Photosynthesis in sessile oak and common beech provenances under drought in relation to different soil phosphorus concentrations

Poster presented at the XX International Botanical Conference, Madrid, Spain, July 21–27, 2024.

Authors:

Antonia Vukmirovic¹, Željko Škvorc¹, Saša Bogdan¹, Daniel Krstonošic¹, Marko Bacurin¹, Magdalena Brener¹, Ida Katicic Bogdan¹, Tomislav Karažija², Krunoslav Sever¹

Affiliations:

1. University of Zagreb Faculty of Forestry and Wood Technology, Zagreb, Croatia
2. University of Zagreb Faculty of Agriculture, Zagreb, Croatia

Abstract:

Inhibition of photosynthesis is the primary physiological consequence of drought stress. This research aimed to examine the response of photosynthesis of common beech and sessile oak saplings from two provenances, Karlovac (KA) and Slavonski Brod (SB) under the impact of drought and phosphorus fertilization (P). During the growing season of 2022, the saplings were treated with regular watering (W) and drought (D). Half of the plants treated with regular watering or drought were fertilized (+P), and the other half were not fertilized with P (-P). Accordingly, the saplings were subjected to four treatments (W/+P, W/-P, D/+P and D/-P). The dry period was interrupted on September 1^st by re-watering. Every 10 days during the growing season, the photosynthetic performance index (PI_abs) and rate of net photosynthesis (A_net) were measured. The significance of the main effects (provenance and treatment) and their interactions on the PI_abs and A_net in drought and post-drought periods in common beech and sessile oak was tested by factorial ANOVA. In both species, during the drought period, the highest values of A_net and PI_abs were recorded in W/-P treatment and the lowest in D/+P treatment. During the drought period A_net and PI_abs in oak, as well as PI_abs in beech, were higher in KA compared to SB provenance. During the post-drought period A_net and PI_abs in both species, regardless of the provenances, were still lower in drought (D/+P and D/-P) compared to regularly watered (W/+P and W/-P) treatments. However, PI_abs in both species was higher in the D/-P compared to D/+P treatment in both provenances. Our results indicate that elevated P concentrations did not have a significant effect on photosynthesis in oak and beech saplings in drought and post-drought periods.