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| Publication Type:
| Refereed |
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| Author(s): | Karnok, K. J.;
Beard, James B |
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| Author Affiliation: | Department of Crop and Soil Sciences, Texas Agricultural Experiment Station, Texas A&M Univerisity |
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| Title: | The effects of chilling temperatures on the chloroplast ultrastructure of Cynodon dactylon as affected by gibberellic acid |
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| Source: | Acta Agronomica Academiae Scientiarum Hungaricae. Vol. 34, No. 3/4, 1985, p. 259-265. |
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| Publishing Information: | Budapest, Hungary: Az Akademia |
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| # of Pages: | 7 |
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| Keywords: | TIC Keywords: Temperatures; Chilling; Chloroplasts; Cynodon dactylon; Gibberellic acid; Photosynthesis; Discoloration; Mesophyll; Cold
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| Cultivar Names: | Pee Dee; Ormond |
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| Abstract/Contents: | "Low temperature discoloration of warm season perennial grasses is the result of a series of physiological disruptions referred to as chilling injury. Chilling injury occurs when air temperature is above freezing, but below 15 °C. Photosynthesis is one of the first physiological disruptions occurring in chill sensitive plants exposed to chilling temperatures. This disruption is closely followed by a deterioration or necrosis of the leaf tissue. It has been suggested that the photosynthetic reduction may be the result of excessive starch grain accumulation in the chloroplasts. It has also been suggested that exogenous gibberellic acid (GA₃) may dissipate accumulated starch by stimulating amylase activity. This theory was tested by exposing GA₃ treated and non-treated Pee Dee (chill sensitive) and Ormond (chill tolerant) bermudagrass [Cyndon dactylon (L.) Pers.] to chilling temperatures and then examining their chloroplast ultrastructure with a transmission electron microscope. Starch grain accumulation in the bundle sheath chloroplasts of both non-treated bermudagrass cultivars at the end of the initial chilling day were similar and always substantially lower than the pre-stress levels. Ormond treated with GA₃ showed a reduction in the number of starch granules in the bundle sheath chloroplasts when compared to non-treated Ormond turf. However, there was no reduction in the number of starch grains in the bundle sheath chloroplasts from GA₃ treated Pee Dee when compared to non-treated Pee Dee plants. Mesophyll and bundle sheath chloroplast ultrastructure, including granal stacking, lamellae system and peripherial reticulum when present, appeared normal in both bermudagrass cultivars after 18 hours of chilling stress." |
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| Language: | English |
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| References: | 10 |
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| Note: | Pictures, b/w |
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| ASA/CSSA/SSSA Citation (Crop Science-Like - may be incomplete):
Karnok, K. J., and J. B. Beard. 1985. The effects of chilling temperatures on the chloroplast ultrastructure of Cynodon dactylon as affected by gibberellic acid. Acta Agronomica Academiae Scientiarum Hungaricae. 34(3/4):p. 259-265. |
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MSU catalog number: S16 .18 A6 |
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