Estimation of the light distribution between photosystems I and II in intact wheat leaves by fluorescence and photoacoustic measurements

✍ Scribed by S. Malkin; C. L. Morgan; R. B. Austin

• Publisher: Springer
• Year: 1986
• Tongue: English
• Weight: 586 KB
• Volume: 7
• Category: Article
• ISSN: 0166-8595
• DOI: 10.1007/bf00014679

✦ Synopsis

Usisng intact leaves, the extent of the decrease in chlorophyll a fluorescenece caused by the addition of continuous 710 nm light superimposed on modulated (20 Hz) 550nm light was used to determine the distribution of this absorbed light between photosystems I (a) and II (/3). The F o and F m levels, which defined the total variable fluorescenece, were taken as equal to those obtained with excess 710 nm light and with saturating blue-green light, respectively.

An analogous procedure was used with a photoacoustic detector, saturating white light defining a base line for oxygen yield, the levels with an without 710 nm light being used to define ~3 and a respectively.

The two methods gave similar values for the distribution of light between the two photosystems for the experimental conditions used, ~ averaging 0.55 for a range of Triticum genotypes and Brachypodium sylvaticum grown in high or low light.