Iron (Fe) chlorosis reduces the concentration of photosynthetic pigments, photosynthates, and crop yield. The effect of Fe chlorosis on leaf composition and cell structure was evaluated in Mexican lime (Citrus aurantifolia) with different degrees of Fe chlorosis. Iron chlorosis significantly reduced concentrations of chlorophylls a, b, and a + b, and caused thickening of leaves, due to the increase in palisade and spongy parenchyma cells. The chloroplasts of the chlorotic and albino leaves showed a disorganized ultrastructure; they had an elongated shape with disarrayed thylakoids, underdeveloped grana, scarce starch granules, and hole-like folds in the thylakoid membranes. The accumulation of calcium oxalate crystals in the upper and lower sides of the epidermis, crystal length, and total crystal content increased with Fe chlorosis severity. The green leaves, in contrast, had chloroplasts with typical ultrastructure. The degree of Fe chlorosis in the leaves significantly affected the concentrations of potassium (K); Fe, manganese (Mn), Fe²⁺, and the phosphorus (P)/Fe and K/calcium (Ca) ratios.

The aim of this research was to evaluate the nutritional value, bioactive compounds and capacity antioxidant in ligulate flowers of dahlia with different colour. The statistical analysis reveals that the petals of the pink and purple colour have more protein and raw fibre (18.54 and 19.25, 16.54 and 15.81%, respectively) and similar raw fat values between the analysed colours. Likewise, the flowers with the highest content of vitamin C, phenols and total flavonoids were observed in the pink, purple and cherry colours, where the latter also stands out for its content of total anthocyanins (3.2 mg cyanidin-3-glucoside 100 g–1). However, the yellow ones showed higher antioxidant capacity (68.82 mg AAEVC 100 g–1), which coincides with that found with the concentration of total carotenoids (0.64 μg β-carotene g–1). For the consumers who choose to change their eating habits and seek to include ingredients of vegetable origin (vegetarian and vegan) with low caloric content and a sufficient

During the Pre-Colombian period magueys were used in Mesoamerica for their sap, which is named “aguamiel” (literally “honey water” in Spanish). Aguamiel is then fermented into “pulque”, followed by (in order of importance): textiles, apparel, different thicknesses cords, food (sweetener, syrup, vinegar, flower buds, and cooked immature flowering stalks), firewood and construction materials. The maguey syrup is a product that is traditionally obtained by concentrating the aguamiel by means of an artisanal evaporation treatment (high temperatures, atmospheric pressure and prolonged times). The nutritional and nutraceutical value of this concentrate is unknown despite its wide consumption since pre-Hispanic times in various regions of Mexico. The objective of this work was to evaluate the nutritional value and the content of antioxidant compounds of the maguey syrup obtained from the aguamiel (Agave salmiana and A. mapisaga) through three elaboration treatments (artisanal evaporation, evaporation under reduced pressure and lyophilization). The best species for the production of maguey syrup turned out to be the aguamiel of the A. salmiana due to its nutritional and nutraceutical attributes, higher content of reducing sugars and lower sucrose compared to that of A. mapisaga. The maguey syrup is a sweetener with a higher content of protein (3320 mg 100-1) in comparison to bee honey (152.7 mg 100 g-1). The maguey syrup obtained by lyophilization (LYT) retained the nutraceutical value; but its antioxidant activity was statistically equal to the syrup obtained by evaporation under reduced pressure (RPT), and the artisanal evaporation treatment (AET) had a decrease in vitamin C content in comparison to LYT and RPT. The syrups obtained by RPT and AET presented different degrees of non-enzymatic darkening, possibly due to the formation of melanoidins (dark pigments). The darkest syrup obtained by AET had the highest antioxidant capacity (987.24 μM TE 100 g-1) associated to a higher content of phenolic compounds (593.74 mg GAE 100 g-1).

Morphological variation is useful in conservation and genetic improvement programs. Euphorbia fulgens, a range-restricted local endemic species of Mexico, is used locally during the altars in the festivities of different saints and is also cultivated as an ornamental plant mainly in Europe. Thus, in the present study, morphological variation was evaluated in wild populations and cultivated populations. Characterization of 90 individuals from three wild populations (the only ones recorded to date) was done by measuring 30 morphological traits both vegetative and reproductive. Thereafter, seeds were collected, and established under greenhouse conditions, and 39 morphometric variables were evaluated in adult plants. An analysis of variance (ANOVA) was done for wild and cultivated groups independently, and when significant differences were found, Tukey’s comparison of means was applied (p < 0.05). To identify the traits responsible for the differences between wild and cultivated groups, a linear discriminant analysis (LDA) was conducted. Morphological variation was found among wild populations, and this variation decreased in cultivated populations, mainly in reproductive structures. The LDA separated the wild populations from the cultivated groups, according to inflorescence length, petiole length/blade length ratio, and leaf roundness. The variables that determined the separation of individuals between wild and cultivated populations were cyme number, foliar Feret diameter, and inflorescence length, variables that can be important for breeding strategies and artificial selection.

The aphid Melanaphis sacchari/sorghi is considered the most important pest of sorghum cultivation in Mexico. It can cause losses in production of up to 100%. This research was conducted at the Universidad Autonoma Chapingo during 2018 and 2019 with the objective of determining the relationship between chemical fertilization in sorghum and M. sacchari/sorghi (Hemiptera: Aphididae) populations. Different levels of nitrogen (125, 250 and 500 kg ha-1), phosphorus (19.5, 39 and 78 kg ha-1) and potassium (210 and 420 kg ha-1) were supplied to sorghum plants planted in polyethylene pots with a capacity of 6 L under greenhouse conditions. The plants were infested with a total of 15 third-instar nymphs within 60 days of crop emergence. A total of 6 samplings were carried out at 7 day intervals, starting at 7 d after the infestation. Quantifications of total soluble proteins, total soluble sugars, reducing sugars, and levels of nitrogen, phosphorus, potassium and magnesium in leaf tissue were also performed. We observed that higher doses of nitrogen and phosphorus increased the aphid population, while increasing the potassium dose considerably decreased the aphid population. We also found a positive correlation between the aphid population and the total soluble protein concentrations, reducing sugars and nitrogen levels, while the correlation was negative with potassium levels in leaves.

High concentrations of sodium chloride (NaCl) in soil and water are increasingly common conditions in tomato (Solanum lycopersicum L.) production that impair the development and yield of this crop, generating the need for tolerant varieties. This research aimed to identify tomato lines tolerant to salinity during germination and early seedling development. A standard germination test was carried out in which 93 lines were evaluated under conditions of 0 and 80 mM NaCl for 12 days in a germination chamber with a temperature of 28 ± 1 °C and relative humidity of 80 ± 5%. At the seedling stage, 88 lines were evaluated under conditions of 0 and 150 mM NaCl in a floating raft system. During germination, saline conditions decreased germination percentage (37%), plumule (43%) and radicle (47%) length, dry matter (44%) and germination rate index (70%). At the seedling stage, NaCl decreased (p ≤ 0.05) plant height (44%) and leaf area (50%), without modifying root, aerial and total dry matter or root length. Twenty-eight tolerant lines were identified at germination and twenty-three at the seedling stage, seven of which were tolerant at both stages. This implies that salinity tolerance mechanisms differ in the developmental stages studied and makes it possible to combine these mechanisms to prolong tolerance during plant development.