Known as the largest cactus in the United States, the saguaro cactus grows in southern Arizona and usually grows to about 12 meters in height. Courtesy Desert Botanical Garden
2023.07.28 Fri posted at 13:30 JST
(CNN) At a botanical garden in Phoenix, Arizona, a cactus is dying because it can’t stand the heat.
Arizona’s record-breaking heat and absence of seasonal monsoons have put the saguaro cactus under “high stress” at the Phoenix Botanical Garden, a collection of desert plants.
A saguaro cactus that looks normal or slightly limp can suddenly topple over, experts at the botanical garden said. Such cacti are rotten from the inside due to heat-related stress.
The botanical garden counts the number of saguaro cacti each February to diagnose their individual conditions. After 2020, the number of cacti withered due to stress due to record heat will increase. This year’s record heat has overwhelmed the affected cacti, causing them to lose branches or collapse.
Dead Cactus/Courtesy Desert Botanical Garden
Phoenix’s 16-day record of over 90 degrees Fahrenheit (about 32 degrees Celsius) ended on Friday night. However, the temperature on the 27th is expected to exceed 110 degrees (43 degrees) again.
During the night, cacti open their stomata for gas exchange, taking in the carbon dioxide they use for photosynthesis during the day. But Phoenix’s record-breaking nighttime heat is suffocating the cacti, increasing stress and dehydration, making them more susceptible to infections and insect damage.
The saguaro cactus “has adapted well to heat and drought, but it still has its limits,” experts say.
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2023-07-28 04:30:00
