Alongside water and nutrients, solar radiation is of most importance for regulating photosynthesis, plant growth and adaptation. The lack or too much solar radiation can become a stress factor in a relatively short time (minutes, hours), while other stress factors, like water content in the soil needs a few days or weeks. Many studies have shown that plant biomass and photosynthetic parameters (net assimilation rate, stomatal conductance) decrease in low light conditions. By determining the photosynthetic parameters and photosynthesis irradiance curve, we aimed to see if several correlations could be made. High values for stomatal conductance and net assimilation were recorded in all four plants, but the highest were observed for Origanum vulgare and the lowest for Satureja montana. The higher assimilatory pigments quantity over the unit area (mg/m2) were determined for Thymus vulgaris 718.32 chlorophyll b and 1464.76 chlorophyll a, maintaining the ratio between chlorophyll a and chlorophyll b to that of ~2, corresponding with the literature of values found in medicinal and aromatic plants. Medicinal plants usually refer to plants that could be used directly, without further isolation of compounds (foods with healing properties), but similarly, they could also be used as medical agents and starting materials for compound isolation (aromatic plants for essential oils, sources of phenolic compounds, alkaloids). The medicinal plants belonging to Lamiaceae family cultivated in west side of Romania show great promise as a dietary and therapeutic source involved in human health. Lamiaceae is a family of medicinal and aromatic plants of great economic importance, which produces a wide variety of secondary compounds, being highly recognized for its essential oils secreted by glandular trichomes. Usually it comprises a large group of herbaceous, shrubs and subshrubs, perennial or annual plants, having antispasmodic, antioxidant, antitumor, excitatory, carminative, antiarthritic, tonic and many other health effects. Thymus vulgaris has the smallest plant height, forcing it to be in a permanent competition for sunlight with all the surrounding vegetation.

aromatic plants, photosynthesis, light intensity, assimilatory pigments, Lamiaceae

field crops and pastures

Presentation: poster