Amino acids foliar application for maximizing growth, productivity and quality of peanut grown under sandy soil

Exploring the mechanism of nano-selenium treatment on the nutritional quality and resistance in plum plants

The impact of emerging stressors, such as pesticides and heavy metals, on the nutritional quality, resistance, and antioxidant systems of crops is the subject of intense monitoring. Due to its low toxicity and biocompatibility, nano-selenium (nano-Se) increases antioxidant capacity more effectively than selenium (Se). However, the protective mechanism of nano-Se in plum trees is still unknown when subjected to long-term abiotic stress. In this study, nano-Se foliar application enhanced the fruit's fresh weight and diameter and plant growth and development by increasing the content of trace elements (Zn and Se) and amino acids (Try, Phe, Pro, and Arg) in leaves and fruits. Compared to the control, nano-Se treatment dramatically improved the plant's antioxidant system, resulting in a substantial increase in SOD (44.3 %), POD (24.3 %), and CAT (95.6 %) levels. It also increased IAA (118.8 %), total flavonoids (23.0 %), total phenols (15.8 %), rutin (37.7 %), quercetin (146.8 %), and caffeic acid (19.8 %) contents by regulating phenylpropane metabolic pathways. Targeted amino acid analysis indicated that nano-Se biofortification greatly enhanced the levels of His (60.7 %), Ser (123.5 %), Thr (105.7 %), Val (202.1 %), Ile (236.2 %), Leu (84.0 %), Tyr (235.0 %), and Phe (164.7 %). The non-target metabolomics results showed that nano-Se treatment stimulated plum growth and nutrition by boosting phenylpropane metabolism and amino acid production. Therefore, nano-Se can improve the quality and resistance of plums by regulating both the primary and secondary metabolic pathways of plants and enhancing the antioxidant capacity. This investigation provides a reference for extrapolating the positive effects of nano-Se on crop quality to other plant species.

Precise partial root-zone irrigation technique and potassium-zinc fertigation management improve maize physio-biochemical responses, yield, and water use in arid climate

BACKGROUND

To optimize irrigation water use and productivity, understanding the interactions between plants, irrigation techniques, and fertilization practices is crucial. Therefore, the experiment aims to assess the effectiveness of two application methods of potassium humate combined with chelated zinc under partial root-zone drip irrigation techniques on maize nutrient uptake, yield, and irrigation water use efficiency across two irrigation levels.

METHODS

Open-field experiments were carried out in two summer seasons of 2021 and 2022 under alternate and fixed partial root-zone drip irrigation techniques to investigate their impacts at two irrigation levels and applied foliar and soil applications of potassium humate or chelated zinc in a sole and combinations on maize.

RESULTS

Deficit irrigation significantly increased hydrogen peroxide levels and decreased proline, antioxidant enzymes, carbohydrate, chlorophyll (a + b), and nutrient uptake in both partial root-zone techniques. The implementation of combined soil application of potassium humate and chelated zinc under drought conditions on maize led to varying impacts on antioxidant enzymes and nutritional status, depending on the type of partial root-zone technique. Meanwhile, the results showed that fixed partial root-zone irrigation diminished the negative effects of drought stress by enhancing phosphorus uptake (53.8%), potassium uptake (59.2%), proline (74.4%) and catalase (75%); compared to the control. These enhancements may contribute to improving the defense system of maize plants in such conditions. On the other hand, the same previous treatments under alternate partial root zone modified the defense mechanism of plants and improved the contents of peroxidase, superoxide dismutase, and the uptake of magnesium, zinc, and iron by 81.3%, 82.3%, 85.1%, 56.9%, and 80.2%, respectively.

CONCLUSIONS

Adopting 75% of the irrigation requirements and treating maize plants with the soil application of 3 g l-1 potassium humate combined with 1.25 kg ha-1 chelated zinc under alternate partial root-zone technique, resulted in the maximum root length, leaf water content, chlorophyll content, yield, and irrigation water use efficiency.

Foliar Application of Amino Acids and Nutrients as a Tool to Mitigate Water Stress and Stabilize Sugarcane Yield and Bioenergy Generation

Extended periods of water stress negatively affect sugarcane crop production. The foliar application of supplements containing specific nutrients and/or organic molecules such as amino acids can improve sugarcane metabolism, stalk and sugar yields, and the quality of the extracted juice. The present study assessed the effectiveness of the foliar application of an abiotic stress protection complement (ASPC) composed of 18 amino acids and 5 macronutrients. The experiments were carried out in the field with two treatments and twelve replicates. The two treatments were no application of ASPC (control) and foliar application of ASPC. The foliar application of ASPC increased the activity of antioxidant enzymes. The Trolox-equivalent antioxidant capacity (DPPH) was higher in ASPC-treated plants than in control plants, reflecting higher antioxidant enzyme activity and lower malondialdehyde (MDA) levels. The level of H2O2 was 11.27 nM g-1 protein in plants treated with ASPC but 23.71 nM g-1 protein in control plants. Moreover, the application of ASPC increased stalk yield and sucrose accumulation, thus increasing the quality of the raw material. By positively stabilizing the cellular redox balance in sugarcane plants, ASPC application also increased energy generation. Therefore, applying ASPC is an effective strategy for relieving water stress while improving crop productivity.

Potassium humate and cobalt enhance peanut tolerance to water stress through regulation of proline, antioxidants, and maintenance of nutrient homeostasis

Water stress is an important factor that substantially impacts crop production. As a result, there is a need for various strategies that can mitigate these negative effects. One such strategy is the application of potassium humate (Kh) and cobalt (Co), which have been reported to enhance the resistance of crop plants. Therefore, the present experiment was designed to investigate whether the application of Kh and Co could positively affect proline, chlorophyll and mineral elements contents, and antioxidant defense systems which in turn will mitigate the negative impact of water stress under different irrigation strategies. In 2021 and 2022, an open-field experiments were conducted by using a split-plot design. The main plots were divided to represent different irrigation strategies (ST), with additional control of full irrigation requirements (ST1). Four STs were implemented, with ST1, followed by the application of 75%, 50%, and 25% irrigation strategies in ST2, ST3, and ST4 respectively, in the next irrigation, followed by the full requirements, and so on. In the subplots, peanut plants were treated with tap water (Control), Kh at 2 g l-1 and 3 g l-1, Co, Co + Kh 2 g l-1 and Co + Kh 3 g l-1. The yield was negatively affected by the implementation of ST4, despite the increase in proline contents. Furthermore, there was a decrease in relative water content, chlorophyll content, antioxidant enzymes, protein, and mineral nutrient elements. However, the application of Kh or Co showed better improvements in most of the studied parameters. It is worth noting that there was an antagonistic relationship between Co and iron/manganese, and the intensity of this relationship was found to depend on the STs implemented. The highest mineral nutrient accumulation, chlorophyll content, relative water content, protein content, oil content, seed yield, and water productivity were observed when peanut plants were treated with Kh 3 g l-1 + Co under the ST2 water strategy.

Amino Acids Biostimulants and Protein Hydrolysates in Agricultural Sciences

The effects of different types of biostimulants on crops include improving the visual quality of the final products, stimulating the immune systems of plants, inducing the biosynthesis of plant defensive biomolecules, removing heavy metals from contaminated soil, improving crop performance, reducing leaching, improving root development and seed germination, inducing tolerance to abiotic and biotic stressors, promoting crop establishment and increasing nutrient-use efficiency. Protein hydrolysates are mixtures of polypeptides and free amino acids resulting from enzymatic and chemical hydrolysis of agro-industrial protein by-products obtained from animal or plant origins, and they are able to alleviate environmental stress effects, improve growth, and promote crop productivity. Amino acids involve various advantages such as increased yield and yield components, increased nutrient assimilation and stress tolerance, and improved yield components and quality characteristics. They are generally achieved through chemical or enzymatic protein hydrolysis, with significant capabilities to influence the synthesis and activity of some enzymes, gene expression, and redox-homeostasis. Increased yield, yield components, and crop quality; improved and regulated oxidation-reduction process, photosynthesis, and physiological activities; decreased negative effects of toxic components; and improved anti-fungal activities of plants are just some of the more important benefits of the application of phenols and phenolic biostimulants. The aim of this manuscript is to survey the impacts of amino acids, different types of protein hydrolysates, phenols, and phenolic biostimulants on different plants by presenting case studies and successful paradigms in several horticultural and agricultural crops.