Apoplastic Antioxidant Enzymes in the Leaves of Two Strawberry Cultivars and Their Relationship to Cold-Hardiness
AbstractIn this study, apoplastic antioxidant enzymes in the leaves of two strawberry cultivars (â€˜Aromasâ€™ and â€˜Diamanteâ€™) and their relationshipto cold-hardiness were investigated. Fully expanded, uniformly sized leaves from 1-year-old field plants of the cultivars were collected atthe hardening (late autumn, in November and winter, in January) and de-hardening (summer, in July) stages. Leaf samples were exposedto low temperatures of 5, -5, -10, -20 and -30ÂºC for 12 h to determine their cold-hardiness (LT50; lethal temperature, where 50% of theplants were killed). Cold-acclimation produced a remarkable increase in cold-hardiness. It was found that â€˜Diamanteâ€™ had higher coldhardinessthan â€˜Aromasâ€™. Moreover, malondialdehyde and total carotenoid content increased during the hardening stage and decreasedduring the de-hardening stage. The activities of catalase, peroxidase and ascorbate peroxidase in the leaf apoplast and nicotinamideadenine dinucleotide phosphate oxidase activity in the leaf tissue were correlated with changes in cold-hardiness. The activities of theseenzymes were higher in the hardening stage than in the de-hardening stage. The activities of apoplastic catalase, peroxidase and ascorbateperoxidase varied significantly depending on the cold-acclimation stage and the cold-hardiness level of the cultivars. This study indicatesthat elevated apoplastic antioxidative enzymes may be determinants of cold-hardiness in the strawberry plant. The lower malondialdehydecontent and higher total carotenoid and apoplastic enzyme activities in â€˜Diamanteâ€™ indicated an enhanced cold-hardiness capacity of thiscultivar, serving to protect the plant from oxidative damage.
How to Cite
Open Access Journal:
The journal allows the author(s) to retain publishing rights without restriction. Users are allowed to read, download, copy, distribute, print, search, or link to the full texts of the articles, or use them for any other lawful purpose, without asking prior permission from the publisher or the author.