Exogenous Application of Mg, Zn and B Influences Phyto-Nutritional Composition of Leaves and Fruits of Loquat (Eriobotrya japonica Lindl.)

Improved plant yield of potato through exogenously applied potassium fertilizer sources and biofertilizer

Excessive usage of chemical fertilizers has detrimental effects on the environment and the safety of food. Conversely, utilizing organic fertilizers such as sage offers several advantages, including cost-effectiveness, soil enhancement, and promotion of root development. A two-year field experiment was conducted to investigate the impact of different potassium fertilizer sources and biofertilizers (specifically Bacillus cereus (MBc)) on potato plants. The experiment employed a split-plot design with three replicates, where the main plot factor was MBc (with and without), and the subplot factor was the sources of potassium fertilizer (control without K fertilizer, 100% Feldspar (FD), 100% Filter cake (FC), 75% FD + 25% FC, 25% FD + 75% FC, and 50% FD + 50% FC). The purpose was to examine the growth response of potato plants to these treatments. The results indicated that all treatments increased plant height, stem count, and tuber dry matter compared to the control. Furthermore, all treatments exhibited a higher uptake of macronutrients (N, P, and K) compared to the control. Notably, the plants treated with 100FC combined with MBc showed a significant 104.74% increase in total tuber weight compared to the control treatment. Additionally, the addition of 100FC with MBc significantly enhanced the availability of N, P, and K by 73.13%, 110.33%, and 51.88% respectively, compared to the control treatment. Apart from the biofertilizers, the individual application of FC and its combination with FD also demonstrated positive effects on soil fertility, potato growth, and yield.

Exogenously applied zinc improves sugar-acid profile of loquat (Eriobotrya japonica Lindl.) by regulating enzymatic activities and expression of their metabolism-related genes

Soluble sugars and organic acids are the most abundant components in ripe fruits, and they play critical roles in the development of fruit flavor and taste. In this study, loquat trees were sprayed with 0.1, 0.2 and 0.3% zinc sulphate. The contents of soluble sugars and organic acids were determined using HPLC-RID and UPLC-MS, respectively. The activities of key enzymes involved in sugar-acid metabolism were measured and expression profiling of related genes was done using RT-qPCR. The results revealed that 0.1% zinc sulphate was a promising treatment among other Zn applications with respect to the increased levels of soluble sugars and decreased acid contents in loquats. Correlation analysis showed that the enzymes i.e., SPS, SS, FK, and HK were may be involved in the regulation of fructose and glucose metabolism in the fruit pulp of loquat. While, the activity of NADP-ME showed negative and NAD-MDH showed a positive correlation with malic acid content. Meanwhile, EjSPS1-4, EjSS2-4, EjHK1-3, and EjFK1-6 may play an important role in soluble sugar metabolism in the pulp of loquat fruits. Similarly, EjPEPC2, EjPEPC3, EjNAD-MDH1, EjNAD-MDH3-5, EjNAD-MDH6 and EjNAD-MDH13 may have a vital contribution to malic acid biosynthesis in loquat fruits. This study provides new insights for future elucidation of key mechanisms regulating soluble sugars and malic acid biosynthesis in loquats.

Nitrogen-doped carbon dots enhanced seedling growth and salt tolerance with distinct requirements of excitation light

Numerous nanomaterials with optical properties have demonstrated excellent capacities to enhance plant growth and stress tolerance. However, the corresponding mechanisms have only been partially characterized, especially the excitation-light dependencies of different actions. Here, nitrogen-doped carbon dots (N-CDs) were developed to explore the excitation-light dependence in N-CD-induced growth enhancement and salt tolerance. Compared to the control, N-CDs induced significant enhancements in Arabidopsis thaliana growth under excitation light, including fresh/dry weight of shoot (21.07% and 16.87%), chlorophyll content (9.17%), soluble sugar content (23.41%), leaf area (28.68%), total root length (34.07%) and root tip number (46.69%). In the absence of excitation light, N-CD-treated seedlings exhibited little differences in these parameters, except the enhancements in root length (24.51%) and root tip number (10.24%). On the other hand, N-CD-treatment could improve seedling salt tolerance with or without excitation light. Under salt stress (150 mM NaCl), in the presence of excitation light, the N-CDs treatment significantly increased shoot/root fresh weight and chlorophyll content by 43.29%, 50.66% and 22.59%, and reduced malondialdehyde (MDA) content and relative conductivity by 17.59% and 32.58% compared to the control group. In the absence of excitation light, significant enhancements in shoot/root fresh weight (34.22%, 32.60%) and chlorophyll content (10.45%), and obvious decreases in MDA content (28.84%) and relative conductivity (16.13%) were also found. These results indicated that N-CDs only induced growth enhancement under excitation light, but they improved salt tolerance with and without excitation light, suggesting that the two effects occurred via distinct signaling pathways. This study revealed the excitation-light dependencies of nanomaterial-involved agriculture applications, providing insight into designing more efficient nanomaterials in the future.

Biofortification of mungbean (Vigna radiata L. (Wilczek)) with boron, zinc and iron alters its grain yield and nutrition

Mungbean [Vigna radiata L. (Wilczek)] is considered as an extremely nutritious crop possessing a high level of micronutrients, but their low bioavailability in the crop leads to micronutrient malnutrition in humans. Therefore, the present study was conducted to investigate the potential of nutrients viz. boron (B), zinc (Zn) and iron (Fe) biofortification on productivity, nutrient concentration and uptake as well as the economics of mungbean cultivation. In the experiment, the various combinations of RDF with ZnSO₄.7H₂O (0.5%), FeSO₄.7H₂O (0.5%) and borax (0.1%) were applied to mungbean variety ML 2056. The combined foliar application of Zn, Fe and B was highly efficient in increasing the yield of grain as well as straw in mungbean exhibiting maximum values i.e. 944 kg ha^-1 and 6133 kg ha^-1, respectively. Similar results for B, Zn and Fe concentration in grain (27.3 mg kg^-1, 35.7 mg kg^-1 and 187.1 mg kg^-1, respectively) and straw (21.1 mg kg^-1, 18.6 mg kg^-1 and 376.1 mg kg^-1, respectively) of mungbean were observed. Also, uptake of Zn and Fe by grain (31.3 g ha^-1 and 164.4 g ha^-1, respectively), as well as straw (113.7 g ha^-1 and 2295.0 g ha^-1, respectively), was maximum for the above treatment. Whereas, the B uptake was found to enhance significantly through the combined application of B, Zn and Fe, where the values 24.0 g ha^-1 and 128.7 g ha^-1 corresponded to grain and straw, respectively. Thus, combined use of ZnSO₄.7H₂O (0.5%) + FeSO₄.7H₂O (0.5%) and borax (0.1%) significantly improved the yield outcomes, the concentration of B, Zn and Fe, uptake and economic returns of mungbean cultivation to alleviate the B, Zn and Fe deficiency.

Sugar and acid profile of loquat (Eriobotrya japonica Lindl.), enzymes assay and expression profiling of their metabolism-related genes as influenced by exogenously applied boron

Soluble sugars and organic acids are the most abundant components in ripe fruits, and they play critical roles in the development of fruit flavor and taste. Some loquat cultivars have high acid content which seriously affect the quality of fruit and reduce the value of commodity. Consequently, studying the physiological mechanism of sugar-acid metabolism in loquat can clarify the mechanism of their formation, accumulation and degradation in the fruit. Minerals application has been reported as a promising way to improve sugar-acid balance of the fruits. In this study, loquat trees were foliar sprayed with 0.1, 0.2 and 0.3% borax, and changes in soluble sugars and organic acids were recorded. The contents of soluble sugars and organic acids were determined using HPLC-RID and UPLC-MS, respectively. The activities of enzymes responsible for the metabolism of sugars and acids were quantified and expressions of related genes were determined using quantitative real-time PCR. The results revealed that 0.2% borax was a promising treatment among other B applications for the increased levels of soluble sugars and decreased acid contents in loquats. Correlation analysis showed that the enzymes i.e., SPS, SS, FK, and HK were may be involved in the regulation of fructose and glucose metabolism in the fruit pulp of loquat. While the activity of NADP-ME showed negative and NAD-MDH showed a positive correlation with malic acid content. Meanwhile, EjSPS1, EjSPS3, EjSS3, EjHK1, EjHK3, EjFK1, EjFK2, EjFK5, and EjFK6 may play an important role in soluble sugars metabolism in fruit pulp of loquat. Similarly, EjPEPC2, EjPEPC3, EjNAD-ME1, EjNAD-MDH1, EjNAD-MDH5-8, EjNAD-MDH10, and EjNAD-MDH13 may have a vital contribution to malic acid biosynthesis in loquat fruits. This study provides new insights for future elucidation of key mechanisms regulating soluble sugars and malic acid biosynthesis in loquats.

Heat stress mitigation in tomato (Solanum lycopersicum L.) through foliar application of gibberellic acid

Phytohormones mediate physiological, morphological, and enzymatic responses and are important regulators of plant growth and development at different stages. Even though temperature is one of the most important abiotic stressors for plant development and production, a spike in the temperature may have disastrous repercussions for crop performance. Physiology and growth of two tomato genotypes ('Ahmar' and 'Roma') were studied in two growth chambers (25 and 45 °C) when gibberellic acid (GA₃) was applied exogenously. After the 45 days of planting, tomato plants were sprayed with GA₃ at concentrations of 25, 50, 75, and 100 mg L⁻¹, whereas untreated plants were kept as control. Under both temperature conditions, shoot and root biomass was greatest in 'Roma' plants receiving 75 mg L⁻¹ GA₃, followed by 50 mg L⁻¹ GA₃. Maximum CO₂ index, photosynthetic rate, transpiration rate, and greenness index were recorded in 'Roma' plants cultivated at 25 °C, demonstrating good effects of GA₃ on tomato physiology. Likewise, GA₃ enhanced the proline, nitrogen, phosphorus, and potassium levels in the leaves of both genotypes at both temperatures. Foliar-sprayed GA₃ up to 100 mg L⁻¹ alleviated the oxidative stress, as inferred from the lower concentrations of MDA and H₂O_2, and boosted the activities of superoxide dismutase, peroxidase, catalase. The difference between control and GA₃-treated heat-stressed plants suggests that GA₃ may have a function in mitigating heat stress. Overall, our findings indicate that 75 mg L⁻¹ of GA₃ is the optimal dosage to reduce heat stress in tomatoes and improve their morphological, physiological, and biochemical characteristics.

Preharvest Foliar Applications of Citric Acid, Gibberellic Acid and Humic Acid Improve Growth and Fruit Quality of ‘Le Conte’ Pear (Pyrus communis L.)

A two-year (2020-21) study was conducted to investigate the possibility of relying of ten-years old pear trees grown on sandy loam soil irrigated by drip on citric acid (CA), gibberellic acid (GA3) and humic acid (HA). The CA was applied at the concentrations of 500, 1000 and 1500 ppm, GA3 at 50, 100 and 150 ppm and HA at 3, 4 and 5%, whereas water spray was used as the control. The results of our study proved that CA, GA3 and HA improved the shoot length, shoot thickness, leaf area and leaf chlorophyll of pear as compared with the control. Moreover, they also positively increased the fruit set percentage and final yield of ‘Le Conte’ pear. The fruit weight, size and firmness were also improved under the influence of aforementioned treatments. The fruit soluble solids, total sugars, leaf nitrogen, leaf phosphorus and leaf potassium of pear were also enhanced as compared with the control. Additionally, spraying of GA3 at 150 ppm, as well as, HA at 5 and 4% were the superior treatments and showed the most significant impact on plant growth, yield, fruit quality and leaf mineral content of pear. This study provides a basis for the future elucidation of HA-, GA3- and CA-modulated molecular mechanisms in pear, which can make a significant contribution in the scientific community.

Effect of Paper and Aluminum Bagging on Fruit Quality of Loquat (Eriobotrya japonica Lindl.)

Bagging regulates the fruit microenvironment and improves the quality and market value of fruits. It is a safe and ecofriendly technique to protect fruits from insect/pest infestation and multiple biotic and abiotic stresses. In the current study, the influence of fruit bagging was evaluated on the development and quality of loquat fruits. Fruits from a healthy loquat orchard (Cv. Zaozhong No.6), located in Fujian, China, were enveloped in paper (T1), aluminum (T2), and aluminum-polyethylene bags (T3), while unbagged fruits were maintained as control (T0). In general, fruit bagging improved fruit quality in terms of fruit physiological and biochemical attributes and protected fruits from physical damage. In particular, aluminum-polyethylene bagging enhanced fruit weight, length, and width by 1.37-, 1.18-, and 1.13-fold, respectively. Loquat fruits bagged with paper bags exhibited the maximum soluble sugar and lowest titratable acid content. Fruits treated with paper and aluminum-ethylene bags showed twofold higher sugar-acid ratio as compared to control. Aluminum-polyethylene bagging caused 66.67%, 55.56%, and 33.33% reductions in skin burn, fruit rotting, and black spot of loquat. The fruits bagged in aluminum and aluminum-polyethylene did not show insect or bird damage, while unbagged fruits had 14.70% and 17.65% insect and bird damage, respectively. Overall, the results suggest that paper, aluminum, and aluminum-polyethylene bagging improved fruit health by 75%, 131%, and 144%, respectively, as compared to control. To delineate bagging type-dependent effects, principal component analysis was performed. Paper bagging was positively correlated with fruit firmness, rotting, soluble sugars, sugar-acid ratio, and proline content. Aluminum bagging was highly associated with improvements in titratable acids, cystine, and methionine. Aluminum-polyethylene bags were correlated with fruit weight, size, peel thickness, edible rate, and certain amino acids.

Genome-Wide Identification, Characterization and Expression Profiling of Aluminum-Activated Malate Transporters in Eriobotrya japonica Lindl

Aluminum-activated malate transporters (ALMTs) have multiple potential roles in plant metabolism such as regulation of organic acids in fruits, movement of guard cells and inducing tolerance against aluminum stress. However, the systematic characterization of ALMT genes in loquat is yet to be performed. In the current study, 24 putative ALMT genes were identified in the genome of Eriobotrya japonica Lindl. To further investigate the role of those ALMT genes, comprehensive bioinformatics and expression analysis were performed. In bioinformatics analysis, the physiochemical properties, conserved domains, gene structure, conserved motif, phylogenetic and syntenic analysis of EjALMT genes were conducted. The result revealed that the ALMT superfamily domain was conserved in all EjALMT proteins. EjALMT proteins were predicted to be localized in the plasma membrane. Genomic structural and motif analysis showed that the exon and motif number of each EjALMT gene ranged dramatically, from 5 to 7, and 6 to 10, respectively. Syntenic analysis indicated that the segmental or whole-genome duplication played a vital role in extension of the EjALMT gene family. The Ka and Ks values of duplicated genes depicted that EjALMT genes have undergone a strong purifying selection. Furthermore, the expression analysis of EjALMT genes was performed in the root, mature leaf, stem, full-bloom flower and ripened fruit of loquat. Some genes were expressed differentially in examined loquat tissues, signifying their differential role in plant growth and development. This study provides the first genome-wide identification, characterization, and relative expression of the ALMT gene family in loquat and provides the foundation for further functional analysis.

Deep eutectic solvents based on carboxylic acids for metals separation from plant samples: Elemental analysis by ICP-OES

Deep eutectic solvents based on choline chloride, carboxylic acids, urea, and polyols were investigated for separation of 14 metals from plant samples. It was found that carboxylic acid as precursor of DES played key-role for effective metals separation. It was established that the solvent synthesized from choline chloride and malic acid provided highest extraction recovery (from 73 to 88%). Mixing and heating the solvent and sample for 30 min at a temperature of 70 °C provided effective separation of metals from plant sample. The developed procedure is not required a microwave digestion of samples. After separation the solvent phase containing analytes was dissolved in aqueous phase and analyzed. The developed procedure was applied to elemental analysis of plant tobacco and lettuce samples by inductively coupled plasma optical emission spectroscopy. Limits of detection calculated as three times the signal-to-noise ratio were in the range from 0.2 to 17 mg kg^-1.