Saguaro National Park Protects Plants 

That Breathe Only At Night

 Welcome to Day # 208 of our "365 Parks in 365 Days" adventure!


"Crassulacean Acid Metabolism."


  Saguaro cactus in Saguaro National Park 'hold their breath' during daylight hours to conserve water and only breathe at night. National Geographic Photo.


The cacophony of noise coming from our government sent me hurtling back in time to find an experience in nature that puts our current political paralysis in perspective. I found it among the giant saguaro cactus in Saguaro National Park in Arizona's Sonoran Desert where, the huge dramatic cactus plants have adapted to their parched environment by breathing only at night. The process is known as "Crassulacean Acid Metabolism"


When our brilliant and accomplished tour guide uttered those words, the eight of us in close knit birding group tripped over our tongues trying to repeat it. Only Frank was able to remember and enunciate it perfectly, and for the remainder of the trip he and Betsy would throw it out at odd times. Peals of laughter and admiration rang out from the rest of us, and six years or so later, Frank was still able to remember it when I asked him.


These blooms represent an incredible output of energy for the desert plants. Wiki Photo


The saguaro cactus in offer a prime example of adaptation for sustainability.  I wish our government would take a leaf out of their book - oh wait! They don't have leaves because they've adapted so perfectly to their environment. And therein lies the lesson.

To my chagrin, all the Park Service's websites are down, but that's a mild inconvenience compared to what our friends who work for the service and other branches of government are facing. I was able to find this information to supplement my warm memories:


" In the desert, there is no water to spare and to waste.  The cactus therefore does the exact opposite of what almost all plants do; it opens its stomata to "breathe" during the night and closes them during the day.  By closing stomata when it is hottest and opening them when it is cooler, the cactus conserves huge amounts of water.  


". . .cacti still need a constant input of carbon dioxide in order to carry out photosynthesis during the day, and without the stomata open there is no direct supply.  To overcome this, cacti absorb huge amounts of carbon dioxide at night time when their stomata are open.  They do not absorb this carbon dioxide like a balloon would though.  Instead, they convert it to a chemical called malic acid, in which form the carbon dioxide can be stored until day light.  


"Once daylight appears the, malic acid is then converted back to carbon dioxide needed to carry out photosynthesis.. ."



According to this  park-related website:


 "The life of the saguaro is a struggle from the beginning. The saguaro begins its life as a shiny black seed no bigger that a pinhead. What it lacks in size, it more than makes up for in numbers. One saguaro produces tens of thousands of seeds in a year, and as many as 40 million in a life time of 175 - 200 years. From the start, the odds against survival are great. Out of all the seeds that saguaro produces in its new life, few will survive to adulthood.


"A saguaro's growth is extremely slow. Growth occurs in spurts, with most of it taking place in the summer rainy season each year. By the end of a year, the saguaro seedling may measure only 1/4 inch. After 15 years, the saguaro may be barely a foot tall. At about 30 years saguaro can begin to flower and produce fruits. By 50 years, the saguaro may be as tall as 7 feet. After about 75 years, it may sprout its first branches or "arms." The branches begin as prickly balls, then extend out and upward.




"By 100 years the saguaro may have reached 25 feet. Saguaros that live 150 years or more attain the grandest size, towering as much as 50 feet and weighing 8 tons, sometimes more, dwarfing every other living thing in the desert. These are the largest cacti in the United States. Their huge bulk is supported by a strong but flexible cylinder-shaped framework of long woody ribs. . ."


"Saguaro National Park has two districts. The Rincon Mountain District is located to the East of Tucson Arizona and the Tucson Mountain District is located to the West of Tucson AZ. In 1933 Saguaro National Monument was created. The Saguaro Wilderness Area of 71,400 acres was added in 1975. Saguaro National Park was created from these areas in 1994 and currently encompasses 91,327 acres in its two districts. The Eastern Rincon Mountain District rises to over 8,000 feet and includes over 128 miles of trails. The Western Tucson Mountain District is generally lower in elevation with a denser saguaro forest. . ."


Sitting here with my laptop at 7 am EST, I  visualize the saguaro beginning to close down their stomata (it's 4 a.m. PST) and shield themselves from the coming high temperatures of the day.. They have adapted to climactic conditions and they do what it takes for their species to continue in perpetuity.


There's a lesson here for our government of the people, for the people, and by the people. Clearly things are not working and some practical adaptations need to be made so that we are working together, instead of hurling insults at each other and seeming to go in opposite directions. I think I'll close my "stomata:" to the cacophony today and spend time among the cactus observing their Crassulacean Acid Metabolism.


 If you've missed any of our "365 Parks in 365 Days" adventures, find them here  (Archive) Pick up your indispensable copy of "Our True Nature" while you're on my website. If you don't have it, you can't know what you're missing....


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