الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 186 |  |  |
| | | from | 186 | | |
Abstract
The present investigation included the effects of two auxin-like (2,4-D and 2,4,5-T) and Fusilade® herbicides on the growth and yield of marjoram (Origanum majorana L.) in the field and under aseptic conditions and the changes in its chemical composition under the previous conditions during two stage of growth (vegetative and floweing stages). All growth parameters (plant height (cm), number leaves/plant, number of lateral branches/plant, number of flowers/plant, fresh and dry weights of plant leaves g/plant) measured of marjoram plants were reduced at lowest and highest concentrations of herbicides. This accompanied with removal of most of post-emergent young short annual grasses. While at herbicides concentrations 2 & 4 g/L 2,4-D and 2,4,5-T and 4.5 ml/L Fusilade® , all growth parameters measured were increased with reduction of numbers of weeds as compared with non-treated control. The pigment contents (chlorophyll a, chlorophyll b, carotenoids and total pigments) pigment contents had shown a significant increase in marjoram leaves with all herbicides treatments except 2,4-D. Protein was detetcted with SDS-PAGE method and showed that, the number of polypeptide bands increased in herbicide conc. of 2,4-D (2 g/L) & 2,4,5-T (4g/L and 2g/L), while it decreased in herbicide conc. of 2,4-D (4 g/L) & Fusilade® (4.5.ml/L(v) & (f) as compared with the number of polypeptide bands in control. Analysis of essential oils by Gas chromatography (GC) revealed the presence of 19 components were identified. The essential oil was found to be rich in β-phyllandrene (63.98% - 69.8%) when irrigated by 2 and 4 g/L 2,4-D and 4.5 ml/L Fusilade® as respectively, while Linalool as important component increased to (70.62%-72.39%) if irrigated by 2,4 g/L 2,4,5-T as respectively. Results obtained showed that later vegetative stage is characterized by the highest contents of bioactive compounds and therefore it could be considered as the best stage for harvesting marjoram plants. For induction of marjoram callus, the 2,4-D +Kn (2+ 0.5 mg/L) and NAA+ 6BAP (4+0.4 mg/L) were the most responsive for callus induction from seed and hypocotyle. After the 3rd and 4th subcultures the calli grew slower, turned brown and didn’t survive in subsequent subcultures or herbicides treatment irrespective of the phytohormones concentrations. Aseptic seedlings of Origanum majorana L. growing on MS medium free of phytohormones but supplemented with different concentrations of auxin-like herbicides 2,4-D (6, 11, 22.5, 23.7 and 45 mg/L) herbicides in 10 hr photoperiod. The results showed that, the highest growth rate was observed on medium contained 2,4-D (6 and 11mg/L. The intracellular protein profile was traced on SDS-PAGE, and the results cleared that, there is no distinct variation on the proteinous bands of the treated marjoram seedlings with 2,4-D (6 and 11mg/L), and the control of non-treated seedlings. However the density of protein bands was increased upon 2,4-D (6 and 11mg/L. The aqueous extract of marjoram seedlings have an antifungal effects and the aqueous extract of herbicide treated marjoram seedlings was more effective than of non treated control. Finally we concluded that the concentration of 2 g/L/16m2 of two auxin-like herbicides (2,4-D and 2,4,5-T) and 4.5 ml/L/16m2 of Fusilade® herbicide were more effective in removal of number of most of post-emergent young short annual grasses growing with of marjoram (Origanum majorana L.) and have an enhancement effects on growth and yield of marjoram plants.