Benefits of rice seed priming are offset permanently by prolonged storage and the storage conditions

Abstract

Seed priming is a commercially successful practice, but reduced longevity of primed seeds during storage may limit its application. We established a series of experiments on rice to test: (1) whether prolonged storage of primed and non-primed rice seeds for 210 days at 25°C or −4°C would alter their viability, (2) how long primed rice seed would potentially remain viable at 25°C storage, and (3) whether or not post-storage treatments (re-priming or heating) would reinstate the viability of stored primed seeds. Two different rice cultivars and three priming agents were used in all experiments. Prolonged storage of primed seeds at 25°C significantly reduced the germination (>90%) and growth attributes (>80%) of rice compared with un-stored primed seeds. However, such negative effects were not observed in primed seeds stored at −4°C. Beneficial effects of seed priming were maintained only for 15 days of storage at 25°C, beyond which the performance of primed seeds was worse even than non-primed seeds. The deteriorative effects of 25°C storage were related with hampered starch metabolism in primed rice seeds. None of the post-storage treatments could reinstate the lost viability of primed seeds suggesting that seeds become unviable by prolonged post-priming storage at 25°C.

Seed priming in dry direct-seeded rice: consequences for emergence, seedling growth and associated metabolic events under drought stress

“…4,7) and faster rate of starch breakdown in germinating primed seeds, which presumably provided the substrates necessary for generating the energy required for growth and maintenance processes (Hussain et al 2015b). Conclusively, studies conducted under controlled and field conditions revealed that seed priming can alleviate the negative effects of drought stress on emergence as well as seedling establishment and growth of dry-direct seeded rice.…”

“…In rice, amylase activity is highly induced during germination (Hussain et al 2015b); however, this activity begins to appear even earlier, during seed maturation. Present study highlighted the importance of a-amylase activity and total soluble sugar contents during germination and early seedling growth under drought conditions.…”

“…Seed priming is a controlled hydration technique that allows the pre-germination metabolisms without actual germination (Hussain et al 2015b). It is one of the most effective, pragmatic and shortterm approaches for increasing seed vigor, synchronization of germination, as well as the seedlings growth of many crops under different abiotic stresses including drought (Kaya et al 2006;Farooq et al 2009).…”

Salinity Tolerance in Wheat Cultivars Is Related to Enhanced Activities of Enzymatic Antioxidants and Reduced Lipid Peroxidation

“…Neto et al also supported higher activities of antioxidants in salt tolerant species. A positive correlation of activities of antioxidant enzymes with stress tolerance has been documented , and their enhanced expression has been suggested as a stress marker. The decline observed in the activities of some antioxidants for several salt‐sensitive wheat cultivars at upper limits of salinity might be due to their inability to cope with stress induced oxidative damage.…”

Effects of pre-sowing seed treatments on establishment of dry direct-seeded early rice under chilling stress

“…The high α-amylase activity in primed seeds and seedlings is also reflected through higher soluble sugar concentrations and a faster rate of starch breakdown in germinating primed seeds, which presumably provided the substrates necessary to generate the energy required for growth and maintenance processes. It has also been proposed that the degradation and conversion of seed reserves during the germination process are related to the increase in soluble sugar contents, which presumably provides the substrates necessary to generate the energy required for growth and maintenance processes (Hussain et al 2015). In addition to the mechanisms associated with starch metabolisms, the chilling tolerance during rice seed germination and early seedling growth induced by seed treatments might be attributed to increased level of antioxidant activity and greater membrane stability (Pouramir et al 2014; Khaliq et al 2015).…”