Significant Increase In Root Length Research Articles

Unravelling the potential plant growth activity of halotolerant Bacillus licheniformis NJ04 isolated from soil and its possible use as a green bioinoculant on Solanum lycopersicum L.

Immensely expanding world population and narrowing arable land for agriculture is a mighty concern faced by the planet at present. One of the major reasons for decline in arable lands is the increased soil salinity, making it unfavourable for crop cultivation. Utilisation of these saline land for agriculture is possible with suitable invention for improving the soil quality. Biofertizers manufactured out of Plant Growth Promoting Rhizobacteria is one such innovation. In the present study, Bacillus licheniformis NJ04 strain was isolated and studied for its halotolerance and other effective plant growth promoting traits. The NJ04 strain was able to tolerate salt up to 10% and highlighted remarkable antifungal activity against common fungal phytopathogens. The preliminary seed germination test in Solanum lycopersicum seeds revealed a significant increase in root length (16.29 ± 0.91 cm) and shoot length (9.66 ± 0.11 cm) of treated plants as compared with the control plants and thereby shows its possible use as a green bioinoculant in agriculture and an ideal candidate to compete with salt stress.

Melatonin enhanced low-temperature combined with low-light tolerance of pepper (Capsicum annuum L.) seedlings by regulating root growth, antioxidant defense system, and osmotic adjustment.

Melatonin (MT) is an important biologically active hormone that plays a vital role in plant growth and development. In particular, it has been investigated for its roles in abiotic stress management. In this study, pepper seedlings were subjected to low-temperature combined with low-light stress (LL) (15/5°C, 100 μmol m-2s-1) prior to a foliar spray of 200mM MT for 168h to investigate the protective role of MT in pepper seedlings. Our results demonstrated that LL stress negatively affected root growth, and accelerated the accumulation of reactive oxygen species (ROS), including H2O2 and , changed the osmolytes contents, and antioxidative system. However, these were reversed by exogenous MT application. MT effectively promoted the root growth as indicated by significant increase in root length, surface area, root volume, tips, forks, and crossings. In addition, MT reduced the burst of ROS and MDA contents induced by LL, enhanced the activities of SOD, CAT, POD, APX, DHAR, and MDHAR resulted by upregulated expressions of CaSOD, CaPOD, CaCAT, CaAPX, CaDHAR, and CaMDHAR, and elevated the contents of AsA and GSH, declined DHA and GSSH contents, which prevented membrane lipid peroxidation and protected plants from oxidative damages under LL stress. Furthermore, seedlings treated with MT released high contents of soluble sugar and soluble protein in leave, which might enhance LL tolerance by maintaining substance biosynthesis and maintaining cellular homeostasis resulted by high levels of osmolytes and carbohydrate in the cytosol. Our current findings confirmed the mitigating potential of MT application for LL stress by promoting pepper root growth, improving antioxidative defense system, ascorbate-glutathione cycle, and osmotic adjustment.

Evaluation of Different Fertilizer Types in the Suppression of Root Knot Nematode Infection on Sweet Potato (Ipomoea batatas) in Makurdi, Benue State

A field experiment was conducted at the Agronomy Teaching and Research Farm, Federal University of Agriculture Makurdi in the 2020/2021 planting season. To evaluate the effects of different fertilizer types in the control of root knot nematode of sweet potato. The experiment was laid out in a randomized complete block design (RCBD). The treatments were Liquid fertilizer (Super gro) and poultry dropping and control which were replicated three times. Before the treatments were applied, soil samples were collected for nematode extraction and the nematodes were extracted in the laboratory using the modified Bearmann tray technique. Super gro and geese droppings were applied at 2 weeks interval and 4 weeks interval. The results show a significant (p<0.05) reduction of root gall index, significant increase in root length, weight of roots and number of roots on the plots treated with fertilizer. This research work recommends the application of poultry droppings for the management of root knot nematode in sweet potato (Ipomoea batatas).

Endodontic pulp revitalization in traumatized necrotic immature permanent incisors: Early failures and long-term outcomes-A longitudinal cohort study.

AimThis prospective cohort study evaluates clinical and radiographical outcomes of endodontic pulp revitalization (PR) of traumatized necrotic incisors.MethodologyPulp revitalization was performed in 75 traumatized necrotic immature incisors from 71 patients. The radiographic outcome measures were continued root formation (width and length), root resorption, apex closure, periapical index, and root development stage. The clinical outcome measures were percussion pain, palpation pain, pathological tooth mobility, swelling, sinus tract, ankylosis, crown discolouration, response to pulp sensitivity test, and subjective pain. Treatment outcomes were categorized as a success based on the absence of clinical symptoms and when radiographic evidence was present for apical healing and continued root development. The performed statistical tests were repeated measures anova, pairwise comparisons of interactions (t‐test), McNemar's test, and linear regression model.ResultsIn 45 of 75 teeth (60%), PR was successful with the resolution of clinical and radiographic signs and continued root development. PR failed due to the absence of bleeding (n = 19) and persistent infection (n = 11). PR showed statistically significant increases in root length (11%), and dentinal wall thickness (30%), root maturation (pre‐operative 3.38 [CI 1.88; 4.88]; post‐operative 4.04, [CI 2.56; 5.52]) apical closure (71.4%), healing of pre‐operative apical periodontitis (100%), and healing of pre‐operative inflammatory root resorptions (100%). Three predictive variables for continued root maturation were identified – root development stage at entry (p = .0001, β 0.649), [CI 0.431; 0.867], trauma to the soft tissues (p = .026, β −0.012), [CI −0.0225; −0.015], and pre‐operative dentinal wall thickness (p = .009, β −0.001); [CI −0.001; 0.0001].ConclusionsOur findings indicate that PR provides satisfactory clinical and radiographical outcomes in traumatized necrotic incisors. The failed cases were related to lack of bleeding and persistent infections, indicating that new techniques are needed to improve the predictability of PR.

Do alternative scaffolds used in regenerative endodontics promote better root development than that achieved with blood clots?

The aim of this integrative review was to identify whether alternative scaffolds used in regenerative endodontics contribute to better root development, in relation to the increase in root length and thickness of dentin walls, compared with blood clot (BC) scaffolds. The literature search was conducted in PubMed, SciELO and Lilacs databases, using descriptors related to the topic. After applying the eligibility criteria, 11 articles were selected and analyzed according to the proposed aim. Five clinical and six in vivo studies, conducted in animals, compared different types of alternative scaffolds with BCs, with emphasis on platelet-rich plasma (PRP) and platelet-rich fibrin (PRF). All scaffolds, alternative or BC, promoted an increase in root length and dentin wall thickness, with varying percentages of increase between studies. In general, there was a significant increase in root length and dentin thickness promoted by PRF and PRP scaffolds, compared with BC. It was concluded that the majority of the scaffolds tested contributed to the increase in root length and thickness of dentin walls, with emphasis on PRF and PRP.

An Evaluation of Aluminum Tolerant Pseudomonas aeruginosa A7 for In Vivo Suppression of Fusarium Wilt of Chickpea Caused by Fusarium oxysporum f. sp. ciceris and Growth Promotion of Chickpea.

Chickpea wilt, caused by Fusarium oxysporum f. sp. ciceris, is a disease that decreases chickpea productivity and quality and can reduce its yield by as much as 15%. A newly isolated, moss rhizoid-associated Pseudomonas aeruginosa strain A7, demonstrated strong inhibition of Fusarium oxysporum f. sp. ciceris growth. An in vitro antimicrobial assay revealed A7 to suppress the growth of several fungal and bacterial plant pathogens by secreting secondary metabolites and by producing volatile compounds. In an in vivo pot experiment with Fusarium wilt infection in chickpea, the antagonist A7 exhibited a disease reduction by 77 ± 1.5%, and significantly reduced the disease incidence and severity indexes. Furthermore, A7 promoted chickpea growth in terms of root and shoot length and dry biomass during pot assay. The strain exhibited several traits associated with plant growth promotion, extracellular enzymatic production, and stress tolerance. Under aluminum stress conditions, in vitro growth of chickpea plants by A7 resulted in a significant increase in root length and plant biomass production. Additionally, hallmark genes for antibiotics production were identified in A7. The methanol extract of strain A7 demonstrated antimicrobial activity, leading to the identification of various antimicrobial compounds based on retention time and molecular weight. These findings strongly suggest that the strain’s significant biocontrol potential and plant growth enhancement could be a potential environmentally friendly process in agricultural crop production.

Selection and Characterization of Burkholderia spp. for Their Plant-Growth Promoting Effects and Influence on Maize Seed Germination

Burkholderia sp. is a bacterial genus extremely versatile in the environment and has been reported for a great potential to promote plant growth via different mechanisms. Here we evaluate the plant growth-promoting mechanisms in twenty-six Burkholderia strains. Strains were evaluated for their ability to promote plant growth by means of: indole-3-acetic acid (IAA) production under different conditions of pH, salt stress and the presence or absence of L-tryptophan; exopolysaccharides (EPS) production and quorum sensing (ALH). The strains were also characterized in terms of their genetic variability and species identification through Sanger sequencing. Then, the bacteria most responsive in the greatest number of plant-growth promotion mechanisms were selected for a corn seed germination test. All bacteria synthesized IAA in medium with 0.0 or 5.0 mM of L-tryptophan in combination with either 1 or 5% of NaCl, and pH values of either 4.5 or 7.2. The EPS production was confirmed for 61.54% of the bacterial strains. Quorum sensing also occurred in 92.3% of the selected bacteria. The Jaccard similarity coefficient revealed 16 clusters with high genetic variability between bacterial strains. Bacterial strains were assigned to seven species: B. anthina, B. cepacia, B. gladioli, B. ambifaria, B. graminis, B. heleia, and Burkholderia spp. The corn seed bacterization did not affect the germination velocity index (GSI), as well as the first count of germinated seeds (FC). However, inoculations formulated with B. heleia strain G28, B. gladioli strain UAGC723, and B. graminis strain UAGC348 promoted significant increases in root length, seedling height and fresh and dry seedling phytomass, respectively. These results indicate the high biotechnological potential of several strains in the genus Burkholderia sp. as seed inoculants, favoring germination and seedling initial development.

A Prospective Study of Long-Term Regenerative Endodontics Outcomes of Necrotic Immature Permanent Teeth: An 8-Year Follow-Up.

For the management of necrotic immature teeth, regenerative endodontics offers the advantage of further root lengthening, thickening of dentin wall, and apical closure. This prospective study aimed to evaluate the long-term outcome of regenerative endodontics in immature necrotic permanent teeth. A total of 23 immature roots were medicated by triple antibiotic paste. After 21 days, bleeding was induced by over-instrumentation, and then mineral trioxide aggregate and coronal restoration were applied. Patients were scheduled for clinical and radiographic follow-up for 8 years. The radiographic changes of root dimensions were assessed using the ImageJ Plugin and statistically analyzed by Kruskal–Wallis test at a 95% confidence level. For qualitative evaluation, images were overlapped and analyzed using Photoshop software. All teeth were asymptomatic one month after the treatment. All teeth (n = 18) with preoperative periapical radiolucency showed complete resolution within 6–9 months. Recall rate at two, three, and eight years was 69.6%, 56.5%, and 34.8%, respectively. Continuous root development with a significant increase in root length and thickening of dentin wall accompanied by a significant decrease in apical canal diameter was seen at the end of the observation period (p < 0.001). In conclusion, the long-term outcome of regenerative endodontics revealed successful clinical and radiographic results with appropriate case selection.

Performance of Actinobacteria isolated from rhizosphere soils on plant growth promotion under cadmium toxicity

This work aimed to evaluate the potential use of plant growth-promoting actinobacteria (PGPA) for enhanced cadmium (Cd) phytoremediation and plant growth. Forty-two actinobacteria were isolated from rhizosphere soils in Thailand. Among isolates tested, only Streptomyces phaeogriseichromatogenes isolate COS4, showed the high ability to produce siderophores as a plant growth stimulant and had a strong Cd tolerance potential. The significance of siderophores production and Cd tolerance ability under different Cd concentrations suggests the potential of isolate COS4 to work effectively. Plant culture revealed that the significant increase in root length, root to tip length, and total dried weight of sunflower were obtained after 2 h incubation of sunflower seeds with isolate COS4. The efficiency of Cd uptake was found to range between 42.3 and 61.3%. Translocation factor results confirmed that plant growth promoting S. phaeogriseichromatogenes isolate COS4-assisted phytoremediation can be considered as Cd absorbents for the restoration of polluted sites due to high translocation values.

Three-dimensional qualitative and quantitative analyses of the effect of periradicular lesions on the outcome of regenerative endodontic procedures: A prospective clinical study

Qualitative and quantitative evaluation of the outcomes of regenerative endodontic procedure (REP) on human immature necrotic teeth with apical periodontitis using cone-beam computed tomography (CBCT) MATERIALS AND METHODS: Immature permanent teeth (n = 50) with necrotic pulp and periradicular pathosis were treated with a cell-homing concept-based REP. Following the procedure, a limited field-of-view CBCT scan was obtained. At each recall session (6, 12, 18 months), clinical tests were performed, and a digital periapical radiograph was taken. When significant radiographic changes were evident in the follow-up, a final CBCT scan was taken for qualitative and quantitative assessment. These initial and follow-up CBCT scans were assessed for quantification of changes in root length, pulp space diameter and periradicular lesion size. The data were statistically analysed using t test, one-way ANOVA, post hoc test and paired t test (P = 0.05). Of the teeth, 94.6% were clinically successful based on the lack or regression of signs and symptoms after 48 months follow-up. REP resulted in a statistically significant increase in root length, decrease in pulp space diameter and periradicular radiolucency (P < 0.05). CBCT images illustrated various patterns of root maturation including an increased thickening of the canal walls and continued root maturation (37.1%), continued root development with the apical foramen remaining open (57.1%), severe calcification (obliteration) of the canal space (2.9%) and hard tissue barrier formation in the canal space between the coronal plug and the root apex (2.9%). This study highlighted that the expected outcome of radiographic root development was less predictable when immature permanent teeth with periradicular pathosis were treated with REP. The size and extent (expansion/destruction of the cortical plate) of periradicular lesions and abscesses influence the outcome of REP. These factors must be taken into consideration during treatment planning.

Binary mixture of nanoparticles in sewage sludge: Impact on spinach growth

Present study carried out pot experiments and evaluated effects of single and binary mixture of nanoparticles (exposed via sludge as soil conditioner) on spinach plant. Exposure of Ag2O nanoparticles (NPs) (1 and 10 mg/kg soil-sludge) did not show significant reduction in plant as compared to control. On the other hand, TiO2 NPs (exposed as single and in binary mixture) resulted in significant increase in root length (29% and 37%) and fresh weight (60% and 48%) at highest exposure concentration. Total chlorophyll content decreased for Ag2O and binary mixture (7% and 4%, respectively) and increased for TiO2 (5%) at 10 mg/kg soil-sludge. The toxic interaction between Ag2O and TiO2 NPs was additive at both exposure concentrations. Ag2O NPs had higher tendency of root surface adsorption than TiO2 NPs. Metal content in spinach leaves at highest exposure concentration was Ag: 2.6 ± 0.55 mg/g plant biomass(for Ag2O NPs) and 1.02 ± 0.32 mg/g plant biomass (for Ag2O + TiO2 NPs) and for Ti: 1.12 ± 0.78 (for TiO2 NPs) mg/g plant biomass and 0.58 ± 0.41 mg/g (for Ag2O + TiO2 NPs). The inadvertent ingestion of NPs- contaminated spinach resulted in projected daily intake (DI) of Ag and Ti for different age-mass classes (child to adult) exceeding the oral reference dose for toxicity during oral ingestion. In conclusion, we report no acute toxicity of single and binary mixture of NPs to spinach but significant accumulation of Ag and Ti metals in spinach leaves. There are high chances that ingestion of spinach grown in such environment might lead to human health risks.

The effect of laboratory samples of new biological products and their mixtures with organomineral fertilizers on growth and development of winter wheat and sunflower plants

Currently, there is an active development of environmentally friendly methods of farming. However, the range of products for this type of farming system is limited. Growth stimulation is one of the mechanisms ensuring plant resistance to diseases that reduce crop yields. The aim of the work is to study the effect of laboratory samples of new biological products based on B. subtilis BZR 336 g, B. subtilis BZR 517, P. chlororaphis 245 F strains and organo-mineral fertilizers PRK White Pearl Brown (WPB) and PRK White Pearl Universal” (WPU) on plant growth and development of plants, as well as study of the possibility of their joint use for subsequent inclusion in organic farming systems or integrated plant protection. Growthpromoting ability was assessed in winter wheat and sunflower plants grown in sand in a climatic chamber. As comparison variants there were seed treatment with water (control), chemical (Dividend Star, KS) and biological (Fitosporin-M, F, B. subtilis 26 D) standards. In two plant cultures there was an expected retardant effect of the chemical standard and the growth-promoting effect of the biological standard. Statistically significant data were obtained for such a parameter as the shoot length. On winter wheat, laboratory samples provided the shoot length of 24.1-25.2 mm (an addition to the control of 3.4-8.2%), organic and mineral fertilizers - 23.9-24.5 mm (2.6-5.2%), mixtures with WPU - 23.2-24.4 mm (-0.4-4.7%), mixtures with WPB - 24.1-25.9 mm (3.4-11.2%), a significant increase in root length was not observed in this culture. On winter wheat, it is advisable to use the studied products separately. Sunflower is more responsive to the action of laboratory samples. They provided a shoot length of 13.6-14.6 mm (20.9-27.0%) and a root of 9.2-10.2 mm (4.5-15.9%). Organo-mineral fertilizers provided a shoot length of 14.2-14.5 mm (23.5-26.1%) and the root length of 10.8 mm (22.7%). Mixtures with WPU provided shoot length of 14.7-15.4 mm (27.8-33.9%), mixtures with WPB provided shoot length of 11.9-14.5 mm (3.5-26.1%), and no significant increase in root length was noted. The data obtained indicate the presence in the laboratory samples of fungicidal biological products growth-promoting properties, which vary depending on the culture and additionally used organic and mineral fertilizers. To confirm the results, additional experiments are necessary. Research in this direction will allow the rational use of the studied means of protection and increase plant yields in systems of organic, ecologized and integrated farming, and can help reduce the pesticidal pressure on agrocenoses.Conflict of interest: the authors stated that there was no conflict of interest.

Carbon dioxide and precipitation alter Reaumuria soongorica root morphology by regulating the levels of soluble sugars and phytohormones

Significant increases in the concentration of carbon dioxide (CO2) have been shown to cause changes in precipitation patterns. These changes can severely affect the desert ecosystem. Therefore, it is important to investigate the impacts of CO2 concentration and precipitation on root morphology, so as to better predict the responses of desert ecosystems to the global climate change. For this purpose, we studied Reaumuria soongorica that is a dominant plant in the desert. Open top chambers were used to simulate changes in CO2 concentrations (350 μmol mol−1 and 700 μmol mol−1), to study the effects of 30% reduction in precipitation (W−), natural precipitation (W), 30% increase in precipitation (W+), and to study the synergistic effects of precipitation with CO2 on R. soongorica root morphological characteristics, endogenous hormones, and soluble sugars. Higher CO2 levels caused a significant increase in root length, mean root diameter, root biomass, total root surface area and total root volume regardless of alterations in precipitation; whereas the root–shoot ratio increased only with increased precipitation. Elevated concentrations of CO2 and decreased precipitation significantly increased the contents of fructose, sucrose, glucose and other soluble sugars in the R. soongorica root system. Meanwhile, the two environmental factors showed significantly synergistic effects on R. soongorica root morphology. With elevated concentrations of CO2, R. soongorica roots showed increased levels of endogenous hormones, including abscisic acid (ABA), indole-3-acetic acid (IAA) and gibberellin (GA). The effect of precipitation on hormone levels varied among hormones. IAA and GA levels were increased, regardless of changes in precipitation; ABA decreased with higher precipitation, whereas zeatin (ZT) increased with more precipitation. Correlation analyses indicated a significant correlation between root morphology and the levels of soluble sugars and endogenous hormone, as well as between the level of soluble sugars and the level of endogenous hormones. We conclude that future changes in climate conditions such as CO2 levels and precipitation will synergistically induce the root system of R. soongorica to undergo morphological and physiological alterations.

IMPACT OF PLANTING DENSITY, NITROGEN AND POTASSIUM FERTILIZER LEVELS ON YIELD AND QUALITY OF SUGAR BEET

Two field experiments were carried out at the experimental farm (Ghazala Village), Faculty of Agriculture, Zagazig University, Sharkia Governorate, during 2016/2017 and 2017/2018 seasons to study the influence of three planting densities, (28000, 35000 and 46666 plants/fad.) three levels of N fertilizer (80,100 and 120 kg/fad.) and two levels of potassium fertilizer (24 and 48 kg k2O/fad.) on yield and its attributes as well as quality of sugar beet grown in clay soil. Results of combined analysis illustrated that, decreasing planting density from 46666 to 35000 or 28000 plants/ fad., significantly increased root length, root diameter and fresh root weight g/plant; on the other hand the highest planting density (46666 plants/fad.) produced higher sucrose, extractable sugar percentages, sugar and recoverable sugar yields/fad., than low or medium densities. Raising N fertilizer levels significantly affected yield and its attributes as well as quality of sugar beet. Where, the results of the combined analysis indicated that, each increment of nitrogen fertilizer level from 80 up to 120 kg N/fad., cm was accompanied with a significant increase in root length, root diameter, fresh root weight/plant, root and recoverable sugar yields/fad., but significantly decreased sucrose (%). Data of combined analysis also revealed that application of 48 kg K2O/fad., significantly increased root yield attributes i.e., root length root diameter (cm), fresh root weight g/plant, sucrose, extractable sugar percentages, as well as, root and recoverable sugar yields ton/fad., compared with supply of 24 kg K2O/fad. Interactions between the studied factors (according to the combined analysis) indicated that the highest root yield (ton/fad.) was achieved when sugar beet was sown with the highest plant density of 46666 plants/fad., and fertilized with 120 kg N/fad. As well as, the highest value of root diameter (cm) was achieved under the application of 120 kg N/fad., and addition of 48 kg K2O/fad., while, the interaction between planting densities and potassium fertilizer levels had no significant effects on all studied traits.

Fungal endophytes from medicinal plants: growth promotion in Oryza sativa L. and Cicer arietinum L.

In the present investigation, four endophytic fungi were isolated from two medicinal plants from two medicinal plants and identified using molecular technique and tested the efficacy of four isolates on the growth of Cicer arietinum and two varieties of rice (Sarath and Gomati). The molecular characterization using amplification of internal transcribed spacer (ITS) region of fungal ribosomal DNA (rDNA) reveals four fungi namely Diaporthe phaseolorum, Penicillium oxalicum, Fusarium sp. and Syncephalastrum monosporum. The efficacy of isolates on the growth of plants indicated that there was significant increase in shoot length, root length and shoot dry weight with inoculation of D. phaseolorum, P. oxalicum and Fusarium sp. on Sarath variety of rice. Significant increase in shoot length and root dry weight was observed in Gomati rice variety with the inoculation of D. phaseolorum, P. oxalicum and Fusarium sp. Again there was significant increase in root length, shoot dry weight and root dry weight with inoculation of D. phaseolorum, P. oxalicum and Fusarium sp. on the growth of C. arietinum. However, no significant difference was observed between S. monosporum and uninoculated treatment on the growth of rice variety Gomati and C. arietinum. The results indicated that out of four, P. oxalicum, Fusarium sp. and D. phaseolorum were better plant growth promoting endophytic fungi.

Genotype-specific response of Foeniculum vulgare grain yield and essential oil composition to proline treatment under different irrigation conditions

Drought stress is a major environmental stress which severely affects growth, yield, as well as quality and quantity of crop products. Proline as a multifunction amino acid has a crucial role in ameliorating of drought stress. In order to study the effect of external proline on the response of fennel to drought stress, three fennel genotypes (namely Urmia, Shiraz, and Kerman) were exposed to two irrigation regimes (drought stress and non-stress control) and two levels of foliar-applied proline (0 and 20 mM) in a pot experiment. Drought led to significant decreases in umbels/plant, plant height, 1000-grains weight, harvest index, above-ground dry mass, grain weight and grain and dry mass WUE, root volume, root fresh and dry mass, ratio of shoot/root, grains and stems essential oil weight/plant and significant increases in root length and grains limonene content. Foliar-applied proline led to notable increases in harvest index and grain essential oil weight in the presence of drought. It also led to increases in umbels/plant, 1000-grains weight, harvest index, above-ground dry mass, grain weight and grain and dry mass WUE and ratio of shoot/root in Urmia and Shiraz genotypes. Anethole, limonene, fenchone, estragole and α-pinene were the main essential oil constituents in both grain and stems. Grain fatty acid and phytosterol compositions were not affected by experimental treatments. It may be concluded that drought stress suppresses fennel growth and grain weight, but foliar-applied proline is potent to mitigate the adverse reaction through increasing growth, grain weight/plant, WUE and grains limonene content in genotypes such as Urmia and Shiraz.

Genetic diversity and antagonistic activity of plant growth promoting bacteria, isolated from tea-rhizosphere: a culture dependent study

Microbial activity in root environment is responsible for plant nutrition, growth and defence. The objective of this study is to analyse the plant growth promoting and antagonistic activity rendered by the rhizospheric bacteria of tea plant. In this study, 292 bacterial isolates were screened for indole acetic acid (IAA) production, phosphate solubilisation, ammonia production, chitinase production and protease production. Among all the bacterial isolates, 58 isolates were able to elicit minimum four plant growth promoting rhizobacteria (PGPR) traits, which were further analysed quantitatively for hydrogen cyanide (HCN), siderophore production and antagonistic activity. Based on the plant growth promoting potential scores and principle component analysis, 12 samples were further screened for the study of salt tolerance and antifungal activity profile against tea fungal pathogens (Rhizoctonia solani, Fomes lamenensis, Corticium invisum). The identity the isolates was revealed by 16s rDNA sequence analysis. Six isolates (n63, k32, n61, 31k, n57, n56) showing efficient PGPR traits were evaluated for growth promotion studies on rice seedlings. Isolate n61 (Bacillus cereus) induced significant increase in root length (9.85 mm), shoot length (7.86 mm), germination percentage (92.44) and vigour index (1566.42) in rice seedlings. Fresh bio mass was significantly higher in 31k (Pseudomonas putida) (81.33 mg) followed by n61 (Bacillus cereus) (80.84 mg) and dry mass was higher in n63 (Bacillus pseudomycoides) (15.84 mg) followed by n61 (Bacillus cereus ) (15.82 mg) while compared with control and the other isolates selected for in vitro growth experiments. ANOVA analysis showed significant (P<0.05) increase compared with control, indicating that, bacterial isolates are potent for plant growth promotion and productivity.

Phytoremediation of Light Crude Oil by Maize (Zea mays L.) Bio-Augmented with Plant Growth Promoting Bacteria

ABSTRACTThe aim of this study was to evaluate the converged effect of maize and plant growth promoting bacteria on degradation of petroleum hydrocarbons under axenic conditions. Artificially spiked sand with 10 g kg−1 light crude oil was planted with maize alone and in combination with eight bacterial isolates having plant growth promotion and bioremediation potential to observe the dissipation of petroleum hydrocarbons. Results showed remarkable suppression of maize growth and biomass production due to phytotoxicity of the crude oil contamination. However, bio-augmentation of plants with bacteria having ACC-deaminase activity significantly compensated the reduction in plant growth compared to uninoculated plants. The results revealed that plants bio-augmented with PM32Y exhibited significant increase in root length (75%), plant height (74%), and biomass (67%) as compared to uninoculated plants after 60 days of planting. The same bacterium in convergence with maize caused 43% degradation of petroleum hydrocarbons as compared to the unplanted and uninoculated control. Amplification, sequencing and phylogenetic analysis of 16S rRNA gene sequence identified PM32Y bacterium as Bacillus subtilis strain. It is concluded that bio-augmentation of plants with plant growth promoting bacteria having bioremediation potential and ACC-deaminase activity can successfully be used in phytoremediation of petroleum hydrocarbons.

Regenerative Endodontics Versus Apexification in Immature Permanent Teeth with Apical Periodontitis: A Prospective Randomized Controlled Study

IntroductionThe aim of the study was to compare the outcomes of regenerative endodontic treatment (RET) and apexification on immature permanent teeth with pulp necrosis and apical periodontitis. MethodsA total of 118 patients (118 teeth) were recruited and randomly assigned to either RET or apexification treatment. Each treatment group was divided into 2 subgroups according to the etiology: dens evaginatus or trauma. Clinical symptoms and complications were recorded, and cone-beam computed tomographic imaging with a limited field of view was used to measure the change of root length, root thickness, and apical foramen size at the 12-month follow-up. The t test/rank sum test and Fisher exact test were applied to compare the change of root morphology between RET and apexification. ResultsOne hundred three of 118 cases were completed at the 12-month follow-up. The survival rate was 100% for both treatment groups. All cases were asymptomatic with apical healing. The RET group showed a significant increase in root length and root thickness compared with the apexification group (P < .05). In the RET group, the cases caused by dens evaginatus achieved increased root length and root thickness compared with those caused by trauma (P < .05). ConclusionsRET and apexification achieved a comparable outcome in regard to the resolution of symptoms and apical healing. RET showed a better outcome than apexification regarding increased root thickness and root length. The etiology had an impact on the outcome of RET. Dens evaginatus cases showed better prognoses than trauma cases after RET.

The impact of rapid maxillary expansion on maxillary first molar root morphology of cleft subjects

The aim of this prospective cohort study was to determine the effects of rapid maxillary expansion (RME) on the first molar roots of cleft lip and palate subjects along different root development stages. Thirty participants with unilateral cleft lip and palate were divided into three groups (n=10), according to the type of expander used: Hyrax, iMini and Fan-type. A cone beam CT scan was performed before (T1) and 3months after stabilization of the appliance (T2). Measurements of root lengths of the first permanent maxillary molars were taken to evaluate root development and external apical root resorption (EARR). Roots presenting open apexes before treatment exhibited a statistically significant increase in root length after treatment (P<.001). Conversely, there were no significant changes in the root length of roots that had closed apexes at the beginning of treatment (P>.05). Furthermore, there were no differences among groups, or correlation between cleft side and gender was found vis-à-vis to changes in the root length (p>.05). Orthopaedic forces of RME were neither able to interrupt the root development process nor to cause EARR in cleft subjects. As the RME is the most common orthodontic procedure in patients with cleft lip and palate, understanding its impact on dental structures is of fundamental importance.