Plants are mainly multicellular organisms, predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, plants were treated as one of two kingdoms including all living things that were not animals, and all algae and fungi were treated as plants. However, all current definitions of Plantae exclude the fungi and some algae, as well as the prokaryotes (the archaea and bacteria). By one definition, plants form the clade Viridiplantae (Latin name for "green plants"), a group that includes the flowering plants, conifers and other gymnosperms, ferns and their allies, hornworts, liverworts, mosses, and the green algae, but excludes the red and brown algae.
Green plants obtain most of their energy from sunlight via photosynthesis by primary chloroplasts that are derived from endosymbiosis with cyanobacteria. Their chloroplasts contain chlorophylls a and b, which gives them their green color. Some plants are parasitic or mycotrophic and have lost the ability to produce normal amounts of chlorophyll or to photosynthesize, but still have flowers, fruits, and seeds. Plants are characterized by sexual reproduction and alternation of generations, although asexual reproduction is also common.
There are about 320,000 species of plants, of which the great majority, some 260–290 thousand, produce seeds. Green plants provide a substantial proportion of the world's molecular oxygen, and are the basis of most of Earth's ecosystems. Plants that produce grain, fruit, and vegetables also form basic human foods and have been domesticated for millennia. Plants have many cultural and other uses, as ornaments, building materials, writing material and, in great variety, they have been the source of medicines and psychoactive drugs. The scientific study of plants is known as botany, a branch of biology.
Hello guys,
I have been wracking my little brain with this one. Why do fruit trees generally prefer a more acidic soil than vegetable plants. Veg plants like 6-7ph (except potatoes - why again !) Fruit around 5-6pH. Thanks in advance :)
There are a lot of nuclear power plants around the world that have smoke stacks, the kind you'd usually see at a coal fired power plant. Are they to release steam in an emergency, or are they some kind of exhaust system the plant uses, or something else? Most nuclear power plants in America have...
I watched that documentary by Dr. Brian Cox about nuclear fusion development and in one segment Dr. Saul Griffith tries to calculate how much would World need renewable power sources like wind farms, solar panels, hydroelectric generators etc. to substitute oil use completely in like 20 years...
I was reading my textbook, Power Generation, Operation, and Control, third edition, and was thinking of the possibility of supplying peak load using a nuclear fission reactor. The reasoning behind my interest is that to supply the grid with nuclear energy at anywhere near 100% from nuclear you...
I'm new to this forum, and would just like to say this is a very impressive site. My question is what is the best path way in school to design heat exchangers for power plants (more geared towards nuclear power plants.)
I'm currently finishing my first year of school studying mechanical...
Hello everyone,
Just posting this because I was wondering if it's possible to build 5-10km deep closed loop geothermal power plants from microgrid sizes of 1-5MWe to commercial power plant sizes of 0.5-1GWe that can have construction costs in the $3,000,000 per MWe range (similar to solar and...
In process plants many heating applications will use steam at approx 120 C whereas the standard cooling utility is cooling water at approx. 30 C.
In the dozens of plants I've seen I cannot recall having seen even one Heat Pump. Why is this so? Is the capex too high? Or are compressors too...
“Plants are usually charged negatively and emit weak electric fields. On their side, bees acquire a positive charge as they fly through the air. No spark is produced as a charged bee approaches a charged flower, but a small electric force builds up that can potentially convey information. The...
The Venus Flytrap, like most carnivorous plants, meets its nitrogen requirements by trapping insects and digesting them. What will happen if this plant grows in nitrogenous soil? Will it even grow in such soil? If it grows will it stop trapping insects?
Thank you
We know that a steam power plant is basically a heat engine with steam as the working fluid.
According to the second law of thermodynamics a heat engine must operate between two thermal energy reservoirs one at a higher temperature(source) than the other(sink) to produce net work in a...
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I tried to look for the answer but didn't find enough one for being satisfied
How excitation happens in big generators? If we produce electricity from electromagnet on the rotor, and electromagnets need electricity to be activated... and this happens by excitater on same rotor!
and this...
Hey Guys,
I was wondering in Sewage treatment plants ,how are detergents (Bleach and such )generally dealt with ,especially if the treated output is expected to be used in agricultural applications and such .
Thank You
Fruit growers sometimes protect their crops by spraying them with water when overnight temperatures are expected to drop below freezing. Some fruit crops, like the strawberries in the figure, can withstand temperatures down to freezing (0° C), but not below freezing. When water is sprayed on...
Can't find a clear answer online. I have some carnivorous plants that I feed distilled water, which I always run out off so it's a bit of an inconvenience. I can't collect rain water, so I was thinking about using the water from my condensor tumble drier.
Has anyone used that type of water...
Since plants contain proteins that help them identify gravity in order to grow the right way, and they also contain phytochromes that recongize photons, could a possible relationship between phytochromes and the gravity receptors within plants indicate that the gravity sensors are actually...
I have a list of various organic components I would like to extract from different fruits, vegetables, and plants and get the organic chains as pure as possible. How is that achieved? What science provides insight on the subject? I actually say science, but I'm looking for specific titles...
What in general prevents plants from rotting while they are alive?
Do plants that go dormant in the winter need to spend energy to maintain a defense, say a flower bulb?
Thanks for any help!
I'm curious as to how much of a factor the lack of a sensible way of dealing with the radioactive waste is in regards whether to build a nuclear plant? I mean, the closest that we recently had for an option was the Yucca disposal site until work was stopped. Granted, it wasn't a perfect plan...
Experience teaches plants to learn faster and forget slower in environments where it matters
Gagliano, M, et al. (2013). Experience teaches plants to learn faster and forget slower in environments where it matters. Oecologia, Epub.
i wish to know why have plants with exactly required medicinal value has evolved. is there a some sort of lock and key like reason which helps to evolve medicinal plants for many disease? i also want to the logic behind using water and other solvent for extraction of solvents. some time...
If we put a system that functions like the hydroelectric power plants do ( the gravity produces the movement of the water, producing electricity ) in vacuum and we put and object ( of a considerable mass ) that causes gravity and makes the "water" to orbit around it, wouldn't be a source of...
Anyone know an equation for comparing water absorption by plotted plants vs. evaporation of the water collecting in the pot's water collector? That is, if I water a plant and much of the water leaks through to the collection area how much of that leaked water will evaporate vs. be absorbed by...
I looked into the field of chemical engineering because of my interests in chemistry and making things, but I saw only things that involved power plant. Do chemical engineers do anything besides building, maintaining and supervising power plants?
Thanks.
Part 1 can be found here:
https://www.physicsforums.com/showthread.php?t=480200
Magnitude-5.3 earthquake hits Japan's Fukushima
http://www.usatoday.com/story/news/world/2013/09/19/japan-fukushima-nuclear-plant/2835493/
Dynamos & Power Plants -- Question
Please Read!
I know that cars need batteries to generate electricity to the dynamo to make the dynamo produce electricity continuously without stopping unless you switched off the car. The same to motorcycles. But I don't know whether the power plants do the...
Why do frequent water changes cause aquatic plants to grow faster? In an aquarium, the more frequent the water changes the faster flora grow. But why is that?
Homework Statement
Suggest a hypothesis to explain why algal and plant cells have cell walls. Suppose that mutant individuals from each group lacked a cell wall. How could you use these individuals to test your hypothesis?
Homework Equations
There aren't really...
The Attempt at...
Why no desalination plants ?
Many parts of the world face water crisis today ( especially Africa ) . This can be avoided if the sea water ( which is saline ) is made useful by desalinating it. many desalination techniques have been developed but why is not desalination applied on large...
Hello!
I'm looking for a book, a website or a person that could clearly explain the basics and the differences between post-transcriptional gene silencing (PTGS) and virus-induced gene silencing (VIGS) in plants. All the articles I've found this far have been very confusing (or maybe it's...
Are there any nuclear power plants on oceanic coastlines like Fukashima Daiichi which are vulnerable to being damaged by powerful tsunamis and earthquakes?
Do any of these coastal plants exist in the United States?
Homework Statement
It has been argued that power plants should make use of off-peak hours (such as late at night) to generate mechanical energy and store it until it is needed during peak load times, such as the middle of the day. One suggestion has been to store the energy in large flywheels...
I know that some peanut doesn't have oil separation, but this is due to emulsifier chemicals that are added. I'm wondering what causes the oil to be released. I assume the storage structure is ruptured, and the oil molecules are consequently released.
What exactly is a peanut? It's not a...
I came across this in a magazine and I'm skeptical about it. Does anyone have any evidence to support this or a link to the "studies' it references?
Per attachment: "We know that plants utilize biochemical signaling molecules to communicate, especially when a predator is nearby. But...
Per wikipedia's article on wilting: http://en.wikipedia.org/wiki/Wilting
:confused:
Edited the article. The article before the revision can be found here: http://en.wikipedia.org/w/index.php?title=Wilting&oldid=497326200
How can we calculate [via an equation] the number of pea-pods hit on a zombie in a given interval of time.
for those who haven't played the game its briefly this:
from point A to B, on A there is a pea shooting plant [constant position]. on B a zombie is closing in with constant velocity...
http://www.yomiuri.co.jp/dy/national/T120209007089.htm "Fukushima No. 2 plant was 'near meltdown'"
http://ex-skf.blogspot.com/2012/01/japanese-expert-says-fukushima-ii-not-i.html "Just In: Japanese Expert Says Fukushima II (not I) Nuke Plant's Containment Vessel Has Been Damaged by the Quake"
Why can`t coal be the fuel for combined cycle power plants?
Why is the succession of Brayton cycle and the Rankine cycle the most common design solution? Why using two Brayton cycles in series, using the lower temperature heat to drive a second gas turbine be a bad idea? Why would efficiency...
The pattern could be at an arterial, arteriole or capillary level.
There are plenty of examples of branched patterns in organisms.
(C) Baccar et al, Difficulté du diagnostic étiologique d’un poumon clair unilatéral, La tunisie Medicale - 2011 ; Vol 89 ( n°06 ) : 578-579
But are there...
Hi, I'm confused about C3 and C4 plants.
I know that their differences stem from how they photosynthesise differently but I am struggling to see how this relates to their different saturation and light compensation points?
I know that C4 plants have a higher light saturation point...
I know the seeds are mildly poisonous, but what about the leaves? What about the leaves of other trees like, orange trees, plum trees, maple trees, ground banana tree leaves, etc? If the bark of a tree is edible, does that imply that it's leaves, seeds, and sap are edible as well? Vice versa...
Hello everyone, it's been a while since I posted here! Unfortunately, I've been away from the nuclear engineering scene and detoured to computer science. My job now is as a programmer for avionics. I enjoy it, but it isn't my first love.
Recently, though, I got invited by my uncle to help out...
I found a recent article suggesting that solar storms predicted in in the next few years pose a serious threat to the electrical grid and thus to nuclear plant cooling systems:
"Severe Solar Storms Could Disrupt Earth This Decade: NOAA," International Business Times...