Low root zone temperature effects on bean (Phaseolus vulgaris L.) plants inoculated with Rhizobium leguminosarum bv. phaseoli pre-incubated with methyl jasmonate and/or genistein

Abstract

Methyl jasmonate (MeJA) has recently been shown to act as a plant-to-bacteria signal. We tested the hypothesis that pre-induction of Rhizobium leguminosarum bv. phaseoli cells with genistein and/or MeJA would at least partially overcome the negative effects of low root zone temperature (RZT) on bean nodulation, nitrogen fixation and plant growth. Otebo bean plants were grown at constant air temperature (25^oC) and two RZT regimes (25 and 17^oC) and inoculated with R. leguminosarum bv. phaseoli pre-induced with MeJA and/or genistein. Our results indicate that low RZT inhibited nodulation, nitrogen fixation and plant growth. The plants growing at low RZT began fixing nitrogen seven days later compared to those at higher RZT. The low RZT plants had fewer nodules, lower nodule weight, less N fixation, slower plant growth, fewer leaves, smaller leaf area, and less dry matter accumulation comared to plants at a higher RZT. Rhzobium leguminosarum bv. phaseoli cells induced with genistein and/or MeJA enhanced bean nodulation, nitrogen fixation and growth at both optimum and suboptimum RZTs. The results of this study indicate that MeJA improves bean nitrogen fixation and growth at both optimum and suboptimum RZTs, and can be used alone or in combination with genistein to partially overcome the low RZT induced inhibitory effects on nodulation and nitrogen fixation.     

Isolation and characterization of multi-potential Rhizobium strain ND2 and its plant growth-promoting activities under Cr(VI) stress

Soil contaminated by chromium (Cr) is a major concern for sustainable agriculture. Considering this as a basis, the present study was designed to isolate Cr(VI)-reducing and plant growth-promoting bacterial strain from contaminated sampling sources. In this study, Rhizobium strain ND2 was isolated from the root nodules of Phaseolus vulgaris grown in leather industrial effluent contaminated soil. The strain ND2 exhibited strong resistance to different heavy metals and reduced 30 and 50 µg ml^?1 concentrations of Cr(VI) completely after 80 and 120 h of incubation, respectively, as well as chromium adsorption and immobilization were confirmed by scanning electron microscopic equipped with energy X-ray spectroscopy. In addition, the strain produced 21.73 and 36.86 µg ml^?1 of indole-3-acetic acid at 50 and 100 µg ml^?1 of L-tryptophan supplimentations, respectively. Strain ND2 positively affected the exo-polysaccharide, ammonia, protease and catalase production and stimulated root length of various test crops under Cr(VI) stress. Moreover, Rhizobium strain ND2 has the potential to colonize the diverse agricultural crops. Thus, the present findings strongly suggested that the multipotential properties of ND2 could be exploited for bioremediation of contaminated sites with Cr(VI) as well as potential bio fertilizer for enhancing the agricultural productivity.     

Response of field-grown bean (Phaseolus vulgaris L.) to Rhizobium inoculation and nitrogen fertilization in two Cerrados soils

 Most soils sown with field beans (Phaseolus vulgaris L.) contain indigenous rhizobia which might interfere with the establishment of inoculated strains. As a consequence, the benefits of bean inoculation are usually questioned, and the use of N fertilizer is gradually becoming a common practice. The present study had the objective of evaluating the effectiveness of inoculation and N fertilization in field soil with (site 1) and without (site 2) a previous bean-cropping history. At site 1, which had a rhizobial population of 7×10² cells g^–1 soil, inoculation had no effect on nodulation or yield, whereas at site 2 (<10 cells g^–1 soil) inoculation increased nodulation, nodule occupancy by the inoculated strain and grain yield. N fertilizer decreased nodulation at both sites, but increased grain yield at site 1 but not at site 2, indicating that the response to inoculation and N fertilization depends on the cropping history. When bean was cultivated for the first time, indigenous populations of rhizobia were low and high yields were accomplished solely with seed inoculation, with no further response to N fertilizer. In contrast, previous cultivation of bean increases soil rhizobia, preventing nodule formation by inoculated strains, and N fertilizer may be necessary for maximum yields. A significant interaction effect between N fertilizer and inoculation was detected for serogroup distribution only at site 2, with N fertilizer decreasing nodule occupancy by the inoculated strain and increasing the occurrence of indigenous strains. Consequently, although no benefits were obtained by the combination of inoculation and N fertilizer, this practice may be feasible with the selection of appropriate N-tolerant strains from the indigenous rhizobial population. Received: 26 May 1999     

Competition and persistence of Rhizobium tropici and Rhizobium etli in tropical soil during successive bean (Phaseolus vulgaris L.) cultures

Strains of Rhizobium tropici IIB, CIAT899 and F98.5, both showing good N₂ fixation, and a R. etli strain W16.3SB were introduced into a field which had no history of bean culture. Plant dilution estimates showed that in the presence of its host (Phaseolus vulgaris cv. Carioca) during the cropping seasons and the subsequent fallow summer periods, the bean rhizobial populations increased from less than 30 to 10³ g^–1 dry soil after 1 year and to 10⁴ g^–1 dry soil after 2 years. In the 1st year crop, the inoculated strains occupied most of the nodules, which resulted in a higher nodulation and C₂H₂ reduction activity. Without reinoculation for the second and third crops, however, little R. tropici IIB was recovered from the nodules and the bean population consisted mainly of R. etli, R. leguminosarum bv. phaseoli, and R. tropici IIA. Reinoculation with our superior R. tropici IIB strains before the second crop resulted in R. tropici IIB occupying the main part of the nodules and a positive effect on nodulation and C₂H₂ reduction activity, but reintroduction of the inoculant strain in the third season did not have any effect.     

Effect of location on dwarf French bean (Phaseolus vulgaris L.) seed production and seedling vigour

ABSTRACT

This study examined if dwarf French bean (Phaseolus vulgaris L.) grown at northern latitudes develop seeds with superior yielding potential compared with plants grown at more southern latitudes. Two lines (BND3085 and BND3106) were grown at four sites across latitudes ranging from 52°N to 3°S. BND3085 and BND3106 seeds from Saskatoon grown plants (52°N) had the least damaged seed coats but the highest degree of electrolyte leakage from the seed and the lowest maximum germination rates. The Saskatoon (BND3085 and BND3106) and Nunhem (BND3106) seed lots had the lowest maximum germination rates when germinated at 28°C, 12°C, or when exposed to saline (100?mM NaCl) conditions. Saskatoon BND3085 seed produced plants with the lowest aboveground vegetative and total seed dry matter as well as the lowest pod number per plant. In contrast, plants grown from Saskatoon BND3106 seed produced 1.5-fold more total pods, 1.3-fold more total pods and 1.4-fold higher seed dry matter per plant as compared to plants grown from the Nunhem (51°N) or Arusha seed sources. This resulted in a 2.4–4.5% higher harvest index. These results suggest cultivar-specific dwarf French bean seed propagation at more northern sites may increase the productivity of the resulting crop.     

Effects of vermicomposts obtained from rose oil processing wastes,dairy manure,municipal open market wastes and straw on plant growth,mineral nutrition,and nutrient uptake of corn

Study aims to investigate the effects of vermicomposts containing oil processing wastes, dairy manure, municipal open market wastes and straw on the growth, nutrient concentrations and nutrient uptakes of corn plant. For this, there different mixtures were prepared. Vermicomposts were applied with the rates of 0, 5000, 10000, and 20000 kg ha^?1 to 2 kg soil containing pots. Study was conducted in growth chamber for 2 months. Vermicompost applications increased plant growth, some plant nutrient concentrations and uptake. Also, vermicomposts showed the variation on parameters depending on their mixtures. Results showed that nutrients taken by the plant increased with the vermicompost until 10000 kg ha^?1 dose. Most of the nutrient concentrations such as phosphorus, potassium, calcium, magnesium, iron, and manganese (P, K, Ca, Mg, Fe, and Mn) were not increased in plant tissues, whereas uptake of them by the plant showed a significant increase. In addition, residual soil nutrients increased with the increase in vermicompost levels.     

Seed Bacterization with Fluorescent Pseudomonas spp. Enhances Nutrient Uptake and Growth of Cajanus cajan L.

Among plant-growth-promoting rhizobacteria (PGPR), fluorescent Pseudomonas spp. are an important group affecting plant growth. Pigeon pea is an important pulse crop and most of the studies were aimed at using Pseudomonas spp. for pest management in pigeon pea. Seventy-five fluorescent Pseudomonas spp. were isolated from diverse agroecosystems of India and evaluated for their plant-growth-promoting ability, primarily by the paper cup method. Seventeen selected isolates were further evaluated by short-term pot assay for plant growth promotion. Seeds treated with bacteria showed greater nutrient concentration and growth than the control. Isolate P17 showed significant growth promotion in terms of root length (54.5 cm), dry mass (323 mg), chlorophyll (24 spad units), carbohydrates (21.2 percent), nitrogen (2.45 percent), calcium (1.82 percent), iron (984 ppm), and manganese (564 ppm). Pseudomonas sp. P17 strain was identified as a potential PGPR for nutrient uptake and plant growth promotion in pigeon pea, and this finding paves a way for integrated plant nutrient management in rainfed agroecosystems.     

Effect of exudate released from seeds and seedling roots of common bean (Phaseolus vulgaris L.) on proliferation of Rhizobium sp. (Phaseolus)

Effects of seed and root exudates obtained from common bean on the proliferation of Rhizobium sp. (Phaseolus) were examined in a combination of three plant cultivars with three Rhizobium strains. In the first experiment, seed or root exudate was mixed with an Andosol soil extract, and bacterial proliferation in the mixture was traced. Seed exudate was prepared from hydroponic solution used in seed imbibition for 24 h, and a series of root exudates was prepared from a hydroponic solution collected every 24 h from the initiation of rooting up to 96 h after rooting. Regardless of the common bean cultivars and Rhizobium strains used, Rhizobium population markedly increased of the 24 h of culture in the mixture containing seed exudates, whereas a negligible increase was detected in the mixture with root exudates. The mixture containing root exudates collected within a period of 72–96 h after initial rooting (96–120 h after seed imbibition) exerted an inhibitory effect on Rhizobium proliferation. The seed exudates contained large amounts of sugars, amino acids, nitrogen, phosphorus, potassium, and magnesium compared to any root exudates. In the second experiment, Rhizobium was inoculated directly to common bean seeds sowed in a vermiculite bed which was sterilized and moistened with a plant nutrient solution. Compared with the control (without seed), a remarkable increase in the number of bacterial cells was observed in all the combinations of plant cultivars and Rhizobium strains 24 h after sowing. These results reveal that seed exudates of common bean have a substantial potential to promote Rhizobium proliferation, and that root exudates in a particular period of culture contain some inhibitory factors.     

Potential of seed and root exudates of the common bean Phaseolus vulgaris L. for immediate induction of rhizobial chemotaxis and nod genes

Abstract

Immediate induction of rhizobial chemotaxis and nod genes by seed and root exudates of the common bean Phaseolus vulgaris L. was investigated. One hour after the onset of Rhizobium incubation in a culture medium composed of common bean exudates and soil extract, a large number of Rhizobium cells were attracted by the seed exudates of all the cultivars (cvs Hokkaikintoki, Himetebou and Kurodanekinugasa), while the media containing root exudates was not statistically different from the control. After 1 h of incubation, the nod genes were induced significantly by the seed exudates of Himetebou and Kurodanekinugasa. In contrast, the seed exudate of Hokkaikintoki and the root exudates of all the cultivars failed to exert a beneficial effect on the immediate induction of the nod genes. These results suggested that the seed exudates displayed a higher potential for immediate induction of rhizobial chemotaxis and nod genes than the root exudates, except for nod gene induction by the seed exudate of Hokkaikintoki.     

Ferti-irrigation Effect of Paper Mill Effluent on Agronomical Practices of Phaseolus vulgaris (L.) in Two Seasons

The potential of agrobased paper mill effluent (PME) as ferti-irrigant was assessed. Ferti-irrigation responses to 5, 10, 25, 50, 75, and 100% of PME doses on Phaseolus vulgaris L., cv. Annapurna, in the rainy and summer seasons were investigated. The fertigant concentrations produced changes in electrical conductivity (EC), pH, organic carbon (OC), sodium (Na⁺), potassium (K⁺), calcium (Ca²⁺), magnesium (Mg²⁺), total Kjeldahl nitrogen (TKN), phosphate (PO₄^3–), sulfate (SO₄^2–), iron (Fe²⁺), cadmium (Cd), chromium (Cr), copper (Cu), manganese (Mn), and zinc (Zn) of the soil in both seasons. The agronomic performances of P. vulgaris increased from 5 to 25% in both seasons compared to controls. The accumulation of metals increased in soil and P. vulgaris from 5 to 100% PME concentrations in both seasons. The contamination factor (Cf) of various metals was in order of Cr > Mn > Cu > Cd > Zn for soil and Mn > Zn > Cu > Cd > Cr for P. vulgaris in both seasons after fertigation with PME. Therefore, PME can be used to improve the soil fertility and yield of P. vulgaris after appropriate dilution.     

K和Al对水稻生长和养分吸收的影响

The effects of K and Al in K-deficient and complete nutrient solutions on the growth and nutrient uptake of rice were studied in the work.The effect of Al on the growth of roots and above-ground part of rice was associated with the concentration of Al in solution .A low level(0.1 mmol L^-1) of Al promtoed but a high level(1 mmol L^-1)of Al inhibited the growth of both the root and the aerial part of rice,and the magnitude of K concentration in the nutrient solution also had an appreciable impact on this,Thus ,in the low-Al solution,the plant treated with K2(80 mg K L^-1)produced much longer roots,showing the presence of interaction between Al and K; in the high-Al solution the K-reated plant had more and longe roots and a considerably greater dry weigh of the above-ground part compared with the plant deficient in K, showing the alleviating effect of K^ on Al toxicity.The mechanism of the Al-K interaction affecting the rice aerial part growth is not yet known,but part of the reason might be that the excessive amount of Al inhibited the uptake of some nutrients such as Ca and Mg and reduced their transfer to the plant aerial organs,whereas K showed its compensating effect on this;therefore,K could relieve Al toxicity at a high level of Al and promoted rice growth at a low level of Al.     

Competitive interaction among strains of Rhizobium leguminosarum bv. phaseoli in the nodulation of kidney beans (Phaseolus vulgaris L.)

We examined the competitiveness of five effective Rhizobium leguminosarum biovar phaseoli strains in the nodulation of kidney beans (Phaseolus vulgaris L.), either alone or in pairwise combination, against the indigenous strains. The results showed that the introduced Rhizobium sp. strains (B2, B17, B36, T2, or CIAT 652) occupying 64–79% of the total nodules (as single inocula) were more competitive in nodulation than the native rhizobia. However, the competitiveness of the individual Rhizobium sp. strain either increased or decreased when used in a pairwise combination of double-strain inocula. For example, strain B17, although quite competitive against the indigenous population (68% nodule occupancy), became poorly competitive in the presence of strain B2 (reduced from 68 to 2.5%). A similar reduction in nodule occupancy by strain B17 was observed in the presence of B36 or CIAT 652, indicating that two competitive strains may not always be compatible. These results suggest that it is important to co-select competitive as well as compatible rhizobia for multistrain inoculant formulation.     

Biostimulant effects of rhizobacteria on wheat growth and nutrient uptake depend on nitrogen application and plant development

The capacity of plant growth-promoting rhizobacteria (PGPR) – Bacillus amyloliquefaciens GB03 (BamGB03), B. megaterium SNji (BmeSNji), and Azospirillum brasilense 65B (Abr65B) – to enhance growth and nutrient uptake in wheat was evaluated under different mineral N fertilizer rates, in sterile and non-sterile soils, and at different developmental stages. In gnotobiotic conditions, the three strains significantly increased plant biomass irrespective of the N rates. Under greenhouse conditions using non-sterile soil, growth promotion was generally highest at a moderate N rate, followed by a full N dose, while no significant effect was observed for the inoculants in the absence of N fertilizer. At 50N, plant biomass was most significantly increased in roots (up to +45% with Abr65B) at stem-elongation stage and in the ears (+19–23% according to the strains) at flowering stages. For some nutrients (N, P, Mn, and Cu), the biomass increases in roots and ears were paralleled with reduced nutrient concentrations in the same organs. Nevertheless, growth stimulation resulted in a higher total nutrient uptake and higher nutrient uptake efficiency. Furthermore, Abr65B and BmeSNji counteracted the reduction of root development caused by a high N supply. Therefore, combining PGPR with a proper cultivated system, N rate, and plant stage could enhance their biostimulant effects.     

Effect on plant growth and nutrient uptake of a saturated gypsum solution given to a soil rich in CA

Abstract

Barley plants were grown in 201 pots containing a sandy soil rich in exchangeable and watersoluble Ca. Results from earlier experiments have indicated that the mode of action of supplementary Ca may differ according to, for example, the associate anion. In this experiment soil‐Ca was activated by placing NH₄NO₃ at three depths in the soil and by adding solutions of Ca salts. Yields were found to increase with successively deeper placements of NH₄NO₃ in treatments without Ca application, whereas only small differences between placement depths were observed when Ca was added as a saturated gypsum solution or equivalent amounts of CaCl₂. The very pronounced responses to Ca application were in good agreement with visual symptoms of Ca deficiencies later in the season and with the nutrient uptake rates and growth rate over the intire growth period.     

Effects of Azospirillum brasilense on root morphology of common bean (Phaseolus vulgaris L.) under different water regimes

 The effects of inoculation with Azospirillum brasilense Cd on root morphology and growth of common bean (Phaseolus vulgaris L.) were studied under different growth systems and water regimes. The root systems were evaluated by image analysis. In a PVC-tube growth system, inoculation with A. brasilense at 10⁷ colony forming units (CFU) ml^–1 increased root length, root projection area, specific root length (m g^–1) and specific root area (cm² g^–1), as compared with non-inoculated controls, resulting in root systems with longer and thinner roots. Water stress induced similar root responses to those observed after inoculation with A. brasilense. No increase in plant biomass was observed in inoculated plants, suggesting that under the tested growth conditions, a relatively larger amount of resources is required for the maintenance of the thinner roots. In water-stressed potted plants, the effect of A. brasilense on tap root length was inoculum-concentration dependent. At 10⁷ CFU ml^–1 this effect was significant as compared to non-inoculated controls. In a pouch system without water stress, inoculation with A. brasilense at a concentration of 10⁵–10⁷ CFU ml^–1 2 days after germination resulted initially (2 days after inoculation) in an increase in root length (95%) and root fresh weight (66%), but reduced root diameter (20%), compared to controls. At this early stage of growth the distribution of root length among the different root diameter classes changed: the thinner-root classes had the largest proportion of longer roots. Received: 3 January 2000     

Enhanced root uptake of acibenzolar-S-methyl (ASM) by tomato plants inoculated with selected Bacillus plant growth-promoting rhizobacteria (PGPR)

The combination of plant growth-promoting rhizobacteria (PGPR) and plant resistance inducers is an alternative crop protection approach in modern agricultural systems. Despite the numerous reports regarding the improved suppression of plant pathogens by their combined application, little is known about the interactions among these components. In the present study, the persistence behavior of the plant activator acibenzolar-S-methyl (ASM) in the rhizosphere of tomato plants and its root uptake as well as systemic translocation ability in aboveground parts after combined use with certain Bacillus PGPR strains (B. amyloliquefaciens IN937a, B. pumilus SE34, B. subtilis FZB24 and GB03) were investigated. Additionally, the population dynamics of the PGPR strain B. subtilis GB03 at the tomato root system and rhizosphere soil applied with or without the pesticide were studied. The results showed that the addition of PGPR inocula did not affect the dissipation rate of ASM in rhizosphere soil. Also, the formation of its major metabolite CGA 210007 in soil was rapid, since it was detected one hour after root drench and it was maintained at high levels during the sampling period without considerable variations among the bacterial treatments compared to the control. The uptake and systemic translocation of ASM and its metabolite CGA 210007 from root to shoot was rapid and maximum concentrations were observed at 48–96 h after its application. It was revealed that in plants treated with the PGPR strains B. subtilis GB03 and B. pumilus SE34 the uptake and systemic translocation of ASM and CGA 210007 in the aerial parts of the tomato plants was significantly higher compared to the control receiving no bacterial treatment. Also, the populations of the strain B. subtilis GB03 showed high colonizing ability in the root system and the rhizosphere soil. PGPR strains that lead to enhanced pesticide uptake by plants should be further evaluated as components in integrated management systems.     

补灌与施肥对甜菜干物质积累、产糖量及养分吸收的影响

通过研究甜菜在雨养条件下施肥和施肥后补灌对甜菜干物质积累、产量、产糖量和养分吸收的影响规律，可以为甜菜栽培中施肥和灌溉提供理论依据。试验在田间条件下，设置雨养无肥(对照)、雨养施肥、补灌施肥3个处理，大区试验设计，3次重复。结果表明：收获期补灌与雨养施肥处理相比显著提高了甜菜总干物质积累量和产糖量；补灌施肥、雨养施肥与无肥处理相比显著提高了地上部和总干物质积累量、产量、产糖率和产糖量；收获期补灌与雨养施肥处理相比显著降低了甜菜地下部、地上部氮吸收量和总氮、总钾吸收量，雨养施肥与无肥处理相比显著提高了总氮、总钾吸收量；收获期补灌与雨养施肥处理相比显著提高了甜菜地下部、地上部干物质积累量和总磷吸收量，雨养施肥与不施肥处理相比显著提高了地上部干物质积累量和总磷吸收量。综合分析认为，补灌与雨养施肥处理相比利于促进甜菜生长发育，提高产量、产糖量和磷吸收量，降低甜菜对氮、钾的吸收量，建议在5—6月发生季节性干旱时进行人工补灌。     

在受控条件下植物促生菌对扁豆的生长，结瘤和养分积累的效应

Application of plant growth-promoting rhizobacteria (PGPR) has been shown to increase legume growth and development under field and controlled environmental conditions. The present study was conducted to isolate plant growth-promoting rhizobacteria (PGPR) from the root nodules of lentil (Lens culinaris Medik.) grown in arid/semi-arid region of Punjab, Pakistan and examined their plant growth-promoting abilities. Five bacterial isolates were isolated, screened in vitro for plant growth-promoting (PGP) characteristics and their effects on the growth of lentil were assessed under in vitro, hydroponic and greenhouse (pot experiment) conditions. All the isolates were Gram negative, rod-shaped and circular in form and exhibited the plant growth-promoting attributes of phosphate solubilization and auxin (indole acetic acid, IAA) production. The IAA production capacity ranged in 0.5-11.0 μg mL-1 and P solubilization ranged in 3-16 mg L-1 . When tested for their effects on plant growth, the isolated strains had a stimulatory effect on growth, nodulation and nitrogen (N) and phosphorus (P) uptake in plants on nutrient-deficient soil. In the greenhouse pot experiment, application of PGPR significantly increased shoot length, fresh weight and dry weight by 65%, 43% and 63% and the increases in root length, fresh weight and dry weight were 74%, 54% and 92%, respectively, as compared with the uninoculated control. The relative increases in growth characteristics under in vitro and hydroponic conditions were even higher. PGPR also increased the number of pods per plant, 1 000-grain weight, dry matter yield and grain yield by 50%, 13%, 28% and 29%, respectively, over the control. The number of nodules and nodule dry mass increased by 170% and 136%, respectively. After inoculation with effective bacterial strains, the shoot, root and seed N and P contents increased, thereby increasing both N and P uptake in plants. The root elongation showed a positive correlation (R2 = 0.67) with the IAA production and seed yield exhibited a positive correlation (R2 = 0.82) with root nodulation. These indicated that the isolated PGPR rhizobial strains can be best utilized as potential agents or biofertilizers for stimulating the growth and nutrient accumulation of lentil.     

Effects of different organic materials on forage yield and nutrient uptake of silage maize (Zea mays L.)

The use of organic materials as a source of nutrients on agricultural lands ameliorates soil physical properties as well as being an environmentally friendly way of disposing of their wastes. This study was conducted to determine effects of three organic materials (poultry litter, cattle manure, leonardite) on yield and nutrient uptake of silage maize. Poultry litter and cattle manure were applied based on phosphorus (P) or nitrogen (N) requirements of the crop whereas leonardite was applied only one dose (500 kg ha^?1) and also combined with three inorganic fertilizer doses (100%, 75%, 50% of recommended inorganic fertilizer dose). According to the results, the highest green herbage yield and nutrient uptake values were observed in LEO-100 whereas N-based treatments significantly decreased yield and nutrient uptake of silage maize. The use of organic materials as a combination with inorganic fertilizer in silage maize cultivation is highly beneficial for sustainable forage production.