Effects of salinity stress on growth indices,physiological parameters and element concentration in Banebaghi (Pistacia sp.) as rootstock for pistachio

Banebaghi is considered a natural hybrid in Pistacia genus that can be used as rootstock for pistachio. In order to study the effects of salinity stress on growth indices, physiological parameters and element concentration in Banebaghi, an experiment was arranged as a factorial in completely randomized design (CRD). Factors were salinity of irrigation water (0, 60 and 120 mM of sodium chloride, calcium chloride, magnesium chloride, respectively), growth type (mutica growth type and pistachio growth type) and stem height (stem height lower half of the plant and stem height upper half of the plant) with four replications. Our results showed that salinity reduced vegetative parameters, SPAD index, leaf relative water content (RWC) and water use efficiency (WUE). Shoot dry weight of seedlings in both heights, decreased at the salinity level of 120 mM, at about 60% compared with control. At the highest level of salinity (120 mM), seedlings with a height lower half of the plant had lower reduction in the fresh and dry weight of the root and showed more resistance to the salinity stress because of maintaining RWC of leaves and high levels of potassium and calcium in the shoot. Salinity increased sodium (Na) concentration of shoot and root in both growth types: mutica and pistachio. Seedlings with pistachio growth type and a height upper half of the plant and seedlings with mutica growth type and a height lower half of the plant had more resistance to salinity stress.     

Morpho-physiological and biochemical response of maize (Zea mays L.) plants fertilized with nano-iron (Fe3O4) micronutrient

Nano-sized formulations of micronutrient iron (Fe) were found to substantially alter the growth and metabolism of maize plants. Plants fertilized with the optimal recommended dose of Fe in the nano-form (54 μM) registered an enhancement in morphological features, viz. plant height, biomass (shoot and root), and diminution in antioxidant enzyme activities than the plants fertilized with the sub-optimal dose of Fe in the macroform (salts). However, half of the recommended dosage of Fe (27 μM) in the nano-form positively influenced leaf area and proline content of plants too. This indicated that there is a possibility of reducing the dose of Fe supplement for plants in the nano-form to increase the nutrient use efficiency in a major cereal crop like maize. This may open a new era in plant nutrient management with a scope for improvement in nutrient use efficiency using nano-nutrient formulations.     

不同浓度镉胁迫对玉米幼苗光合作用、脂质过氧化和抗氧化酶活性的影响

以玉米为材料,通过营养液培养试验,研究浓度为5~100 μmol/L的镉胁迫后不同时间内,植株体内活性氧代谢及其抗氧化酶活性的变化特征,探讨镉胁迫导致植物体内活性氧自由基累积的原因及不同程度镉胁迫对植物体内活性氧代谢的影响。随着加镉量的增加,玉米地上部生物量明显降低,而根部生物量未表现出差异。镉处理降低了叶片光合作用速率,高镉处理的影响较早。镉处理4d后,5、20、和100 mol/L Cd2+浓度处理玉米叶片Fv/Fm减小,PSII系统的原初光能转换效率下降,但比光合作用速率下降的时间要晚;镉处理7d的叶片中丙二醛（MDA）含量还没有受到明显影响,但20和100 μmol/L Cd2+处理4d后,根系膜质过氧化增强,MDA含量升高。随着镉浓度升高,处理时间延长,活性氧酶清除系统包括超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）和谷胱甘肽还原酶（GR）等酶活性明显增加,受到镉胁迫诱导,高浓度镉处理该现象出现更早。本文试验结果表明,镉胁迫下植物体内活性氧形成增多,诱导活性氧酶清除系统活性升高,其中一个重要原因是与CO2同化受到限制有关。     

Effect of vermicompost on some morphological,physiological and biochemical traits of bean (Phaseolus vulgaris L.) under salinity stress

Vermicompost can play an effective role in plant growth and development and also in reducing harmful effects of various environmental stresses on plants due to its porous structure, high water storage capacity, having hormone-like substances and plant growth regulators and also high levels of macro and micro nutrients. The aim of this study was to investigate the effects of vermicompost and salinity interactions on some morphological and physiological features and concentration of mineral elements of bean (Phaseolus vulgaris L. cv. Light Red Kidney) cultivar. A factorial experimental with five different volumetric ratios of vermicompost and sand, including to: 0:100; 10:90; 25:75; 50:50 and 75:25 and four levels of salinity [20, 40, 60 and 80 mmol l^?1 sodium chloride (NaCl)], and control was conducted base on Randomized Complete Block Design with three replications. Bean seeds were sowed in plastic pots, the seedlings being sampled 42 days old (flowering stage).The results showed that vermicompost had significant effect on all studied traits under stress and non-stress (p ≤ 0.05).In this experiment, the vermicompost significantly increased the photosynthetic rate and concentrations of potassium (K⁺) and calcium (Ca²)⁺in leaf and root tissues. In salinity levels of 20, 40 and 60 mmol l^?1NaCl, all subjected ratios of vermicompost and in 80 mmol l^?1NaCl the ratios of 10% and 75% vermicompost, significantly ameliorated negative effects of salinity. In both stress and non-stress conditions, using 10% volume of vermicompost is recommended to improve the growth of bean plants.     

Interactive effects of salinity and two phosphorus fertilizers on growth and grain yield of Cicer arietinum L.

Chickpea is considered among the most sensitive grain legumes to salinity. The improvement of tolerance of lines in combination with tolerant rhizobial strains depends on various environmental and cultural conditions such as soil properties. This investigation was undertaken to evaluate the effect of phosphorus fertilization (0, 90 and 200 kg ha^?1 of P₂O₅) on biomass, nodular traits and grain yield (GY) of chickpea (cv. Flip 84-79C) growing under salinity (0 and 150 mM NaCl). The trial was laid out following a randomized block design with three replicates during 2010–2012, at the experimental farm of Oued Smar (Algiers). Salinity did not significantly decrease the dry biomass of the plants but the relative shoot growth was more affected than control, P and SP1 treatments. Besides, salinity significantly reduced GY (?20%) and nodulation traits compared to the control plants while an inversely proportional relationship was found between protein, leghemoglobin and MDA content, K/Na ratio and the increase in salt concentration. Application of two P levels to saline soil enhanced growing conditions of plants. Particularly, the (90?kg?ha^–1 of P ×?150?mM?NaCl) combination significantly increased leghemoglobin (92%), reduced proline content (?69%) and protected membranes against peroxydation compared to saline conditions. A significant increase was observed in the GY (about 30%) of plants at both P doses combined with salt stress compared to other cases. Statistically, the low P level combined with salinity induced similar responses of plants and sometimes better responses to control plants. Finally, our results support the roles of phosphorus fertilizer in the alleviation of salt stress and enhancing the soil quality for better symbiosis efficiency and yield of chickpea.     

Effect of Potassium Supplies on the Nutritional Status of Maize (Zea mays L.)

The effect of soil potassium (K) supplies on the yield and nutritional status of maize and on interactions between the nutrients was examined in a long-term mineral fertilization experiment on maize. The experiment was set up in 1989 in Hungarian Great Plain, Szarvas on chernozem meadow soil calcareous in the deeper layers, with four levels each of nitrogen (N), phosphorus (P) and potassium (K) supplies. The present paper describes the results of K fertilization in the 7–19th years of the experiment, from 1996 to 2008. The ammonium (NH₄)-lactate (AL) potassium oxide (K₂O) content of the ploughed layer ranged from 200 to 550 mg kg^–1 depending on the K fertilization level. No significant yield surpluses were recorded in any of the 13 years in response to the better K supplies ensured by K fertilizer. The results of leaf analysis indicated that the K concentrations representing satisfactory K supplies at a grain yield level of 10–14 t ha^–1 were 2.3–4.3% at the 5–6-leaf stage and 1.5–2.6% at the beginning of tasselling. When the AL-K₂O content of the soil was above 200–320 mg kg^–1, K– calcium (Ca), K–magnesium (Mg) and K–copper (Cu) antagonism was observed in the nutrient concentrations of the maize leaves in most years. The limit values of satisfactory nutrient supplies for maize in the 5–6-leaf stage and at the beginning of tasselling were 0.25–0.60% for Ca, 0.15–0.40% for Mg, and 7–11 mg kg^–1 and 2–11 mg kg^–1, respectively, for Cu. In dry years the iron (Fe) and zinc (Zn) concentrations of maize leaves declined at higher soil K supply levels.     

Effect of dimethylarsenic acid (DMAA) on growth,tissue arsenic,and photosynthesis of rice plants

The effect of dimethylarsenic acid (DMAA) applied to the root on arsenic (As) uptake and concentration, net photosynthesis (Pn), and growth parameters of rice (Oryza sativa L. cv. ‘Mercury') plants was studied. The experiment consisted of four treatments (0, 0.2, 0.8, and 1.6 mg As/L) with four replications in a completely randomized design. The DMAA was applied in nutrient solution as its sodium salt. The solution culture was changed every four days to avoid changes in the As chemical form. Arsenic uptake and concentration in shoot and root increased upon increased DMAA concentration in solution. Upon uptake, DMAA was readily translocated to the shoot. At the two higher rates of DMAA application (0.8 and 1.6 mg As/L), Pn and photosynthetic capacity were significantly decreased in response to tissue As concentration. Leaf area and dry matter production were also significantly reduced at the two higher rates of DMAA. At the lower rate (0.2 mg As/L) of DMAA application, there was no significant reduction in Pn or growth. Dimethylarsenic acid application did not affect nutrient allocation within the rice plant at concentration levels used in this study.     

Response of wheat genotypes to foliar spray of ZnO and Fe2O3 nanoparticles under salt stress

This study evaluated the effects of iron oxide (Fe₂O₃) and zinc oxide (ZnO) on two wheat genotypes (Kavir and Tajan) at three levels (0, 75, and 150 mM sodium chloride (NaCl)) of salinity. Spray treatments included two forms of normal and nanoparticles of Fe₂O₃ and ZnO, a mixture of nanoparticles of Fe₂O₃ and ZnO (2 g L^?1) and a non-spray treatment. The pot experiment was arranged as factorial in a randomized complete block design with four replications. Two forms of Fe₂O₃ and ZnO significantly accelerated plant height, leaf area, shoot dry weight, and the concentration of iron (Fe) and zinc (Zn) in comparison with non-spray treatment. The highest plant height and leaf Fe concentration belonged to Fe₂O₃ nanoparticles; however, it seems that the spray of nanoparticles may not be superior compared with normal forms in alleviation of salinity impacts.     

Effect of salinity and silicon on root characteristics,growth, water status,proline content and ion accumulation of purslane (Portulaca oleracea L.)

Abstract

A significant part of potentially mineralizable organic nitrogen (N) in soil comprises microbial cells (Bonde et al. 1988). Since the major part of organic N in cow dung also consists of microbial biomass N (Marsh and Campling 1970), it may be worth comparing the origin and the successive processes of N mineralisation in cow dung with those in soil. We studied the effect of the dung beetle, Onthophagus lenzii H., on the decomposition of cow dung and found that the dung beetle played a significant role in this process (Yokoyama et al. 1990). We employed, here, the acid hydrolysis method to analyze the effect of the dung beetle on N transformation in dung balls and residual cow dung.     

Characterization of Zinc Oxide Nano Particles and Their Effect on Growth of Maize (Zea mays L.) Plant

In the current literature, the impact of nano-particles (NPs) on growth of higher plants has scantly been reported. An investigation was carried out to study the effect of zinc oxide nano-particles (<100 nm) on growth of maize (Zea mays L.) plant, as one of the major agricultural crops, in a solution culture system. Various concentrations of zinc (Zn) were applied through nano-zinc oxide (ZnO) particles (<100 nm) in suspension form and in ionic form through zinc sulfate (ZnSO₄) salt in Hoagland solution culture. Experimental results showed that nano zinc oxide particles could enhance and maintain the growth of maize plant as well as conventional Zn fertilizer (as ZnSO₄). The plant parameters like plant height, root length, root volume, and dry matter weight were all improved due to application of zinc oxide nano-particle. These findings indicate that plant roots might have the unique mechanism of assimilating nano-Zn and using for its growth and development. Different enzymatic activities were also studied and experimental results revealed that nano-ZnO particles (<100 nm) also governed the enzymatic activity of maize plant. A separate laboratory experiment was also carried out to characterize the zinc oxide nano particle for its size, zeta potential, etc.     

Salinity stress on various physiological and biochemical attributes of two distinct maize (Zea mays L.) genotypes

Present study investigates the effect of salinity stress on physiological and biochemical characteristics of two maize genotypes cultivated under controlled growth conditions. The selected maize genotypes being salt-tolerant and salt-sensitive were respectively designated as Sahwal-2002 and Sadaf. The experiment was conducted in triplicates, two varieties, three priming treatments and two salinity levels, in the Government College University, Faisalabad. The antioxidants activity was measured by comparing the tolerance in response to acute and prolonged salinity treatment. The difference of genotype with salinity tolerance as well as seed priming with phenylalanine were not dependent on antioxidant activity when salt exposure was prolonged. The results show that an indirect relationship was present for PAL seed priming and oxidative damage due to salt. The antioxidant enzymes present in plant effectively reduced the oxidative damage of salt and thus, increased the overall crop yield.     

Effect of microbial‐based inoculants on nutrient concentrations and early root morphology of corn (Zea mays)

Microbial‐based inoculants have been reported to stimulate plant growth and nutrient uptake. However, their effect may vary depending on the growth stage when evaluated or fertilizer applied. Thus, the objective of this study was to test the hypothesis that microbial‐based inoculants known to promote root growth and nutrient uptake will promote plant growth, enhance early root development, and increase nutrient concentrations of corn (Zea mays L.). Plants were evaluated at four different growth stages and in the presence of three different nitrogen (N) fertilizers. The microbial‐based treatments evaluated were: SoilBuilder™ (SB), a filtered metabolite extract of SoilBuilder™ (SBF), a mixture of four strains of plant growth‐promoting Bacillus spp (BM), and a water‐inoculated control. The experiment also included four fertilizer treatments: urea (U), urea‐ammonium nitrate (UAN), calcium‐ammonium nitrate (CAN), and an unfertilized control. Corn plants were evaluated at growth stages V2, V4, V6, and VT. Plant growth parameters for biomass, height, and SPAD readings were enhanced by the three microbial‐based treatments. A greater effect of microbial‐based treatments was observed when plants were evaluated at V6 and VT stages. Parameters of early root development such as total root length (TRL), root surface area (RSA), and length of fine roots were enhanced when microbial‐based treatments were applied. Concentrations of N, P, and K were also increased by microbial‐based treatments compared to the non‐inoculated control. Increases in plant N concentration due to microbial‐based treatments were on average 72% for CAN, 61% for UAN, 72% for urea, and 54% for the unfertilized control. Phosphorus concentration was increased most (138%) when BM was applied with CAN. In the same way, when CAN was present, K concentration was increased by 95% with BM and 65% when SB and SBF were applied. Overall, the results demonstrate that microbial‐based inoculants evaluated in this study can positively impact corn growth and nutrient concentration, especially during the late vegetative stages. Furthermore, the results indicate that the enhancement of nutrient concentrations (N, P, and K) in this case was related to the capacity of microbial‐based treatments to impact root morphology at early stages of corn growth.     

Effect of individual and combined exposure of Fe2O3 nanoparticles and oxytetracycline on their bioaccumulation by rice (Oryza sativa L.)

Purpose

It has been reported the bioaccumulation of γ-ferric oxide nanoparticles (Fe₂O₃ NPs) or oxytetracycline (OTC) in crops. However, there have been little references investigating their uptake and bioaccumulation in crops after the combined exposure. The present study focused on Fe₂O₃ NPs and OTC accumulation on root surface and in the tissues of rice (Oryza sativa L.) seedlings under combined exposure. And, the interactive influence mechanism was also discussed.

Materials and methods

Hydroponic experiments were conducted to investigate the Fe and OTC accumulation on root surface and in rice tissues under individual and combined exposure of Fe₂O₃ NPs and OTC. The dynamic change of particulate Fe, ionic Fe, and Fe plaque concentrations on root surface was determined under the influence of OTC from Fe₂O₃ NPs and Fe-EDTA exposure. Fe²⁺ from Fe-EDTA was selected in order to compare the Fe bioaccumulation from ionic Fe and nanoparticle Fe exposure. Hydrodynamic diameter and ζ-potential of Fe₂O₃ NPs in solution were investigated when OTC was present or not, and the changes of OTC concentrations were also determined during hydroponic culture. SEM, XRD, and TEM were used to analyze Fe₂O₃ NP distribution on root surface and inside root under the influence of OTC.

Results and discussion

OTC promoted surface-Fe and shoot-Fe accumulation in Fe₂O₃ NPs treatments, which was just an opposite result from Fe-EDTA treatments. Upon Fe₂O₃ NP exposure, Fe plaque was formed through the direct adsorption of NPs on the outside root surface and then incorporated into plaque as its crystalline components. OTC elevated notably surface-Fe accumulation mainly through increasing adsorption and precipitation of Fe₂O₃ NPs on the root surface due to low repulsive electrostatic interaction between NPs and the root surface after adding OTC. Fe₂O₃ NPs increased surface-OTC and root-OTC levels. Compared to Fe-EDTA, surface-Fe from NP treatments can hold strongly OTC due to Fe₂O₃ particle precipitated on root surface with high specific surface area. NPs reduced shoot-OTC under 25 mg L^?1 OTC, but not under 100 mg L^?1 OTC.

Conclusions

This study clearly demonstrates that Fe/OTC accumulation in rice was always in the order root surface > shoot > root, whether Fe₂O₃ NPs/OTC was individual or combined exposure. The combined exposure will increase their root surface distribution comparing with individual exposure, and Fe₂O₃ NPs increased also root-OTC levels, which could pose a potential risk to food safety in subsequent growth of rice.

     

Effects of salicylic acid on growth and accumulation of phenolics in Zea mays L. under drought stress

The accumulation of total soluble and cell wall-bound phenolics and total soluble proteins in Zea mays plants exposed to drought stress and foliar spray of salicylic acid (SA) at 10^?4?mol/L and 10^?5?mol/L was investigated. Drought stress was imposed at the four-leaf stage for 10 days (30–35% field capacity). Dehydration of maize leaves was accompanied by the accumulation of both total soluble and cell wall-bound phenolics, reduction in leaf relative water content (LRWC), and shoot and root growth attributes. Foliar spraying of SA further augmented the content of total soluble and cell wall-bound phenolics and total soluble proteins content under drought stress. SA ameliorated the adverse effects of drought stress on LRWC, shoot fresh weight, shoot dry weight, root fresh weight, root dry weight, root length and root area. The accumulation of both soluble and cell wall-bound phenolics by foliar spray of SA may be a mechanism related to SA-induced drought stress tolerance in maize. It was concluded that foliar spraying of SA at 10^?5?mol/L can be highly economical and effective for modifying the effects of drought stress on maize at the four-leaf stage.     

焦化废水胁迫对玉米幼苗生长和抗氧化系统的影响

针对焦化废水污染现状,采用水培试验,研究了不同体积浓度焦化废水对玉米幼苗生长、生物量、抗氧化酶活性及非酶类抗氧化物质含量的影响,以期为焦化废水的毒性检测及生物监控指标的确定提供理论依据。结果表明,焦化废水经过A2/O工艺处理后,仍然能够显著抑制玉米幼苗的生长和生物量,且该抑制作用表现为对处理浓度和作用时间的双重依赖,处理浓度增大或作用时间延长对玉米幼苗生长和生物量的抑制作用增强;同时,经焦化废水处理后,染毒组玉米幼苗抗坏血酸（AsA）含量和抗坏血酸过氧化物酶（APX）活性明显增高,而谷胱甘肽（GSH）含量和谷胱甘肽过氧化物酶（GPX）活性却降低。这一结果提示,焦化废水经过处理后,CODCr、BOD5、NH3-N、挥发酚、氰化物、硫化物、油等物理化学指标大幅降低,但其生态风险依然存在。     

Characterization of a flint maize (Zea mays L. convar. mays) Italian landrace: I. Morpho-phenological and agronomic traits

Maize (Zea mays L.) landraces have the highest genetic variation and adaptation to the natural and anthropological environment where they have evolved. Surveying both qualitative and quantitative morphological traits of existing landraces may be useful in maintaining their genetic diversity and preserving them from genetic erosion. Our research deals with the morpho-phenological and agronomic characterization of a flint maize landrace, named 'Nostrano di Storo', still grown in an inland hilly environment in the low valley of Chiese River in Trentino, North-Eastern Italy. The majority of plants from twenty field populations proved to belong, with few exceptions (NSt2, NSt9, NSt11), to a single population. It means that the plant material long grown in this area and maintained by local farmers through yearly selection forms a single landrace within which some populations (i.e. NSt1, NSt3, NSt4, NSt7, NSt10, NSt18, NSt19, NSt20) could be considered as most representative and taken as 'core'. This is supported by the fact that the genetic variability was much higher within than between field populations: half of the plant and ear traits investigated did not show any significant difference between populations whereas all traits but two showed highly significant differences within populations. Selection carried out over the years by each farmer according to his own criteria produced little genetic differentiation within the original population. Gene flow among farmer populations, most likely occurred through both pollen dispersion to neighboring cultivated fields and seed exchange among farmers, may help to explain the low genetic differentiation. This information is useful for both planning conservation and recognizing the landrace as a unique germplasm source of specific geographic origin.     

重金属铅镉对玉米生长及土壤微生物的影响

采用温室盆栽土培方法,研究了土壤中不同浓度重金属铅（Pb,0-800 mg.kg^-1）、镉（Cd,0-50 mg.kg^-1）单一及其复合处理对玉米（Zea mays L.）生长及土壤微生物（细菌、放线菌、真菌）数量的影响。结果表明,在重金属Pb、Cd单一及其复合处理下,玉米的株高、干重均低于对照,重金属Pb、Cd处理对玉米的生长存在负面影响。重金属Pb、Cd单一处理抑制细菌、真菌的生长,中低浓度Pb（≤300 mg.kg^-1）、Cd（≤10 mg.kg^-1）单一处理促进放线菌数量的增加,高浓度（Pb≥800 mg.kg^-1、Cd≥50 mg.kg^-1）则呈现抑制效应;Pb、Cd复合在高中低浓度下都抑制土壤微生物生长,减少微生物数量。玉米株高同土壤微生物之间相关性不显著;玉米干重同土壤细菌、真菌显著相关,同土壤放线菌之间相关性不显著。     

干旱胁迫对玉米根系生长及根际养分的影响

通过盆栽模拟干旱试验，测定了干旱胁迫下玉米根系生长情况和根际土壤中速效N、P、K的含量。结果表明，干旱胁迫抑制了玉米拔节期和抽雄-开花期玉米根系的生长，减弱了玉米根系的吸收能力。干旱胁追下玉米根际NH4^＋-N、NO3^--N、速效P和速效K均发生根际富集现象。其中有效N和速效K含量高于正常供水．而速效P却呈现低于正常供水的趋势。干旱胁追抑制玉米根系生长、减弱根系吸收能力是玉米减产的重要原因。