Rhododendron Essay, Research Paper

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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