Biotoxic Effects of Herbicides on Growth,Nodulation, Nitrogenase Activity,and Seed Production in Chickpeas

Abstract

The effects of pre‐emergent (PRE) application of methabenzthiazuron (MBT), terbutryn, and linuron on plant vigor, number of nodules formed, nitrogenase activity (NA), chlorophyll contents, nitrogen (N) uptake, and seed yield were assessed in inoculated chickpeas, grown in sandy clay loam soil, in a controlled environment. The PRE application of MBT, terbutryn, and linuron at 2.5, 1.25 and 2 g a.i. kg^?1, respectively, had no significant adverse effect on plant vitality, yield, and NA of excised nodules in inoculated chickpea plants, but reduced these parameters at 7.5, 3.75, and 6 g a.i. kg^?1 of soil. Among the herbicides tested, linuron at each dose rates significantly (P≤0.05) decreased the grain yield, whereas terbutryn at 1.25 and 2.5 g a.i. kg^?1 improved the grain yield by 19.4% and 11%, respectively, relative to the nonherbicide control. While comparing the sum of mean values of toxicity of all dose rates of each herbicide on grain yield, the toxicity increased in the following order: control=linuron>methabenzthiazuron>terbutryn. Nodulation (nodule number per plant and their dry mass) and chlorophyll contents per plant decreased consistently with increased herbicide rates, except linuron, which at 2 g a.i. kg^?1 improved nodulation at both 45 and 90 days after seeding and corresponded with Mesorhizobium activity. The N content in grain and straw significantly decreased at the highest tested rates of each herbicide. Linuron at 2 and 4 g a.i. kg^?1 improved N content in straw, whereas at 4 g a.i. kg^?1 it significantly reduced N content in grain.     

京郊设施土壤盐分累积及组成变化特征

针对北京市郊区设施土壤存在次生盐渍化的问题,以房山、延庆、密云、大兴、昌平地区规模化设施园区为研究对象,采用田间随机取样的方法,对5个地区主要栽培类型的设施园区土壤盐分累积和组成变化进行研究,以期为设施栽培的科学管理和高效施肥提供参考。结果表明,79%的点位土壤全盐量≥2.0 g/kg,69.3%的点位电导率≥50 mS/m,次生盐渍化趋势明显;监测园区的盐分离子均有一定程度的富集,不同地区盐分离子累积存在一定差异;除HCO3-外,K+、Na+、Ca2+、Mg2+、Cl-、SO42-、NO^3-的累积在一定程度上均造成了土壤的次生盐渍化,其中阳离子以Ca2+、Mg2+为主,阴离子以SO42-、NO^3-为主;京郊设施土壤盐分组成主要以硝酸盐和硫酸盐的形式存在。针对北京郊区存在盐分累积现象,建议开展有机肥料的筛选和品质质量检测,同时加强水肥管理,避免加重土壤次生盐渍化程度。设施生产中不仅要注重经济效益,更应该关注土壤的健康状况,以实现设施生产可持续的发展目标。     

Study on the Effects of Organic and Inorganic Nitrogen Fertilizer on Yield,Yield Components,and Nodulation State of Chickpea (Cicer arietinum L.)

To study the effects of organic and inorganic nitrogen (N) on yield and nodulation of chickpea (Cicer arietinum L.) cv. ILC 482, a spilt-plot experiment based on randomized complete block design with four replications was conducted in 2008 at the experimental farm of the Agriculture Faculty, University of Mohaghegh, Ardabili. Experimental factors were inorganic N fertilizer at four levels (0, 50, 75, and 100 kg ha^?1) in the main plots that applied in the urea form, and two levels of inoculation with Rhizobium bacteria (with and without inoculation) as subplots. Nitrogen application and Rh. inoculation continued to have positive effects on yield and its attributes. The greatest plant height, number of primary and secondary branches, number of pods per plant, number of filled and unfilled pods per plant, number of grains per plant, grain yield, and biological yield were obtained from the greatest level of N fertilizer (100 kg urea ha^?1) and Rh. inoculation. Application of 75 and 100 kg ha^?1 urea showed no significant difference in these traits. Furthermore, the greatest rate of N usage (100 kg urea ha^?1) adversely inhibited nodulation of chickpea. Number and dry weight of nodules per plant decreased significantly with increasing N application rate. The lowest values of these traits recorded in application of 100 kg ha^?1 urea. Results indicated that application of suitable amounts of N fertilizer (i.e., between 50 and 75 kg urea ha^?1) as starter can be beneficial to improve nodulation, growth, and final yield of inoculated chickpea plants.     

NaCl胁迫下甜瓜幼苗离子吸收特性研究

以厚皮甜瓜黄河蜜和薄皮甜瓜白沙蜜为试材,在人工控制条件下,研究了NaCl胁迫对甜瓜幼苗Na+、K+、Ca2+和Cl-吸收与分配的影响。结果表明,随NaCl浓度的增加,两个甜瓜品种各器官中Na+和Cl-含量均逐渐增加,K+含量逐渐减少,叶片中Ca2+含量逐渐降低,而根中的 Ca2+含量逐步增加;各器官中Na+/K+和叶片中Na+/ Ca2+逐渐增加;SK、Na 和SCa、Na逐步下降。NaCl胁迫下,黄河蜜叶片和茎中Na+ 积累和叶、茎、根中Cl-积累及K+ 、Ca2+ 降低幅度均明显低于白沙蜜;黄河蜜对K+ 和Ca2+的选择吸收和运输能力受胁迫的影响小于白沙蜜。表明厚皮甜瓜黄河蜜比薄皮甜瓜白沙蜜具有更强的耐盐性和盐适应性。     

盐分胁迫对不同品种甘薯苗期离子吸收和分配的影响

选取3种类型共6个甘薯品种(阜薯062-20,浙紫1号,徐薯18,白尾稍,烟薯25,徐菜1号),比较NaCl(0、85 mmol/L)处理20 d后,盐分对甘薯幼苗离子吸收和分配的影响。结果表明:盐分胁迫抑制甘薯幼苗的生长,以阜薯062-20、浙紫1号、徐薯18受影响相对较轻。盐分胁迫下植株大量积累Na+和Cl-,并抑制Ca2+和K+的积累;地上部Na+、Cl-的积累量明显高于根系。白尾稍、烟薯25、徐菜1号Na+和Cl-含量显著高于其他品种。NaCl处理下,阜薯062-20、浙紫1号、徐薯18甘薯幼苗的K+/Na+略高于白尾稍、烟薯25、徐菜1号;品种间Ca2+/Na+差异不大,但阜薯062-20、浙紫1号、徐薯18的SCa,Na较高。因此,6个甘薯品种中,阜薯062-20、浙紫1号、徐薯18苗期耐盐性表现更好。     

The diversity of rhizobia nodulating chickpea (Cicer arietinum) under water deficiency as a source of more efficient inoculants

Chickpea is an important pulse crop grown mainly in the arid and semi-arid regions. The effect of water deficiency on nodulation, biomass production, and competition for nodule occupancy was evaluated in three different soils with two chickpea cultivars, Amdoun I and Chetoui. Two watering regimes were considered; a control that was irrigated three times per week and a water-deficient treatment that was irrigated only one time a week. Results showed that water deficiency significantly decreased the nodule number and the shoot dry weight for both cultivars. Root-nodule bacteria were isolated and characterized by PCR-RFLP of 16S rDNA and nifD-K intergenic spacer. The results show that water deficiency affects the diversity of nodulating rhizobia. The nodulation by Mesorhizobium mediterraneum was reduced while inefficient nodulation by Ensifer meliloti was favoured. In both treatments, chickpea was preferentially nodulated by nifD-K type N6. Analysis for NaCl tolerance showed that most of rhizobia nodulating chickpea under water deficiency are NaCl tolerant. Inoculation with the selected salt-tolerant strain of M. mediterraneum LILM10 increased significantly nodule number and grain yield in the field.     

Identification and selection of low-phosphate-tolerant germplasm in barley (Hordeum vulgare L.)

Phosphorus (P) deficiency is one of the major constraints to crop yield worldwide, and genotypes or cultivars with high phosphate use efficiency (PUE) sustain growth when exposed to phosphate stress. Therefore, it is imperative to develop the genotypes or cultivars with high PUE. A pot experiment was conducted to evaluate the PUE among 150 barley (Hordeum vulgare L.) genotypes. Two high-tolerant and -sensitive accessions were selected. These two candidate materials were used to investigate the differences among the root morphology characteristics, antioxidant enzyme activity, inorganic phosphate (Pi) content and gene expression of HvPT5 under P-deficiency and P-sufficiency conditions. The values of these parameters were higher in the low-P-tolerant genotype than in the sensitive one. In pot experiment 1, all genotypes showed a significant difference in low-P tolerance, with variety GN121 achieving the highest tolerance, and GN42 being most sensitive. The results of this study may provide elite genetic germplasms for future work on isolation of P-related genes, and the improvement of PUE in barley.

Abbreviations: PUE: phosphate use efficiency; CAT: catalase; POD: peroxidase; SOD: superoxide dismutase; DMSO: dimethyl sulphoxide; MDA: malondialdehyde; TOPSIS: technique for order preference by similarity to an ideal solution; MCDM/MADM: multi-criteria (or attribute) decision making     

Alfalfa Responses to Combined Use of Lime and Limiting Nutrients on an Acidic Soil

An on-farm field experiment was conducted on an acidic soil to investigate the effects of combined use of lime and deficient nutrients on herbage yield of alfalfa (Medicago sativa L.). Omitting lime and limiting nutrients led to elevated concentrations of aluminium (Al), iron (Fe), and manganese (Mn) in alfalfa leaves and stems and caused severe reductions in herbage yield of alfalfa. Combined use of lime (2 t ha^?1) and nutrients [phosphorus (P): 20 kg ha^?1, sulfur (S): 20 kg ha^?1, zinc (Zn): 4 kg ha^?1, and boron (B): 2 kg ha^?1] had the maximum increase in groundcover, root biomass, nodulation, leaf retention, leaf-to-stem ratio, herbage yield, crude protein, and nutrient composition of alfalfa. These beneficial effects were due to raised soil pH; improved calcium (Ca), P, S, Zn, and B nutrition; and reduced Al, Mn, and Fe toxicity. Aluminium and all the nutrients except copper (Cu) were more concentrated in alfalfa leaves than stems.

Aluminum concentration was about three times greater in the lower leaves than in upper leaves. Lower leaves also had much greater concentrations of Ca, Mg, K, S, Fe, Mn, Cu, and B compared with upper leaves. In contrast, P and Zn concentrations were greater in the upper leaves than in lower leaves. Results suggest that the combined use of lime and all the limiting nutrients may realize potential beneficial effects of alfalfa on acidic soils where more than one essential nutrient is deficient. This may increase growth potential, nitrogen contributions, and groundcover by alfalfa and reduce soil erosion and runoff.     

Changes in Phosphate Fractions Extracted From Different Organs of Phosphorus Starved Nitrogen Fixing Pea Plants

The present work investigates the impact of phosphorus (P) starvation on plant growth, symbiotic nitrogen fixation, and internal P status (determined as extracted P fractions) of leaves, roots, and nodules of 27-days–old pea (Pisum sativum L) plants inoculated with Rhizobium leguminosarum bv viciae strain D293. The procedure of separation of organic and inorganic P compounds in 10% perchloric acid (HCLO₄) and the absorption of nucleotides in active charcoal gave several fractions, containing different phosphorus compounds, which were extracted and determined as inorganic phosphate after combustion. These are acid soluble and insoluble P, sugar P, nucleotide P, and inorganic P. The P starvation of plants inhibited significantly plant dry mass accumulation, nodulation rate and specific nitrogenase activity of nodules. These results were accompanied with lower quantities of total P per plant, acid soluble and acid non-soluble P fractions in all plant organs. The inhibited accumulation of P in the acid soluble P fraction was associated with decrease of sugar, nucleotide and inorganic P in all plant organs. The most negatively affected were all P fractions extracted from nodules and leaves. The low content of inorganic P in the stressed plant tissues was regarded as primary reason for induced alterations in the content of analyzed P fractions.     

Effects of NaCl and Supplementary Potassium on Gas Exchange,Ionic Content,and Growth of Salt-Stressed Strawberry Plants

Strawberry cultivar ‘Selva’ was grown in a hydroponic culture in a heated greenhouse to study the effects of supplementary potassium (K) added to nutrient solution and applied to the plants grown at high sodium chloride (35 mmol/L) concentration. Treatments were: (1) nutrient solution alone (N); (2) N + sodium chloride (NaCl) (35 mmol/L) (NS); (3) N + NaCl + potassium sulfate (K₂SO₄; 5 mmol/L) (NSK1); (4) N + NaCl + K₂SO₄ (10 mmol/L) (NSK2). Leaf area, biomass production, and gas exchange variables (Pn, E, gs, Ci) negatively affected by salinity. In addition, ionic concentrations (sodium, chlorine, and potassium) increased by salinity treatments. Supplementary potassium had positive effects to ameliorate the harmful effects of NaCl on leaf area. Shoot growing was decreased by potassium (K) application. Ionic concentrations of this cultivar show contradictory results. Although supplementary potassium increased K accumulation, but sodium (Na) and chlorine (Cl) concentrations of plant parts was increased. These results show that potassium can be applied for this cultivar in salinity conditions.     

Responses of Growth and Chemical Composition of Pistachio Seedling to Phosphorus Fertilization Under Saline Conditions

A greenhouse study was conducted to evaluate effects of phosphorus (P) levels (0, 50 and 100 mg kg^?1 soil) under saline (0, 1000 and 2000 mg sodium chloride (NaCl) kg^?1 soil) conditions on growth and chemical composition of pistachio seedlings (Pistacia vera L.) cv. ‘Badami-zarand’ in a completely randomized design (CRD) with four replications. Results showed that salinity application decreased leaf, stem, and root dry weights, number of leaf, length of stem and leaf area, while this effect diminished with P fertilization. By increasing salinity levels, all of the nutrients concentration in leaf, stem and root except sodium (Na) content were reduced. P application increased P and potassium (K) concentrations in the leaves, stem and root, while decreased Na and Zinc (Zn) leaf, stem and root concentrations. However, the results indicated that proline accumulation and reducing sugar content were increased by salinity, P and their interaction application. The results suggest that fertilization of phosphorus can diminish some adverse effects of high salinity on growth and chemical composition of pistachio seedlings.     

Induced Salinity and Supplementary Phosphorus on Growth and Mineral Content of Frijolillo

Abstract

A greenhouse pot experiment was carried out using pumice material to investigate the response of frijolillo [Rhynchosia minima (L.) DC] grown at high salinity to supplementary P (P). Plants were tested during a period from germination to vegetative growth stage. Four levels of sodium chloride (NaCl; 0, 25, 50, and 100 mM) combined with two levels of P (4 and 8 meq L^?1) were tested in a factorial arrangement with four replications. This cultivar was tolerant to salinity stress up to 50 mM of NaCl and its growth was not affected. However, with high salinity (100 mM of NaCl), growth of both stem and root was reduced. Concentration of potassium (K) and P was affected adversely. The increment of P in the saline solution results in a greatest accumulation of biomass and in a better response to the osmotic adjustment of this wild specie. The amount of NaCl was correlated negatively with the amount of K and calcium (Ca) and positively correlated with P and magnesium (Mg).     

工业型城乡交错区土壤重金属含量及其空间分异的特征-以无锡典型城乡交错区为例

Phosphorus （P） is necessary for growth and nitrogen fixation, and thus its deficiency is a major factor limiting legume production in most agricultural soils. The effect of phosphorus supply on nodule development and its role in soybeans （Glycine max L.） was studied in a nutrient solution. Plants were inoculated with Bradyrhizobium japonicum and grown for 35 days in a glasshouse at a day and night temperature of 25℃ and 15℃, respectively. Although increasing P supply increased the concentrations of P and N in the shoots and roots, the external P supply did not significantly affect the P concentration in the nodules, and the N fixed per unit nodule biomass decreased with increasing P supply. The nitrogen content in the shoots correlated well with the P content （r=0.92＊＊）. At an inoculation level of 10^2 cells mL^-1, the P supply did not affect the number of nodules; however, at inoculation levels of 10^3.5 and 10^5 cells mL^-1, increasing P supply increased both the number and size of nodules. Irrespective of the inoculation level, increasing P supply increased the nodule biomass relative to the biomass of the host plant. It is suggested that the P deficiency specifically inhibited the nodule development and thereby the total N2 fixation.     

外源多元醇对盐胁迫下甜瓜幼苗生长和离子平衡的影响

为了探讨外源甘露醇和山梨醇对盐胁迫下甜瓜幼苗生长和离子平衡的影响,以甜瓜‘桂蜜12号’为试验材料,以Hoagland营养液为培养液进行沙培(CK0),采用100 mmol/L NaCl模拟盐胁迫(CK1),然后添加不同浓度的甘露醇和山梨醇,观察不同处理的甜瓜幼苗生长情况和离子平衡变化。结果表明,在100 mmol/L NaCl盐胁迫(CK1)下,与对照(CK0)相比,甜瓜幼苗根系鲜质量、干质量、根总长度、根表面积以及根体积显著下降,K⁺/Na⁺、Ca²⁺/Na⁺、Mg²⁺/Na⁺显著降低。添加0.4 mmol/L的甘露醇,可显著增加甜瓜幼苗茎叶部Ca²⁺、Mg²⁺含量,而不增加Na⁺含量,不降低K⁺含量;显著提高Mg²⁺/Na⁺,而Ca²⁺/Na⁺及K⁺/Na<...     

Nodulation Productivity and Nutrient Uptake of Cowpea (Vigna unguiculata L. Walp) with Phosphorus and Potassium under Rainfed Conditions

Low availability of phosphorus (P) and potassium (K) in acidic soil is a major constraint for crop production. Therefore, a field study was conducted to determine the effects of K and P on nodulation, productivity, and nutrient uptake of cowpea (Vigna unguiculata L. Walp) under rainfed conditions. The K and P were subjected to main and subplots, respectively with 100, 75, and 50% of fertilizer application. The growth and yield attributes were better using 100% K with 100% P. However, 100% K resulted in 20.9 and 16.9% greater green pod and stover yield than 50% K. Similarly, 100% P recorded 20.2 and 15.6% greater green pod and stover yield than 50% P. Uptake of nutrients such as nitrogen (N), P, and K followed the trend of greater to lower, 100% > 75% > 50%, in order for K and P. Similarly, nutrient-use efficiencies and production efficiency followed the trend of nutrient uptake.