Chlorophyll fluorescence imaging of photosynthetic activity with the flash-lamp fluorescence imaging system |
| |
Authors: | Email author" target="_blank">H?K?LichtenthalerEmail author G?Langsdorf S?Lenk C?Buschmann |
| |
Institution: | (1) Botanical Institute (Molecular Biology and Biochemistry of Plants), University of Karlsruhe, Kaiserstrasse 12, D-76128 Karlsruhe, Germany |
| |
Abstract: | A flash-lamp chlorophyll (Chl) fluorescence imaging system (FL-FIS) is described that allows to screen and image the photosynthetic
activity of several thousand leaf points (pixels) of intact leaves in a non-destructive way within a few seconds. This includes
also the registration of several thousand leaf point images of the four natural fluorescence bands of plants in the blue (440
nm) and green (520 nm) regions as well as the red (near 690 nm) and far-red (near 740 nm) Chl fluorescence. The latest components
of this Karlsruhe FL-FIS are presented as well as its advantage as compared to the classical single leaf point measurements
where only the fluorescence information of one leaf point is sensed per each measurement. Moreover, using the conventional
He-Ne-laser induced two-wavelengths Chl fluorometer LITWaF, we demonstrated that the photosynthetic activity of leaves can be determined measuring the Chl fluorescence decrease ratio,
RFd (defined as Chl fluorescence decrease Fd from maximum to steady state fluorescence Fs:Fd/Fs), that is determined by the Chl fluorescence induction kinetics (Kautsky effect). The height of the values of the Chl fluorescence
decrease ratio RFd is linearly correlated to the net photosynthetic CO2 fixation rate P
N as is indicated here for sun and shade leaves of various trees that considerably differ in their P
N. Imaging the RFd-ratio of intact leaves permitted the detection of considerable gradients in photosynthetic capacity across the leaf area
as well as the spatial heterogeneity and patchiness of photosynthetic quantum conversion within the control leaf and the stressed
plants. The higher photosynthetic capacity of sun versus shade leaves was screened by Chl fluorescence imaging. Profile analysis of fluoresence signals (along a line across the leaf
area) and histograms (the signal frequency distribution of the fluorescence information of all measured leaf pixels) of Chl
fluorescence yield and Chl fluorescence ratios allow, with a high statistical significance, the quantification of the differences
in photosynthetic activity between various areas of the leaf as well as between control leaves and water stressed leaves.
The progressive uptake and transfer of the herbicide diuron via the petiole into the leaf of an intact plant and the concomitant loss of photosynthetic quantum conversion was followed with
high precision by imaging the increase of the red Chl fluorescence F690. Differences in the availability and absorption of soil nitrogen of crop plants can be documented via this flash-lamp fluorescence imaging technique by imaging the blue/red ratio image F440/F690, whereas differences in Chl content are detected by collecting images of the fluorescence ratio red/far-red, F690/F740. |
| |
Keywords: | blue-green fluorescence chlorophyll fluorescence decrease ratio diuron absorption flash light pulses nitrogen supply RFd-ratio sun and shade leaves water stress |
本文献已被 SpringerLink 等数据库收录! |
|