Use and degradation of light energy in water-stressed Digitalis lanata

Title:

Use and degradation of light energy in water-stressed Digitalis lanata

Creator:

Fock, H. P., Biehler, K., and Stuhlfauth, T.

Identifier:

https://cdk.lib.cas.cz/client/handle/uuid:4ed7bdf8-4273-4a71-bdcc-7e55bf824a4f
uuid:4ed7bdf8-4273-4a71-bdcc-7e55bf824a4f
urnnbn:urn:nbn:cz:aba007-000fca

Type:

model:internalpart and TEXT

Format:

print

Description:

Using ^^C02, ^^02 and H2O gas exchange as weU as metabolite analysis, net CO2 uptake (P]4) and transpiration rate (£) were measured in the water-stressed plants of Digitalis lanata EHRH. The leaf conductance (gcch). the gross CO2 uptake (Pq), Úie photorespiration (Rp) and reassíinilation (RA) rates were calculated from measuied parameters. The pulse modulated fluorescence was measured duiing the steady statě photosynthesis. After withholding iirigation, the leaf water potential decreased to -2.S MPa, but leaves remained turgid and fully exposed to iiradiance even at a severe water stress. Due to the stress-induced reduction of gcch. and E were drastically reduced, whereas Pq and Rp were less affected. Water use efficiency (WUE), which was higher in 1 000 than 350 cm3(C02) increased as the water stress developed. The stomatal closure induced an increase in the reassimilation (RA) of internally liberated CO2 (Rp). The increased CO2 recycling in relation to the water stress was high in 350 cm^(C02) m-^ and still substantial in 1 000 cm3(C02) and consumed a substantial amount of radiant energy in the form of ATP and reduction equivalents. Consequently, the metabolic demand for radiant energy was reduced by less than 40 %, whereas was diminished by more than 70 % in severely stressed plants at 350 cm3(C02) m*3. Additionally, the quantum efiBciency of photosystem 2 as a measure for the flux of photosynthetically generated electrons was reduced upon the stress. This (and possibly other mechanisms) enabled the stressed plants to avoid overreduction of the photosynthetic electron transport chain.

Language:

Multiple languages

Rights:

http://creativecommons.org/licenses/by-nc-sa/4.0/
policy:public

Coverage:

571-577 and 147-153

Source:

Photosynthetica | 1992 Volume:27 | Number:4

Harvested from:

CDK

Metadata only:

false