Infrared and CO2-based assessment of seed viability in Lafoensia pacari A.St.-Hil. (Lythraceae)

Abstract

Rapid methods for assessing seed viability were evaluated using Lafoensia pacari as a biological model, focusing on infrared emission (IRe) and carbon dioxide (CO₂) as potential indicators. Seed Morphology, dimensional traits, thousand-seed mass, water content, temperature profiles (air, seeds, and substrates) via IRe, respiratory activity (CO₂, IRe, and tetrazolium [TZ] tests), as well as imbibition, electrical conductivity (EC), germination at 14 and 21 days on paper and sand, seedling abnormalities, and mortality were assessed. Seeds were found to be flattened, winged, and light, with a brittle seed coat that did not impede water uptake. Viability estimates from TZ (71%) and IRe (75%) at temperatures of 25.07-26.32 ºC after 96 hours were correlated, although neither matched germination rates on paper (34%) or sand (53%). Early deterioration was detected by EC and 14-day germination, particularly on paper, indicating that substrate type influenced seed vigor and germination outcomes. CO₂ measurement proved ineffective, whereas IRe allowed reliable estimation of seed viability.