Plant adaptations

Water is the key component for both plants and people. We can survive long periods without food, but only a relatively short time without water. Our body weight, and that of plants, is made up principally of water. Seventy percent of your body weight is water, but a cabbage is made up of over ninety percent water. Small wonder then that rainfall plays such an important part in determining what grows where.

Water is the key component for both plants and people. We can survive long periods without food, but only a relatively short time without water. Our body weight, and that of plants, is made up principally of water. Seventy percent of your body weight is water, but a cabbage is made up of over ninety percent water. Small wonder then that rainfall plays such an important part in determining what grows where.

While we watch the rain fall on our gardens, we need to remember that the water will, eventually, return upward again through a process known as transpiration. Only one-third of rainfall drains away; the other two-thirds is taken up by the plants. A big tree can draw 300-400 gallons of water a day from the soil, releasing it back into the atmosphere through its leaves.

In various parts of the world, the rainfall is very high or very low at certain times of the year, and the plants in these areas have adapted to survive in these conditions.
One thing quickly becomes clear to you when you neglect to water your garden: some plants quickly wither and die while others survive apparently untroubled. Why should this be so? And what can you learn from this?

Plants from great extremes of climate have evolved to cope with different quantities and timings of water deliver}’, and their cell structure has adapted to cope with these fluctuations. The most obvious manifestation of this is in leaf shape. If you look around a garden, you will see a wide variety of leaf shapes. Since the leaves are the main means by which a plant captures sunlight through Climate changes (below) the climate changes (he farther north or south you move from the equator. Some plants are very hardy and can tolerate extreme northern and southern temperatures; some will only thrive in the hot temperatures 0/equatorial regions; and others have a wide range 0/temperature tolerance. The map and key below show the different climates in the various regions of the world.

Since reduced sunlight lowers the possibility of leaf scorch, these leaves need less surface protection than those in strong sunshine, where the leaves may be coated with wax, felt, or hair to prevent moisture loss. In low light areas, the way the leaves are held may be significant. The leaves of ivy are held flat and face the light to absorb the maximum amount.

In desert regions, the characteristics of the plants are rosettes of leaves that catch the water in their base, a waxy or glaucous coating to the leaves, and fierce spines to deter predators.

On the sunny slopes of the Mediterranean, plants have evolved with fine, divided, felted, or waxy leaves in order to reduce moisture loss. In the prostrate form of rosemary, the grayish leaves help to reflect light and keep the leaves cool, which prevents water loss.
In areas where water loss may jeopardize the plant, leaves are often fine and needle-like. This is true of hot regions and also of very cold ones, where the wind dries the moisture and where, in frozen ground, the plant needs to prevent transpiration.

Quirks of nature

Nature also produces oddities. In some plants albino forms develop, with leaves that have no or patchy coloring. These quirks have become sought-after variations, in the form of variegated leaves, which are exploited by plant breeders to produce an even wider range of characteristics.

Advertisements
This entry was posted in Uncategorized. Bookmark the permalink.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s