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

Ozean Journal of Applied Sciences 2(4), 2009
ISSN 1943-2429
© 2009 Ozean Publication
PHYSIOLOGICAL EFFECT OF PHENYLALANINE AND TRYPTOPHAN
ON THE GROWTH AND CHEMICAL CONSTITUENTS OF ANTIRRHINUM
MAJUS PLANTS
Nahed, G. Abdel Aziz, Mona, H. Mahgoub and Azza, A.M. Mazher
Department of Ornamental plant and Woody trees,
National Research Centre, Dokki, Cairo, Egypt
________________________________________________________________________________
Abstract : A pot experiment was carried out in the nursery of the National Research Center, during the
two successive seasons of 2007/2008 and 2008/2009, with the aim of studying the effect of foliar
application of the amino acids phenylalanine and tryptophan (each at the rate of 50 or 100 ppm),
applied separately or in combinations of the different concentrations (plus untreated plants), on the
growth and chemical constituents of Antirrhinum majus plants. Results showed that, increasing the
two amino acids concentrations gradually increased significantly all growth parameters, vegetative
and flowering stages (plant height, number of branches, fresh and dry weights of plant as well as
length of inflorescence, number of inflorescences/plant and fresh and dry weights of
inflorescences/plant), and the contents of the photosynthetic pigments, total soluble sugars and total
free amino acids in the leaves. The effect of tryptophan was superior to that of phenylalanine on
increasing plant growth at vegetative growth. The maximum plant growth as determined by all the
recorded parameters as obtained from plants treated tryptophan and phenylalanine at rate of 100
ppm); separately or in combined between them gave the best results than the others treatments and
untreated plants.
Key words: amino acids, Antirrhinum majus, tryptophan and phenylalanine
__________________________________________________________________________________
INTRODUCTION
Antirrhinum majus (Snapdragon) is a species of Antirrhinum native of the Mediterranean region. It is
a herbaceous perennial plant growing to 0.5 – 1.0 m tall, rarely up to 2.0 m. Numerous cultivars are
available, including plants with lavenduer, orange, pink, yellow or white flowers. The regulation of
plant growth and reproduction could be achieved through many bioregulators especially as recently
accepted to use naturally occurring regulators as amino acids. Amino acids as organic nitrogenous
compounds are the building blocks in synthesis of proteins which probably occurs by a process in
which ribosomes catalyze the polymerization of amino acids (Bidwell, 1979; Davis, 1982).
Research on the response of plant to amino acid is therefore necessary for improving plant growth and
plant production in these regions. Gamal El-Din et al.,(1997) reported an increase in vegetative
growth of lemongrass as a result of ornithine and phenylalanine treatments. In addition, phenylalanine
application significantly increased fresh and dry weight of datura during vegetative and flowering
stages (Youssef et al.,2004). Mona and Iman (2005) on Pelargonium graveolens, Gamal El-Din et al.,
(2005) on Lupinus termis and Karima et al., (2005) on Matricaria chamomilla showed that all
vegetative growth parameters were increased by treatments of the phenylalanine.
The role of the amino acid tryptophan in stimulating the growth of several species were studied by
Russell (1982) who reported that the increase in growth as a result of tryptophan application may be
due to its conversion into IAA. Attoa et al.,(2002) on Iberis amara L., Iman et al.,(2005) on
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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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cells. The positive effect of amino acids on growth was stated by Goss (1973) who indicated that
amino acids can serve as a source of carbon and energy when carbohydrates become deficient in the
plant's amino acids are determinate, releasing the ammonia and organic acid form which the amino
acid was originally formed.
The organic acids then enter the Kerb's cycle, to be broken down to release energy through respiration.
Thon et al.,(1981) pointed out that amino acids provide plant cells with an immediately available
source of nitrogen, which generally can be taken by the cells more rapidly than inorganic nitrogen.
Similar increases in growth parameters as a result of amino acids treatments have been previously
observed by several investigators on a number of plant species, Gamal El-Din et al.,(1997) on lemon
grass, Talaat and youssef (2002) on basil plant, El-Fawakhry and El-Tayeb (2003) on Chrysabthemum,
Mona and Iman (2005) on Pelargonium graveolens plant and Nahed and Balbaa (2007) on Salvia
farinacea plants, they found that amino acids significantly increased vegetative growth.
Data presented in Table (1) showed also that foliar spray of Antirrhinum majus L. plant with
phenylalanine (100 ppm) combined with tryptophan (100 ppm) resulted in the tallest plants. It is also
clear from the obtained data that foliar spray of snapdragon plants with 100 ppm phenylalanine
combined with 100 ppm tryptophan resulted in highest pronounced effects on number of branches as
well as fresh and dry weights of plants in growth stages. These results coincided with those obtained
Mona and Iman (2005) on Pelargonium graveolens L. and Abou Dahab and Abd El-Aziz (2006) on
Philodendron erubescens plant.
Table (1) Effect of phenylalanine, tryptophan and their interaction on growth of Anterrhinum majus L.
during two stages (vegetative & flowering) (mean of two seasons)
Treatments (ppm)
Control
Plant
height
No. of
branches
Vegetative Flowering
F.W of
plant
401
D.W of
plant
Plant
height
No. of
branches
F.W of
plant
cm gm cm gm
Effect of Phenylalanine
D.W of
plant
58.28 10 78.26 12.59 83.33 14.67 151.27 38.1
Phynyl.50 59.56 11.56 87.12 12.43 84.78 16.33 155.55 40.74
Phynyl.100 63.39 13.22 95.62 15.09 91 18.22 180.09 47.68
LSD 5% 1.62 0.87 2.68 0.9 2.07 0.97 8.35 1.18
Control
Effect of Tryptophan
55.44 8.22 70.49 1084 81.22 15.22 150.63 38.91
Tryp. 50 59.78 11.56 88.79 13.59 85.89 15.56 163.48 41.81
Tryp. 100 66 15 101.72 16.68 92 18.44 172.79 45.8
LSD 5% 1.62 0.87 2.68 0.9 2.07 0.97 8.35 1.18
Control
Effect of Interaction
50.5 6.33 56.07 9.53 71.33 12.33 115.8 27.33
Tryp. 50 58 9 77.97 11.77 89.33 14.67 164.2 41.35
Tryp. 100 66.33 14.67 100.73 16.47 89.33 17 173.83 45.6
Phynyl.50 57.33 8.67 70.8 11 77.67 14 140.53 37.06
Phynyl.100 58.5 9.67 84.6 12 94.67 19.33 195.57 52.33
Phynyl.50+Tryp. 50 60 12 91.07 12.9 89.7 18 180.5 46.47
Phynyl.50+Tryp.100 61.33 14 99.5 16.4 87 17 145.6 38.69
Phynyl.100+Trup.50 61.33 13.67 97.33 16.1 81.3 13.67 145.74 37.6
Phynyl.100+Tryp.100 70.33 16.33 104.93 17.17 99.7 21.33 198.96 55.16
LSD 5% 2.81 1.51 4.65 1.57 3.58 1.68 14.47 2.04

gram
Fig. (1) Effect of phenylalanine and tryptophan on fresh and dry weight (gm) on Anterrhinum majus L.
plant at vegetative stage.
Value (g)
200
150
100
50
0
250
200
150
100
50
0
Fig. (2) Effect of phenylalanine and tryptophan on fresh and dry weight (gm) on Anterrhinum majus L.
plant at flowering stage.
On flowering:
Vegetative
stage
Control
Flowering stage
T 50
T 100
Ph 50 ppm
Data presented in Tables (1, 2) and Fig.(1, 2) showed that increasing different amino acids
(phenylalanine or tryptophan) from 50 to 100 ppm significantly increased plant height, number of
branches, fresh and dry weights of plant as well as length of inflorescence, number of
inflorescences/plant and fresh and dry weights of inflorescences/plant. Phenylalanine caused
increments on fresh and dry weights of inflorescence/plant by (3.3 % and 18.6%) respectively for the
50 ppm and 38.4 % and 57.9 %, respectively for 100 ppm compared with the untreated plants.
However, tryptophan caused increments on fresh and dry weights of inflorescence/plant by (4.3 % and
14.6 %) respectively for the 50 ppm and( 27.4 % and 30.7 %), respectively for 100 ppm compared with
the untreated plants. Our results are combatable with those obtained by Bekheta and Mahgoub (2005)
on Dianthus caryophyllus, Mona and Iman (2005) on Pelargonium graveolens L. and Nahed and
Balbaa (2007) on Salvia farinacea plants, they stated that application of amino acids led to the
increments of flowering parameters and found that amino acids produced a high quality of
inflorescences. The stimulatory effect were found to be correlated with the increase in content and
activity levels of endogenous promoters particularly gibberellins and IAA which are known to promote
linear growth of plant organs (Stoddart, 1986 and Wilkins, 1989).
In addition, the results obtained in table (2) indicated that, the interaction between different involved
factors (phenylalanine and tryptophan) were almost significant for flowering parameters. The highest
values due to amino acids were obtained due to (100 ppm phenylalanine and 100 ppm tryptophan ) for
flowering parameters.
402
Treatment (ppm)
Ph100
Ph 50+T 50
Treatment (ppm)
Ph 50+T100
FW of plant
DW of plant
Ph 100+T 50
FW of plant
DW of plant
Ph 100 +T 100

Table (2) Effect of phenylalanine, tryptophan and their interaction on flowering parameters of
Anterrhinum majus L. plants (mean of two seasons)
Treatments (ppm)
Control
Length of
inflorescence
No, of
inflorescence/pla
nt
403
F.W of
inflorescences/
plant
cm gm
Effect of Phenylalanine
D.W of
inflorescences
/plant
19.06 16 9.98 1.88
Phynyl.50 19.22 17.11 10.31 2.23
Phynyl.100 20.67 20.78 13.81 2.97
LSD 5% 0.87 0.95 0.52 0.25
Control
Effect of Tryptophan
18.06 16.56 10.28 2.05
Tryp. 50 20.06 17.22 10.72 2.35
Tryp. 100 20.83 20.11 13.1 2.68
LSD 5% 0.87 0.95 0.52 0.25
Control
Effect of Interaction
15 13.33 6.98 1.03
Tryp. 50 20.5 16.67 11.16 2.33
Tryp. 100 21.67 18 11.81 2.3
Phynyl.50 18 16 8.66 1.99
Phynyl.100 21.17 20.33 15.21 3.12
Phynyl.50+Tryp. 50 19 16.33 10.41 2.19
Phynyl.50+Tryp.100 20.67 19 11.87 2.5
Phynyl.100+Trup.50 19 16 9.14 1.95
Phynyl.100+Tryp.100 21.83 26 17.07 3.56
Value (g)
20
18
16
14
12
10
8
6
4
2
0
LSD 5% 1.52 1.64 0.89 0.44
Infloresences
Treatment (ppm)
FW DW
Fig.(3) Effect of phenylalanine and tryptophan on fresh and dry weight (gm) on Anterrhinum majus L.
plant inflorescences.

Chemical composition:
Pigments content: data in Table (3) showed that, the leaves contents of photosynthetic pigments
(chlorophyll a, b, a+b and carotenoids) increased by increasing amino acids concentration compared
with the untreated plants. In addition, data indicated that the amino acids treatments which were used
in this study had significant effect on all photosynthetic pigments. Plants treated with 100 ppm
tryptophan had the highest total chlorophyll content (1.63 mg/g FW), while untreated plants gave the
lowest value (1.27 mg/g FW). The recorded data also revealed that plants treated with tryptophan at
100 ppm had the highest carotenoids content, compared to that found in plants receiving any other
treatments. The comparison between the effect of phenylalanine and tryptophan revealed that the
influence of tryptophan on increasing the photosynthetic pigments (especially at the rate of 100 ppm,
which can be described as the most effective treatment) was superior to that of Shoola (2000) on
Lavendula multifida plant and Abou Dahab and Abd El-Aziz (2006) on Philodendron erubescens
plants.
As for the interaction between the different levels of the two amino acids (phenylalanine+ tryptophan)
application, the higher values provided when spraying 100 ppm phenylalanine and 100 ppm
tryptophan. The positive effect of foliar amino acids on enhancing all photosynthetic pigments
percentage may be due to the succnyl COA (Kerb's cycle intermediate) and the amino acid glycine,
initiate the biosysnthetic pathway leading to chlorophyll formation.
Total soluble sugars contents:
Effect of foliar application with different levels of two amino acids (phenylalanine and tryptophan)
were presented in Table (3) fig. (4) indicated that total soluble sugars contents as affected by different
levels treatments, followed the same trend obtained previously on photosynthetic pigments, were
gradually increased by increasing the level of amino acids. Comparing the effect of phenylalanine and
tryptophan , the data indicated that tryptophan was superior to phenylalanine. The percentages of
increase in the total soluble sugars content caused by treating the plants with tryptophan at 100 ppm
(compared with the control) was 52.88%. the promotive affect of the amino acids on the total soluble
sugars percentages may be due to their important role of the biosynthesis of chlorophyll molecules
which in turn affected total soluble sugars content. Similar results have been reported in other plant
species, Attoa et al.,(2002)on Iberis amara L., Iman et al.,(2005) on Catharanthus roseus L and Nahed
and Balbaa (2007) on Salvia farinacea plants. Considering the interaction, the maximum values of the
soluble sugars percentage was obtained at 100 ppm phenylalanine + 50 ppm tryptophan.
404

Table (3) Effect of phenylalanine, tryptophan and their interaction on chemical constituents of
Anterrhinum majus L. plants (mean of two seasons)
Treatments Chl. a
Control
Chl.
b Chl. a+b Carotenoids
405
Free amino
acids
Soluble
sugars
mg/g % mg/g
Effect of Phenylalanine
1.01 0.37 1.38 0.27 5.69 3.24
Phynyl.50 1.09 0.38 1.47 0.3 5.89 3.63
Phynyl.100 1.1 0.41 1.51 0.29 6.24 3.87
LSD 5% 0.02 0.01 0.03 0.01 0.19 0.06
Control
Effect of Tryptophan
0.95 0.32 1.27 0.26 2.79 4.69
Tryp. 50 1.1 0.37 1.47 0.29 3.63 5.97
Tryp. 100 1.16 0.47 1.63 0.31 4.31 7.17
LSD 5% 0.02 0.01 0.03 0.01 0.06 0.19
Control
Effect of Interaction
0.81 0.26 1.07 0.22 3.64 2.15
Tryp. 50 1.07 0.34 1.41 0.29 5.87 3.31
Tryp. 100 1.15 0.5 1.65 0.32 7.57 4.26
Phynyl.50 1 0.34 1.35 0.28 4.6 2.97
Phynyl.100 1.04 0.35 1.39 0.29 5.82 3.25
Phynyl.50+Tryp. 50 1.11 0.36 1.47 0.3 5.92 3.71
Phynyl.50+Tryp.100 1.13 0.42 1.55 0.31 7.16 4.2
Phynyl.100+Tryp.50 1.12 0.4 1.52 0.27 6.12 3.88
Phynyl.100+Tryp.100 1.19 0.49 1.68 0.32 6.77 4.48
LSD 5% 0.04 0.02 0.05 0.02 0.32 0.1
Value
10
8
6
4
2
0
Control
T 50
T 100
Ph 50 ppm
Fig(4) Effect of phenylalanine and tryptophan on fresh and dry weight (gm) on free amino acids and
soluble sugars.
Ph100
Ph 50+T 50
Treatment (ppm)
Ph 50+T100
Free amino acids mg/g
Soluble sugars %
Ph 100+T 50
Ph 100 +T 100

Total free amino acids:
The results recorded in Table (3) and fig.(4) showed that spraying Antirrhinum majus plants with
different amino acids treatments caused a significant increase in the content of total free amion acids in
leaves. Application of the high phenylalanine concentration (100 ppm) was the most effective
treatment in producing the highest values, followed by tryptophan of the rate of 100 ppm. The
increase in the content of total free amino acids as a result of the tryptophan treatments may be
attributed to its conversion of to IAA, as stated by Phillips (1971). Furthermore, the combination
between the two amino acids were almost positive for the content of the total free amino acids.
Tryptophan at 100 ppm + phenylalanine at 100 ppm gave the highest values of the total free amino
acid.
Our results are in agreement with the findings of Harridy (1986) on Catharanthus roseus L and Abou
Dahab and Abd El-Aziz (2006) on Philodendron erubescens.
Hence, it could be recommended that treatment of Antirrhinum majus plants with tryptophan and
phenylalanine (especially at the concentration of 100 ppm) had a beneficial effect growth and chemical
constituents.
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