DETERMINATION OF PHOTOSYNTHETIC RATE AT SEVERAL AROMATIC PLANTS.

Medicinal and aromatic plants are expressed by roots, rhizomes, leaves, flowers or fruits and the scientific interest for natural medicine and traditional practice of treatment increase more and more. The purpose of research are related with the theoretical and practical knowledge regarding the cultivation technology of the medicinal and aromatic species (Salvia officinalis, Ocimum basilicum and Thymus vulgaris), being interested also in the intensity of plants photosynthesis, during different vegetation periods. Establishing the photosynthesis rote is made with the help of CO₂ infrared analyzer. This equipment determines the photosynthesis rate by analyzing the CO₂ content in the leaf chamber, the photosynthesis rate being given by the difference of CO₂ in the air and the one released by the leaf, on surface unit in µmol CO₂/m²/s. The data taken with the help of this equipment are transferred after that to the LabPru interface, which with the help of a soft is transferred on PC to be interrelated. Determinations were made in five moment within the different vegetation phases: at 20 days from springing (control variant), before flowering, at flowering, at 10 days after flowering and at 20 days after flowering. There were used for each specie and vegetation phases a number of 5 plants, randomized and the experimental results were statistic interrelated with the help of the variant analyze. At Salvia officinalis L, the photosynthetic rate has low values in the first phases of vegetation (14,25 µmol CO₂/m²/s), followed by a progressive growing which reaches a maximum of 16,64 µmol CO₂/m²/s in the period of flowering. At 20 days after flowering, the rate of photosynthesis decreases at 14,22 µmol CO₂/m²/s. At Thymus vulgaris L, it is registered 14,20 µmol CO₂/m²/s at 20 days from springing, 15,12 µmol CO₂/m²/s during the flowering period (the maximum of photosynthesis) and 14,17 µmol CO₂/m²/s at 20 days after flowering. At Ocimum basilicum L., the rate of photosynthetic taken as control variant, is 14,23 µmol CO₂/m²/s, followed by the progressive increase up to 16,13 µmol CO₂/m²/s registered at flowering vegetation phase. This value overdue significant the rate of photosynthesis control. At 20 days after the reach of the maximum values registered, is noticed an average rate of photosynthesis of 14,19 µmol CO₂/m²/s. The comparative analyze of the photosynthetic rate at studied species shows that the evolution during the determination period is similar; the maximum point of the photosynthetic rate is registered in the flowering phase. The maximum values of the photosynthetic rate differs depending on specie, being higher at Salvia officinalis, followed by Ocimum basilicum, the lowest values are registered at Thymus vulgaris. [ABSTRACT FROM AUTHOR]