasing plant phosphorus (P) supply can increase or decrease salt tolerance of many plants. Barley (Hordeum vulgare L., cv. ACSAD 176) was grown in nutrient solution under controlled conditions to determine effects of P level on detrimental effects of sodium chloride (NaCl). Increasing level of P improved tolerance of barley to NaCl. At 3, 30, and 60 μM P, the NaCl concentrations to reduce shoot dry matter (DM) by 50% were 158, 193, and 260 mM, respectively. Increased NaCl levels reduced shoot P concentrations. Plants grown with NaCl had higher Internal P requirements. When NaCl in solution was 10, 150, and 300 mM, the corresponding concentrations of P in shoots required to obtain 50% DM were 1.6, 4.2, and 4.7 mg‐g‐1 dry weight, respectively. Increasing solution P level from 3 to 60 μM P decreased sodium (Na) and increased potassium (K) concentrations in shoots. Accumulation of mineral ions for osmotic adjustment and restriction of Na accumulation in shoots was involved in P enhancement of sal...

Summary Phosphorus deficiency and drought can reduce plant growth and alter metabolic processes such as N metabolism. The amino acid proline often accumulates in leaves of many plants grown under water stress, but information about effects of P nutrition on proline accumulation is not available. Two sorghum [Sorghum bicolor(L.) Moench] and two bean (Phaseolus vulgarisL. andP. acutifoliusA. Gray) cultivars with different tolerances to drought were grown in a greenhouse in soil mixes with different levels of P with and without water stress imposed by withholding water to determine the effects of P nutrition and water stress on proline accumulation. Shoot dry matter of sorghum and bean increased with increasing P level regardless of water stress. Leaves of water-stressed sorghum had lower P concentrations than non water-stressed plants, while leaves of water-stressed and non water-stressed bean had similar P concentrations. Leaf diffusive resistance (rs) values became greater and leaf water potential (ΨL) values became more negative (greater tension) as severity of water stress increased compared to non water-stressed plants. These traits became lower and less negative (less tension), respectively, and nearly comparable to non waterstressed plants 5 d after water stress was relieved. Both plant species had higher proline accumulation during water-stressed than under non water-stressed conditions, but differed in their response to added P Sorghum leaves had highest proline when grown with high P, while bean leaves had highest proline when grown with low P Five days after plants were relieved of water stress, proline accumulation in sorghum leaves decreased extensively yet remained at relatively high levels, while proline accumulation in bean leaves decreased to the level for non water-stressed plants. High proline accumulation in leaves of waterstressed plants grown at high P levels might be an adaptive response to drought for sorghum, but did not appear to be so for bean.

Mycorrhizal plants often have greater tolerance to drought than nonmycorrhizal plants. This study was conducted to determine the effects of arbuscular mycorrhizal (AM) fungi inoculation on growth, grain yield and mineral acquisition of two winter wheat (Triticum aestivum L.) cultivars grown in the field under well-watered and water-stressed conditions. Wheat seeds were planted in furrows after treatment with or without the AM fungi Glomus mosseae or G. etunicatum. Roots were sampled at four growth stages (leaf, tillering, heading and grain-filling) to quantify AM fungi. There was negligible AM fungi colonization during winter months following seeding (leaf sampling in February), when soil temperature was low. During the spring, AM fungi colonization increased gradually. Mycorrhizal colonization was higher in well-watered plants colonized with AM fungi isolates than water-stressed plants. Plants inoculated with G. etunicatum generally had higher colonization than plants colonized with G. mosseae under both soil moisture conditions. Biomass and grain yields were higher in mycorrhizal than nonmycorrhizal plots irrespective of soil moisture, and G. etunicatum inoculated plants generally had higher biomass and grain yields than those colonized by G. mosseae under either soil moisture condition. The mycorrhizal plants had higher shoot P and Fe concentrations than nonmycorrhizal plants at all samplings regardless of soil moisture conditions. The improved growth, yield and nutrient uptake in wheat plants reported here demonstrate the potential of mycorrhizal inoculation to reduce the effects of drought stress on wheat grown under field conditions in semiarid areas of the world.

Date palm (Phoenix dactylifera) is a significant and developing crop especially in the Arabian Peninsula, the Middle East and North Africa regions. The area under cultivation of this tree is increasing annually. Date palms usually grown under harsh and unfavorable growing conditions with low rainfall and high rates of evaporation as well as in soils with low organic matter and nutrient deficiencies. Hence, date palm cultivation becomes dependent on application of high levels of fertilizers as well as on irrigation. This may lead to salinization of soil and leaching of nutrients to deep soils that might affect ground water. Therefore, it is important that date palm plantations are managed in a sustainable way to reduce the impact of date palm cultivation on ecosystems while maximizing dates yield through using such practices as mycorrhizal fungi technology. The application of mycorrhizal fungi technology is an option that can benefit both agronomic plant health and ecosystems. Mycorrhizae confer numerous benefits to host plants including improved plant growth and mineral nutrition, water uptake, tolerance to diseases and stresses such as drought, temperature fluctuation, metal toxicity and salinity. Mycorrhizae may also play a role in the formation of stable soil aggregates, building up a macro porous structure of soil that allows penetration of water and air and prevents erosion. All of these beneficial effects on plant health and soil fitness mean that mycorrhizae have the potential to increase agricultural productivity and are crucial for the sustainable functioning of agricultural ecosystems. This study provides an insight into the application of mycorrhizae in date palm cultivation.