Hot answers tagged

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Short answer Blue color is not only rare in edible organisms - Blue color is rare in both the animal and plant Kingdoms in general. In animals, blue coloring is generated through structural optic light effects, and not through colored pigments. In the few blue-colored plants, the blue color is generated by blue pigment, namely anthocyanins. The reason for ...


118

Although @AliceD's answer is a great simple demonstration of the rarity of blue in our natural world, there's likely a more nuanced/technical reason. Short answer Blue light was the most available wavelength of light for early plants growing underwater, which likely led to the initial development/evolution of chlorophyll-mediated photosytems still seen in ...


71

The three "holes" are the result of the 3 carpels in coconut flowers, and three carpels is typical of the family Arecaceae (Palms). The "holes" are actually germination pores, where one is usually functional and the other two are plugged. The new coconunt shoot will emerge from the functional, open, germination pore. For further info and pictures, see this ...


68

It's a matter of perspective. Most of the chemicals that are addictive to us humans (particularly alkaloids), and may be addictive for some other animals as well, are also insecticides. Lots of plants that we consider poisonous are good food for other species, and lots of plants that insects would consider poisonous are treats for us. This is a great ...


64

The phenomenon in question is probably related to geotropism. If the hill soil is "on the move" it will cause the bend on the trees - If the soil in a slope is moving downward, the trees on this slope will tip downward. As the tree continues to try to grow upward, the trunk will show a curve. The degree of bending could indicate the rate or ...


56

The most classic example if you want to win this argument would be the family Solanaceae. Also referred to as the Nightshade family, it includes the deadly nightshade or Atropa belladonna and many other plants not safe to eat. Other members of the family are tomatoes, peppers, potatoes, and more. Plant families can be massively diverse, and toxicity doesn'...


48

Interesting question! The cause of tears and itching is the chemicals produced by onion (Allium cepa). Lets go into some details. Onions, coming from the family Liliaceae (also containing garlic, chives, scallions and leeks) store compounds known as amino acid sulfoxides, and the one we are talking about here is S-1-propenyl-L-cysteine sulfoxide (...


45

There are at least two separate answers to your question. First, with respect to plants needing CO2, they have evolved to deal with the limited amounts of CO2 normally in the atmosphere. That's really all they need, or "want": adding more doesn't really benefit them. Think of it this way: you need water to live, right? And drink a certain amount of it ...


43

That molecule is called Geosmin. It is mainly produced 1 by Actinomycetes such as Streptomyces which are filamentous bacteria that live in soil. Other organisms also produce geosmin: Cyanobacteria Certain fungi An amoeba called Vanella A liverwort It is an intracellular metabolite and cell damage is the primary reason attributed to its release. However ...


38

There are 5 answers, all "yes" (though the first one is disputable). First: there exists at least one animal which can produce its own chlorophyll: A green sea slug appears to be part animal, part plant. It's the first critter discovered to produce the plant pigment chlorophyll. The sea slugs live in salt marshes in New England and Canada. In ...


38

The vast majority of the mass of a plant is carbon-based which is obtained directly from the air via photosynthesis. So trees are, in a loose sense, solidified air! And most of the mass that comes from the ground is water which, of course, is constantly being replaced when it rains (or by Charlie with her watering can).


36

The Apiaceae family has many edible plants including carrot, parsley, fennel, celery, and parsnip, and has toxic plants such as poison hemlock, fool's parsley, and giant hogweed.


36

Exhaust gasses from combustion contain many compounds in addition to CO2. Some of them under the right circumstances‡ can be of limited benefit to some plants, but others such as ozone are damaging to all forms of life. Other compounds in vehicle exhaust that are known to cause damage to plants are oxides of sulfur and nitrogen — these react with water to ...


31

The vast majority of a tree's carbon comes from the air, which averages 0.03-0.04% by volume (300-400 ppmv) CO2. This is fixed through photosynthesis and eventually stored as glucose which the plant can then use for its metabolism. Doing some quick math, this means that in order to produce 1 kilogram of carbohydrates (e.g. cellulose) a plant needs to ...


31

This is the "Acer palmatum" or Japanese maple, which shows a wide variety of different leaf forms (from here): Specically you found "Acer palmatum dissectum 'Red Dragon'", for more information look here (picture also from this site):


30

Most varieties of corn bred for modern use have between 8-20 rows of kernels (Bommert et al. 2013.. Nearly all varieties have an even number of kernel rows. This is due to the early development of the ear. Ears of corn are developed from pistillate flowers on the ear (Bortiri and Hake 2007). Pistillate flowers are the female flowers, so they will bear ...


30

Ripening of bananas (and other fruits) is induced by acetylene and ethylene (Ethyne and Ethene) (see reference 1), which acts as a hormone and induces the ripening process. The incomplete combustion of the leaves produces ethylene, additionally the warmth of the process will help the enzymes as well. There is even a paper about this technique (although it is ...


29

Short answer It has been shown that plants may already suffer from doubling the atmospheric CO2 concentration from 340 to 610 ppm, something that might happen during the next hundred years or so based on current emissions. Background A popular science website tells us that an excess of carbon dioxide (CO2) reduces the rate of transpiration of some plants. ...


29

Both the cashew and poison ivy are members of the Anacardiaceae family.


27

As someone commented earlier, chemicals such as nicotine and morphine were products of evolution meant to repel animals. It is explained in more details in this article here. Evolutionary biologists studying plant–herbivore interactions have convincingly argued that many plant secondary metabolites, including alkaloids such as nicotine, morphine and ...


25

The use of a genus-species notation gives more exact information. For example there are multiple species of chamomile: There is Roman chamomile (Chamaemelum nobile), German chamomile (Matricaria recutita, or Chamomilla recutita) and Dyer's chamomile (Anthemis tinctora). The first two species are appraised for their medicinal properties and help to calm upset ...


25

Short answer Moss plants form spores; minute, invisible, typically one-celled, reproductive units that are carried off by the wind and into your pots. Background Mosses belong to the Bryophytes. Bryophytes are embryophytes; i.e., non-vascular land plants. They are spore-producing, rather than seed-producing and they do not bear flowers. The leafy moss ...


23

This is actually not a gall as other answers have suggested. This is likely a fungus called Cedar-apple rust (Gymnosporangium juniperi-virginianae). The fungus only thrives in the presence of both Juniperus virginiana (Eastern red cedar) and apple (Malus spp.) trees. The leaf in the picture belongs to some species of the apple genus and the growths are ...


22

I've been doing some reading, and have come up with the following interesting information. Telomeres During cell division the DNA is replicated, but the mechanism is imperfect and in each round of cell division a small section is lost from the end of each chromosome. To compensate and protect the genetic information there are caps – regions of excess ...


22

Seeds are spread by many mechanisms Wind dispersal: When air currents used to spread seeds. Often these plants have evolved features to facilitate wind catching, for example dandelions. Aka, anemochory. Propulsion & bursting: When seeds are propelled from the plant in an such as in these videos. This is called Ballochory. Water: Similarly to wind ...


22

This is due to a lachrymatory agent called as syn-propanethial-S-oxide. The process goes as follows: Lachrymatory-factor synthase is released into the air when we cut an onion. The synthase enzyme converts the amino acids sulfoxides of the onion into sulfenic acid. The unstable sulfenic acid rearranges itself into syn-ropanethial-S-oxide. Syn-propanethial-...


20

There are some other good answers which provide part of the picture, but I think there is a fundamental organising principle which has been missed. Konrad has touched on it in his answer. The reason trees, and most plants, tend to grow equally in all directions is that they have iteratively generated branching and radial symmetry which is controlled in a ...


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