Do Cherry Trees Hire Guards with “Nectar”? The Secret Survival Strategy Hidden in Jagged Leaves and Tiny Red Dots
Hi, I’m Ken Kuwako, your Science Trainer. Life is one big experiment!
【This article is also available on my radio channel!】
The Surprising Side of Sakura
Let’s take a quick look at the “profile” of the cherry blossom tree, or Sakura. Scientifically, it belongs to the Rosaceae (Rose) family and is a deciduous broad-leaved tree. Did you know that the cherries we love to eat also come from trees in this same family? It is a very familiar presence in our lives, providing beautiful flowers and delicious fruit enjoyed all over the world.
Sakura trees are monoecious, meaning a single tree produces both male and female reproductive parts. Depending on the species, they can grow to be massive towering trees or remain as smaller shrubs perfect for garden landscaping.
“Breathing Marks” Hidden in the Bark
Have you ever looked closely at the trunk of a Sakura tree? The bark of a young tree is often glossy and features distinct horizontal lines. You can find similar patterns on Birch trees as well. These lines are called lenticels. They aren’t just decorations; they are actually tiny gaps between cells that act as breathing pores. It is living proof that the tree, just like us, is taking in air to survive!
The roots of a Sakura tree tend to be shallow and spread out horizontally. Because of this, you will often see suckers (new shoots growing from the base) or adventitious roots popping up in unexpected places. In the fall, the leaves turn into vibrant autumn colors, giving us one last show before dropping for the winter.
A World of Petals: From “Single” to “Double”
The number of petals on a cherry blossom can vary wildly depending on the variety.
Generally, flowers with up to 5 petals are called single. Those with 5 to 10 are semi-double, and anything with more than 10 is known as a double blossom (or Yaezakura in Japanese). Some incredible varieties can even have over a hundred petals on a single flower!
Nature’s Artwork: The “Net” Pattern on the Leaves
Did you know that the true brilliance of the Sakura tree is hidden in the “season of green” that begins right after the flowers fall? It is truly awe-inspiring to watch the leaves, which were hiding while the flowers were in full bloom, suddenly burst forth with such life. If you look closely at the surface of a leaf, you will see a delicate network of veins. This is called reticulate venation, a feature common in dicots like broad-leaved trees.
On the other hand, monocots like tulips have parallel venation, where the veins run in straight lines. Just asking yourself, “Is this a net pattern or a parallel pattern?” can turn a simple walk into a fun scientific discovery! Here is a photo of a tulip leaf for comparison.
Also, take a look at the “serrated” edges of the Sakura leaf. In science, we call these serrations. Sakura leaves are unique because they often have “double serrations”—tiny teeth tucked inside larger ones. This complex shape is likely the result of millions of years of evolution, designed to improve photosynthesis and adapt to the environment.
The Mystery of the “Red Dots”
Finally, let’s talk about the most fascinating secret of all. Look at the very base of the leaf where it meets the stem. Do you see those two tiny red dots?
These organs are called extrafloral nectaries. Isn’t it strange that a tree would produce nectar somewhere other than its flowers? These dots actually secrete a sweet liquid. Out of curiosity, I once tried to taste it, but unfortunately, my human tongue couldn’t pick up the sweetness (haha)! (If you try it, please be careful and do so at your own risk!)
So, why does the tree have nectar glands on its leaves? It turns out this is a brilliant strategy to hire “bodyguards.” For a tree, having its leaves eaten by moth larvae or caterpillars is a major problem. To solve this, the Sakura tree produces nectar to lure in ants!
The ants, drawn by the sweet treat, begin to patrol the leaves. If they find moth eggs or hungry caterpillars along the way, they chase them off or carry them back to their colony as food. In short, the Sakura tree pays the ants a “nectar salary” in exchange for their protection.
While I was out taking photos, I happened to capture this rare shot of an ant actually visiting a nectary!
It is amazing to think that a single tiny red dot represents such a complex symbiotic relationship between a tree and an insect. Next time you see a cherry tree after its petals have fallen, take a moment to look at the leaves. You will find a quiet but dynamic “survival drama” unfolding right before your eyes.
As a bonus, I’ve created a smartphone wallpaper so you can carry the beauty of the Sakura with you. Feel free to download and use it!
If you’d like to use this in a classroom setting, please check here:
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