Two Peas In A Pod

Gregor Mendel was an Austrian monk who spent his life pollinating peas in his cloister garden, and proving that nothing, after all, is so unlike as two peas in a pod. To a great extent he revealed the secret of heredity, showing that strains repeat themselves in a regular mathematical pattern, and, by breeding, can often be perpetuated, increased, eliminated, or blended. Thus, by pollinating a rose that has a factor (scientists call it a gene) for ever-blooming, but no gene for fragrance, with a rose that has a gene for fragrance but none for ever-blooming, today's breeder hopes to get a rose that will be both fragrant and ever-blooming.

This and far more important things are done by breeders of all sorts of plants from beans to orchids, working with frail pollen as their strongest tool. It is fascinating to visit a plant experiment station and watch the delicate, swift, accurate technique of the breeders. The varieties to be pollinated first have their own pollen-bearing organs cut out before the bud opens, to prevent inbreeding. Then the bud is shut in a bag to prevent bees from bringing unknown, perhaps undesirable, pollen to the flower. The breeder now goes to the male parent strain he has selected and collects the fresh, fertile pollen just as the flower opens. This he puts in a little glass dish, marked with the name and number of the bush it came from.

He may collect pollen from many varieties at once, and with a whole trayful of dishes he then moves down the row of female parents, each kept immaculate in its bag. Opening each bag, he applies the selected pollen to the stigma of the female flower, closes the bag, and goes on. His work is then complete; he can only await results. But the pollen grain is just beginning to work. On the stigma or receptive surface of the female flower it begins to sprout, sending out a very fine tube that grows down and down in the tissues of the ovary, toward the egg cells at the bottom. The distance it may have to travel may be about a thousand times the diameter of the pollen grain, as in the case of the amaryllis. Yet somehow the grain is able to take this entire "pipeline" out of itself. For the pollen is actually drawn toward the waiting egg cells by a chemical stimulator called a hormone.

So, in the flower, the precious passenger in the pollen grain at last reaches journey's end, and the new life is started. The result may be a new strain of wheat that will help feed the starving world. It may be a hybrid tea rose, breathing its exquisite perfume in your garden. Or it may be a noble tree to shade the roof of your children's children. Truly, pollen is the wonder dust of Nature.

By: davidbunch

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