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The primary objectives of modern agriculture includes the environmental sustainability, low production costs, improved plants’ resilience to various biotic and abiotic stresses, and high sowing seed value. Delayed and inconsistent field emergence poses a significant threat in the production of agri-crop, especially during drought and adverse weather conditions. To open new routes of nutrients’ acquisition and revolutionizing the adapted solutions, stewardship plans will be needed to address these questions. One approach is the identification of plant based bioactive molecules capable of altering plant metabolism pathways which may enhance plant performance in a brief period of time and in a cost-effective manner. A biostimulant is a plant material, microorganism, or any other organic compound that not only improves the nutritional aspects, vitality, general health but also enhances the seed quality performance. They may be effectively utilized in both horticultural and cereal crops. The biologically active substances in biostimulant biopreparations are protein hydrolysates (PHs), seaweed extracts, fulvic acids, humic acids, nitrogenous compounds, beneficial bacterial, and fungal agents. In this review, the state of the art and future prospects for biostimulant seedlings are reported and discussed. Biostimulants have been gaining interest as they stimulate crop physiology and biochemistry such as the ratio of leaf photosynthetic pigments (carotenoids and chlorophyll), enhanced antioxidant potential, tremendous root growth, improved nutrient use efficiency (NUE), and reduced fertilizers consumption. Thus, all these properties make the biostimulants fit for internal market operations. Furthermore, a special consideration has been given to the application of biostimulants in intensive agricultural systems that minimize the fertilizers’ usage without affecting quality and yield along with the limits imposed by European Union (EU) regulations.

Drought stress is considered to be a major factor responsible for reduced agricultural productivity, because it is often linked to other major abiotic stresses, such as salinity and heat stress. Understanding drought-tolerance mechanisms is important for crop improvement. Moreover, under drought conditions, it is possible that growth regulators are able to protect the plants. Brassinosteroids not only play a regulatory role in plant growth, but also organize defense mechanisms against various tresses. This study aimed to evaluate the effect of brassinolide on physio-biochemical amendment in two contrasting cultivars (drought-tolerant RH 725, and drought-sensitive RH 749) of Brassica juncea under drought stress. Two foliar sprayings with brassinolide (10 and 20 mg/L) were carried out in both cultivars (RH 725 and RH 749) at two stages—i.e., flower initiation, and 50% flowering—under stress conditions. The results clearly revealed that the activities of antioxidative enzymes and non-enzymatic antioxidants (carotenoids, ascorbic acid, and proline) increased significantly in RH 725 at 50% flowering, whereas 20 mg/L of brassinolide showed the most promising response. The different oxidative stress indicators (i.e., hydrogen peroxide, malondialdehyde, and electrolyte leakage) decreased to a significant extent at 20 mg/L of brassinolide spray in RH 725 at 50% flowering. This study indicates that brassinolide intensifies the physio-biochemical attributes by improving the antioxidant system and photosynthetic efficiency in RH 725 at 50% flowering. It is assumed that enhanced production of proline, improvement of the antioxidant system, and reduction in the amount of stress indicators impart strength to the plants to combat the stress conditions.

Micronutrient deficiency, micronutrient malnutrition or hidden hunger is an increasingly severe global challenge for humankind. As wheat, rice and maize are the major staple food crops and are frequently consumed, it has become necessary to biofortify cereal crops with micronutrients, especially iron and zinc, in order to fulfill the requirements for better human health. Cellular and molecular mechanisms should be understood to maintain the homeostasis of micronutrients for increasing iron and zinc in plants. For metal ions uptake under deficiency conditions, plants have established strongly regulated two different strategies. Reduction-based strategy-I is followed by non-graminaceous monocots and dicots, whereas chelation-based strategy-II is followed by grasses. Strategy-II plants (graminaceous species) facing Zn, Fe and other micronutrient deficiency have mechanism of Fe chelation which depends on methionine derivative synthesis known as mugineic acid family phytosiderophores. Graminaceous plants also show quantitative and qualitative differences in MAs production. Wheat, rice and maize release only 2-deoxymugineic acid (DMA) in a very small fraction, thus due to low Fe availability these are reported as susceptible. Whereas, in low Fe availability, barley is reported more tolerant due to production of large amounts of different types of MAs, including MA, 3-epi-hydroxymugineic acid and 3-hydroxymugineic acid. In graminaceous plants, chelation and uptake of non-Fe metals are also facilitated by MAs, like Zn in the form of Zn (II)-MAs. Therefore, to solve the above problem, there is a requirement for alternative and eco-friendly technology such as plant growth-promoting rhizobacteria (PGPR) and organic farming practices to enhance zinc solubilization and its availability to plants.

Abstract An efficient and facile route for the synthesis of substituted imidazoles (10a-10g) has been developed by reacting substituted aldehydes (1–7), benzil (8) and ammonium acetate (9) in presence of solid supported acid catalyst viz. Rice Husk Ash.SO3H (RHA.SO3H) at room temperature. The purity of compounds was confirmed by melting point and thin layer chromatography. After the completion of reaction the crude product was recrystallized with ethylacetate to give pure samples (10a-10g) in good yield. All synthesized compounds (10a-10g) were characterized by 1HNMR and FTIR spectral techniques. The solid acid catalyst has been characterized by SEM, TEM and X-ray diffraction method. All synthesized compounds were tested in vitro herbicidal activity against Raphanus sativus L. seeds. The compounds (10a-10g) were also screened for their antifungal activity against Rhizoctonia solani and Aspergillus niger by poisoned food technique method. From bio evaluation data, it was found that compounds 10c and 10a were most active against Raphanus sativus L. seeds. Compound 4-(4,5-diphenyl-1H-imidazol-2-yl)phenol (10g) was found most active against R. solani fungus at highest concentration. Compound 2-(4,5-diphenyl-1H-imidazol-2-yl)phenol (10f) has shown maximum percentage inhibition i.e. 71.89 against A. niger at 200 µg/mL concentration.

Salt stress is one of the most brutal abiotic stresses that arrests crop survival and productivity. It affects various physiological, biochemical and metabolic processes in plants, depending on severity and duration of the stress. Plant adaptation or tolerance to salinity stress involves complex physiological traits, metabolic pathways, and molecular or gene networks. In response to high salinity stress, various genes get upregulated, the products of which are involved either directly or indirectly in plant protection. Some of the genes encoding osmolytes, ion channels, receptors, components of calcium signaling and some other regulatory signaling factors or enzymes are able to confer salinity tolerance, when transferred to sensitive plants. Overall, the susceptibility or tolerance to high salinity stress in plants is a coordinated action of multiple stress-responsive genes. Plants that grow under different soil conditions are usually inhabited by microbes which are beneficial for the enhancement of their salinity tolerance mechanisms. Microbes, either independently or by interacting with plants, synthesize some organic osmolytes and other substances which offer an adaptive strategy to salinity stress. The partnership of plants with nitrogen-fixing bacteria and arbuscular mycorrhizal fungi can serve as a second possible and sustainable strategy to increase crop yields in saline soil. A comprehensive understanding on how plants respond to salinity stress at different levels and an integrated approach of combining molecular tools with physiological and biochemical techniques are inevitable for the development of salt-tolerant varieties of plants in salt affected areas.

Rice straw, a by-product of the rice production is mainly used as a source of feed for ruminant livestock is the major forage in rice-producing areas in India. The disposal of the rice straw is a serious problem in areas where it is the major agricultural product. It is rich in polysaccharides and has a high lignin and silica content, limiting voluntary intake and reducing degradability by rumen microbes. By rice straw treatment, its quality and digestibility can be improved and enhanced the protein content. Several methods have been used to improve the utilization of rice straw by ruminants or supplemented by other ingredients to increase digestibility and nutrient value before it can be considered a suitable animal feed. In recent years, biological treatments have been investigated for improvement in nutritional value of rice straw. The use of ligninolytic fungi and their extracellular ligninolytic enzymes for treatment of rice straw results in degrading cellulose and hemicelluloses contents which improve its nutritional value. The use of fungi and enzyme treatments is expected to be a practical, cost-effective and environmental-friendly approach for enhancing the nutritive value and digestibility of rice straw. Therefore, the treated rice straw has a good potential as feed for ruminants.