Soaking injury and its reversal with polyethylene glycol in relation to respiratory metabolism in high and low vigor soybean seeds

Abstract

Germination and growth of unaged (high vigor) and accelerated aged (41°C and 100% RH for 4 days; low vigor) soybean [Glycine max (L.) Merr. cv. Essex] seeds were severely reduced by soaking the seeds under water at 25°C during the first 1 to 8 h of imbibition. Soaking in 30% polyethylene glycol (PEG) did not injure high vigor seeds and improved the performance of low vigor seeds. Soaking in water increased subsequent RQ values and acetaldehyde and ethanol levels. In high vigor seeds, the increase in RQ lasted only 1 h after transfer to aerobic conditions, whereas in low vigor seeds the increase persisted into the second h. Increases in ethanol and acetaldehyde after soaking were more pronounced in low than in high vigor seeds. The data indicate that relatively short periods under water can cause water uptake injury to imbibing soybean seeds and that this injury can be avoided by osmotically reducing the initial rate of water uptake. Seeds whose vigor has declined during accelerated aging show an additional injury which increases with soaking duration and involves alterations in respiratory metabolism including accumulation of acetaldehyde and ethanol to high, and possibly toxic, levels during imbibition.

The Role of Seed Structure and Oxygen Responsiveness in Pre-Germination Flooding Tolerance of Soybean Cultivars

“…In their study, the damage was markedly reduced by the use of an osmotic-regulating solution of polyethylene glycol (PEG 6000). They also found that the cells that failed to be stained with TTC were observed only on the periphery of the cotyledon; a similar result was reported by Woodstock and Taylorson (1981). Nordin (1984) demonstrated that the seed coat acted as a semi-permeable membrane, permitting the entry of water and certain solutes while restricting others.…”

Does Pre-Germination Flooding-Tolerant Soybean Cultivar Germinate Better under Hypoxia Conditions?

“…Muramatsu et al (2008) also found that both the seed coat and the aleurone layer play a role in reducing the speed of water absorption in 'Peking'. Soybean seeds are severely damaged by water with a high osmotic potential (Woodstock and Tao, 1981;Woodstock and Taylorson, 1981;Nakayama et al, 2005). At higher temperatures, seed germination was reduced significantly by increasing duration of soaking (Hou and Thseng, 1991); the results of the present study agreed with their finding (Table 1), but further study is needed to clarify the mechanism underlying the difference in the responses to 20ºC and 25ºC among cultivars.…”

Association of Pythium and Phytophthora with Pre-emergence Seedling Damping-off of Soybean Grown in a FieldConverted from a Paddy Field in Japan

“…Leguminous seeds are known to be intolerant to water immersion (Woodstock and Taylorson, 1981). Rapid water uptake by dry seeds of soybean causes physical destruction to the cotyledons (Nakayama et al, 2004;Kokuryu et al, 2009), and injures the membranes.…”

“…Rapid water uptake by dry seeds of soybean causes physical destruction to the cotyledons (Nakayama et al, 2004;Kokuryu et al, 2009), and injures the membranes. Anaerobic conditions force soybean seeds to change from respiration to fermentation (Woodstock and Taylorson, 1981), the latter reducing the level of energy acquisition.…”