Responses of Strawberry (Fragaria x ananassa) to Supplemental UV-B Radiation and Selenium Under Field Conditions

• Published in: Plant and soil Vol. 282; no. 1-2; pp. 27 - 39
• Main Authors: Heijari, J, Kivimäenpää, M, Hartikainen, H, Julkunen-Tiitto, R, Wulff, A
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer 01.04.2006; Springer Nature B.V
• Subjects: chlorophyll; Cultivars; Epidermal cells; Flavonoids; Flowers & plants; Fluorescence; Fragaria ananassa; Growing season; Leaves; Mesophyll cells; Parenchyma; Photosynthesis; photosystem II; physiological response; plant biochemistry; plant ecology; plant growth; plant morphology; plant response; plant stress; Plants; secondary metabolites; Selenium; soil nutrients; stomata; strawberries; Tannins; ultrastructure; Ultraviolet radiation
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-005-5168-x

In greenhouse experiments, selenium (Se) has been shown to defend plants against detrimental effects of heavy UV-B radiation stress. The aim of this study was to investigate whether this positive effect can be found in open-field conditions with enhancement of UV-B radiation. In the experiment, conducted with strawberry (Fragaria×ananassa, cultivars "Jonsok" and "Polka") over two growing seasons, plants were exposed to UV-B radiation (including UV-A) and cultivated without Se or supplied with Se added at two levels (0.1 and 1.0 mg kg-1). The plants were monitored for growth, flavonoids, chlorophyll fluorescence, net photosynthesis as well as tissue and cell structure. Photosystem II was observed to be sensitive to UV-B stress under field conditions. In the leaves, a decrease in Fv/Fm was seen at the end of the growing season, implying a cumulative effect of UV-B stress. Several parameters, especially cell and tissue structures, were affected by UV-B and UV-A treatments, which proves the need for UV-A control in outdoor UV-B supplementation studies. Addition of Se did not ameliorate the harmful effects of UV-B but the lower Seincrement level increased leaf growth. The effects of UV-B and Se differed during the two experimental years, indicating the need to repeat experiments during several growing seasons.