Beneficial Effects of Plant Growth Promoting Rhizobacteria,Arbuscular Mycorrhizal Fungi and Compost on Lettuce (Lactuca sativa) Growth Under Field Conditions

Two independent field experiments (2017 and 2019) were conducted to evaluate the effects of plant growth promoting rhizobacteria (PGPR), arbuscular mycorrhizal fungi (AMF; AMF1: Rhizophagus irregularis strain and AMF2: AMF consortium) and compost (Comp) in comparison to chemical NPK fertilizers on growth and yield of lettuce plants and soil properties. The biofertilizers-biostimulants were applied alone or in combinations and increased significantly the lettuce dry weight (DW), number of leaves, and yield compared to the control. In the first experiment, the highest plant DW was obtained by NPK, PGPR?+?AMF2?+?Comp and PGPR treatments recording an increase of 109, 109, and 95%, respectively, compared to the control plants. In the second experiment the highest plant DW was obtained by the NPK (77%), followed by Comp and PGPR?+?AMF1?+?Comp treatments increasing the plant DW by 52 and 51%, respectively, compared to the control. Concerning to lettuce yield, in the first experiment, the highest yields were obtained by NPK, PGPR?+?AMF2, PGPR?+?AMF1?+?Comp, PGPR, AMF2?+?Comp, AMF1?+?Comp and AMF2 treatments recording an enhancement of 68, 64, 63, 58, 57, 57, and 55%, respectively. In the second experiment, the application of NPK based fertilizers resulted in the highest yield (77%), followed by PGPR?+?AMF1?+?Comp, PGPR?+?AMF2?+?Comp, AMF1?+?Comp, and AMF2?+?Comp treatments, increasing the yield by 61, 61, 54, and 55%, respectively, compared to the control. Concerning the soil organic matter (OM), the applied treatments had significantly increased the amount of the OM compared to the control. The highest amounts of OM were obtained by the PGPR?+?AMF2?+?Comp treatment in the first experiment and the PGPR?+?AMF1?+?Comp treatment in the second experiment. The available phosphorus (P) was significantly increased by the application of all treatments. The highest records were obtained by the application of Comp, PGPR?+?AMF1 and PGPR?+?AMF1?+?Comp treatment after the first experiment. In the second experiment, the highest amount of P was obtained by PGPR?+?AMF2?+?Comp treatment. Application of biofertilizers-biostimulants in combination proved to be beneficial for the improvement of the tested culture yield.

     

Ascorbic Acid Enhances Growth and Yield of Sweet Peppers (Capsicum annum) by Mitigating Salinity Stress

Salinity is a crucial problem which has affected crop productivity globally. Ascorbic acid is considered helpful against abiotic stresses due to its powerful antioxidant potential. In the pot experiment, salinity stress (0, 35, 70, and 105?mM) was applied to sweet peppers in split doses after 20 days of transplantation. To mitigate the adverse effects of salinity, ascorbic acid (0, 0.40, 0.80, and 1.20?mM) was applied as foliar spray after a 6-day interval during vegetative growth. Sweet pepper plants sprayed with distilled water (control) recorded maximum plant height (cm), leaf area (cm²), number of branches, stem diameter (mm), number of fruit plant^?1, fruit diameter (cm), yield plant^?1 (g), and chlorophyll content (mg 100?g^?1), while the maximum polyphenol oxidase (PPO) activity (unit mg protein^?1 min^?1) and ascorbate peroxidase (APX) activity (unit mg protein^?1 min^?1) were recorded in plants treated with 70?mM NaCl application. Salinity stress beyond 70?mM significantly reduced all the studied parameters. An ascorbic acid concentration of 1.20?mM significantly mitigated the negative effects of salt stress and recorded maximum plant height (cm), number of leaves plant^?1, leaf area (cm²), number of branches plant^?1, stem diameter (mm), number of fruit plant^?1, fruit diameter (cm), yield plant^?1 (g), chlorophyll content (mg 100?g^?1), PPO activity (unit mg protein^?1 min^?1), and APX activity (unit mg protein^?1 min^?1). Hence, a 1.20?mM concentration of foliar ascorbic acid could be used in saline conditions up to 70?mM of sodium chloride (NaCl) for better growth, productivity, and enzymatic activity of sweet peppers.

     

Automation in Agriculture by Machine and Deep Learning Techniques: A Review of Recent Developments

Precision Agriculture - Recently, agriculture has gained much attention regarding automation by artificial intelligence techniques and robotic systems. Particularly, with the advancements in...     

Correction to: Automation in Agriculture by Machine and Deep Learning Techniques: A Review of Recent Developments

Precision Agriculture - A correction to this paper has been published: https://doi.org/10.1007/s11119-021-09824-9     

Application of coupled liquid chromatography–mass spectrometry in photolysis studies of the herbicide triflusulfuron‐methyl

The photochemical fate of the herbicide triflusulfuron‐methyl in aqueous solution under UV light (λ > 290 nm) was investigated. Nine photoproducts were detected and tentatively identified by LC/MS and LC/MS/MS analysis. The main routes of degradation involve the cleavage and/or contraction of the sulfonylurea bridge with the elimination of sulfur dioxide, which increases the acidity of the reaction medium. On the basis of the results obtained a photodegradation pathway is proposed. © 2001 Society of Chemical Industry     

Efficient in vitro multiplication in Ornithogalum ulophyllum Hand.-Mazz. from twin scale explants

Ornithogalum ulophyllum Hand.-Mazz. with beautiful white flowers is an important medicinal and ornamental plant of the Middle Eastern countries and need exploitation for commercial propagation. The study reports in vitro mass proliferation of bulblets achieved from twin scales and “in vitro regenerated bulblet” explants on MS medium supplemented with various concentrations of BAP–NAA. The best regeneration on twin scales and “in vitro regenerated bulblets” was obtained on MS medium containing 2 mg l⁻¹ BAP–0.5 mg l⁻¹ NAA and 2 mg l⁻¹BAP–1 mg l⁻¹ NAA, respectively. However, bulb scales seemed to be more potent for bulblet regeneration. A large number of the developing bulblets rooted on the regeneration medium. Remaining non-rooting bulblets were rooted on MS medium containing 1 mg l⁻¹ NAA. All plants were acclimatized in the environmental chamber for 4 weeks and were transferred to the greenhouse for flowering. Regenerated bulblets developed into morphologically normal plants.     

A comparison of the gelling of isubgol,agar and gelrite on in vitro shoot regeneration and rooting of variety Samsun of tobacco (Nicotiana tabacum L.)

Agar is being used to solidify media for plant tissue culture since long. Both purity and type of agar or gelling agent influence the behaviour and growth of tissues in culture. The study using leaf disc explants of variety Samsun of tobacco compares adventitous shoot regeneration on 0.5 cm × 0.5 cm leaf discs cultured on MSD4X2 medium and rooting on MSO medium gelled with different blends of agar–isubgol, gelrite–isubgol, phytagel–isubgol or isubgol singly. It was found that irrespective of some problems associated with isubgol gel, the maximum number of shoot per explant were recorded on MSD4X2 medium gelled with 7 g/l isubgol. The longest shoots were recorded on MSD4X2 medium gelled with 9 g/l isubgol. Likewise, the highest number of roots were also recorded on MSO medium gelled with 7 g/l isubgol. For a given quantity of a medium, agar, gelrite/isubgol blends are very cheap compared to agar used singly. Moreover, blends of agar/isubgol, gelrite/isubgol gelled at low temperatures indicated safe use of these gels for heat labile substances in genetic transformation or tissue culture experiments. The results emphasized the potential of the isubgol used singly or in combination with agar and gelrite for economic commercial application, replacing the costliest, though not indispensable, gelling agent agar.     

Concurrent vaccination of goats with foot and mouth disease (FMD) and peste des petits ruminants (PPR) booster vaccines

Foot and mouth disease (FMD) remains subclinical and self-limiting in small ruminants, but risk of spread of infection to susceptible cohorts is of great epidemiological significance; therefore, small ruminants must be included in vaccination campaigns in FMD endemic regions. Three groups of goats already immunized against peste des petits ruminants (PPR) were vaccinated with FMD and PPR vaccines alone or concurrently. The specific antibody response against three FMD virus strains and PPR virus were evaluated by competitive enzyme-linked immunosorbent assay (cELISA). Goats concurrently vaccinated with PPR + FMD vaccines had significantly (p < 0.05) higher antibody titers to two serotypes of FMD virus at 28, 45, and 60 days post-immunization compared to goats vaccinated with FMD vaccine alone, while goats vaccinated with PPR vaccines alone or PPR + FMD vaccines concurrently showed similar antibody kinetics against PPR virus up till 60 days post-vaccination. Overall, antibody kinetic curves for all three tested strains of FMD virus and PPR virus were similar in vaccinated groups during the course of experiment.     

Sperm preparation through Sephadex™ filtration improves in vitro fertilization rate of buffalo oocytes

Routinely, swim‐up method is used to separate high‐quality sperm; however, long processing time and close cell‐to‐cell contact during the centrifugation step are inevitable elements of oxidative stress to sperm. The objective was to evaluate Sephadex^? and glass wool filtration to separate motile, intact and viable sperm for in vitro fertilization in buffalo. The cumulus–oocyte complexes (COC s) were collected from ovaries of slaughtered buffaloes by aspiration and matured for 24 hr in CO ₂ incubator at 38.5°C and 5% CO ₂. Matured COC s were rinsed twice in fertilization TALP and placed in the pre‐warmed fertilization medium without sperm. Cryopreserved buffalo semen was thawed at 37°C for 30 s and processed through Sephadex^?, glass wool filtration and swim‐up (control). Total and motile sperm recovery rates were assessed, resuspended in fertilization TALP and incubated for 15–20 min in CO ₂ incubator. Samples prepared by each method were divided into two aliquots: one aliquot was studied for sperm quality (progressive motility, membrane integrity, viability, liveability), while the other was subjected to co‐incubation with sets of 10–15 in vitro matured oocytes. Data on sperm quality were analysed by ANOVA , while in vitro fertilizing rates were compared by chi‐squared test using SPSS ‐20. Least significant difference (LSD ) test was used to compare treatment means. Glass wool filtration yielded higher total and motile sperm recovery rate, while Sephadex^? filtration improved (p  <  .05) sperm quality (progressive motility, membrane integrity, viability, liveability). Sperm preparation through Sephadex filtration yielded higher in vitro fertilization rate in terms of cleavage rate compared to glass wool filtration and swim‐up (control). In conclusion, cryopreserved Nili‐Ravi buffalo sperm selected through Sephadex filtration showed improved quality and yielded better fertilization rates (cleavage rate) of in vitro matured/fertilized oocytes. Sephadex filtration could be a promising technique for use in in vitro fertilization in buffalo.