Abstract

The foliar spray of seaweed liquid extracts (SLE) (Fucus spiralis and Ulva rigida) was applied at three different concentrations (12.5, 25 and 50) to the plants of Salvia plants (Salvia officinalis L.) submitted or not to water stress (moderate and severe stress). The application of seaweed extract significantly enhanced growth parameters. The highest plant height was obtained with application of 50% concentration of U. rigida,followed by 25% concentration of F. spiralis that resulted in 40 and 15% increases, respectively, compared to the control plants. The maximum dry weight was also achieved with the same concentration of seaweed extract. Improved photosynthetic pigment content such as chlorophyll a and chlorophyll b was also observed with seaweed extracts application. Total chlorophyll amount was enhanced to 2.15 and 1.62 times when the plants were sprayed with U. rigida (50%) and F. spiralis (25%) extracts, respectively. Water deficit effect on S. officinalis L was notably reduced by the application of seaweed extracts. Thus, under moderate stress, the plant showed an important reduction of total chlorophyll (55.34%) compared to plant treated with U. rigida extract (32%) and F. spiralis (33%). The lipid peroxidation was low pronounced in plants stressed and treated by seaweed extract. Hence, low content ofmalondialdehyde (MDA) (7.30 µM g^-1 FW. and 5.7 µM g^-1 FW.) was exhibited in plant stressed and treated with 50% of U. rigida extract and 25% of F. spiralis extract, respectively, compared to plant controls (13.99 µM g^-1 FW). In conclusion, these data suggests that seaweed extract can be applied as natural fertilizer in agricultural sector.

Key words: Fucus spiralis, growth parameters, Morocco, peroxidation, proline, Salvia officinalis, seaweed extract, Ulva rigida, chlorophyll.

Abbreviation

Abbreviations:  SWE, Seaweed extract; SWC, seaweed concentration; MWD, moderate water deficit; SWD; severe water deficit; TBARS, 2-thiobarbituric acid–reactive substances; TBA, 2–thiobarbituric acid; MDA, malondialdehyde; IAA, 3-indoleacetic acid; IBA, indole-3 butyric acid; ROS, reactive oxygen species.