Digital Analysis on Cone-Thorn Density and Morphology in Mutant Aralia elata Seedlings Induced by Ethyl Methanesulfonate

Natural Aralia elata reserves have been heavily exploited for medical and edible uses, resulting in an essential demand to rehabilitate the understory population using artificially cultured seedlings.Thorns around the cone tip generate a significant obstacle to affect the efficiency of A. elata development.In this study, ethyl methanesulfonate (EMS) was employed to induce mutagenesis and then growth and biomass in A. elata seedlings.EMS was applied to seedlings by root soaking or whole-plant spraying at doses of 0 (control), 19 (EMS-19), 38 (EMS-38) and 76 M (EMS-76).Height growth was higher in the spraying treatment by 10% than in the root-soaking treatment.Compared to the control, the EMS-38 treatment resulted in lower conethorn density (1.3 individuals cm -2 ) and the EMS-76 treatment resulted in lower fine root biomass (0.07 g plant -1 ), length (215 cm), and tip-number (39.8).Through digital analysis on shoot image, EMS-treated seedlings had lower green-color index (41-56) than controlled seedlings (61-84).Color and brightness indices were positively correlated with fine root growth and biomass, while red-color index had a positive relationship with height growth.