Plant growth promoting rhizobacteria (PGPR) and their eco-friendly strategies for plant growth regulation: a review

As a natural engineer, Plant Growth Promoting Rhizobacteria (PGPR) play an important role in increasing plant growth, yield and enhancing plant tolerance to stressful conditions. These beneficial bacteria take up their position in the rhizosphere, around the plants’ root tissues. They may be in, or on their host tissues and help to provide nutrients to their host plants. For sustainable agriculture, PGPR transmit their extensive assistance in ecosystem management, soil structure maintenance, stress management and plant morphology and physiology modulation in an environmentally friendly manner. Plant- PGPR interactions also stimulate nutrient acquisition and accumulation, improve plant performance and enhance plants’ tolerance to abiotic and biotic stresses. Beside these, PGPR are good biofertilizers and safe for our environment. Nanotechnological advances with PGPR applications are important today to increase the impact of PGPR in agriculture. Undoubtedly, PGPR concept is intimately involved with agriculture, horticulture, forestry and they are too enough to establish a vibrant environment. In this review we have focused on the versatility of PGPR-their performance and aimed to address some future prospects of PGPR as an eco-friendly tool for plant growth regulation

Investigation on microfloral association in the roots of Macrotyloma uniflorum (Lam.) Verdc., a medicinally important tropical pulse-crop and their possible applications for crop improvement: a review

Macrotyloma uniflorum (Lam.) Verdc., an economically important medicinal plant belongs to the Leguminosae family. Being Afro-Asian origin, the plant has long tradition of uses. It is primarily used for its antiurolithiatic property although it has other medicinal uses. Being Leguminosae member, this plant can form rhizobial nodules and mycorrhizal associations. The rhizobia obtained from this plant are mostly belonged to Bradyrhizobium sp. Although, Rhizobium pusence has also been reported. Microbes as biofertilizers can be used to increase yield of this plant, as well as there is great potential for utilizing the microbes derived from this plant. In this review we aim to describe the plant M. uniflorum - its taxonomic characteristics, economic uses, putative active constituents, and beneficial microflora along with their applications

Drought stress tolerance in rice: a critical insight

Drought is currently a serious threat for farming especially in rice cultivation, due to its substantial water requirements throughout its lifecycle. Drought is one of the major environmental constraints disrupting the growth and yield of rice plants, affecting them at physiological, morphological, biochemical and molecular levels. Global climate change exacerbates this issue, leading to substantial economic losses. As rice is a major food crop worldwide, the demand for rice production is increasing in tandem with the expanding human population. Consequently, it has become imperative to utilize drought-prone areas for agriculture and develop drought-tolerant rice genotypes. In addition to conventional breeding methods, the application of multi-omics approaches proves most effective in meeting the need to enhance drought tolerance in rice plants. Protective mechanisms, such as morphological adaptation, physiological acclimatization, cellular adjustments and antioxidant defense, play pivotal roles in helping plants overcome drought stress. Plant-microbial interactions are important for plants to overcome drought-induced adversities. Furthermore, applications of conventional approaches, omics approaches and nanotechnology are very promising for generating climate smart agriculture. Our aim in this review is to focus on drought stress tolerance in rice including drought-tolerant rice genotypes, their adaptation mechanisms, the unveiling the genes, transcription factors, microRNAs (miRNA) involved, microbial assistance and exploring approaches to mitigate drought stress in rice plants. The present review might throw some light on understanding the mechanism of drought stress tolerance in rice, including its molecular crosstalk and biochemical dynamics, for future researchers

Endophytic microbes and their diverse beneficial aspects in various sectors: A critical insight

Endophytes are ubiquitous and grow in plant tissues without causing any harmful effects to the host. They include different groups of microorganisms such as bacteria, fungi and actinomycetes. Along with the host plants, the existing endophytes also co-evolve after a long relationship between them. Host plant-endophyte interaction is similar to that of plant growth promoting microbes as they induce the growth of the host plant and increase resilience against biotic and abiotic stresses. The interaction of plant endophytes at the molecular level and the effect of endophytes on host gene expression is a new field of study and are still rarely explored. Endophytes act as a promising resource of many invaluable bioactive secondary metabolites. Some of these bioactive compounds include alkaloids, polyphenols, sterols, xanthones, terpenoids, flavones, coumarins, polyketides, quinones, saponins, tannins, benzopyrones, dibenzofurans. These secondary metabolites are beneficial for agriculture, industrial and pharmacological purposes. As endophytes have beneficial effects in sustainable agriculture, plant disease management, pharmaceuticals, industry and environmental management in an eco-friendly way, thus improving the strategy of application of endophytes as biological agents in every aspect of our life is a very challenging field of research. Our aim in this present review is to focus on plant-endophyte interactions and their various dimensions in order to address some future possibilities for expediting the bioactive secondary metabolite production

Spontaneous Combustion in Relation to Drying of Low Rank Coal

The water molecules associated with coal play a significant role in spontaneous ignition and combustion of coal. This paper deals with studies to evaluate the impact of moisture content on crossing point temperature (CPT) and ignition point temperature (IPT) of some low-rank coal and lignite after various stages of drying. Experimental data suggest (i) existence of critical moisture content value determining the propensity of a particular coal toward self-heating and (ii) content of moisture and nature of oxygen-bearing functional groups to be the most influencing factors in self-heating. The auto-oxidation cum self-heating characteristics of coal become more conducive with increase in the ratio of quantity of hydroxyl to carboxyl functional groups. The FTIR studies further corroborate that the initial stages of auto-oxidation cum self-heating occur presumably at the surface of the coal

Spontaneous Combustion in Relation to Drying ofLow Rank Coal

The water molecules associated with coal play a significant role in spontaneous ignition and combustion of coal. This paper deals with studies to evaluate the impact of moisture content on crossing point temperature (CPT) and ignition point temperature (IPT) of some low-rank coal and lignite after various stages of drying. Experimental data suggest (i) existence of critical moisture content value determining the propensity of a particular coal toward self-heating and (ii) content of moisture and nature of oxygen-bearing functional groups to be the most influencing factors in self-heating. The auto-oxidation cum self-heating characteristics of coal become more conducive with increase in the ratio of quantity of hydroxyl to carboxyl functional groups. The FTIR studies further corroborate that the initial stages of auto-oxidation cum self-heating occur presumably at the surface of the coal

An Autopsy of Spontaneous Combustion of Lignite

The increasing demand of lignite in the power sector has led to a renewed interest to study the possibilities of spontaneous combustion behavior. Bulk storage of lignite with unknown histories of their proneness to self-ignition phenomena has become a concern in their selection. The present evaluation has been directed to delve into the fundamentals of the heat transfer process, to understand the complexity of the spontaneous combustion process, to recognize the multitude influences of moisture as heat and mass transfer agent, and to look into their role in the initiation of coal–oxygen reactions. The roles of moisture and oxygen at various temperature levels have been examined and their possible mechanism has been reviewed. Cause of significant delay to catch fire in the bed of lignite stack even after attaining critical temperature (>70 °C) and some anomalous behavior observed during low-temperature oxidation of lignite has been explained in light of chemical structural parameters

Studies on Preparation of adsorbent Precursor From Coal; Using Oxidative Technique

Studies on converting a low rank high ash Lingaraj open cast project coal of Mahanadi Coalfield Limited, India to an adsorbent via its structural modification through partial oxidation have been carried. Oxidation studies on high ash low rank coal from this Mahanadi coalfield was carried out at 150 ± 5ºC for different time durations, namely 24 hr, 50 hr, 216 hr. similar studies using varying nitric acid concentration, namely 1N, 2n, 3n and 4N were also carried out. The oxidized coals thus obtained were characterized in terms of elemental composition, oxygenated functional groups, like COOH and OH, CO2 surface area, etc. it was found that consequent upon oxidation, the surface area decreased in both the cases, that is on air oxidation as well as on nitric acid oxidation. FTIR spectra of 24 hr, 50 hr, 216 hr air oxidized coals were recorded and compared. It was found that there has been a gradual decrease in aliphatic- CH groups with increase in duration of aerial oxidation along with formation of –COOH and > CO groups. The characterization of mineral matter constituents present in coal during heating was considered to be important because these may form a wide variety of newly formed phases. Hence FTIR spectra of mineral matter constituents of raw and oxidized coal sample were also recorded and compared. It was observed that there have been no significant changes in the kaolinite structure during aerial oxidation. A possible hypothesis has been forwarded to correlate the progressive decrease in surface area with the physic-chemical properties of the oxidized coals. The above studies have been carried out keeping in view of preparation of adsorbent precursor

A Semi-Analytic Approach for Direct Slicing Of Free Form Surfaces for Layered Manufacturing Abstract Purpose of this paper

To develop an efficient Surface-Plane Intersection algorithm for direct slicing of free-form surfaces to be produced by layered manufacturing. Design/methodology/approach A semi-analytical method for direct slicing has been formulated and tested on Bezier and B-spline surfaces commonly used in CAD modeling. This method solves for the intersection points by a ‘root ’ finding procedure and establishes their connectivity, unlike the conventional ‘marching ’ procedures. Findings The proposed algorithm solves intersection contours between free form surfaces and planes. The solution procedure is efficient with respect to computational time (CPU time