Effects of temperature on germination and mitochondrial dehydrogenases in two soybean (Glycine max) cultivars

Abstract
The effects of eight germination temperatures from 10°C to 35°C on germination and dehydrogenase activities of two soybean (Glycine max [L.] Merr.) cultivars were investigated after 48 h of seedling growth. Axis fresh weights of cv. Chippewa increased as germination temperature increased from 10°C to 35°C. In contrast, axis fresh weights for the cv. Wells increased more slowly with increasing temperature and reached a maximum at c. 25°C. In general, in vitro activities of glutamate dehydrogenase (GDH), NADP‐isocitrate dehydrogenase (NADP‐ICDH), and malate dehydrogenase (MDH) from the axes of cv. Chippewa correlated well with increases in axis fresh weights. GDH and MDH activities from axes of the cv. Wells also reflected increases in axis fresh weights although the correlation was not as evident as for the cv. Chippewa. NADP‐ICDH activity from ‘Wells’ axes was highest at 35°C even though germination was poor at this temperature. GDH and MDH activities from cotyledons of both cultivars were not correlated with axis weight increases. No GDH activity was detected in ‘Wells’ cotyledons from seeds germinated at 35°C.