scholarly journals Microbial Inoculants Differentially Influence Plant Growth and Biomass Allocation in Wheat Attacked by Gall-Inducing Hessian Fly (Diptera: Cecidomyiidae)

2020 ◽  
Vol 49 (5) ◽  
pp. 1214-1225
Author(s):  
Deirdre A Prischmann-Voldseth ◽  
Tülin Özsisli ◽  
Laura Aldrich-Wolfe ◽  
Kirk Anderson ◽  
Marion O Harris

Abstract Beneficial root microbes may mitigate negative effects of crop pests by enhancing plant tolerance or resistance. We used a greenhouse experiment to investigate impacts of commercially available microbial root inoculants on growth and biomass allocation of wheat (Triticum aestivum L. [Cyperales: Poaceae]) and on survival and growth of the gall-inducing wheat pest Hessian fly, Mayetiola destructor (Say). A factorial design was used, with two near-isogenic wheat lines (one susceptible to Hessian fly, the other resistant), two levels of insect infestation (present, absent), and four inoculants containing: 1) Azospirillum brasilense  Tarrand et al. (Rhodospirillales: Azospirillaceae), a plant growth-promoting bacterium, 2) Rhizophagus intraradices (N.C. Schenck & G.S. Sm.) (Glomerales: Glomeraceae), an arbuscular mycorrhizal fungus, 3) A. brasilense + R. intraradices, and 4) control, no inoculant. Larval feeding stunted susceptible wheat shoots and roots. Plants had heavier roots and allocated a greater proportion of biomass to roots when plants received the inoculant with R. intraradices, regardless of wheat genotype or insect infestation. Plants receiving the inoculant containing A. brasilense (alone or with R. intraradices) had comparable numbers of tillers between infested and noninsect-infested plants and, if plants were susceptible, a greater proportion of aboveground biomass was allocated to tillers. However, inoculants did not impact density or performance of Hessian fly immatures or metrics associated with adult fitness. Larvae survived and grew normally on susceptible plants and mortality was 100% on resistant plants irrespective of inoculants. This initial study suggests that by influencing plant biomass allocation, microbial inoculants may offset negative impacts of Hessian flies, with inoculant identity impacting whether tolerance is related to root or tiller growth.

2020 ◽  
Author(s):  
David Robinson

AbstractUsing a simple plant growth model based on the logistic equation I re-evaluate how biomass allocation between roots and shoots articulates dynamically with the rate of whole-plant biomass production. Defined by parameters reflecting lumped physiological properties, the model constrains roots and shoots to grow sigmoidally over time. From those temporal patterns detailed trajectories of allocation and growth rate are reconstructed. Sigmoid growth trajectories of roots and shoots are incompatible with the dominant ‘functional equilibrium’ model of adaptive allocation and growth often used to explain plants’ responses to nutrient shortage and defoliation. Anything that changes the differential rates of growth between roots and shoots will automatically change allocation and, unavoidably, change whole-plant growth rate. Biomass allocation and whole-plant growth rate are not independent traits. Allocation and growth rate have no unique relationship to one another but can vary across a wide spectrum of possible relationships. When root-shoot allocation seems to respond to the environment it is likely to be a secondary illusory consequence of other primary responses such as localised root proliferation in soil or leaf expansion within canopy gaps. Changes in root-shoot allocation cannot themselves compensate directly for an impairment of growth rate caused by an external factor such as nutrient shortage or defoliation; therefore, such changes cannot be ‘adaptive’.‘The reasons are so simple they often escape notice.’ (James 2012, p. 6).


2021 ◽  
Vol 914 (1) ◽  
pp. 012046
Author(s):  
L Agustini ◽  
S S Hakim ◽  
S A Faulina ◽  
T W Yuwati ◽  
P B Santosa ◽  
...  

Abstract As peatland ecosystems were formed from layered partially decomposed plant biomass, they were considered more vulnerable to fire, especially during extreme drought season. Woody debris accumulation in the field may increase the risk of peatland fire. In order to minimize the chance of repeated fire, an initial study on woody debris decomposition by employing a consortium of wood-decay microbes (consists of Scedosporium apiospermum, Pycnoporus sp., Pycnoporus sanguineus, and unidentified cellulolytic bacterial isolate) was conducted. Series of experiments of in vitro-, semi-controlled-, and field- conditions were carried out. After 12-weeks of incubation, the in vitro trial showed that all treatments on mineral-soil basal media were colonized by fungal mycelia, including the control. Meanwhile, the treatments on peat soil seem less supportive for fungal growth since only six out of ten treatments have been colonized by fungal mycelia. In semi-controlled conditions, effects of microbial inoculation showed questionable results as the trials were randomly occupied by Schizophylum commune, which was not included in the microbial inoculants. Un-clear effects of the microbial inoculants were also observed on the field trial as no significant difference of dry-weight loss between the inoculated woody logs and the un-inoculated control. Further comprehensive studies to reduce woody debris in peatland areas are required.


2021 ◽  
Vol 931 (1) ◽  
pp. 012015
Author(s):  
P Zhang ◽  
V V Matichenkov ◽  
E A Bocharnikova ◽  
S M Sevostianov

Abstract Numerous investigations demonstrate that active forms of silicon (Si) enhance the plant tolerance against abiotic stresses by several mechanisms, including increasing the antioxidant activities and minimizing oxidative damage. Soil contamination with oil and oil products relates to abiotic stress that detrimentally affects soil microbial population and plant growth. Considering the crucial role of microorganisms and plants in bioremediation of oil-polluted areas, Si substances can be beneficial to acceleration of soil reclamation. In greenhouse experiment, wheat was grown in Grey Forest Soil contaminated with used motor oil. The effect of fumed silica and monosilicic acid on soil enzymatic activity and plant growth was studied. Both Si substances provided increasing the plant biomass and the activities of catalase and dehydrogenase. As regards the plant growth, the effect of Si was more pronounced in polluted soil, while the enzyme activity was higher affected in unpolluted soil. The activities of catalase and dehydrogenase were closely correlated to the water-soluble Si in soil (R=0.91-0.92). Silicon substances with high content of, plant-and microorganism-available Si might be promising for involvement in bioremediation technology for oil-contaminated soil.


Agronomy ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 33 ◽  
Author(s):  
Ying Ma ◽  
Aleš Látr ◽  
Inês Rocha ◽  
Helena Freitas ◽  
Miroslav Vosátka ◽  
...  

Cowpea (Vigna unguiculata L. Walp) is an important legume grown primarily in semi-arid area. Its production is generally inhibited by various abiotic and biotic stresses. The use of beneficial microorganisms (e.g., plant growth promoting bacteria (PGPB) and arbuscular mycorrhizal fungi (AMF)) can enhance agricultural production, as these microorganisms can improve soil fertility and plant tolerance to environmental stresses, thus enhancing crop yield in an eco-friendly manner. Application of PGPB and AMF in large scale agriculture needs to be improved. Thus, the use of seed coating could be an efficient mechanism for placement of inocula into soils. The aim of this study was to evaluate the effects of the AMF Rhizophagus irregularis BEG140 and the PGPB Pseudomonas libanensis TR1 alone or in combination on the biomass and physiological traits of cowpea. Four treatments were set: (i) non-inoculated control; (ii) PGPB; (iii) AMF applied via seed coating; and (iv) PGPB + AMF applied via seed coating. Cowpea plants inoculated via seed coating with R. irregularis and those inoculated with R. irregularis + P. libanensis showed root mycorrhizal colonization of 21.7% and 24.2%, respectively. PGPB P. libanensis was efficient in enhancing plant biomass and seed yield. There was no benefit of single (AMF) or dual (PGPB + AMF) inoculation on plant growth or seed yield. The application of beneficial soil microorganisms can be a viable approach for sustainable cowpea production in precision agriculture scenarios.


2020 ◽  
Vol 10 (17) ◽  
pp. 5767 ◽  
Author(s):  
Elisa Gamalero ◽  
Nicoletta Favale ◽  
Elisa Bona ◽  
Giorgia Novello ◽  
Patrizia Cesaro ◽  
...  

Bacterial endophytes can colonize plant tissues without harming the plant. Instead, they are often able to increase plant growth and tolerance to environmental stresses. In this work, new strains of bacterial endophytes were isolated from three economically important crop plants (sorghum, cucumber and tomato) grown in three different regions in soils with different management. All bacterial strains were identified by 16S rRNA sequencing and characterized for plant beneficial traits. Based on physiological activities, we selected eight strains that were further tested for their antibiotic resistance profile and for the ability to efficiently colonize the interior of sorghum plants. According to the results of the re-inoculation test, five strains were used to inoculate sorghum seeds. Then, plant growth promotion activity was assessed on sorghum plants exposed to salinity stress. Only two bacterial endophytes increased plant biomass, but three of them delayed or reduced plant salinity stress symptoms. These five strains were then characterized for the ability to produce the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase, which is involved in the increase of stress tolerance. Pseudomonas brassicacearum SVB6R1 was the only strain that was able to produce this enzyme, suggesting that ACC deaminase is not the only physiological trait involved in conferring plant tolerance to salt stress in these bacterial strains.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xiaochen Yao ◽  
Yun Cao ◽  
Guodi Zheng ◽  
Adam T. Devlin ◽  
Xiao Li ◽  
...  

AbstractWater level conditions are the key factors that affect the growth and distribution of wetland plants. Using Carex cinerascens (C. cinerascens) as the study species, we employ indoor simulations and field surveys. Our results show that C. cinerascens can adapt to rhythmic changes in the water level through different adaptation strategies. Compared to that of the control group, plant growth was better with a 0–0.4 cm/d water level rate, and plant growth was in the 42–56 cm range to that a 1.0–1.4 cm/d water level rate. Furthermore, it was observed that 0–0.4 cm/d was the most suitable growth rate, with 0.6–1.0 cm/d and 0–32 cm being the ideal plant tolerance ranges, and increasing to 1.0–1.4 cm/d and 32–56 cm exceeds the plant tolerance threshold. In the middle and late period of the experiment (25–45 d), the ecological characteristics of the plants changed significantly. For example, the root-to-shoot ratio of the plant in the stable water level reached 26.1. In our field observations, plant biomass can be influenced by a variety of environmental factors. The frequency of the species was the largest at an elevation of 15 m, and the growth status of the dominant and companion species of C. cinerascens was weakened with an increase in soil moisture content. The suitable water content for C. cinerascens growth was 27.6–57.3%, the distribution elevation was 12.54–16.59 m, and the optimum elevation was 13.56–15.54 m. The study is expected to provide a reference for wetland ecology research and wetland protection and restoration, a theoretical reference for the coordination of water resource development and utilization of Poyang Lake and ecological protection of important lakes and wetlands, and an important scientific basis for wetland hydrologic regulation, ecological restoration and biodiversity conservation.


Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 598
Author(s):  
Muneeba Qurban ◽  
Cyrus Raza Mirza ◽  
Aqib Hassan Ali Khan ◽  
Walid Khalifa ◽  
Mustapha Boukendakdji ◽  
...  

The problem of metal-induced toxicity is proliferating with an increase in industrialization and urbanization. The buildup of metals results in severe environmental deterioration and harmful impacts on plant growth. In this study, we investigated the potential of two ornamental plants, Catharanthus roseus (L.) G.Don and Celosia argentea L., to tolerate and accumulate Ni, Cr, Cd, Pb, and Cu. These ornamental plants were grown in Hoagland’s nutrient solution containing metal loads (50 µM and 100 µM) alone and in combination with a synthetic chelator, ethylenediaminetetraacetic acid (EDTA) (2.5 mM). Plant growth and metal tolerance varied in both plant species for Ni, Cr, Cd, Pb, and Cu. C. roseus growth was better in treatments without EDTA, particularly in Ni, Cr, and Pb treatments, and Pb content increased in all parts of the plant. In contrast, Cd content decreased with EDTA addition. In C. argentea, the addition of EDTA resulted in improved plant biomass at both doses of Cu. In contrast, plant biomass reduced significantly in the case of Ni. In C. argentea, without EDTA, root length in Cd and Cu treatments was significantly lower than the control and other treatments. However, the addition of EDTA resulted in improved growth at both doses for Pb and Cu. Metal accumulation in C. argentea enhanced significantly with EDTA addition at both doses of Cu and Cd. Hence, it can be concluded that EDTA addition resulted in improved growth and better metal uptake than treatments without EDTA. Metal accumulation increased with EDTA addition compared to treatments without EDTA, particularly for Pb in C. roseus and Cu and Cd in C. argentea. Based on the present results, C. roseus showed a better ability to phytostabilize Cu, Cd, and Ni, while C. argentea worked better for Ni, Cd, Cu, and Pb.


Author(s):  
L. M. Manici ◽  
F. Caputo ◽  
G. A. Cappelli ◽  
E. Ceotto

Abstract Soil suppressiveness which is the natural ability of soil to support optimal plant growth and health is the resultant of multiple soil microbial components; which implies many difficulties when estimating this soil condition. Microbial benefits for plant health from repeated digestate applications were assessed in three experimental sites surrounding anaerobic biogas plants in an intensively cultivated area of northern Italy. A 2-yr trial was performed in 2017 and 2018 by performing an in-pot plant growth assay, using soil samples taken from two fields for each experimental site, of which one had been repeatedly amended with anaerobic biogas digestate and the other had not. These fields were similar in management and crop sequences (maize was the recurrent crop) for the last 10 yr. Plant growth response in the bioassay was expressed as plant biomass production, root colonization frequency by soil-borne fungi were estimated to evaluate the impact of soil-borne pathogens on plant growth, abundance of Pseudomonas and actinomycetes populations in rhizosphere were estimated as beneficial soil microbial indicators. Repeated soil amendment with digestate increased significantly soil capacity to support plant biomass production as compared to unamended control in both the years. Findings supported evidence that this increase was principally attributable to a higher natural ability of digestate-amended soils to reduce root infection by saprophytic soil-borne pathogens whose inoculum was increased by the recurrent maize cultivation. Pseudomonas and actinomycetes were always more abundant in digestate-amended soils suggesting that both these large bacterial groups were involved in the increase of their natural capacity to control soil-borne pathogens (soil suppressiveness).


Sign in / Sign up

Export Citation Format

Share Document