Some studies on the effect of putrescine, ascorbic - Ozean ...

Chatharanthus roseus L. and Abou Dahab and Abd El-Aziz (2006) on Philodendron erubescens,
reported that spraying plants with the amino acid tryptophan increased plant growth.
Rashad et al., (2002) on Capsicum annuum L. indicated that all used amino acids led to marked
increase in leaves photosynthetic pigmentrs. Iman et al.,(2005) on Catharanthus roseus L. showed
that photosynthetic pigments (chlorophyll a, b and carotenoids) in the leaves were increased as a result
of application of tryptophan. Harridy (1986) on Catharanthus roseus L. and Abou Dahab and Abd El-
Aziz (2006) on Philodendron erubescens found that foliar application of different amino acid
treatments caused a significant increase in the content of total free amino acids. Talaat and Youssef
(2002) on Ocimum basilicum L., Wahba et al., (2002) on Antholyza aethiopica and Abou Dahab and
Abd El-Aziz (2006) on Philodendron erubescens indicated that application of the amino acids as a
foliar spray caused an increase in the contents of total soluble sugars.
The aim of this work to study the effect of amino acids phenylalanine and tryptophan, as well as their
combinations, on the growth and chemical constituents of Antirrhinum majus plants and feasibility of
using those chemical to improve plant quality.
MATERIALS AND METHODS
Pot experiment was conducted during two successive seasons 2007/2008 and 2008/2009 in
experimental greenhouse of National Research Center, Dokki, Cairo, Egypt. It was intended to study
the effect of foliar application of amino acids phenylalanine and tryptophan on the growth and
chemical constituents of Antirrhinum majus L. plant. Snapdragon seeds were grown on pots filled
with loamy soil in September of 2007 and 2008. Then, they were thinned to three seedlings per pot.
Fertilization of the plants was carried out at the rate of 2 g calcium superphosphate (16.0 % P2O5), 2 g
calcium nitrate (15.5 % N) and 1 g potassium sulphate (48-52 % K2O) per pot. Each pot was irrigated
with one liter of tap water twice weekly. The plants were grown under natural conditions: 15-35 o C
and 10-20 o C day and night temperatures, respectively, with 12-13 h photoperiod. The plants were
sprayed with the two amino acids phenylalanine and tryptophan, (each concentration of 50 or 100
ppm) applied either separately, or in combinations (at concentrations of 50:50, 50:100, 100:50 and
100:100 ppm of phenylalanine and tryptophan, respectively), in addition to the untreated plants. The
amino acids foliar spray treatments were applied one month after transplanting (on October 5 th in both
seasons) and were repeated two times at one month intervals.
The pots were arranged in a randomized complete blocks design, with 9 treatments (control plus eight
amino acids treatments), replicated three times, with each replicate (block) consisting of 10 plants /
treatment.
For determination of growth parameters, two samples of plants were harvested, the first one at full
vegetative stage (on February) and the second one at full flowering stage (0n April). The following
data were recorded: plant height (cm) , number of branches, fresh and dry weights of plant (g) as well
as length of inflorescence (cm), number of inflorescences/plant and fresh and dry weights of
inflorescences/plant (g) were determined at different growth stages (vegetative and flowering stages,
respectively). All previous data were subjected to statistical analysis of variance according to the
method described by Snedecor and Cochran (1980). Treatment means compared by LSD test and the
combined analysis of the two means was calculated according to the method of Steel and Torrie
(1980). Fresh leaf samples were collected from plants receiving the different treatments and were
chemical analyzed to determine their contents of photosynthetic pigments (chlorophyll a, chlorophyll b
and carotenoids) using the method described by Saric et al., (1967). Leaf samples were dried and
their contents of the total soluble sugars were determined according to Dubois et al.,(1956). The
content of total free amino acids in leaves was determined according to Rosein (1957).
RESULTS AND DISCUSSION
Effect of phenylalanine, tryptophan and their interaction:-
On growth stage:
Treatments of Antirrhinum majus L. plants with the amino acids phenylalanine and tryptophan had a
significant effect on growth parameters (Table 1) and(Figure 1). However, all growth parameters,
plant height, number of branches, fresh and dry weights of plant were increased by the different levels
of phenylalanine and tryptophan as compared with the untreated plants. The positive effect of amino
acids on yield may be due to the vital effect of these amino acids stimulation on the growth of plant
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