International Journal of Horticulture 2015, Vol.5, No.9, 1
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a particular variety to draw it up. The reds and pinks
enjoy an alkaline or neutral soil where aluminum is
not actively absorbed. The whites stay white but
usually enjoy the same conditions as the reds and pinks.
Bailly found in (1992) that to encourage "bluing" of
the flowers, we need to raise the acidity of the soil.
Acidity levels need to be around 5.5 - 6.0 on the pH
scale. To lower the pH and increase the amount of
aluminum in the soil, one should apply around the
hydrangea aluminum sulfate several times at intervals
in the spring and again in the fall if the desired color is
not achieved. The amount of aluminum sulfate really
depends on the concentration because aluminum is
toxic in large doses (Ghanati et al., 2005).
According to Kochain (1995), Al is the third most
abundant element in the earth´s crust, comprising
about 7% of the total mass of the earth (Delhaize and
Ryan, 1995; Zhang et al., 2007). Lidon and Barreiro
(2002) reported that rocks contain from 0.45 to 10%
Al. (Yakimova et al., 2007) considered that Al is one
of the most abundant toxic elements with the ability to
contaminate soil, water and trophic chains. Nonetheless,
the specific biological functions of Al for plants are
unknown, and so it is not regarded as an essential
nutrient (Poschenrieder et al., 2008).
Hydrangea (
Hydrangea macrophylla
) is also a well
known Al-accumulating plant, and the relationship
between Al and the blue coloration of Hydrangea
sepals has been thoroughly investigated (Takeda et al.,
1985a, 1985b). Hydrangea plants can accumulate as
much as 5 mg Al/ g dry weight in the leaves within
several months (Martin, 1988). It is well known that
the color of Hydrangea sepals changes from red to
blue when soil pH is shifted from weak alkaline or
neutral to acidic. However, it was found that it is the
Al dissolved in acid soils that responsible for the blue
color of the sepals, not soil pH itself (Allen, 1943).
However, the blue and pink color of hydrangea flower
sepals due to only one anthocyanin, delphinidin
3-glucoside. In the presence of aluminum, a blue color
will form due to the aluminum binding with the
anthocyanin. The reason for the blue color under acid
conditions is due in part to an increase in availability and
uptake of aluminum from the soil (yoshida et al., 1995).
The aim of this research is
to study the effect of
Aluminum on chlorophyll a, b and Carotenoids content
in leaves of Hydrangea and the amount of anthocyanin
in sepals.
Materials and Methods
Used Plants:
In this work, two cultivars were used of
the species
Hydrangea macrophylla
. The first cultivar
is Nikko Blue (a cultivar with blue color flower), the
second cultivar is Pia (a cultivar with deep pink color
flower).
These plants were tow years old and planted in pots
(one plant in every pot), the media was peat moss and
perlite (2:1).
Study Area:
The study was in Bammraa village in
Hama in Syria. Bammraa is considered as a mountaineer
