Viability and Vigor of Osmotically Primed Muskmelon Seeds After Nine Years of Storage

Abstract

<jats:p>The viability and vigor of osmotically primed (0.3 <jats:sc>m</jats:sc> KNO<jats:sub>3</jats:sub>, 6 days, 25C) and nonprimed `PMR 45' muskmelon (<jats:italic>Cucumis melo</jats:italic> L.) seeds were compared after storage for 9 years at &lt;20C and 6% moisture content (MC, dry weight basis). Viability was compared at 20, 25, and 30C at water potentials of 0, -0.2, -0.4, -0.6, and -0.8 MPa and in soil. Additionally, stored primed and nonprimed seeds were either primed, aged (15% MC and 45C) for up to 8 days, or aged for 72 hours and primed. The force required to puncture 5-mm-long, micropylar seed pieces was measured using an Instron universal testing machine. Less force was required to puncture primed seed pieces at 0, 5, 15, 20, and 25 hours of imbibition, demonstrating that osmotic priming weakens the perisperm envelope tissue that the radicle must penetrate for germination to occur. In an earlier report, germination rate and final germination percentages were higher for osmotically primed seeds both in laboratory tests and field emergence studies conducted immediately after priming. After 9 years in storage, nonprimed seeds germinated to higher percentages in water at 30C and reduced water potential at all temperatures, while primed seeds germinated to higher percentages in water at 20 and 25C and exhibited a higher percentage of seedling emergence at a soil MC of 17%. Priming durations of ≤5 days had no effect on the viability, while longer durations decreased the viability of stored primed and nonprimed seeds. Priming generally decreased the log mean time to germination of stored nonprimed seeds but increased values for stored primed seeds. Controlled deterioration increased the log mean time to germination and decreased the viability of primed seeds faster than nonprimed seeds. Priming following controlled deterioration had no effect on nonprimed seeds and reduced the percent viability of primed seeds by 20%. Osmotic priming has a deleterious effect on the seed storage life of muskmelon seeds.</jats:p>

Muskmelon seed priming in relation to seed vigor

“…However, Nascimento & West (2000) reported the importance of drying conditions during seed priming and that the main benefits of using muskmelon primed seeds (i.e, germination at low temperature) may be lost following unfavorable drying conditions. In addition, Oluoch & Welbaum (1996a;1996b) found that priming was deleterious for 'Top Mark' muskmelon seed longevity. For tomato, the enhancement of seed germination rate by priming treatments lowered the resistance of seeds in relation to deterioration .…”

“…The improvement in germination performance resulting from priming treatments has been suggested as a result of repair mechanisms that occur during soaking (Burgass & Powell, 1984); the seeds during the maturation process and/or during storage deteriorate and need repair during imbibition in order to germinate (Osborne, 1983). Thus, aged (more deteriorated) seeds could benefit more from priming treatments.…”

“…A number of important factors may affect seed priming response, including seed quality (Parera & Cantliffe, 1994). Therefore, the response to seed priming treatments may vary among seed lots (Brocklehurst & Dearman, 1983) because of differences in seed vigor.…”

Anaerobic conditions improve germination of a gibberellic acid deficient rice

“…Mechanical disruption of the seed structure (i.e. seed coat, perisperm) may occur at high temps, as in priming (Oluoch and Welbaum, 1996).…”

Seed research for improved technologies

“…(Sanchez et al, 1986), tomato (Groot & Karssen, 1987), and muskmelon (Welbaum et al, 1995;Wilson et al, 1994) seeds. Instron measurements have also offered evidence for priming induced hydrolysis of the endosperm tissue of muskmelon seeds (Oluoch & Welbaum, 1996a;Wilson et al, 1994).…”