Abstract

The use of synthetic dyes such as acetocarmine in cell division preparations has proven effective, but has the potential to cause negative impacts on health and the environment. Therefore, safer and more environmentally friendly natural dye alternatives are needed for biology practicum activities. Red spinach leaves (Amaranthus tricolor L.) contain anthocyanin pigments that have the potential to be used as natural dyes. This study aims to determine the effect of variations in the concentration of red spinach leaf extract and determine the optimal concentration in coloring red onion root cell division preparations (Allium cepa L. var. aggregatum). This study used an experimental method with a Completely Randomized Design (CRD). The treatments consisted of synthetic dye acetocarmine as a control and red spinach leaf extract with concentrations of 20%, 40%, 60%, 80%, and 100%, each with three repetitions. Data collection was carried out through microscopic observation and digital documentation. Assessment of staining quality was carried out using a questionnaire validated by experts, including indicators of color quality, the ability to distinguish cell nuclei, cell nucleus color, cell membrane color, and color contrast. Data analysis was carried out descriptively qualitatively in the form of percentages. The results showed that red spinach leaf extract was able to color onion root cell division preparations with varying quality at each concentration. Concentrations of 20%–80% produced staining quality with good criteria, with average values ranging from 75.56%–77.78%. A concentration of 100% showed the highest value of 84.44% with very good criteria and approaching the quality of acetocarmine dye. Increasing the extract concentration had a positive effect on color intensity, cell nucleus brightness, and preparation contrast, although in some preparations there was a decrease in the cell brightness limit due to the preparation technique. Red spinach leaf extract, particularly at 100% concentration, has the potential to be used as an alternative natural dye in onion root cell division preparations. Although its effectiveness is still slightly lower than the synthetic dye acetocarmine in highlighting cell nuclei, red spinach leaf extract is safer and more environmentally friendly, making it suitable for use in biology lab activities, especially at the high school level. Further research is needed to optimize the concentration and preparation techniques to improve the staining quality.