Rhododendron Essay, Research Paper
Rhododendron
The plant rhododendron belongs to the family
Ericaceae which also includes the Heath, and there are
about eight-hundred fifty species which grow worldwide
(Turner and Szczawinski, 171-2). The Heath family is a
large one with so many species, all of the poisonous
species fall into two of its subfamilies, one of which is
the rhododendron.
These cultivated plants occur naturally in temperate
regions of the northern hemisphere and in the mountains of
Southeast Asia. They are located in the Himalayas with
seven-hundred species, southwest China, Burma, and in New
Guinea with over three-hundred species (Turner and
szczawinski, 172). It has been popular as ornaments in
gardens and has led to a major horticultural industry with
its widely uses in landscaping.
There are twenty-seven species native to North
America, (Turner,172) and is the state plant of
Washington. This specific plant is called R. macrophyllum
or the Pacific rhododendron (Pojar and Mackinnon, 61). It
forms a shrub layer in forests ranging from shoreline pine
groves to stands of Douglas-fir and western Hemlock up in
the mountains. Usually they are located everywhere from
homes to freeway sides and also in the forests.
The rhododendron shows a great variety in size,
habit, and flower color, colors from white to pink,
dark-purple, yellow, red, and orange (McKenzi,1). They
range from small shrubs to small trees with evergreen
leaves that are leathery. The leaves are short stalked,
simple, and alternate, and the flowers are large,
bell-shaped, and born in dense clusters. They are best
grown on acidous soil with a ph of 4.5 and 6.5, included
with lots of moisture and organic material (McKenzie, 3).
The leaves, flowers, pollen, and nectar of many
rhododendron species contain several toxins (Kingsbury,
50). These toxins are called grayanotoxins or
andromedotoxin, a resinoid carbohydrate (Kingsbury, 51).
It is prevalent in the flower nectar, and has caused
poisoning of bees and the honey produced. The symptoms
are similar to both humans and all animals. The human
cases are that in which children chew the leaves and get
the poison in their system, or when people drink tea made
from the honey and plant (Abrahams, 2). It has been
reported that animals clip the leaves for boredom or when
they get hungry, as food is short (U.S food and drug
admin., 3).
The rhododendron is a beautiful plant which lies
outside homes for decorations. People should become more
aware of its toxicity and should take precautions when
handling them.
Grayanotoxin
The plant rhododendron contains several toxins called
grayanotoxins. Other well known but former names are
rhodotoxin, andromedotoxin, and acetylandrome (U.S. food
and drug admin., 1). They are included in almost all of
the species rhododendron.
The name of the disease is honey intoxication, which
is caused by the consumption of honey produced (Abrahams
1). The grayanotoxins cause this intoxication, and the
specific toxins vary with the plant species. Other names
associated with this disease is rhododendron poisoning,
mad hone intoxication or grayanotoxin poisoning. (U.S food
and drug admin., 1)
The poisoning results from the ingestion of
grayanotoxin contaminated honey. The other ways that it
can get into your system is if you consume plant parts.
Every part of the plant is poisonous, the flowers, nectar,
honey, and especially the leaves, which contain more.
In humans, symptoms of poisoning occur six hours
after a dose. These symptoms include salivation,
vomiting, very low blood pressure, loss of coordination,
muscular weakness, slow and irregular heartbeat, and
comas, followed by death in extreme cases. (U.S. FDA,2)
All organisms such as animals and humans are affected
in the same way. The treatments are to induce vomiting,
or perform gastric lavage, replace fluids and maintain
electrolyte balance, monitor heart beat, blood pressure
and breathing.
Even though the cases reported have been rare, people
still should become aware of this toxin. House pets eat
the plants, children do also, so they should be taught to
stay away from these plants.
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