The Science in My Lunch Today
I whipped out an orange from my lunch bag today and it was as large as a baby’s head. Amazing! The thing weighed about a pound and looked to be in perfect health, glowing a bright rich… well orange color. I thought to myself, why the heck is this orange so big? Well first of all it’s a navel orange. The navel orange comes from a single mutation in a normal orange tree that happened in 1820 in a Brazilian orchard. This tree made oranges that were actually growing a SECOND orange in its “head”. So it was effectively a conjoined twin orange, a hideous mutant freak, right? Wrong, it was delicious and the planters new they had hit on something big. The mutation also did something else to this delectable fruit abomination, it made it sterile. Navel Oranges have no seeds, another good thing! For us anyway. It’s not for the tree because now there is no way to for this wonderful sin against nature to procreate. The only thing the Brazilian planters could do was cut off parts of the tree and graft it to other trees. Yup, that is possible with plants. You can cut parts of the flowering plant and stick it onto the roots of another and they naturally fuse together and grow. (Interestingly, some farmers graft tomato stems on potato roots making a plant that has tomatoes on top and potatoes on the bottom!) Anyway, a cutting from that original Brazilian mutant tree was sent to Riverside and the rest is history. In effect, every navel orange in the world is a genetic clone of oranges from that first tree. We are all eating essentially the fruit of one tree that has remained in existence for over a hundred years.
Ok, I totally never realized that navel oranges have no seeds. That is bizarre, and makes me feel a little weird about eating something that’s essentially a clone!
But they sure are tasty.
A few other fun facts:
1. You can only graft a citrus branch to another citrus tree if it has appropriate rootstock (trifoliate is commonly used here – that’s what my meyer lemon tree is on). Most rootstock in use today was developed in the last 100 years.
2. Your orange isn’t really orange. It is most likely dyed, spending time in Florida I learned that most ripe oranges are light orange, yellow, or green, but grocery store shoppers like that deep orange color. Another “miracle” of science.
3. Grapes are also commonly grafted onto rootstock.
You should also graft on lime budwood AND orange budwood to make a super citrus tree.
I have to ask… Do you just know this stuff, or do you look it up when these questions come to you? Because I do not know nearly this much about fruit.
I think it’s a little of both. I guess I may have an abnormally long attention span, hah!