Proline: use as an indicator of temperature stress in bean seeds
Nelson Barbosa Machado Neto, Ceci Castilho Custódio, Ana Beatriz Gatti, Maria Regina Priolli, and Victor José Mendes Cardoso
Temperature stress can lead to several metabolic alterations along the entire plant cycle, including germination. To verify the effect of high or low temperatures, constant or in alternate cycles, 10 bean genotypes (eight cultivars and two landraces) were sown to germinate in trials for proline quantification, which were conducted in a climatic chamber under five thermal treatments: T1 – suboptimal temperature (96h at 8 ºC); T2 – cold shock (48h at 18 ºC followed by 48h at 8 ºC); T3 – optimal temperature (96h at 18 ºC); T4 – heat shock (48h at 18 ºC followed by 48h at 37 ºC) and T5 – supra optimal temperature (96h at 37 ºC). Proline was quantified at 520 nm in a spectrophotometer. There were responses to different environments for each genotype. The assessment of proline is recommended in germinating seeds as a means to discover stress temperature responsive bean lines, as for example ‘Guarumbé’.