MATURATION AND DESICCATION SENSITIVITY IN DEVELOPING SEEDS OF LETTUCE (LACTUCA SATIVA L.)
| Autor: | Miller B. McDonald, Roel C. Rabara, Yael Vodovotz, David Tay |
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| Rok vydání: | 2008 |
| Předmět: | |
| Zdroj: | Acta Horticulturae. :67-74 |
| ISSN: | 2406-6168 0567-7572 |
| Popis: | Onsets of germination and desiccation tolerance in developing seeds were determined in greenhouse-grown lettuce plants. Lettuce cv. ‘Tango’ were planted and maintained in the greenhouse throughout its growing period. Flowers were sampled every day starting at 4 days after flowering (DAF). Seeds were manually extracted from the collected flowers and standard germination was done. Moisture content determination was done on the freshly harvested seeds. Sample seeds from the freshly harvested flowers were also dried for 2 days in an activated desiccant (calcium sulfate) and over salt solution, sodium bromide (54% RH) at 25oC to determine desiccation tolerance of the developing seeds at different stages of development. During drying, most water was lost (91-100% of the final seed moisture content) at first day of drying both in dry desiccant and salt-dried seeds. Moisture content of seeds at different stages of development when dried over a desiccant ranged from 2.2 – 6.9% wet basis. Drying over sodium bromide solution, the seeds achieved equilibrium, that is, there is no change in seed weight, in the second day of drying. The moisture content of seeds after 2d drying in sodium bromide ranged between 5.713.9%. Seed maturity in lettuce was achieved 14 DAF but germination of freshly harvested was observed as early as 4 DAF (45%). Maturation drying was observed at 9DAF as indicated by the onset of loss of moisture content in the seeds. The physiological maturity was achieved at 10 DAF. Tolerance to desiccation was observed only starting at 6 DAF for sodium bromide-dried seeds (3% germination of normal seedlings) and 7 DAF in CaSO4-dried seeds (13% germination). Drying of seeds in saltsolutions has improved the vigor of seeds based on the speed of germination. However, drying in a dry desiccant has resulted to decrease in vigor. This could be due to rapid water loss during drying as indicated by low moisture content in seeds dried in desiccant than in salt solution. |
| Databáze: | OpenAIRE |
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