Net CO2 output by CAM plants in the light: the role of leaf conductance

Autor: Volker Frimert, J. Andrew C. Smith, Manfred Kluge
Rok vydání: 1986
Předmět:
Zdroj: Publons
ISSN: 1399-3054
0031-9317
DOI: 10.1111/j.1399-3054.1986.tb03365.x
Popis: Friemert, V., Kluge, M. and Smith, J. A. C. 1986. Net CO, output by CAM plants in the light: the role of leaf conductance. - Physiol. Plantarum 68: 353-358. The reasons for COj release by some CAM plants during the light period were investigated by comparative gas-exchange studies with three leaf-succulent species, Kalanchoe tubiflora Hamet, Sedum morganianum E. Walth. and Sempemivttm tectorum L. Sempervivum showed net CO; output during the day at constant day-night temperatures of both 15 and 25°C, whereas Kalanctioe and Sedum showed no CO, release at this time at either temperature. Net nocturnal CO; uptake was markedly reduced at 25°C compared with 15''C in Katanchoe and Sempervivum, while CO, was released at night at higher temperature by Sedum if leaffair vapour pressure difference was also increased. Values for intercellular partial pressure of CO, (p^**) were calculated from leaf conductance and were characteristically lowest in the dark and highest in the light period. Maximum values of pf^ ranged from 264 Pa in Sedim to 87 Pa in Kalanchoe, but were somewhat lower than those reported from direct measurements of the gas phase in other CAM plants. Leaf conductance declined with increasing p™= in all three species. Minimum values of approximately 0.2 nunol m"' s ' were observed at p™= = 33 Pa in Kalanchoe and Sedum, with no further decrease at higher p™=, implying that this largely represented the conductance of the cuticle. In Sempervivum, however, leaf conductance declined more gradually, and was as much as 0.8 mmol m ' s"' at the highest observed values of pf°=. The cause of net CO, output in the light by Sempervivum thus appeared to be lower stomatal sensitivity to COj, resulting in relatively high leaf conductance even at times when pf°2 greatly exceeded that of ambient air.
Databáze: OpenAIRE
Externí odkaz: