Light Scattering as an Indicator of the Energy State in Leaves of the Crassulacean Acid Metabolism Plant <i>Kalanchoë pinnata</i>

Köster, S.; Winter, Klaus

doi:10.1104/pp.79.2.520

Cited by 16 publications

(9 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In K. pinnata, ATP/ADP ratios have indeed been shown to be lowest during this part of the diurnal cycle (10). pi values are much lower at the beginning and the end of the light period, and although atmospheric CO2 is taken up, the high values of qE indicate decreased rates ofATP consumption and therefore lower CO2 reduction rates than at noon.…”

Section: Discussionmentioning

confidence: 94%

“…This rapidly relaxing component of qE is very small in the middle of the light period when photosynthetic activity is maximal in the chloroplasts, i.e. when A pH is expected to be smallest due to high ATP demand (10). The rapidly relaxing component of qE is responsible for the strong increase in total qE at the beginning and at the end of the light period, when A pH is expected to increase because rates of electron flow fall behind the rate of absorption of excitation energy.…”

Section: Discussionmentioning

confidence: 99%

“…In a previous study, the light scattering method and the slow decay of Chl a fluorescence upon illumination were used as indicators of the energy state in intact leaves of the CAM plant Kalanchoe pinnata (10). Although both parameters are related to qp and qE, the above measurements did not allow one to distinguish between these two variables.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Reduction State of Q and Nonradiative Energy Dissipation during Photosynthesis in Leaves of a Crassulacean Acid Metabolism Plant, Kalanchoë daigremontiana Hamet et Perr

Winter¹,

Demmig²

1987

Plant Physiol.

Self Cite

View full text Add to dashboard Cite

Fluorescence was measured in leaves of the CAM plant Kalanchoe daigremontiana using a pulse modulation technique at room temperature. During a 12-h light period at 500 micromole photons per square meter per second (400-700 nanometers) in air containing 350 microbar CO2, the component of fluorescence quenching related to the reduction state of Q, the primary electron transport acceptor of PSII, remained fairly constant and showed that only 20% of Q were in the reduced form. The reduction state was slightly increased at the onset and at the end of the light period. By contrast, the nonphotochemical component of fluorescence quenching which is a measure of the fraction of nonradiative deexcitation underwent marked diurnal changes. Nonradiative energy conversion was low during the phase of most active malic acid decarboxylation in the middle of the light period when uptake of atmospheric CO2 was negligible, and when internal CO2 partial pressures were higher than in air, this allowed for high rates of CO2 reduction in the chloroplasts.Nonradiative energy conversion was high during the early and the late light period when atmospheric CO2 was taken up and internal CO2 partial pressures were below air level. Manipulation of the internal CO2 partial pressure during the late light period by increasing or decreasing the external CO2 partial pressure to 1710 and 105 microbar, respectively, led to changes in the magnitude of energy dependent fluorescence quenching which were consistent with the relationship between nonradiative energy dissipation and internal CO2 partial pressure observed during the diurnal cycle. Again, the reduction state of Q was hardly affected by these treatments. Thus, changes in electron transport rate during the diurnal CAM cycle at a given photon flux density lead primarily to alterations in the rate of nonradiative energy dissipation, with the reduction state of Q being maintained at a relatively low and constant level. Conditions are described under which nonphotochemical dissipation of excitation energy reaches a maximum value and the reduction state of Q is increased.When leaves are illuminated, the excitation energy of Chl can be dissipated by photosynthesis, as heat or, to a very small extent, as fluorescence. Simultaneous measurements of fluorescence yield and of gas exchange provide information about the partitioning of excitation energy between photochemical and nonphotochemical processes (11,21). Fluorescence emitted at room temperature emanates predominantly from Chl a of PSII and depends on the redox state of the primary electron acceptor of ' Supported by the Deutsche Forschungsgemeinschaft. PSII, Q.2 If, for example, a large percentage of Q is kept oxidized by electron flow to sustain reduction of C02, photochemical quenching, qp, will be high and fluorescence will be low. Nonphotochemical quenching processes, designated qE, relate, first, to the establishment of a proton gradient across the thylakoid membrane and, thereby, to ATP consumption in photosynthesis (12,13). Low ra...

show abstract

Section: Discussionmentioning

confidence: 94%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Reduction State of Q and Nonradiative Energy Dissipation during Photosynthesis in Leaves of a Crassulacean Acid Metabolism Plant, Kalanchoë daigremontiana Hamet et Perr

Winter¹,

Demmig²

1987

Plant Physiol.

Self Cite

View full text Add to dashboard Cite

show abstract

“…These results correlate with the changes in light scattering found in K pinnata, where the decline in scattering (correlating with higher consumption of ATP) during the middle of the day was smaller than that measured at the beginning or end of the light period (15 We tested this idea by supplementing CO2 to CAM leaf tissue in the afternoon, when qN differences were observed to be the greatest. Higher external CO2 shifted the value of qN to a more cycling-like value, i.e.…”

Section: Discussionmentioning

confidence: 52%

“…The amount of variable fluorescence in Kalanchoe daigremontiana, Ananas comosus, and Opuntia stricta changed from morning to evening in concert with the deacidification of the tissue (6,16). Chl fluorescence with light scattering (a putative measure of the H+ fluxes within the chloroplast) has been used to study the day/night cycle of CAM in K. pinnata (15). ' This research was supported, in part, by National Science Foundation grant DCB-8807860 (to IPT).…”

mentioning

confidence: 99%

Fluorescence Quenching in the Varied Photosynthetic Modes of Portulacaria afra (L.) Jacq.

Guralnick¹,

Heath²,

Goldstein³

et al. 1992

Plant Physiol.

View full text Add to dashboard Cite

The kinetics of chlorophyll fluorescence were measured in Portulacaria afra (L.) Jacq. when the plants were functioning in either Crassulacean acid metabolism (CAM) or C3/CAM cycling (called cycling) modes, as determined by fluctuation in titratable acidity and gas exchange properties. Cycling plants showed primarily daytime CO2 uptake typical of C3 plants, but with a slight diurnal acid fluctuation, whereas CAM plants showed nocturnal CO2 uptake, daytime stomatal closure, and a large diurnal acid fluctuation. Results from fluorescence measurements indicated no significant differences in photochemical quenching between cycling and CAM plants; however, sizable differences were detected in nonphotochemical quenching (qN), with the largest differences being observed during the middle of the day. Cycling plants had lower qN than CAM plants, indicating altered photosynthetic regulation processes. This qN difference was believed to be related to reduced internal CO2 concentration in the CAM plants because of daytime stomatal closure and reduced deacidification rates in the late afternoon when most of the malic acid has been utilized. Experimentally, higher external CO2 given to plants in the CAM mode resulted in a decline in qN in comparison to that measured in plants in the cycling mode. No changes were observed in photochemical quenching when CO2 was added.Many studies of CAM species have focused on the shift from C3/CAM cycling (called cycling) to CAM photosynthesis during various stresses (3,8,9,17,21,23 The Chl fluorescence transients correlated with increased light scattering. On the other hand, the results of Buschmann and Buchanan-Bollig (4) indicated that Chl fluorescence transients were dependent upon leaf structure, pigment composition, and the organization of the photosystems rather than the CO2 fixation pathway. The question arises as to how well control of the operation of photosynthesis by internal CO2 levels (7) can be measured by fluorescence techniques. The levels of CO2 inside the leaf certainly change between these two photosynthetic modes (5) and so should alter photosynthesis and, concurrently, the fluorescence patterns (18).A fluorescence technique has been developed that enables the separation of qp and qN quenching of Chl fluorescence (20). This technique uses a weak light beam to measure the fluorescence yield and a high intensity actinic beam to drive photosynthesis. The application of a second light pulse of high intensity is used to overwhelm photochemical quenching, thus permitting direct measurement of qN. This technique was used here to monitor changes in qp and qN in Portulacaria afra (L.) Jacq. (a facultative CAM plant) as it shifted from cycling to the CAM mode of photosynthesis under water stress (9, 13) and, in part, to show how intemal CO2 was changing during the metabolic switch. The critical factor in these experiments is that this shift was not accompanied by any changes in pigment composition (11). The effect of extemal CO2 levels on these same fluorescence measurement...

show abstract

Photosynthesis: Carbon Metabolism: By Day and by Night

Holtum

Kelly

Latzko

Thirty Years of Photosynthesis 1974–2004

View full text Add to dashboard Cite

Light Scattering as an Indicator of the Energy State in Leaves of the Crassulacean Acid Metabolism Plant Kalanchoë pinnata

Cited by 16 publications

References 14 publications

Reduction State of Q and Nonradiative Energy Dissipation during Photosynthesis in Leaves of a Crassulacean Acid Metabolism Plant, Kalanchoë daigremontiana Hamet et Perr

Reduction State of Q and Nonradiative Energy Dissipation during Photosynthesis in Leaves of a Crassulacean Acid Metabolism Plant, Kalanchoë daigremontiana Hamet et Perr

Fluorescence Quenching in the Varied Photosynthetic Modes of Portulacaria afra (L.) Jacq.

Photosynthesis: Carbon Metabolism: By Day and by Night

Contact Info

Product

Resources

About