Abstract
Changes in the properties of water in excised embryos were measured during the late stages of grain development in Zizania palustris cv. Franklin and Johnson and a population of the endangered species Z. texana. The relationships between water content and water activity were determined from water sorption isotherms, measured at temperatures between 35 and 5 degrees C and then derived for lower temperatures. The freezing and melting behaviour of water in embryos at different water contents was determined using differential scanning calorimetry. The moisture content of embryos at high water activities decreased with maturation, as did the moisture content at which freezing transitions were not observed. While the temperatures of freezing and melting transitions decreased as the moisture content of embryos decreased, there were no discernable differences among embryos at different developmental stages. The properties of water measured in maturing Zizania embryos approached those for orthodox seeds as determined from the strength of water sorption, the enthalpy of the melting transition and the moisture content at which water is unfreezable. From these data it is concluded that the properties of water in recalcitrant Zizania embryos change with development to resemble those of embryos of desiccation-tolerant seeds, but that the seeds never achieve the orthodox condition. The effects of interactions between moisture content and temperature on desiccation damage, freezing damage and germination in Zizania are predicted, based on the physical properties of water and the correspondence of these properties with physiological function reported for other species. The resulting 'phase diagram' defines possible combinations of moisture content and temperature for storage under equilibrium conditions.
Original language | English (US) |
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Pages (from-to) | 211-224 |
Number of pages | 14 |
Journal | Seed Science Research |
Volume | 4 |
Issue number | 2 |
DOIs | |
State | Published - 1994 |
Bibliographical note
<p>Last updated - 2018-02-10</p><p>paper presented at the International workshop on desiccation tolerance and sensitivity of seeds and vegetative plant tissues, Kruger National Park, South Africa, 17-22 Jan. 1994//</p>
<p>Paper presented at the International Workshop on Desiccation Tolerance and Sensitivity of Seeds and Vegetative Plant Tissues, Kruger National Park, South Africa, January 17-22, 1994. Includes references</p>
<p>SuppNotes - Seed science research. 1994 June, v. 4, no. 2; Paper presented at the International Workshop on Desiccation Tolerance and Sensitivity of Seeds and Vegetative Plant Tissues, Kruger National Park, South Africa, January 17-22, 1994.</p>
Keywords
- temperature
- seeds
- water relations
- damage
- seed germination
- Development
- Physiology
- Reproduction
- water
- Zizania
- Zizania palustris
- development
- recalcitrant seeds
- seed storage
- storage
- seed development
- cold injury
- maturity stage
- physical properties
- seed maturation
- water activity
- water content
- water stress
- Zizania texana
- moisture content
- desiccation
- plant embryos
- plant water relations
- tolerance
- Biochemistry and Molecular Biophysics
- article
- embryo (plant)