Recent Advances in the Molecular Effects of Biostimulants in Plants: An Overview

As the world develops and population increases, so too does the demand for higher agricultural output with lower resources. Plant biostimulants appear to be one of the more prominent sustainable solutions, given their natural origin and their potential to substitute conventional methods in agriculture. Classified based on their source rather than constitution, biostimulants such as humic substances (HS), protein hydrolysates (PHs), seaweed extracts (SWE) and microorganisms have a proven potential in improving plant growth, increasing crop production and quality, as well as ameliorating stress effects. However, the multi-molecular nature and varying composition of commercially available biostimulants presents challenges when attempting to elucidate their underlying mechanisms. While most research has focused on the broad effects of biostimulants in crops, recent studies at the molecular level have started to unravel the pathways triggered by certain products at the cellular and gene level. Understanding the molecular influences involved could lead to further refinement of these treatments. This review comprises the most recent findings regarding the use of biostimulants in plants, with particular focus on reports of their molecular influence

Enhancing Sustainability by Improving Plant Salt Tolerance through Macro- and Micro-Algal Biostimulants

Algal biomass, extracts, or derivatives have long been considered a valuable material to bring benefits to humans and cultivated plants. In the last decades, it became evident that algal formulations can induce multiple effects on crops (including an increase in biomass, yield, and quality), and that algal extracts contain a series of bioactive compounds and signaling molecules, in addition to mineral and organic nutrients. The need to reduce the non-renewable chemical input in agriculture has recently prompted an increase in the use of algal extracts as a plant biostimulant, also because of their ability to promote plant growth in suboptimal conditions such as saline environments is beneficial. In this article, we discuss some research areas that are critical for the implementation in agriculture of macro- and microalgae extracts as plant biostimulants. Specifically, we provide an overview of current knowledge and achievements about extraction methods, compositions, and action mechanisms of algal extracts, focusing on salt-stress tolerance. We also outline current limitations and possible research avenues. We conclude that the comparison and the integration of knowledge on the molecular and physiological response of plants to salt and to algal extracts should also guide the extraction procedures and application methods. The effects of algal biostimulants have been mainly investigated from an applied perspective, and the exploitation of different scientific disciplines is still much needed for the development of new sustainable strategies to increase crop tolerance to salt stress

Enhancing sustainability by improving plant salt tolerance through macro-and micro-algal biostimulants

Algal biomass, extracts, or derivatives have long been considered a valuable material to bring benefits to humans and cultivated plants. In the last decades, it became evident that algal formulations can induce multiple effects on crops (including an increase in biomass, yield, and quality), and that algal extracts contain a series of bioactive compounds and signaling molecules, in addition to mineral and organic nutrients. The need to reduce the non-renewable chemical input in agriculture has recently prompted an increase in the use of algal extracts as a plant biostimulant, also because of their ability to promote plant growth in suboptimal conditions such as saline environments is beneficial. In this article, we discuss some research areas that are critical for the implementation in agriculture of macro-and microalgae extracts as plant biostimulants. Specifically, we provide an overview of current knowledge and achievements about extraction methods, compositions, and action mechanisms of algal extracts, focusing on salt-stress tolerance. We also outline current limitations and possible research avenues. We conclude that the comparison and the integration of knowledge on the molecular and physiological response of plants to salt and to algal extracts should also guide the extraction procedures and application methods. The effects of algal biostimulants have been mainly investigated from an applied perspective, and the exploitation of different scientific disciplines is still much needed for the development of new sustainable strategies to increase crop tolerance to salt stress

Synergistic Effects of Nano-Silicon and IQ Combi on Yield Traits of Wheat under Saline Irrigation

Background: Salinization negatively affects plant growth and development, removing up to 1.5 million hectares of farmland from production annually. Objective: Evaluate the synergistic of Nano-fertilizers on yield traits of wheat Triticum aestivum below saline irrigation. Methodology: two factorial plot experiments were conducted during Autumn 2022 and 2023 in Diyala, IRAQ. The plants were irrigated every 18 days from planting with three NaCl irrigation levels: 0 (distilled water), 50, and 75 mM. A foliar application of nano fertilizer was sprayed after the third leaf appeared every 15 days, three times in total. Results: The salinity significantly decreased the yield component, biological yield, and harvest index, while the synergistic effects of (S), (Q), and (M) increased by 52.86%, 15.81%, and 18.84%   in 2022 and 41.05%, 20.65% and 22.62 in 2023 growth season, respectively. Additionally, the most significant effects of the synergistic nano-fertilizer on catalase, peroxidase, and Proline under salinity were 23.84%, 70.00%, and 79.78% in 2022 and 24.50%, 73.33% and 74.36% in 2023, respectively. Conclusions: The application of nano-fertilizers enhanced yield parameters and increased the antioxidant enzymes as part of the plant's defense mechanism against oxidative stress. Over time, this response to developing salinity-tolerant wheat varieties with strong antioxidant defense systems

Effects of a new biostimulant on vegetational indexes, yield and quality in common wheat

Wheat is the most cultivated crop in the world with a high nitrogen requirement. In order to reduce nitrogen leaching and abiotic stress risks related to climate change, new agronomic practices are currently being developed to maximise nitrogen use efficiency and crop yield and quality. Among these, the use of biostimulants is spreading worldwide in many crops and may replace late season foliar nitrogen supply. In this thesis, a new biostimulant obtained from sage and husk rice extracts was applied as foliar spraying in three common wheat varieties (i.e. var. Bologna, Vivendo and Solehio) at flowering stage and its effects were compared with untreated controls and two benchmark commercial biostimulants obtained from protein hydrolisates. The trial was arranged at the Experimental farm of the University of Padova at Legnaro in 2020-21, following a completely randomised block design with 3 replicates. After application of biostimulants, the canopy greenness was monitored during the grain filling by weekly detection of NDVI and SPAD, while at harvest grain yield was quantified through a plot combine harvester. Quality and bread-making parameters were measured by NIRS and the Chopin alveograph, respectively. Similarly to the two benchmarks, the new biostimulant significantly delayed leaf senescence that is commonly observed with the approach of ripening. Compared to the untreated controls, higher NDVI values were found with all the three biostimulants for var. Bologna, and the maintenance of high values of leaf chlorophyll content (SPAD values) for longer time in var. Vivendo and Solehio, especially with the new biostimulant. The maintenance of greenness by the crop for a longer period than the control led to significant increases in protein content, wet gluten and the Zeleny index, with more marked improvements in var. Bologna compared to Solehio and Vivendo. The results on yield were contrasting, with a slight decrease in Bologna and Vivendo (more protein-rich varieties) and a slight increase in Solehio, regardless of the type of biostimulant applied. It is believed that yield response was greatly affected by the particular climatic conditions in 2021, with abundant rains and low temperatures in April and May, suggesting the need to repeat the trial for a second year. The qualitative improvements obtained by the biostimulants linked to proteins and gluten did not translate into evident variations in the rheological quality of the doughs. From the nutraceutical point of view, the possible increase in some varieties of the content of antioxidants (phenolic acids) in flour is interesting, in particular with one of the two benchmarks.Wheat is the most cultivated crop in the world with a high nitrogen requirement. In order to reduce nitrogen leaching and abiotic stress risks related to climate change, new agronomic practices are currently being developed to maximise nitrogen use efficiency and crop yield and quality. Among these, the use of biostimulants is spreading worldwide in many crops and may replace late season foliar nitrogen supply. In this thesis, a new biostimulant obtained from sage and husk rice extracts was applied as foliar spraying in three common wheat varieties (i.e. var. Bologna, Vivendo and Solehio) at flowering stage and its effects were compared with untreated controls and two benchmark commercial biostimulants obtained from protein hydrolisates. The trial was arranged at the Experimental farm of the University of Padova at Legnaro in 2020-21, following a completely randomised block design with 3 replicates. After application of biostimulants, the canopy greenness was monitored during the grain filling by weekly detection of NDVI and SPAD, while at harvest grain yield was quantified through a plot combine harvester. Quality and bread-making parameters were measured by NIRS and the Chopin alveograph, respectively. Similarly to the two benchmarks, the new biostimulant significantly delayed leaf senescence that is commonly observed with the approach of ripening. Compared to the untreated controls, higher NDVI values were found with all the three biostimulants for var. Bologna, and the maintenance of high values of leaf chlorophyll content (SPAD values) for longer time in var. Vivendo and Solehio, especially with the new biostimulant. The maintenance of greenness by the crop for a longer period than the control led to significant increases in protein content, wet gluten and the Zeleny index, with more marked improvements in var. Bologna compared to Solehio and Vivendo. The results on yield were contrasting, with a slight decrease in Bologna and Vivendo (more protein-rich varieties) and a slight increase in Solehio, regardless of the type of biostimulant applied. It is believed that yield response was greatly affected by the particular climatic conditions in 2021, with abundant rains and low temperatures in April and May, suggesting the need to repeat the trial for a second year. The qualitative improvements obtained by the biostimulants linked to proteins and gluten did not translate into evident variations in the rheological quality of the doughs. From the nutraceutical point of view, the possible increase in some varieties of the content of antioxidants (phenolic acids) in flour is interesting, in particular with one of the two benchmarks

Allelopathic Effect of Methanol and Water Extracts of \u3cem\u3eCamellia sinensis\u3c/em\u3e L. on Seed Germination and Growth of \u3cem\u3eTriticum aestivum\u3c/em\u3e L. and \u3cem\u3eZea mays\u3c/em\u3e L.

This study describes the possible effects of tea residues on crop production. To investigate the negative effects of tea on two cereal crops, i.e. wheat and maize, laboratory experiments were conducted during May 2014 and repeated in June 2014 to study the effect of black tea extract on wheat and maize seeds’ germination and growth. The experiment was conducted in petri dishes and laid out in completely randomized designs, replicated thrice. The petri dishes were kept in a growth chamber, with the temperature set at 25°C. 50 g of each dried fresh and used black tea was separately soaked in 500 ml of hot and cold distilled water. The same amount of tea residue was soaked in 500 ml of methanol. Ten seeds of each wheat variety (Siran) and maize variety (Azam) were placed in each petri dish. 10 ml of each extract was applied to each petri dish according to the requirement. A control (distilled water) was used for comparison. Analysis of the data revealed that tea extract significantly suppressed seed germination and the growth of wheat and maize. Methanol extracts, on the other hand, completely inhibited seed germination. The negative effects of tea extracts on seed germination of crops warns that apart from polluting the soil, the crop production could be greatly affected by dumping tea waste in agricultural fields. However, used cautiously, the application of tea extract can be used to suppress the growth of weeds in agriculture

Nutrient management: as a panacea to improve the caryopsis quality and yield potential of durum wheat (Triticum turgidum L.) under the changing climatic conditions

The increasing human population and the changing climate, which have given rise to frequent drought spells, pose a serious threat to global food security, while identification of high-yielding drought-tolerant genotypes coupled with nutrient management remains a proficient approach to cope with these challenges. An increase in seasonal temperature, recurring drought stress, and elevated atmospheric CO2 are alarmingly affecting durum wheat production, productivity, grain quality, and the human systems it supports. An increase in atmospheric carbon dioxide can improve wheat grain yield in a certain amount, but the right amount of nutrients, water, and other required conditions should be met to realize this benefit. Nutrients including nitrogen, silicon, and sulfur supply could alleviate the adverse effects of abiotic stress by enhancing antioxidant defense and improving nitrogen assimilation, although the effects on plant tolerance to drought stress varied with nitrogen ionic forms. The application of sewage sludge to durum wheat also positively impacts its drought stress tolerance by triggering high accumulation of osmoregulators, improving water retention capacity in the soil, and promoting root growth. These beneficial effect of nutrients contribute to durum wheat ability to withstand and recover from abiotic stress conditions, ultimately enhance its productivity and resilience. While these nutrients can provide benefits when applied in appropriate amounts, their excessive use can lead to adverse environmental consequences. Advanced technologies such as precision nutrient management, unmanned aerial vehicle-based spraying, and anaerobic digestion play significant roles in reducing the negative effects associated with nutrients like sewage sludge, zinc, nanoparticles and silicon fertilizers. Hence, nutrient management practices offer significant potential to enhance the caryopsis quality and yield potential of durum wheat. Through implementing tailored nutrient management strategies, farmers, breeders, and agronomists can contribute to sustainable durum wheat production, ensuring food security and maintaining the economic viability of the crop under the changing climatic conditions

the role of biostimulants and bioeffectors as alleviators of abiotic stress in crop plants

Abstract The use of bioeffectors, formally known as plant biostimulants, has become common practice in agriculture and provides a number of benefits in stimulating growth and protecting against stress. A biostimulant is loosely defined as an organic material and/or microorganism that is applied to enhance nutrient uptake, stimulate growth, enhance stress tolerance or crop quality. This review is intended to provide a broad overview of known effects of biostimulants and their ability to improve tolerance to abiotic stresses. Inoculation or application of extracts from algae or other plants have beneficial effects on growth and stress adaptation. Algal extracts, protein hydrolysates, humic and fulvic acids, and other compounded mixtures have properties beyond basic nutrition, often enhancing growth and stress tolerance. Non-pathogenic bacteria capable of colonizing roots and the rhizosphere also have a number of positive effects. These effects include higher yield, enhanced nutrient uptake and utilization, increased photosynthetic activity, and resistance to both biotic and abiotic stresses. While most biostimulants have numerous and diverse effects on plant growth, this review focuses on the bioprotective effects against abiotic stress. Agricultural biostimulants may contribute to make agriculture more sustainable and resilient and offer an alternative to synthetic protectants which have increasingly falling out of favour with consumers. An extensive review of the literature shows a clear role for a diverse number of biostimulants that have protective effects against abiotic stress but also reveals the urgent need to address the underlying mechanisms responsible for these effects. Graphical abstract Biostimulants have protective effects against abiotic stress

Enhancing Germination and Early Growth of Curly Lettuce Using Fermented Liquid Extract of Padina australis Hauck

Fermented seaweed liquid extract serves as an affordable and eco-friendly nutrient supplement, biostimulant, or biofertilizer, effectively promoting crop growth and supporting sustainable agricultural practices. This study evaluates the effects of the fermented liquid extract of Padina australis (FLEP) at various concentrations (0, 2, 5, 10, 20, and 100%) on lettuce germination and early growth. Germination parameters were assessed over 14 days under controlled conditions, followed by consecutive greenhouse experiments that examined the impact of foliar FLEP spray on two-week-old seedlings over 21 days, measuring early growth parameters and foliar nutrient concentrations. All data were statistically analyzed using a one-way analysis of variance at a 5% significance level. Results revealed that the FLEP significantly improved the seedling vigor index and length at concentrations ranging from 2 to 20%. The relative growth rate (RGR) for height exhibited significant increases at the 2% and 5% FLEP concentrations, while RGR for leaves, shoot dry biomass, and leaf area demonstrated significant improvements at FLEP concentrations of 2 to 20%. Foliar P content, and not foliar N, was significantly affected by the FLEP treatments, with P levels typically increasing with higher FLEP concentrations. These findings suggest that applying FLEP, particularly at low concentrations (2% and 5%) as a foliar spray significantly enhances lettuce germination and growth. Furthermore, this study highlights the potential of the FLEP as a novel foliar biofertilizer

Improvement of Plant Responses by Nanobiofertilizer: A Step towards Sustainable Agriculture

Drastic changes in the climate and ecosystem due to natural or anthropogenic activities have severely affected crop production globally. This concern has raised the need to develop environmentally friendly and cost-effective strategies, particularly for keeping pace with the demands of the growing population. The use of nanobiofertilizers in agriculture opens a new chapter in the sustainable production of crops. The application of nanoparticles improves the growth and stress tolerance in plants. Inoculation of biofertilizers is another strategy explored in agriculture. The combination of nanoparticles and biofertilizers produces nanobiofertilizers, which are cost-effective and more potent and eco-friendly than nanoparticles or biofertilizers alone. Nanobiofertilizers consist of biofertilizers encapsulated in nanoparticles. Biofertilizers are the preparations of plant-based carriers having beneficial microbial cells, while nanoparticles are microscopic (1–100 nm) particles that possess numerous advantages. Silicon, zinc, copper, iron, and silver are the commonly used nanoparticles for the formulation of nanobiofertilizer. The green synthesis of these nanoparticles enhances their performance and characteristics. The use of nanobiofertilizers is more effective than other traditional strategies. They also perform their role better than the common salts previously used in agriculture to enhance the production of crops. Nanobiofertilizer gives better and more long-lasting results as compared to traditional chemical fertilizers. It improves the structure and function of soil and the morphological, physiological, biochemical, and yield attributes of plants. The formation and application of nanobiofertilizer is a practical step toward smart fertilizer that enhances growth and augments the yield of crops. The literature on the formulation and application of nanobiofertilizer at the field level is scarce. This product requires attention, as it can reduce the use of chemical fertilizer and make the soil and crops healthy. This review highlights the formulation and application of nanobiofertilizer on various plant species and explains how nanobiofertilizer improves the growth and development of plants. It covers the role and status of nanobiofertilizer in agriculture. The limitations of and future strategies for formulating effective nanobiofertilizer are mentioned