Investigations on Temperature and Cultivar Variability in Microbial Dynamics and Enzyme Activity in Sweet Potato Rhizospheres | Chapter 2 | Geography, Earth Science and Environment: Research Highlights Vol. 8

Background: Sweet potato [Ipomea batatas (L.) Lam.] is an important root crop known for its nutritional, medicinal, industrial and economic values. It is the fourth most important root crop in terms of the quantity of production and ranks seventh in global food production.

Aim: To determine the influence of temperature on sweet potato yield, soil enzyme activity and composition of the microbial community in the rhizosphere during early growth stage-65DAP.

Study Design: The study was conducted as a Completely Randomized Design with a 2x2 factorial treatment arrangement of two temperatures and two cultivars —and four replications in time.

Place and Duration of Study: George Washington Carver Agricultural Experiment Station, Tuskegee University, Tuskegee Alabama, between February to December 2022.

Methodology: Two sweet potato cultivars, Beauregard and Whatley/Loretan, were planted and exposed to high (32/26°C) and optimal (28/22°C) diurnal temperatures in a plant growth chamber. Standard cultural practices for irrigation and fertilizer application were followed. The plants were harvested 65 days after planting (65 DAP) and rhizosphere samples from both cultivars were collected. The microbial composition, including bacterial 16S rDNA and fungal ITS (Internal Transcribed Spacer), was analyzed using a standard DNA-Based Quantitative Technique The extracellular enzymes, Acid Phosphatases (P-acid), β-Glucosidase (GLU), N-acetylglucosaminidase (β-NAG) and phosphodiesterase (DIEST) were analyzed using fluorometric microplate enzyme assays.

Results: Bacterial communities were dominated by phyla Acidobacteria and Proteobacteria, whereas fungi were dominated by the Ascomycota across the samples. Temperature significantly affected the abundance of some bacterial phyla (Proteobacteria, Firmicutes, Verrucomicrobia and Chloroflexi) and all identified fungal phyla (Ascomycota, Mucoromycota, and Entomophthoromycota). Cultivars affected bacterial Phylum Gemmatimonadetes and fungi phyla Mucoromycetes and Ascomycota, with their higher relative abundances found in Whatley/Loretan than in Beauregard. There were significant interactions between temperature and cultivars for bacteria phyla Acidobacteria, Verrucomicrobia, Firmicutes and Fungi Entomophthoromycota. Additionally, high temperatures influenced the activities of key soil enzymes—acid phosphatase, β-glucosidase, and β-1,4-N-acetylglucosaminidase—in the rhizosphere of sweet potato, irrespective of cultivars.

Conclusion: The bacterial and fungal populations and activities of key soil enzymes in the rhizosphere of Whatley/Loretan and Beauregard sweet potato cultivars were significantly impacted by high temperatures. These enzymes play a crucial role in the decomposition of organic matter, as well as phosphorus (P), nitrogen (N), and carbon (C) cycling, thereby regulating nutrient availability for plant uptake.

 

Author (s) Details

Devotha Mwazembe
College of Agriculture, Environment and Nutrition Sciences and G. W. Carver Agricultural Experiment Station, Tuskegee University, Tuskegee AL 36088.2, United States.

 

D.G. Mortley
College of Agriculture, Environment and Nutrition Sciences and G. W. Carver Agricultural Experiment Station, Tuskegee University, Tuskegee AL 36088.2, United States.

 

R. Shang
College of Agriculture, Environment and Nutrition Sciences and G. W. Carver Agricultural Experiment Station, Tuskegee University, Tuskegee AL 36088.2, United States.

 

R, O, Ankumah
College of Agriculture, Environment and Nutrition Sciences and G. W. Carver Agricultural Experiment Station, Tuskegee University, Tuskegee AL 36088.2, United States.

 

O. Idehen
College of Agriculture, Environment and Nutrition Sciences and G. W. Carver Agricultural Experiment Station, Tuskegee University, Tuskegee AL 36088.2, United States.

 

J. Quansah
College of Agriculture, Environment and Nutrition Sciences and G. W. Carver Agricultural Experiment Station, Tuskegee University, Tuskegee AL 36088.2, United States.

 

S. Fall
College of Agriculture, Environment and Nutrition Sciences and G. W. Carver Agricultural Experiment Station, Tuskegee University, Tuskegee AL 36088.2, United States.

 

V. S. Santhosh Mithra
ICAR-Central Tuber Crops Research Institute, Sreekariyam, Thiruvananthapuram, 695017, Kerala, India.

 

Please see the book here:- https://doi.org/10.9734/bpi/geserh/v8/4647

Thermal Deformation and Strength of Materials for Heat-shielding Coatings of a Spacecraft on the Trajectory of Descent from Orbit| Chapter 8 | Techniques and Innovation in Engineering Research Vol. 2

 The basis for a fundamental understanding of the process of material interaction with a medium is the agreement between experimental research and the actual operating conditions of a specific model or structure. Thermal Shield Materials (TSMs) are designed based on certain requirements, such as the characteristics of heating and material destruction under the least amount of shield weight. The more useful space load it can give, the lighter it must be. Since the thermal shield serves as a missile's ballast weight, it is only natural to want to lower the weight of TSMs without sacrificing their capacity to reliably perform their thermal shield role. Utilizing calculations based on the physical characteristics of materials discovered during conditions replicating a spacecraft's re-entry into the atmosphere, the performance of thermal shield structures was examined. The dependence of the temperature T of a thermal shield side surface on the period of descent in dense air layers serves as the basis for physical modelling of the natural conditions of thermal shield use (temperature, heating/cooling rate, composition, and pressure of gas medium). A thermal barrier was made composed of a laminated fibreglass shell with a phenol-phormaldehyde matrix. Investigations were done on temperature-dependent mechanical and thermophysical characteristics. By using numerical analysis, elasticity theory, and thermal conductivity equations to solve a 3D problem, it is possible to characterise the thermally stressed state of a cylindrical shield that is being impacted by a high-temperature gas flow. According to the results, the maximum compression stresses in a fibreglass thermal shield shell are located close to the heated surface and are not higher than the material's strength limit at that temperature. A new, 30% lighter thermal protection system for the re-entry vehicle was proposed and put into practise as a result of the experimental and theoretical investigations that were conducted.

Author(s) Details:

Lyudmila I. Gracheva,
G. S. Pisarenko Institute for Problems of Strength, National Academy of Sciences of Ukraine, Kiev - 01014, Ukraine.

Please see the link here: https://stm.bookpi.org/TAIER-V2/article/view/8276