Aluminum has long been recognized as a major limiting factor for root growth in acid subsoils, but little has been done to delineate toxic and nontoxic forms of soil‐solution Al. In an effort to determine if the presence of organic acids in soil solutions affected Al phytotoxicity, short‐term, split‐root experiments were conducted with cotton (Gossypium hirsutum L.) taproots as the growth indicator. Based on pure solution experiments, short‐chain, carboxylic acids can be divided into three groups as Al detoxifiers: (i) strong (citric, oxalic, tartaric), (ii) moderate (malic, malonic, salicylic), and (iii) weak (succinic, lactic, formic, acetic, phthalic). The Al detoxifying capacities of these acids were positively correlated with the relative position of OH/COOH groups on their main C chain, positions that favored the formation of stable 5‐ or 6‐bond ring structures with Al. In addition, analyses of soil solutions from several eluviated acid horizons (E, EB, BE) revealed the presence of several organic acids whose concentrations were generally higher in forested than in cultivated soils. Based on these concentrations, total solution Al (as measured by ICAP) was partitioned into monomeric Al (Al3+ + hydroxy‐Al species) and complexed Al (Al‐organic acid complexes). The latter accounted for 93 and 76% of the total solution Al concentrations of the two acid subsoils into which elongation rate of cotton taproot was studied. Root growth was significantly correlated with monomeric Al but not with total Al in soil solutions.

Eighteen active substances, including 17 organosulfur compounds found in garlic essential oil (T), were identified by GC−MS analysis. For the first time, using the molecular docking technique, we report the inhibitory effect of the considered compounds on the host receptor angiotensin-converting enzyme 2 (ACE2) protein in the human body that leads to a crucial foundation about coronavirus resistance of individual compounds on the main protease (PDB6LU7) protein of SARS-CoV-2. The results show that the 17 organosulfur compounds, accounting for 99.4% contents of the garlic essential oil, have strong interactions with the amino acids of the ACE2 protein and the main protease PDB6LU7 of SARS-CoV-2. The strongest anticoronavirus activity is expressed in allyl disulfide and allyl trisulfide, which account for the highest content in the garlic essential oil (51.3%). Interestingly, docking results indicate the synergistic interactions of the 17 substances, which exhibit good inhibition of the ACE2 and PDB6LU7 proteins. The results suggest that the garlic essential oil is a valuable natural antivirus source, which contributes to preventing the invasion of coronavirus into the human body. Figure 1. Picture of garlic (A. sativum L.).Article

The seriousness of soil acidity and the unavailability of "conventional" liming materials in many developing countries necessitate a search for alternatives. With this goal in mind, the liming potential of two organic manures was investigated. The investigation was conducted in the greenhouse, using a highly weathered, acid Ultisol. Application rates were 0, 5, 10, 20, and 40 g kg -1 for chicken manure and 20 g kg -1 for sewage sludge. Treatments of Ca(OH) 2 at 2, 4, 6, and 8 cmol c kg -1 , were included for comparison.Based on growth response of Desmodium intortum, a tropical forage legume with a relatively high Ca requirement and low Al tolerance, it was demonstrated that soil acidity can be corrected by either Ca(OH) 2 or organic manure additions.Both lime and manures raised soil pH and inactivated Al. In terms of pH increases, 5 and 10 g chicken manure kg -1 were equivalent to 3.4 and 6.7 cmol c kg -1 ; and 20 g sludge kg -1 , equivalent to 6.5 cmol c kg -1 as Ca(OH) 2 . The manures also detoxified soluble Al by organic complexation and enhanced Ca uptake of the Desmodium. The plant's maximum growth required at least 1.0% Ca in leaves, and this growth was reduced by half when leaf Al 76 mg kg -1 and soil-solution Al 3+ activity 4 µM.

The total quantity of P and plant‐available P often differ greatly in soils of the tropics, which typically range in weathering intensity. Assessing available P is fundamental to managing P in many of these soils. Phosphorus availability in some soils has been inferred from the Hedley sequential extraction assuming that each P fraction reflects similar plant availability in different soils. However, experimental measurements of plant P availability were either of short duration or involved multiple P applications, which complicates assessment of the plant availability of P fractions. The objectives of this study were to examine the changes in P fractions under exhaustive cropping on diverse soils and to discern the differences in plant availability among P fractions. Eight soils ranging in weathering from Vertisols and Mollisols to Ultisols and Oxisols were amended with Ca(H2PO4)·H2O to raise soil solution P to 0.2 mg L−1 and planted for 14 crops to remove available P. The results indicated that the Fe‐impregnated strip–P and inorganic NaHCO3–P (NaHCO3–Pi) decreased the most in response to plant P withdrawal in all soils. The inorganic NaOH‐P (NaOH‐Pi) also declined with plant P uptake in all soils. The HCl‐P and residual P seemed to act as a buffer for the strip‐P and the NaHCO3–Pi in the slightly weathered soils, whereas NaOH‐Pi seemed to act as a buffering pool for strip‐P and NaHCO3–Pi in the highly weathered soils. Residual P in the slightly weathered soils was plant‐available on a relatively short time scale. In contrast, residual P in the highly weathered soils accumulated in the presence of intensive plant P removal, indicating that it was unavailable to plants. Organic P (NaHCO3‐ and NaOH‐Po) fractions were not significant contributors to available P in these soils that received high levels of inorganic P. Phosphorus fractions separated by the same sequential method were not of equal availability to plants in all soils.

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Four soils, ranging in texture from loamy sand to clay, were fertilized differently and equilibrated moist for several days. Soil solutions were then separated by column‐displacement, by simple centrifugation, and by immiscible displacement with CCl4 via centrifugation. The ionic compositions of soil solutions were unaffected by the method used to obtain the solutions.

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