Thesis (M.Sc.) - Cairo University - Faculty of Agriculture - Department of Agrcultural Botany

The present study was conducted to investigate the effect of exogenous spray with different levels of seaweed extract (0.0, 0.25, 0.50, 0.75 and 1.0 ml/L.) on morphological characters of vegetative growth (Plant height, number of primary branches/plant and leaves/plant), fresh herb yield /plant, photosynthetic pigments, anatomical features of vegetative organs (main stem and leaf) in addition to percentage and components of volatile oil in sweet marjoram. Results indicated that all investigated levels of seaweed extract showed no significant influence on plant height of sweet marjoram. On the other hand, increased sprayed level of seaweed extract induced a gradual significant increase in number of primary branches/plant, number of developed leaves/plant and fresh herb yield /plant as well as photosynthetic pigments in leaves of sweet marjoram. It was realized that sprayed plants with 1 ml seaweed extract/L. achieved noticeable changes in histological characters of vegetative organs (stem and leaf) of sweet marjoram. Such treatment increased main stem diameter and thickness of leaf blade. The increment of stem diameter could be attributed mainly to the increments in most internal tissues; Phloem, xylem tissues in addition to vessel diameter over those of the control as a result of spraying seaweed extract.The increase in leaf thickness could be attributed to the increase induced in both spongy and palisade tissues as well as the increase induced in size of midvein bundle.Also, such treatment (1 ml seaweed extract/L.) increased the percentage of volatile oil and its major components in fresh herb of sweet marjoram at full blooming stage

Issued also as CD