I was a keen gardener as a kid, by gardener I mean I have beverage tins filled with loamy soil that I plant things in.
Crimson Seedless Grape [CC0]:
Wikipedia I remembered my frustration as a kid after enjoying a delicious grape but was surprised as there was no seed inside for me to plant.
The curiosity got the better of me; I asked an uncle who told me to forget about it that even if there were seeds that grapes of that nature do not thrive in a tropical area like Nigeria. That explanation did not go down well with me as it did not explain how the grapes got to be without seed.
I know that a seed is required to get a fruit, what confuses me is how the grape got into existence if there was no seed. Does it mean it was sterile? If it was how do we get to have other fruits from it?
The seedless fruit can be seen as sterile since the fruit, which can represent the mature ovaries, houses the embryos (seeds) which it lacks.
The journey of a seed begins as an ovule during pollination, which when fertilised forms a zygote or embryo. The zygote is what goes to become a seed, the ovary on the other hand either metamorphoses into a fleshy nature (berries, drupes, etc.) or changes into a hard shell in the case of nuts.
The development sequence of a typical drupe, within 7 1⁄2-month period from bud formation to fruit ripening. Image by John O'Neill [CC-BY-SA-3.0]:
Wikipedia Notice how the flower changes to fruit, the ovaries become fruits, and the ovules are the seeds. The animals can help in its dispersion by consuming the fruits. The seeds are spread when they defecate hence ensuring the continuity of the plant.
But in the case of seedless fruit, it disappears once the fruits get consumed, and that is the end of the specie continuity.
An Organised Defect
The answer to why this defect, which by the way makes for more convenience in consumption, is by a process known as parthenocarpy.
Fruit development normally begins when one or more egg cells in the ovular compartment of the flower are fertilized by sperm nuclei from pollen. In some plants, however, fruit develops without fertilization, a phenomenon known as parthenocarpy. Parthenocarpic fruit has advantages over seeded fruit: longer shelf life and greater consumer appeal. Scientific American
The process allows for seedless fruit production since it does away with seed fertilization.
Using the process of cutting which involes cutting off a part of an "infected" (i.e the seedless clones) vine or branch, which is then dipped into a rooting hormone.
A grape vine cuttings in nursery pots. Image by Mark Shirley [CC-BY-2.0]:
Wikipedia This cutting is put into the soil, and it grows like its clone producing a seedless grape.
The seedless fruits do not lack fruits per se but rather the fruits never get to mature- thus no hard covering on it.
Modern seedless fruits like these grapes require the help of artificial plant hormone known as gibberellin to develop properly. This hormone is sprayed on them as it lacks it as a result of the underdeveloped seeds present in the grapes- the seeds produce the hormone.
How did it first start?
In 1902, the New York Times published an article, The First Seedless Orange. The report was about a woman, Mrs Nellie Desmond while visiting her brother that stays in Brazil noticed a clump of "freak orange trees" that grows without seed. She brought one back and planted it in California in 1872. As they say, the rest is history.
How To Touch Material at More Than 1204 °C (2000°F) And Be Safe
Now to some "magic" in science. There is this video on Youtube that shows a demonstration of a red-hot material brought out of an oven at a temperature of 2200 °F ( 1204 °C) picked up by bare hands seconds after being placed outside.
The magic is not so mysterious again once you know the science behind it. But first, let us check the material, it is called the LI-900 It is merely a type of sponge made from sand- it contains 99.9% silica glass fibres with most (94%) of its volume occupied by air.
It has one of the most amazing thermal properties; it can go from 2200 degree Fahrenheit (1204 degree Celsius) to 70°F (21°C) or less without suffering any damage. That is it can be heated to that maximum temperature of 2200°F and inserted into cold water with no issue to its structural integrity.
A used space shuttle insulation tile. Image by Astrowikizhang [CC0]:
Wikipedia The baked silica squares form part of the 20,000 tiles that protect the space shuttle during its entry into the earth's atmosphere as the temperature could get as high as 2200°F.
Simulation of the outside of the Shuttle as it heats up to over 1,500 °C during re-entry. Image by Astrowikizhang [CC-BY-SA-3.0]:
Wikipedia
People were able to touch it second after coming out of the oven due to its extremely low thermal conductivity. If you watched the Youtube video, you would notice the demonstrator instruction to pick the cubes at the corners. The reason is that the corners cool faster than the other part of the cube due to its geometry. But even at that, the "cool" edges is still hotter than 300°C which means that if the material is, say steel; it would sear the person that touched it.
Again, the reason is scientific; due LI-900's super low thermal conductivity, the rate the heat will travel from the material to the hand is limited. This is the same reason a piece of steel appears colder than that of wood at the same temperature- steel can conduct the heat away from your hand faster than rubber due to its high thermal conductivity. The thermal conductivity of carbon steel at 293 K (20 °C) is 54 watts per metre-kelvin (W·m−1·K−1) while wood is 0.17, the LI-900 thermal conductivity at 400 K is less than 0.05 W·m−1·K−1
In 2010 NASA gave out 7000 of the tiles with an estimated cost of $1000 to schools, for educational purposes, in the USA who only has to pay a paltry $23.20 to cover the cost of the shipping and handling charge.
That was an inspiring gift to the next generation of space explorers.
Thank you for visiting.