scholarly journals Laser-induced chlorophyll fluorescence and reflectance spectroscopy of cadmium treatedTriticum aestivumL. plants

2011 ◽  
Vol 26 (2) ◽  
pp. 129-139 ◽  
Author(s):  
Jitendra Kumar Pandey ◽  
R. Gopal
Keyword(s):  
Chlorophyll Fluorescence ◽  
Plant Growth ◽  
Diode Laser ◽  
Vegetation Index ◽  
Growth Parameters ◽  
Photosynthetic Pigment ◽  
Fluorescence Induction ◽  
Reflectance Spectra ◽  
Integrating Sphere ◽  
Induction Kinetics

The present study deals with laser-induced chlorophyll fluorescence (LICF) spectra, reflectance spectra and fluorescence induction kinetics (FIK) curves ofTriticum aestivumL. plants treated with different concentrations of cadmium (0.01, 0.1 and 1.0 mM). LICF spectra were recorded in the region of 650–780 nm using violet diode laser (405 nm) and FIK curves were recorded at 685 and 730 nm using red diode laser (635 nm) for excitation. Reflectance spectra were recorded in the region of 400–800 nm using spectrophotometer with an integrating sphere. The fluorescence intensity ratios (FIR) were determined from LICF spectra, vitality index (Rfd) from FIK curves and narrow band vegetation index (NBVI) from reflectance spectra. These parameters along with plant growth parameters and photosynthetic pigment contents were used to analyze the effect of cadmium on wheat plants. The results clearly show that lower concentration of Cd (0.01 mM) shows stimulatory response; whereas higher concentrations (0.1 and 1.0 Mm) are hazardous for plant growth, photosynthetic pigments and photosynthetic activity of wheat plants.

Humidity-sensitive Degreening and Regreening of Leaves of Borya nitida Labill. As Followed by Changes in Chlorophyll Fluorescence

1982 ◽  
Vol 9 (5) ◽  
pp. 587 ◽  
Author(s):  
SE Hethzerington ◽  
RM Smillie
Keyword(s):  
Chlorophyll Fluorescence ◽  
Relative Humidity ◽  
Photosystem Ii ◽  
Photosystem I ◽  
Fluorescence Induction ◽  
Physiological Age ◽  
Chlorophyll Fluorescence Induction ◽  
Induction Kinetics ◽  
Mediated Electron Transfer

Fast and slow chlorophyll fluorescence induction kinetics were used to follow changes in photosynthetic activity during humidity-sensitive degreening and regreening of leaves of Borya nidita Labill. During dry periods the leaves of this desiccation-tolerant plant lose chlorophyll, becoming yellow-brown and upon rehydration turn green again. This degreening process can be simulated in detached leaves by slow dehydration at 96% relative humidity. Under these conditions changes in chlorophyll fluorescence in vivo and the activities of photosystems I and II in chloroplasts isolated from dehydrated leaves indicated that degreening was accompanied initially by a stimulation of photosystem II activity and a gradual decrease in photosystem I-mediated electron transfer, while at advanced stages of degreening both photosystems were lost. Control leaves detached and kept at 100% relative humidity remained green and showed little change in chlorophyll fluorescence kinetics. During the rehydration and subsequent regreening of dry yellow leaves, photosystem I activity appeared to recover faster than photosystem II. The ability of the leaves to recover and regreen from the dried state, either on the plant or after detachment, depended upon the physiological age of the leaves at the time of dehydration.

Invivo chlorophyll fluorescence as a possible indicator of the dormancy stage in Douglas-fir seedlings

1985 ◽  
Vol 15 (4) ◽  
pp. 607-612 ◽  
Author(s):  
C. D. B. Hawkins ◽  
G. R. Lister
Keyword(s):  
Chlorophyll Fluorescence ◽  
Photosynthetic Pigment ◽  
Maximum Growth ◽  
Relative Increase ◽  
Douglas Fir ◽  
Fluorescence Induction ◽  
Chlorophyll B ◽  
Total Chlorophyll ◽  
Fluorescence Parameters ◽  
Pigment Contents

Invivo chlorophyll fluorescence and photosynthetic pigment contents of current-year needles from five populations of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco, var. menziesii Franco and var. glauca (Beissn.) Franco) were monitored at 3- to 4-week intervals over 2 years. The results were compared with the reported stage of seedling dormancy to ascertain whether this technique would be suitable for indicating dormancy status. Minimum values of fluorescence-induction parameters, indicating winter photosynthetic inactivation, were observed during the coldest period. The lower the temperature and the greater the irradiance, the greater the apparent inactivation. An increase in chlorophyll a to chlorophyll b ratios and a decrease in total chlorophyll to carotenoid ratios, indicating a relative increase in protective carotene pigments, was associated with this period. Maximum values for the fluorescence parameters were observed during periods of maximum growth. It appears that a rapid and inexpensive means of screening for Douglas-fir's dormancy status could be developed using invivo chlorophyll fluorescence analyses.

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