Descriptive Early Growth Trajectories of Radish (Raphanus sativus L.) Seedlings under Acetic Acid, Levothyroxine, and Combined Exposure: A Pilot Observation

Abstract

Radish (Raphanus sativus L.) is an important cruciferous (Brassicaceae) crop whose early development can respond to environmental conditions and chemical exposure. This descriptive pilot observation documented vertical height and visible morphology in four individual experimental units assigned to distilled water, acetic acid, levothyroxine, or combined acetic acid plus levothyroxine exposure over 14 days. Five seeds were initially sown in each container and thinned to one retained seedling, leaving one independent container/plant per condition. Chemical applications began on Day 5; substantial between-unit height differences were already present on Days 3–4, and the timing of the Day 5 measurement relative to the first application was not documented. The distilled-water unit reached a maximum recorded vertical height of 90 mm and ended at 75 mm. The acetic-acid unit reached 69 mm and ended at 58 mm, with visible browning and wilting late in the observation period. The levothyroxine unit reached 75 mm and ended at 64 mm, whereas the combined-exposure unit reached 81 mm and ended at 75 mm. Because stem bending and leaf expansion influenced vertical measurements, post-peak reductions may reflect plant architecture rather than biomass loss. The recorded protocol did not provide independent treatment replication, a reproducibly specified acetic-acid concentration/dilution, standardised delivered spray volumes, or standardised watering. Accordingly, these data are descriptive observations of individual experimental units and do not establish treatment effects, statistical significance, synergy, or mechanism. They provide a basis for a randomised, standardised, independently replicated factorial follow-up experiment.