Salinity effect on proline, photosynthetic pigments and leaf relative water content in chamomile (Matricaria chamomilla L.) in hydroponic condition

Considering the extent of salinity in soils of Iran, abiotic stresses such as salinity are serious threat to agricultural production, yield and essential oil of medicinal plants. Recognition of threshold for salt tolerance and determining the slope of yield loss in medicinal plants has an important role in the selection of suitable lands for their cultivation. The effect of salinity stress on soluble compound, relative water content (RWC) and biochemical indices were investigated in German chamomile (Matricaria chamomilla L.). This study was conducted in a randomized complete blocks design with three replications. Because the control salinity levels in the soil, during the experimental period was difficult, the hydroponic culture was used to do this research. Electrical conductivity (EC) levels were included: 2 (control, 50% of Hoagland solution), 4, 8, 12 and 16 dS.m ^-1 by NaCl salt. The results showed that with increasing salinity, chlorophyll a content was 29.9% and significantly decreased (P*0.01). With increasing salinity chlorophyll b, carotenoids and anthocyanin decreased 39.7, 22.7, 11.1 percent respectively, and were significant (P*0.05). Proline content measurement showed significantly increased (79.5%) with increasing salinity. Leaf relative water content (RWC) also significantly increased (20.1%) with increasing salinity (P*0.01). In general, the salinity stress was effective on physiological processes of chamomile and optimal yield was obtained in salinity 2 dS.m^-1.