The previous chapter helps us understand the natural process of how water comes to earth and then returns to the sky while simultaneously assisting the plant kingdom to grow and produce.
Many years ago, my dad took on the project of painting the garage. He commissioned me, his young eleven-year-old son, to be part of the project. He was obviously the better painter between the two of us but, for good parental reasons, wanted me involved in the project. I was reluctant, as I wanted to do other things that young boys do in the spring of the year, but he was persistent with his young son.
So, with roller, brush, and paint in hand, I began to do my part. He also made me scrape the garage with a paint scraper and wire brush. My character was being challenged to the max.
As is the case with most buildings, plants grew adjacent to the outer walls. Not being very skilled at painting, and not being very willing in the first place, I found myself not just painting the garage. I wanted this project over in a hurry, so any plant growth I ran into, especially near the lower sections of the garage wall, were painted also.
Many years have gone by since that time, and I now recollect exactly what plants were affected by my lack of character. I do remember painting grass. At the bottom levels of the garage wall, the grass had grown tall enough to be in my way; and I was too lazy to move it. I used the roller or the brush to re-position it, applying a coat of paint to the grass blades in the process of painting the garage wall.
Peony bushes also suffered. The leaves became smeared and discolored by my careless energies. I know we also had some rose bushes in the yard, so they, too, may have experienced my unskilled and hasty efforts to complete the task.
Now, based on what we know from our botanical study of transpiration, which is the process of water evaporating through plants, how might we describe a peony bush painted by a careless young boy?
By itself, a peony bush is like any other plant. It drinks in water, and then that water is released through its stomata via the process described in the previous chapter. The CO2 comes in, mixes with the chlorophyll and light (photosynthesis), and food is produced, thereby causing the peony bush to grow and do what it does best, reflect beauty. The beauty is that portion of the plant we call the flower. A flowering peony bush is gorgeous, a true floral delight.
This transpiration process[1] is such a vital part of what makes a plant grow that botanists say 90% of the water taken up into a plant comes out of the stomata in the process. They also say that most plants experience 200 to 1,000 pounds of water transpiring through their leaves to produce one (1) pound of solid material added to the plant.[2]
But then an imprudent eleven-year-old painter comes along and paints one side of the peony bush, covering several leaves with fresh paint. What did the young painter just do to the peony bush?
He killed it! At least, he killed the portion of the plant coated with paint.
How did he do that? Did he take the water out of the plant? That would certainly kill any plant anywhere. No, he did not take water out of the plant.
Did he pull the plant out of the ground by its roots? That is always a good way to kill plants. But no, that didn’t happen either.
All the painter did was, in essence, permanently close the stomata by gluing them shut with the paint. This prevented the water from exiting that portion of the plant and returning into the sky from where the water originated.
So here is a picture of a plant that is filled with water…and dying.
A plant filled with water. This is good, right?
So why is it dying?
This will prove poignantly essential to a point I will be making a little later; so let’s say that again. “This is a plant filled with water and dying.”
Botanists see transpiration so important that it acts as an engine pulling water up from the roots.[3] If the water is not allowed to come out of the leaves, then it’s over. The engine has been shut down. Though water is present in great abundance, death is nonetheless the resulting consequence—all because the water is prevented from making its egress and returning to the sky.
A plant filled with water and dying.
[1] Most transpiration (90%) occurs from leaves, especially from stomates (stomatal transpiration) when the stomates are open. When the stomates close, plants continue to transpire directly from the epidermal cells despite the cuticle layer that these cells usually have (cuticular transpiration). Tissues with a periderm often transpire via lenticels (lenticular transpiration). Cuticular and lenticular transpiration make up the other 10%. http://www.spaceag.org/lessons3/LessonSetIIExtraordinaryEnvironments/Transpiration2.doc.
http://eve.kean.edu/~breid/Botany/botlab9.html.
[2] http://encyclopedia2.thefreedictionary.com/transpiration.
[3] http://water.me.vccs.edu/courses/SCT112/lecture3b.htm.
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