The pathway of chlorophyll catabolism during leaf senescence is known in a fair amount of biochemical and cell biological detail. In the last few years, genes encoding a number of the catabolic enzymes have been characterized, including the key ring-opening activities, phaeophorbide a oxygenase (PaO) and red chlorophyll catabolite reductase (RCCR). Recently, a gene that modulates disassembly of...

Effects of atmospheric humidity and soil moisture content on the relative intensity of chlorophyll fluorescence of cucumber (Cucumis sativus L.) exposed to high air temperatures were assessed as a measure of heat stress or injury. 1. After exposure to 25 •Ž (control) and 42•‹, 44•‹ and 46•Ž for two to three hours, the intensity of fluorescence decreased a little at 42•‹ and 44•Ž but markedly at...

The yellow-green leaf mutant has a non-lethal chlorophyll-deficient mutation that can be exploited in photosynthesis and plant development research. A novel yellow-green mutant derived from Triticum durum var. Cappelli displays a yellow-green leaf color from the seedling stage to the mature stage. Examination of the mutant chloroplasts with transmission electron microscopy revealed that the sha...

The MERIS Terrestrial Chlorophyll Index (MTCI), a standard level 2 ESA product, provides information on the chlorophyll content of vegetation (amount of chlorophyll per unit area of ground). This is a combination of information on leaf area index (LAI, area of leaves per unit area of ground) and the chlorophyll concentration of those leaves. The MTCI correlates strongly with chlorophyll content...

Published in Agron. J. 103:1090–1099 (2011) Posted online 2 May 2011 doi:10.2134/agronj2010.0395 Copyright © 2011 by the American Society of Agronomy, 5585 Guilford Road, Madison, WI 53711. All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retri...

Most studies assessing chlorophyll fluorescence (ChlF) have examined leaf responses to environmental stress conditions using active techniques. Alternatively, passive techniques are able to measure ChlF at both leaf and canopy scales. However, the measurement principles of both techniques are different, and only a few datasets concerning the relationships between them are reported in the litera...

The loss of chlorophyll and total leaf nitrogen during autumnal senescence of leaves from the deciduous tree Platanus occidentalis L. was accompanied by a marked decline in the photosynthetic capacity of 02 evolution on a leaf area basis. When expressed on a chlorophyll basis, however, the capacity for lightand C02-saturated O2 evolution did not decline, but rather increased as leaf chlorophyll...