Agronomic Behavior of Mexican Roselle Cultivars Produced under Protected Agricultural Conditions.

Growth dynamics and morphological traits are used to define the characteristics of roselle cultivars Hibiscus sabdariffa. The morpho-agronomic variability of plants was evaluated, as well as the concentration of macro and micronutrients in leaves of Mexican roselle cultivars in hydroponic and greenhouse conditions. The following roselle cultivars were studied: 'Cruza Negra', 'UAN16-2', 'Criolla Huajicori', 'UAN 6 Puga', 'UAN 25-1' and '4Q4'. The relative growth rate of the crops was fitted to a positive cubic, negative quadratic and positive linear model, whereas stem diameter, fitted to a linear model, had a negative quadratic response. The foliar surface of the cultivars '4Q4', 'Cruza Negra', 'UAN16-2' and 'Criolla Huajicori' was directly related to the size of the flower, the calyx and the corolla. Nitrogen and potassium are the elements that showed the highest concentration in the cultivars Criolla Huajicori and Cruza Negra, while in the other four cultivars the highest concentrations of minerals in the leaf were nitrogen and calcium. The leaves of cultivar 4Q4 provided the greatest amount of minerals, with 83,565 mg kg-1 dry basis. Criolla Huajicori was the cultivar that exhibited the tallest height, the most productive branches and the greatest calyx number per plant; however, Cruza Negra exhibited the highest yield by having the longest calyx.

Anthocyanin Induction by Drought Stress in the Calyx of Roselle Cultivars.

Abiotic factors can alter the chemical profile of crops and the number of compounds they contain. In this study, the anthocyanin and anthocyanidin contents, determined by ultra-performance liquid chromatography (UPLC-MS/MS), and the colour attributes of the calyces of three cultivars of Hibiscus sabdariffa subjected to three water stress regimes during the stage of physiological maturity were investigated. The total anthocyanin content in calyx increased relative to the control content under a 65% moisture irrigation regime. Among the cultivars, UAN16-2 showed the greatest increases in the contents of cyanidin, delphinidin 3-O-glucoside, cyanidin 3-O-glucoside, and cyanidin 3-O-sambubioside. The content of cyanidin 3-O-sambubioside showed the greatest increase, increasing by 55% relative to the control level. The contents of these compounds are correlated with colour attributes such as luminosity. Water stress under the 33% moisture condition during plant development led to decreased anthocyanin contents in all of the roselle cultivars.

Gene expression of an arabinogalactan lysine-rich protein CaAGP18 during vegetative and reproductive development of bell pepper (Capsicum annuum L.).

Lysine-rich (Lys-rich) proteins encoded by AGP17, AGP18, and AGP19 genes are cell wall-associated glycopeptides related to sexual reproduction in flowering plants. This subclass belongs to classical arabinogalactan proteins (AGPs) widely studied in model plants like Arabidopsis. In this study, we identified the CaAGP18 cDNA from bell pepper (Capsicum annuum L.), as well as its expression pattern during vegetative and reproductive development. The deduced amino acid sequence revealed a Lys-rich AGP18 protein of 238 amino acids residues in length with an estimated molecular mass of 22.85 kDa and an isoelectric point of 9.7. The protein is predicted as canonical AGP due to the presence of a small Lys-rich region and a C-terminal sequence essential for posttranslational modification with a glycosylphosphatidylinositol (GPI). Phylogenetic analysis showed that CaAGP18 is clustered together with NtAGP18, SpAGP18, StAGP18 and NaAGP18 from Solanaceae species. CaAGP18 expression through plant phenological stages had the highest transcription level in leaves at the seedling stage, whereas in reproductive organs there was a significant up-regulation in pistils during anthesis, also in petals 2 days post-anthesis (DPA), and in fruit at the expansion stage. Our results open future research for possible roles of CaAGP18 in cell expansion as a wall-associated plasticizer and reproductive processes like pistil interactions and petal cell death.

Biochemistry and Cell Wall Changes Associated with Noni (Morinda citrifolia L.) Fruit Ripening.

Quality and compositional changes were determined in noni fruit harvested at five ripening stages, from dark-green to thaslucent-grayish. Fruit ripening was accompanied by acidity and soluble solids accumulation but pH diminution, whereas the softening profile presented three differential steps named early (no significant softening), intermediate (significant softening), and final (dramatic softening). At early step the extensive depolymerization of hydrosoluble pectins and the significantly increment of pectinase activities did not correlate with the slight reduction in firmness. The intermediate step showed an increment of pectinases and hemicellulases activities. The final step was accompanied by the most significant reduction in the yield of alcohol-insoluble solids as well as in the composition of uronic acids and neutral sugars; pectinases increased their activity and depolymerization of hemicellulosic fractions occurred. Noni ripening is a process conducted by the coordinated action of pectinases and hemicellulases that promote the differential dissasembly of cell wall polymers.