Search

Golden-Dewdrop (Duranta erecta L.), known for its landscaping applications, undergoes successive pruning to maintain its ornamental structure, a practice known to induce numerous physiological and chemical responses in the plant. Therefore, this study aimed to evaluate the influence of pruning and different extraction methods on the allelopathic potential of Golden-Dewdrop on the germination and initial growth of lettuce. Leaf extracts were obtained by decoction (hot) and maceration (cold) at concentrations of 20%, 40%, 60%, 80%, and 100%, with distilled water as a negative control. Phytochemical screening of the extracts was performed for phenolic compounds, flavonoids, anthocyanidins, tannins, cardioactive heterosides, saponins, alkaloids, and terpenes. For the bioassay, germinative and morphological parameters were measured and characterized. The data were subjected to analysis of variance (ANOVA), and for quantitative data, regression models were adjusted, while for qualitative data, means were compared using the Scott-Knott test with 5% significance. Significant differences were observed between extraction methods and management practices, with the hot aqueous extract from pruned plants significantly reducing germination at higher concentrations. The initial growth of lettuce was severely affected, presenting numerous morphological abnormalities, with severe damage to the root system at all concentrations. This study suggests that pruning practices have a modulating effect on the allelopathic activity of Golden-Dewdrop, providing valuable information for landscaping projects and botanical studies considering its evaluation and production of phytotoxic phytochemicals.

The study of promoters has become essential to elucidate genetic regulation and allow new genetic transformation strategies through plant biotechnology. The challenge is to discover and validate promoters that can regulate gene transcription spatially and/or temporally. The goal of this work was to validate genes associated with tissue-specific promoters of bananas obtained from in silico sequences and selected from the DATAMusa databank. Gene expression was quantified using RT-qPCR from different tissues: leaves, flowers, roots, unripe pulp, ripe pulp, unripe peels, and ripe peels of two different genetic groups: Prata-Anã (PA; group AAB) and Grand Naine (GN; group AAA). After the analysis of the expression of genes associated with the promoters, normalization was performed with the most stable reference genes (TUB and L2) selected using the RefFinder tool. It was determined that five genes were specific or expressed to a greater extent in some tissues than others. The EMB-23 gene was highly expressed in ripe pulp and flowers of GN, EMB-26 in the ripe pulp of GN, EMB-27 in flowers of GN, EMB-28 in roots of PA and ripe pulp and roots of GN, and EMB-31 in roots and flowers of GN and PA, and unripe pulp of GN. The in silico analysis was efficient in the identification of spatial/time-specific genes, thereby decreasing analysis time and cost, making future genetic transformation studies focusing on the application of these tissue-specific promoters possible.

Coumarins are widely distributed substances in plant species that promote phytotoxic effects, allowing them to be exploited as herbicides less harmful to the environment, since many invasive species have demonstrated resistance to commercially available products. The derived coumarins used in this study had not been tested in plant models and their effect on plants was unknown. The objective of this study was to evaluate the phytotoxic action of these coumarins in bioassays with Lactuca sativa L., in order to select the most responsive substance whose toxicity was best elucidated by chromosomal complement and enzymatic antioxidant metabolism studies. From the phytotoxicity assays, coumarin 8-methoxy-2-oxo-6-(prop-2-en-1-yl)-2H-chromene-3-carboxylic acid (A1), reported here for the first time, was selected as the most responsive and caused a reduction in the following parameters: number of normal seedlings, fresh biomass, root length and shoot length. Subsequent studies demonstrated that this coumarin is cytogenotoxic due to damage caused to the cell cycle and the occurrence of chromosomal abnormalities. However, it did not interfere with antioxidant enzyme activity and did not cause lipid peroxidation. The changes caused by coumarin A1 described herein can contribute to better understanding the allelochemical actions of coumarins and the potential use of these substances in the production of natural herbicides.