THE FIRST PLANT PATHOGEN KNOWN
The
first plant pathogen is Mistletoe recognized by Albert Malthus in 1200 A.D.
which lives as parasite on branches of many trees. Mistletoe, both common or
leafy (Viscum in Europe and elsewhere, Phoradendron in North
America) infects many deciduous trees and dwarf mistletoe(Arceuthobium)
infects conifers and it causes considerable damages to the trees it infects.
The mistletoe is an evergreen phanerogamic plant which can be clearly seen
after the normal leaf fall of the deciduous trees in the autumn and in many
cases they make up as much as half of the top of the deciduous trees. They
generally infect plants by making their branches swell up where they affect
leading them to be weak and break there during windstorms. This highly
decreases the quality of timber.
Mistletoes
sink their roots usually called sinkers or haustoria onto the branches of the
trees and absorb all the water and minerals from there. They have well
developed leaves and chlorophyll and carry on photosynthesis and manufacture at
least some of the sugars and other organic substances they need.
They produce separate male and female flowers and berry like fruits containing a single seed. The seeds are coated with a sticky substance and are either forcibly expelled and stick to branches of nearby trees or are eaten by birds but go through their digestive tract and stick to branches on which birds drop them.
The striking visibility of the true mistletoes on deciduous trees, and their ability to remain green while their host leaves fall on the winter, excited the imagination of the people since the times of ancient Greeks and inspired many myths and traditions involving the mistletoe plant through the centuries. The plant itself was thought to possess the mystical powers and became associated with many folklore customs in many countries. It was thought to bestow life and protect against poison, to act as an aphrodisiac, and to bestow fertility. Mistletoe sprigs placed over house and stable doors or hung from ceilings were believed to ward off witches and evil spirits. The Romans decorated their temples and houses in midwinter with mistletoe to please the gods to whom it was sacred. In Nordic mythology, the mistletoe was sacred to Frigga, the goddess of love, but was used by Loki, the goddess of evil, as an arrow and killed the son of Frigga, the god of summer sun. Frigga managed to revive her son under the mistletoe tree and in her joy, she kissed everyone who was under the mistletoe tree. But, for its misdeed to her son, she condemned the mistletoe to, be in future, to be parasite and to have no power to cause misfortune, sorrow or death. She decreed instead that anyone standing under a mistletoe tree was due not only protection from any harm, but also a kiss, a token of peace and love. So, in Scandinavia, mistletoe was thought of as a plant of peace: under the mistletoe, enemies could agree on a truce or feuding spouses could kiss and make up.
In England a ball of mistletoe was decorated with ribbons and ornaments and was hung up at Christmas. If a young lady was standing under a ball, she could not refused to be kissed or she could not expect to get married the following year. A couple in love that kiss under the mistletoe is equivalent to promising to marry and a prediction of long life and happiness together. Nowadays, in many parts of Europe and America, a person standing under a ball or even a sprig of mistletoe at Christmastime is inviting to be kissed by the members of the opposite gender as a sign of friendship and goodwill. There are, actually, more myths and customs associated with mistletoe. Who would think that a minor parasitic higher plant would excite the imagination of so many others and have so many stories about it.
Tags
Plant Pathology