Water uptake dynamics in soybean seeds: influence in seeds performance and DNA integrity

ABSTRACT: Relationships among water uptake rate and temperatures were investigated in five soybean seeds lots cv. M 6410 IPRO. Germination, field emergence and electrical conductivity tests were applied to determine seed performance after fast (complete immersion in water), control (moist substrate) and slow (moist atmosphere) imbibitions both at 20 °C and 30 °C. The fresh weight increment over time in soybean seeds during imbibition was recorded. In parallel, analysis of the DNA integrity of seedlings obtained from such seeds was performed in gel electrophoresis. Absorption pattern of soybean seeds were similar among temperatures, but absorption characteristics vary with time progress according to the way of water entrance into the seeds. Upon fast imbibition seeds germinated lower than non-fast-imbibed seeds, besides loss of seed performance. In contrast, slow-imbibed seeds showed high germination, low abnormal seedlings and maintenance of seeds performance. DNA isolation from fast imbibed seeds was highly degraded; although, some considerably degraded samples were reported in controlled imbibed seeds and the best preserved DNA was found in slow-imbibed seeds. The pattern of DNA degradation is typically passive or non programmed cell death. Our results showed it is important to consider the water uptake rate during germination test, since DNA integrity plays a critical role during seed imbibition, preserving soybean seed performance.