Botany is very important--we simply can't survive without plants--and there are still many unanswered questions.

Plants and animals are composed of mostly tiny cells. Plant cells have walls and can contain chlorophyl. Animal cells have neither. Cell walls are composed of ... cellulose, needed for plant rigidity. But would you ever guess that in a living tree, 98% of the cells in the trunk and branches are dead?

Tropical rain forest trees can reach 180 feet in height, yet have roots that are only 3 feet deep. On the other hand, some desert shrubs have tap roots that are 90 feet deep.

The largest of all seeds: Coconuts. The smallest seeds: Orchid seeds (these are like dust particles, are wind-born and require a certain moss as a substrate before they can germinate).

To quicken seed germination, nick the seeds. You can also dip them in concentrated sulfuric acid and then wash them. So why do seeds have hard coats? It promotes survival of the species during unpredictable seasons.

Plants evidentally are sensitive to gravity, roots grow down, stems grow up. This is essential because seeds can be planted upside down, but how does it work, especially during germination?

Answer: unknown! It's not because the stem/trunk grows toward light. Then trees wouldn't grow straight up, they'd lean toward the South. Why don't branches grow up? They do seem to grow toward light. But I can snip a branch and plant it and it then grows straight up. It now responds to gravity. What's going on?

Oxygen is required for germination to break down stored starch, protein and fats to soluble sugars and amino acids. Young smooth bark has breathing pores that look like scale. Leaves also have breathing pores (take in carbon dioxide, give off oxygen by photosynthesis and create food). These pores also allow water loss, so plants close them at night when there is no photosynthesis (how?) Roots also need to breathe. They store food and water, and require oxygen. That's why clay soil is no good.

Water moves from the roots to the leaves. It leaves as water vapor through leaf pores, but this is not all bad. Water movement acts literally as a pump transporting minerals from the soil to the leaves. A 50 ft tall silver maple pumps 60 gallons of water per hour! Cutting a plant stem causes air to be sucked into the stem because of water lost from the leaves. So, cut flower stems longer than desired, and trim them under water just before putting the flowers in a vase. They'll last longer.

There are several plant hormones that control growth and flowering. You have probably used Auxin, which stimulates root growth. Plants actually form it at their stem tips. Strangley, it inhibits budding below the stem tip, so the plant grows upward. Remove the stem tip by pruning and you allow budding which leads to branching and more flowers.

Ethylene gas is another plant hormone and it promotes fruit ripening -- it is used commercially for bananas. One way to ripen unripe fruit, is to brown-bag it and include chopped pieces of a ripe apple (ethylene source).

Much of the above information is excerpted from a book by Brian Capon entitled, “Botany for Gardeners”.