Abstract
ABSTRACT: The aim of the present study was to evaluate the accumulation of carbohydrates, protein, and proline as well as the activity of the antioxidant enzymes superoxide dismutase and catalase in the Ambiance cultivar of cut rose plants grown with the application of physiological effect products in the Sub-Middle São Francisco River Valley in Brazil. The experiment was performed under a mesh screen with 50% shading. The experimental design used randomized blocks with four repetitions and six treatments: T1) control (water); T2) boscalid; T3) pyraclostrobin; T4) boscalid + pyraclostrobin (T2 + T3); T5) fluxapyroxad + pyraclostrobin; T6) plant growth regulators 4-(indol-3-yl) butyric acid (IBA) + gibberellic acid (GA3) + kinetin; these treatments were applied every 15 days throughout the crop cycle. To determine the accumulation of solutes and enzymatic activity, 8 leaves was collected every 48 h. Leaves were immediately immersed in liquid nitrogen and frozen until further analysis in the laboratory. Results showed that the product combinations boscalid + pyraclostrobin and fluxapyroxad + pyraclostrobin as well as the plant growth regulators were the treatments with the most consistent responses throughout the evaluated cycle, providing a greater accumulation of solutes in rose leaves, as an osmotic adjustment strategy against stress from high temperatures, particularly when proline accumulation is observed. With regard to enzymatic activity, plant regulators showed more consistent results when compared with other treatments, increasing both superoxide dismutase and catalase activity. The marked accumulation of organic solutes and the high enzymatic activity, particularly of catalase, indicated that rose plants use such mechanisms as a defense against the region’s high temperatures.
Highlights
Commercial floriculture has consistently been growing over the years, with roses, orchids, chrysanthemums, and kalanchoe being the most prominent products currently
The aim of the present study was to evaluate the accumulation of carbohydrates, protein, and proline as well as the activity of the antioxidant enzymes superoxide dismutase and catalase in the Ambiance cultivar of cut rose plants grown with the application of physiological effect products in the Sub-Middle São Francisco River Valley in Brazil
Another mechanism used by plants that are subjected to high temperatures is the activation of the enzymatic antioxidant system, superoxide dismutase (SOD) and catalase (CAT), which are enzymes specialized in the deactivation of reactive oxygen species (BARBOSA et al, 2014; AMARO et al, 2018)
Summary
Commercial floriculture has consistently been growing over the years, with roses, orchids, chrysanthemums, and kalanchoe being the most prominent products currently. In conditions of high luminous intensity and high temperatures, such as those present in the semiarid northeastern Brazil, plants tend to present responses that assist in maintaining their physiological processes because in situations of stress, changes in their metabolism may occur. These responses will require osmotic adjustment using the strategy of accumulating organic substances, such as carbohydrates, protein, proline, and other free amino acids (MOURA et al, 2016; TAIZ; ZEIGER, 2017). Rose plants can both synthesize organic solutes and increase antioxidant activity in response to the stress caused by the region’s climate
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