Effect of water supply on the physiological characteristic and production of basil (Ocimum basilicum L.).

Abstract

Different levels of soil water capacity (SWC 30-50-70 %) resulted in significant changes in physio logical parameters of Ocimum basilicum L. 'Genovese' in a pot experiment. Cpmpared to the control plants (water supply to 70% SWC) the driest condition (30 % SWC) caused a decrease of the relative water content (RWC) in the plants by 20 %. Additionally, their water potential was reduced to 45 % of the con trol plants. The same treatment increased the concen tration of malondialdehyde (MDA) indicating the level of oxidative stress, by 52 % compared to the leaves of the control plants. However, under a moderate water deficit (50 % SWC), the plants exhibited a less severe decrease in RWC and water potential, as well as less oxidative stress. Although the reduction of the SWC to 50 % did not significantly affect the dry shoot mass, a more severe water stress (30 % SWC) reduced it by 34 %, compared to the control plants. The essential oil concentration per plant dry mass showed only a slight increase in consequence of drought stress (significant at 90 % confidence level). The essential oil production calculated to a single individual is determined basical ly by the changes in the biomass, thus, the lowest re sults were found in the driest soil. Water supply modi fied the quantitative composition of the ou: the pro portion of linalool decreased from 59.68 to 44.39 %. The samples of the stressed plants contained some mi nor components, (s-myrcene, 2-octanone) not present in the control samples.