Stomata are small pores found in the leaf epidermis. Changes in stomatal aperture regulate leaf gas exchange. An increase in atmospheric [C02] causes a partial stomatal closure, reducing ~vapotranspiration and increasing leaf temperature. The aim of this study was' to use infrared thermal imaging to track changes in leaf temperature in response to high [C02], in order to isolate and characterize Arabidopsis thaliana mutants with aberrant stomatal responses. Two thermal imaging cameras were used to measure leaftemperature difference between Ler and abil-l plants $ld it was found that this was the largest (0.9-1.5 °C) at air relative humidity of 40-60%. Subsequently, a Teflon covered chamber was constructed to test the stomatal response to high [C02] of Col-O plants from 20-35 days old. Plants were imaged while subjected to 360 ppm [C02] for 40 min and then subjected to 1500 ppm [C0 2] for 40- 60 min. 20 day old Col-O plants did not show an increase in leaf temperature, whereas older plants did show an increase of between I-2°C after 40 min of higher [C02]' 20,000 Arabidopsis EMS mutants were screened comparing their leaf temperature at 360 and 1500 ppm [C02]' 68 mutants showed a higher or lower leaf temperature than Col-O at 1500 ppm [C02]' Five of the 44 mutant lines that were fertile were chosen for genetic and physiological characterization: the 'hot' mutant N2, and the 'cool' mutants F, EEA8, E26.2 and MQl. N2 and BEA8 carried recessive mutations while the others carried dominant mutations. Interestingly, the lower epidermis of the N2 mutant had 14.2 % lower SI, 85 % higher SD and 128 % higher ED and the EEA8 mutant had 41 % higher SD and 52 % higher ED compared to Col-O plants. In addition, leaf gas exchange analysis showed that MQl has higher & than Col-O when exposed to 2100 ppm [C02] in the light, as well as in the dark at 360 ppm [C02].
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:485257 |
| Date | January 2006 |
| Creators | Provvidenza Tagliavia, Cecilia Patrizia |
| Publisher | Lancaster University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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