Viorica Urechean

Effect of Sweet Marjoram (Origanum majorana L.) Cogermination and Aqueous Extracts on Maize (Zea mays L.)

Abstract The purpose of this study was to examine the allelopathic effect of sweet marjoram (O. majorana) on the germination and early stages of maize seedlings. Two experiments were performed under laboratory conditions (in Petri dishes). In the first experience, Origanum majorana seeds were cogerminated with maize (Zea mays) seeds in the same Petri dish. For the second experience were used aqueous extracts from fresh and dry aboveground biomass of the sweet marjoram (stem, leaves) in concentrations of 1%, 2% and 3%. Cogermination of O. majorana with maize seeds has significantly stimulated the germination index (Gi) and growth of maize seedlings. Aqueous extracts of sweet marjoram in a concentration of 1% and 2% have significantly stimulated shoot length of maize. On the other hand, aqueous extracts at a concentration of 3% significantly inhibited root length of maize. These results suggest that the cogermination with sweet marjoram seeds may be an alternative to biostimulation of maize initial growth, and aqueous extracts in low concentrations could be used as growth bioregulators.

THE INFLUENCE OF THE HYDRIC STRESS ON THE CAPACITY OF GROWTH AND DEVELOPMENT ON THE SUNFLOWER

The purpose of the present work was to highlight the effect of the climatic conditions of the year 2007, which is characterized through an extreme drought, on a set of 10 hybrids of sunflower found in the tests at SCDA ?imnic. The knowledge of this aspect has great importance in the zoning of the sunflower hybrids. It was detected that in such conditions the seeds of sunflower can remain in the latent state (an enough long period) until they find the optimal conditions of germination. Also, the complex metabolic and physiological whole of the plant modified, the phonological phase of development became shorter and the physiological maturity was rushed.