Leaf morpho-physiological dynamics in Salvia officinalis L. var. purpurascens

Authors: FILIPA MARTINS, IVO OLIVEIRA, ANA BARROS, CARLA AMARAL, SÍLVIA AFONSO, HELENA FERREIRA, JOSÉ MOUTINHO-PEREIRA, BERTA GONÇALVES

Abstract: Salvia officinalis L. var. purpurascens is one of the most insufficiently studied varieties of the genus Salvia. Hence, the study and characterization of this plant, as well as the monitoring of changes occurring during leaf ontogeny, are of great importance and interest. For this purpose, young and adult leaves of Salvia officinalis L. var. purpurascens collected in two different seasons and in two different years were analyzed, considering morpho-anatomical traits but also leaf gas exchange and chlorophyll a fluorescence parameters. Leaf age was found to have significant effects on several of the analyzed parameters, including the parenchyma, mesophyll, xylem, and phloem thickness, as well as transpiration rate (E) and maximum photochemical efficiency of PSII (F_v/F_m). On the other hand, considerable differences were found for several characteristics of Salvia officinalis caused by season, e.g., leaf area, vessel dimensions, stomatal conductance (g_s), waxes, E, and intrinsic water-use efficiency (A/g_s). The year of harvest also resulted in significant variations in several parameters, such as leaf area and leaf mass per area (LMA), and palisade and spongy parenchyma thickness. These results show the dynamics of Salvia officinalis leaf traits, presently poorly known, and are further helpful when aiming towards optimization of characteristics of cultivated sage.

Keywords: Salvia officinalis L. var. purpurascens, morphological traits, leaf gas exchange, chlorophyll a fluorescence

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