Laser-based trace gas detection of ethane as a result of photo-oxidative damage in chilled cucumber leaves (invited)

Abstract

At low temperatures, high light intensity induces strong photooxidative lipid peroxidation in chilling sensitive cucumber leaves. A sensitive laser-based photoacoustic detector was employed to monitor on-line the evolution of ethane, one of the end products of lipid peroxidation. The ⌬vϭ2 CO laser operated in the 2.62-4.06 m infrared wavelength region with a maximum intracavity power of 11 W. In combination with an intracavity placed photoacoustic cell the laser was able to detect ethane down to 0.5 part per billion. Cucumber leaf disks chilled in the light produce ethane; the rate of ethane production depends on the applied temperature, light intensity, and period of chilling.

Kinetics of Ethanol and Acetaldehyde Release Suggest a Role for Acetaldehyde Production in Tolerance of Rice Seedlings to Micro-aerobic Conditions

“…The alternative catalase-based reaction using H 2 O 2 to oxidize ethanol is therefore the more likely route for acetaldehyde synthesis. Indirect experimental evidence that reactive oxygen species (ROS), the putative source of the H 2 O 2 , are present in postanaerobic tissues of rice has come from results showing a post-anaerobic release of ethane (C 2 H 6 ) by seedlings grown under the same conditions used in the present experiments (Santosa, 2002). Supporting evidence is also available from the electron spin resonance studies of Thongbai and Goodman (2000).…”

“…Boamfa et al, 2003), with irradiances as low as 20 mmol m À2 s À1 (Vervuren et al, 2003) being effective in this way. Similarly, submergence in the morning when carbohydrate reserves are already low is especially damaging (Ram et al, 2002;Santosa, 2002). The cultivar FR13A is known to tolerate complete submergence better than most others.…”

Detection of dissolved gas in oil–insulated electrical apparatus by photoacoustic spectroscopy

“…As a result, an acoustic signal continues to be generated as long as the modulated frequency is within a certain range. (3) By using a highly sensitive microphone, the pressure changes in the photoacoustic cell are converted into an electronic signal for subsequent external circuit analysis and processing [12], [13].…”

“…It has found widespread application in various disciplines, such as physics, chemistry, biology, medicine, and geology. The major advantages associated with photoacoustic spectroscopy are that it (1) is characterized by high monitoring sensitivity because it directly measures the energy absorbed by gases without background noise; (2) uses easily available air instead of high-purity inert gases as the carrier gas without consuming the to-be-measured gas; (3) does not require chromatographic columns and sensors, which are easily contaminated, undergo aging, and require frequent replacement; (4) does not require a calibration gas, raising the prospect of realizing true maintenance-free operation; and (5) displays a high lev-el of versatility because it even detects the contents of high-concentration gases in the oil tank of on-load tap changers [8]- [12]. Therefore, photoacoustic spectroscopy can greatly enhance the on-line monitoring of electrical system maintenance owing to its high stability, low drift, and maintenance-free features.…”

Patterns of peroxidative ethane emission from submerged rice seedlings indicate that damage from reactive oxygen species takes place during submergence and is not necessarily a post-anoxic phenomenon

“…A similar set-up was used to detect extremely low concentrations of acetaldehyde and ethanol in relation to fermentation processes by cucumber seeds (Leprince et al 2000), red bell peppers (Zuckermann et al 1997) and rice seedlings (Boamfa et al 2003(Boamfa et al , 2005; methane and water emissions from cockroaches and beetles were measured as performed by Bijnen et al (1996). For ethane detection, the laser was re-designed and adjusted to a mid-infrared wavelength region between 2.6 and 4.1 m (Bachem et al 1993;Martis et al 1998;Santosa 2002;Santosa et al 2003). BrieXy, the trace gases are detected via their absorption of rapidly chopped infrared light, which generates pressure variations, resulting in acoustic energy detected by a miniature microphone.…”