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Metabolic heat and CO2 production rates during germination of melon (Cucumis melo L.) seeds measured by microcalorimetry
Year:
2001
Source of publication :
Seed Science Research
Authors :
אדלשטיין, מנחם
;
.
Volume :
11
Co-Authors:
Edelstein, M., Department of Vegetable Crops, Agricultural Research Organization, Newe ya'Ar Research Center, P.O. Box 1021, Ramat Yishay 30095, Israel
Bradford, K.J., Department of Vegetable Crops, University of California, Davis, CA 95616-8631, United States
Burger, D.W., Department of Environmental Horticulture, University of California, One Shields Avenue, Davis, CA 95616-8631, United States
Facilitators :
From page:
265
To page:
272
(
Total pages:
8
)
Abstract:
Metabolic heat and CO2 production rates were measured by microcalorimetry during germination of two melon (Cucumis melo L.) accessions, Noy Yizre'el (a cold-sensitive cultivar) and Persia 202 (a cold-tolerant breeding line), differing in their ability to germinate at low temperature (14°C). In seeds that were imbibed at either 14 or 25°C, both heat production rates (φ) and CO2 evolution rates (Rco2) were higher in Persia 202 compared to Noy Yizre'el. At 14°C, φ and Rco2 of intact Noy Yizre'el seeds remained close to zero and germination was inhibited, but metabolic activity increased with time in decoated seeds (testa removed) and most embryos germinated. The presence of the testa had less effect on metabolic activity or germination of Persia 202 seeds at 14°C. The ratio of φ/Rco2 (calorespirometric ratio) is an indication of the substrate being utilized for respiration, with lower values (∼455 kJ mol-1) associated with carbohydrate substrates and higher values (∼800 kJ mol-1) associated with lipid substrates. Removal of the testae of Noy Yizre'el seeds increased φ/Rco2 at 14°C, suggesting that improved oxygen supply to the embryo promotes a shift from carbohydrate to lipid respiratory substrates associated with germination. Consistent with this interpretation, when the hilum apertures of the seed coats were sealed with silicone, φ, Rco2 and φ/Rco2 of Noy Yizre'el seeds remained low and germination was inhibited at 25°C, while in Persia 202 seeds the same treatment had relatively little effect on φ and Rco2, φ/Rco2 approached the value expected for lipid respiratory substrates (700 kJ mol-1), and germination occurred. This confirms earlier anatomical work indicating that the testae of Persia 202 seeds were more porous than were those of Noy Yizre'el seeds, contributing to the greater tolerance of Persia 202 seeds to low temperatures. Abscisic acid (ABA) was also inhibitory to melon seed germination; imbibition of seeds at 25°C in 250 μM ABA decreased φ and Rco2, and φ/Rco2 remained lower than in control seeds in both genotypes. This effect of ABA on metabolic activity could be a cause or consequence of inhibition of germination.
Note:
Related Files :
Abscisic acid
Calorimetry
Cucumis melo
Cucumis melo L.
Melo
Metabolic heat rate
respiration
Seed germination
temperature
עוד תגיות
תוכן קשור
More details
DOI :
Article number:
Affiliations:
Database:
סקופוס
Publication Type:
מאמר
;
.
Language:
אנגלית
Editors' remarks:
ID:
19271
Last updated date:
02/03/2022 17:27
Creation date:
16/04/2018 23:27
Scientific Publication
Metabolic heat and CO2 production rates during germination of melon (Cucumis melo L.) seeds measured by microcalorimetry
11
Edelstein, M., Department of Vegetable Crops, Agricultural Research Organization, Newe ya'Ar Research Center, P.O. Box 1021, Ramat Yishay 30095, Israel
Bradford, K.J., Department of Vegetable Crops, University of California, Davis, CA 95616-8631, United States
Burger, D.W., Department of Environmental Horticulture, University of California, One Shields Avenue, Davis, CA 95616-8631, United States
Metabolic heat and CO2 production rates during germination of melon (Cucumis melo L.) seeds measured by microcalorimetry
Metabolic heat and CO2 production rates were measured by microcalorimetry during germination of two melon (Cucumis melo L.) accessions, Noy Yizre'el (a cold-sensitive cultivar) and Persia 202 (a cold-tolerant breeding line), differing in their ability to germinate at low temperature (14°C). In seeds that were imbibed at either 14 or 25°C, both heat production rates (φ) and CO2 evolution rates (Rco2) were higher in Persia 202 compared to Noy Yizre'el. At 14°C, φ and Rco2 of intact Noy Yizre'el seeds remained close to zero and germination was inhibited, but metabolic activity increased with time in decoated seeds (testa removed) and most embryos germinated. The presence of the testa had less effect on metabolic activity or germination of Persia 202 seeds at 14°C. The ratio of φ/Rco2 (calorespirometric ratio) is an indication of the substrate being utilized for respiration, with lower values (∼455 kJ mol-1) associated with carbohydrate substrates and higher values (∼800 kJ mol-1) associated with lipid substrates. Removal of the testae of Noy Yizre'el seeds increased φ/Rco2 at 14°C, suggesting that improved oxygen supply to the embryo promotes a shift from carbohydrate to lipid respiratory substrates associated with germination. Consistent with this interpretation, when the hilum apertures of the seed coats were sealed with silicone, φ, Rco2 and φ/Rco2 of Noy Yizre'el seeds remained low and germination was inhibited at 25°C, while in Persia 202 seeds the same treatment had relatively little effect on φ and Rco2, φ/Rco2 approached the value expected for lipid respiratory substrates (700 kJ mol-1), and germination occurred. This confirms earlier anatomical work indicating that the testae of Persia 202 seeds were more porous than were those of Noy Yizre'el seeds, contributing to the greater tolerance of Persia 202 seeds to low temperatures. Abscisic acid (ABA) was also inhibitory to melon seed germination; imbibition of seeds at 25°C in 250 μM ABA decreased φ and Rco2, and φ/Rco2 remained lower than in control seeds in both genotypes. This effect of ABA on metabolic activity could be a cause or consequence of inhibition of germination.
Scientific Publication
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