<![CDATA[Abstract. Nafisah AZ, Efendi D, Sukma D, Nurcholis W. 2026. Colchicine-induced polyploidization and phytochemical evaluation of selected lavender (Lavandula angustifolia) plantlets. Biodiversitas 27 (10): d271005. https://doi.org/10.13057/biodiv/d271005. Lavender (Lavandula angustifolia) is an introduced aromatic crop in Indonesia, and induced variation can widen its germplasm. We estimated the median Lethal Concentration (LC50) of colchicine for two-node in vitro explants, treated explants around this value, and characterized selected M1V3 lines by flow cytometry, stomatal traits, and colorimetric assays. Survival after 48 h immersion in 0-0.24% colchicine was analyzed with binomial models; the probit model gave an LC50 of 0.147% (95% CI 0.132-0.161%) four weeks after treatment. Explants were then treated with 0, 0.11, 0.14, and 0.17% colchicine. At M1V3, branch number was highest at 0.17% (3.20 versus 1.10 in the control), plantlets from 0.14% had the fewest leaves, and plantlet height did not differ among concentrations. Of five visually selected candidates, flow cytometry indicated one putative tetraploid (K1-B-1.3-1-1; fluorescence ratio 2.22 relative to the diploid control), one mixoploid (K1-B-4.3-1-2), and one putative hexaploid (K3-B-6.3-1-1; ratio 3.23), while two remained diploid. All candidates had lower stomatal density than the control, whereas stomatal size varied widely between leaves of the altered lines, which is consistent with chimerism. In three extraction replicates of pooled tissue per line, mean total flavonoid and phenolic contents and FRAP values of the putative tetraploid and putative hexaploid were 13-32% above those of the diploid control, DPPH values differed by less than 4%, and most extract values overlapped. Because each ploidy class was represented by a single selected line and ploidy stability was not cytologically confirmed, these phytochemical results describe the selected lines rather than a general effect of ploidy.]]>
