Abstract
Summary Formaldehyde, hydrogen peroxide and non-protein thiols were measured in the leaves of intact tobacco plants at 3 ageing stages as the function of plant age and leaf position. The average formaldehyde level changed only slightly during ageing within the range 1.1–1.4 μmole · (g fresh weight)-1. The highest formaldehyde levels were found in the youngest leaves. The H2O2 level depended strongly on plant age and leaf position. The average H2O2 content of leaves was 3.3 μmole · (g fresh weight)-1 in the oldest and in the middle-aged plants, while this value was 2.3 in the youngest plants. Within one plant gradually increasing H2O2 levels were found from the apex toward the base, but it declined in the oldest, yellowing leaves. The maximum values of H2O2 level were 2.9, 4.4 and 5.2 μmole · (g fresh weight)-1 in the young, middle-aged and old age-groups, respectively. The peroxidase activity increased more significantly with the plant age than the H2O2 level. Reversely, the highest catalase activities were found in the young leaves. Gradually decreasing foliar thiol contents were found from the apex towards the base. The reverse changes of H2O2 and thiol concentration in the leaves refer to the alteration of cellular redox potential during ageing.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
