Photosynthetic performance of vegetative and reproductive structures of green hellebore (Helleborus viridis L. agg.)

Title:

Photosynthetic performance of vegetative and reproductive structures of green hellebore (Helleborus viridis L. agg.)

Creator:

Aschan, G., Pfanz, H., Vodnik, D., and Batič, F.

Identifier:

https://cdk.lib.cas.cz/client/handle/uuid:f71c1561-cb2a-440c-9d47-c10a01da916a
uuid:f71c1561-cb2a-440c-9d47-c10a01da916a
issn:0300-3604
doi:10.1007/s11099-005-5064-x

Subject:

carbon budget, chlorophyll fluorescence, CO2 re-fixation, floral photosynthesis, nectaries, and sepals

Type:

model:article and TEXT

Format:

bez média and svazek

Description:

Photosynthetic irradiance response of vegetative and reproductive structures of the green-flowered deciduous perennial green hellebore was studied by the comparative use of chlorophyll (Chl) fluorescence techniques and gas exchange measurements. All the Chl-containing organs (leaves, sepals, stalks, and fruits) examined were photosynthetically active showing high intrinsic efficiencies of photosystem 2 (Fv/Fm: 0.75-0.79) after dark adaptation. Even in the smaller fertile and sterile parts of the flower (nectaries and anthers) a remarkable photosynthetic competence was detected. With increasing photon flux densities (PFD) electron transport rates, actual quantum yields, and photochemical quenching coefficients of the main photosynthetic organs decreased in the order: leaf>sepal>fruit>stalk. At moderate to high PFDs the sepals achieved maximum electron transport rates corresponding to about 80 % of concomitant mature leaves. In contrast, maximum net photosynthetic rate of the sepals [2.3 μmol(CO2) m-2 s-1] were less than one fourth of the leaves [10.6 μmol(CO2) m-2 s-1]. This difference is explained by a 70-80 % lower stomatal density of sepals in comparison to leaves. As the basal leaves emerge late during fruit development, the photosynthetically active sepals are a major source of assimilates, contributing more than 60 % of whole-plant CO2 gain in early spring. The ripening dehiscent fruits are characterized by an effective internal re-fixation of the respirational carbon loss and thus additionally improve the overall carbon budget. and G. Aschan ... [et al.].

Language:

Multiple languages

Rights:

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

Coverage:

55-64

Source:

Photosynthetica | 2005 Volume:43 | Number:1

Harvested from:

CDK

Metadata only:

false