Influence of foliar spray with tryptophan, phenylalanine, thiamin and ascorbic acid on growth, yield and volatile oil content of dragonhead plants

الملخص EN

This work was carried out at the Experimental Station Faculty of Agriculture at Moshtohor for two successive seasons (2005/2006 & 2006/2007) It was aimed to study the effect of foliar spray with tryptophan, phenylalanine, thiamin and ascorbic acid at concentrations of 50 100 and 150 ppm plus the control on growth, yield and volatile oil content of dragonhead (Dracocephalum moldavica, L.) plants.

Generally all tested treatments increased growth parameters oil yield and chemical constituents: plant height, stem diameter branches number, fresh and dry weights of branches/plant leaves number/nlan fresh and dry weights of leaves/plant, yield of fresh leaves/m All treatments also increased root length, fresh and dry eights of roots/plant, leaves oil percentage, leaves oil yield/pan oil components, total carbohydrates0/,, carotenoids, chlorophyll (a&b), N%, P% and K% content compared with the control during the two '^^Moreover, data cleared that spraying dragonhead plants-with tryptophan and phenylalanine at all used concentrations of 50 100 and 150 ppm.

Surpassed vitamin application and improved all s udied vegetative growth parameters as well as yield and volatile oi components.

The highest mean values concerning all growth, yield oil content and chemical constituents were obtained by using tryptophan at the highest concentration (150 ppm) comparing with the other treatments or the control plants in both seasons.

Results also revealed that there were significant increase in root growth parameters of dragonhead plants due to spraying plants with amino acids (tryptophan & phenylalanine) followed by thiamin and ascorbic acid application.

Foliar application of amino acids and vitamins at 150 ppm produced the best results of leaves oil percentage, leaves oil yield/plant, oil components, total carbohydrates%, carotenoids, Chlorophylls (a&b), N%, P% and K% content during the two seasons.

The highest mean values of leaves oil percentage, leaves oil yield/plant, total nitrogen%, phosphorus%, potassium%, chlorophylls (a&b), carotenoids, carbohydrates% were recorded by spraying dragonhead plants with tryptophan treatments comparing with other treatments or control in both seasons.

Using GLC analysis it was found that Eucalyptol, Nerol, Linalool, Geranial, Citral, Geranyl acetate and Caryophyllene were present as volatile oil constituents.

The major constituent of leaves volatile oil of dragonhead plants was (Citral).

The highest Citral percentage was obtained by 150 ppm.

of ascorbic acid followed by treptophan at 150 ppm.

as compared with the other treatments or the control.

Therefore, this study suggest that foliar application of some amino acids i.e., tryptophan and phenylalanine as well as vitamins thiamin and ascorbic acid especially at 150 ppm could play an important role in increasing growth, yield and volatile oils content of leaves of dragonhead {Dracocephalum moldavica, L.) plants, added to its safety on human health.

Key words: Dragonhead, tryptophan, phenylalanine, Thiamin, Ascorbic acid, diameter, Branch, yield, Carbohydrates, chlorophylls, Eucalyptol, Nerol, Linalool, Geranial,and Citral.