Thermotolerance in lettuce seeds: association with ethylene and endo-B-mannanase.
Weakening of the endosperm tissue around the radicle tip before radicle protrusion and a potential role of endo-β-mannanase during germination of lettuce seeds (Lactuca sativa L.) at high temperature (35 °C) were investigated. Seeds from the thermotolerant genotypes ‘Everglades’ and PI 251245 had greater endo-β-mannanase activity before radicle protrusion at 35 °C than the thermosensitive genotypes ‘Dark Green Boston’, ‘Valmaine’ and ‘Floricos 83’. Thermotolerant genotypes also generated more ethylene at high temperature. At 35 °C, germination of ‘Dark Green Boston’ and ‘Everglades’ seeds produced at days/nights of 20/10 °C was 10% and 32%, respectively, whereas germination of seeds produced at days/nights of 30/20 °C was 67% and 83%, respectively. Higher endo-β-mannanase activity was observed before radicle protrusion in ‘Dark Green Boston’ seeds produced at 30/20 °C compared with those produced at 20/10 °C. A relationship between seed germination at high temperature, ethylene production, and an increase in endo-β-mannanase activity before radicle protrusion was confirmed.
| Main Authors: | , , |
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| Format: | Artigo de periódico biblioteca |
| Language: | eng |
| Published: |
2000-09-21
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| Subjects: | Tolerancia, Termodormecia, Tolerance, Thermodormancy, Enzyme, Alface, Enzima, Etileno, Lactuca Sativa, Semente, Temperatura, ethylene, lettuce, temperature, |
| Online Access: | http://www.alice.cnptia.embrapa.br/alice/handle/doc/768128 https://doi.org/10.21273/JASHS.125.4.518 |
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| Summary: | Weakening of the endosperm tissue around the radicle tip before radicle protrusion and a potential role of endo-β-mannanase during germination of lettuce seeds (Lactuca sativa L.) at high temperature (35 °C) were investigated. Seeds from the thermotolerant genotypes ‘Everglades’ and PI 251245 had greater endo-β-mannanase activity before radicle protrusion at 35 °C than the thermosensitive genotypes ‘Dark Green Boston’, ‘Valmaine’ and ‘Floricos 83’. Thermotolerant genotypes also generated more ethylene at high temperature. At 35 °C, germination of ‘Dark Green Boston’ and ‘Everglades’ seeds produced at days/nights of 20/10 °C was 10% and 32%, respectively, whereas germination of seeds produced at days/nights of 30/20 °C was 67% and 83%, respectively. Higher endo-β-mannanase activity was observed before radicle protrusion in ‘Dark Green Boston’ seeds produced at 30/20 °C compared with those produced at 20/10 °C. A relationship between seed germination at high temperature, ethylene production, and an increase in endo-β-mannanase activity before radicle protrusion was confirmed. |
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