Seed O2 Uptake and Germination of Cold-Tolerant and Cold-Intolerant Cultivars of Muskmelon
- Menahem Edelsteina and
- Gregory E. Welbaum *b
Muskmelon (Cucumis melo L.) is a warm-season, frost-sensitive crop that germinates poorly at low temperatures. The cold-sensitive cultivar ‘Noy Yizre’el' (NY) and the cold-tolerant cultivar ‘Persia 202’ (P-202) were compared at 15 and 25°C to determine how seed-coat anatomy and O2 uptake affected low-temperature germinability. A Clark-type oxygen electrode was used to measure the O2 uptake of intact and decoated seeds through the gas phase. Scanning electron microscopy revealed pores on the surface and in the cross sections of seed coats of P-202 but not NY. Both genotypes germinated at 25°C, but only intact P-202 and decoated seeds of both genotypes germinated at 15°C. After 17 h of imbibition at 25°C, O2 uptake was 47% greater for intact seeds of P-202 compared with those of NY. Removing the seed coat increased O2 uptake by 37 and 58% for P-202 and NY, respectively, after 17 h of imbibition. At 15°C, the O2-uptake rate of intact P-202 seeds plateaued at a level 40% higher than that of NY after 80 h of imbibition. Removing the seed coat before imbibition at 15°C increased the O2 uptake of P-202 and NY by 50 and 57%, respectively, compared with intact seeds. The seed coats of both cultivars restricted O2 uptake, but NY had a lower rate of uptake compared with P-202 with or without the seed coat. The poor germination of NY at lower temperatures was related to lower O2 uptake by the embryo and to the restriction of O2 uptake by the seed coat.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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