EFFECT OF LIGHT LEVEL ON ESSENTIAL OIL PRODUCTION OF SAGE (SALVIA OFFICINALIS) AND THYME (THYMUS VULGARIS)

Accumulation of essential oil in herbs directly or indirectly depends upon light. This experiment studied essential oil production in sage (Salvia officinalis) and thyme (Thymus vulgaris) grown at 15%, 27%, 45% and 100% of full sunlight. The total oil concentration in sage was highest in the plants grown at 45% of full sunlight and at this light level the oil had the higher content of (+)-thujanone and a decreased accumulation of camphor as compared with essential oil from sage grown at other light levels. The highest level of essential oil and concentration of thymol and myrcene in thyme occurred in full sunlight. Leaf length, width, and density of peltate hairs on both herbs decreased with decreases in light levels.