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13

The more "dangerous" properties of spicy peppers are chiefly due to capsaicin. Sigma-Aldrich sells purified capsaicin, for which they provide safety information, including an MSDS. Most of it is the usual, unsurprising set of warnings about irritation to eyes and the respiratory system. However, there are LD50 numbers: LD50 Oral - rat - male - 161.2 ...


9

Disclaimer: This is not my field of research. First, this is not a complete answer to our question. A nice explanation of the current hypothesis of water transport in trees (Dixon-Joly cohesion-tension theory, originally proposed 1894) can be found at The Amazing Physics of Water in Trees but also in Tyree (1997). The key points are that the stoma (leaf ...


9

Basically, they don't. Ecosystems are pretty much either de facto, delimited by geographical boundaries, or defined by us. For example, an underground lake would be an ecosystem and it is organized in such a way for the simple reason that there is no communication between it and any other system. Most ecosystems however, do communicate. For example, we ...


8

Basically just search "thing you want" and "phylogeny" and you'll find a million results on Google. For you, I might recommend the Botanist in the Kitchen blog, which has a whole page on the subject and has assembled this phylogeny, including many, many others. It's pretty impressive!


7

In general for plants, before you start trying to make your own phylogeny, you should try to find an existing phylogeny. Phylogenetics is complex, and a lot of people have already done the hard work. You can start by looking at the Angiosperm Phylogeny to figure out which species are most closely related. To make use of the tree you will usually have to look ...


7

Trees need: Deep roots to get more water and anchor their growth. Strong trunks to support themselves against gravity. A vascular system to move water and nutrients throughout the tree. Small leaves that can be supported high by the trunk to compete for sunlight. Water plants need: Just enough root to anchor its location. No vascular system. Water is ...


7

It's Echinacea. I've linked to one site but if you run an images search with Echinacea as the search term you'll see lots of examples. And here is the WP page. Supplementary Echinacea are members of the Compositae. The flower (the head) in your picture is actually made up of lots of individual smaller flowers (i.e. it is a composite flower). The petals ...


6

If you mean if there are viruses, pathogenic bacteria or fungi that may cause diseases both in plants and in animals, the response would be that this is very unlikely (But even so, some fungi and bacteria could do it if some circumstances are given). This is due to some key factors: First of all, the philogenetic distance between plants and animals is huge. ...


6

While it's true that cellulose is full of calories, it's very difficult to get the calories out. Symbiotic bacteria take ages to digest cellulose, and as a result animals that digest cellulose with specialized symbiotic bacteria have a huge gut to house them in. It's likely that the reason humans can't digest cellulose is because mammals generally can't. ...


6

It is a Mimosa pudica, a wonderful plant. According to wikipedia you can find it in the following places: Mimosa pudica is native to South America and Central America. It has been introduced to many other regions and is regarded as an invasive species in Tanzania, South Asia and South East Asia and many Pacific Islands. It is regarded as invasive in ...


6

From How Do Pine Cones Open (Nature): The scales of seed-bearing pine cones move in response to changes in relative humidity. The scales gape open when it is dry, releasing the cone's seeds. When it is damp, the scales close up. The cells in a mature cone are dead, so the mechanism is passive: the structure of the scale and the walls of the cells ...


6

They are basically conjoined apples which share a common stalk. They are rare but do happen. Here is an article of one discovered in a backyard. conjoined apple discovered in a store (reference) It apparently happens because of bad weather conditions, stress and insect damage. Fused fruits are also found in the case of cherries, watermelons, peaches ...


5

Why don't we have any enzyme to digest cellulose? Why should we? We don't use it as a source of energy so why bother? Even animals that do "digest" cellulose, like ruminants, only do so because of symbiotic bacteria; it would be a poor system indeed in which every organism utilized the same resource. We occupy enough of the food chain as it is.


5

cis-3-hexenal is probably the main reason. It is one of the main chemicals in fresh-cut grass smell (lots of references besides wiki if you google it). This fairly comprehensive paper on watermelon odorants also says that they find a lot of cis-3-hexenal in fresh cut watermelon. See tables 3.1, 3.2 and 3.3.


5

The three main cues for flower opening/closing used by plants are temperature, light and humidity (van Doorn & van Meteren 2003, freely available pdf), with the first two being most common. Plants with daily opening and closing of flowers can be divided into nocturnal (open at night) and diurnal (open at day). There exists several different mechanisms ...


5

Perhaps the question may also be phrased, "Why is it common for plants to produce chemicals that possess pharmacological or toxicological effects in man and animals?", and to that question it is often reasoned that plants, being sessile and otherwise defenceless food sources for predators, produce compounds that affect the physiology of animals in such a way ...


5

The cost would increase; either because pollination services are not provided and the supply is decreased; or because the cost to producers goes up as they must pay for artificial pollination. See the extremely detailed analysis in Winfree et al. edit I imagine what you're actually asking for is a $ figure "per apple". This depends on the location, crop, ...


5

There is absolutely no way to tell to be honest because mulberry trees have the capability of changing sex (reference). From a paper titled "Diversification of mulberry (Morus indica var. S36), a vegetatively propagated tree species", I quote The sex expression of plants appears to be a function of hormonal control; there seems to be evidence that ...


4

Firstly, most plants or other natural medicinals existed way before we knew about them; it's not that plants mimic drugs, its that drugs mimic plants. To answer your question succinctly, compounds that we can use for our own medical benefit often do other things, we just adapt them for our own purposes. Penicillin is probably the best example. It didn't ...


4

First, allow me to provide the link to an old paper that deals with development in Ananas comosus, it should be freely available and answer this question in more detail: http://onlinelibrary.wiley.com/doi/10.1111/j.1469-8137.1936.tb06884.x/pdf Now, to briefly explain the observation that a mature plant will grow from the region where the leaves of the ...


4

This is a "Tar Spot" disease usually found in Europe and North America. It mostly affects the Maple tree leaves. Tar spot is caused by 'Rhytisma acerinum' a plant pathogen fungus. This pathogen does not seem harm to tree but disturbs the leaves as it finds a suitable condition in summer with bit of wetness. It enters the leaves through stoma and then creates ...


4

According to this news article, in a NASA experiment one man survived for 15 days in a sealed chamber containing 30,000 small wheat plants. If you read the article you will find that this did not produce a completely balanced system - some excess oxygen had to be removed, and some extra CO2 had to be pumped in.


4

I remember overhearing a botanist some 10 years ago, that he cannot tell male poplar from female when they are not flowering or producing seeds. Poplars and willows are related, so it is a weak indication for you, you will likely not find any visible features in willow neither. But it is an old information, too. (Are you interested in DNA sequencing ...


4

The article you have linked to does explain everything thoroughly, though in a somewhat complex way. I did not know how much genetics you actually know, so I tried to answer very thoroughly. So the article states that the gene Mendel studied and that was responsible for the white color of the pea flower is ANTHOCYANIN1 (in the article it is also called - ...


4

Yes, D. Attenborough probably refers to ploidy number Ploidy number Humans for example are 2N (except during the spermatozoid and ovule phase of human existence) meaning that they carry two copies of each autosome (=non-sexual chromosomes). Some species are 1N (haploid), some are 3N (triploid), etc… It would actually be more correct to talk about the time ...


4

It's a Brown-belted Bumble Bee (Bombus griseocollis). Details: http://bugguide.net/node/view/3538


4

Monstera deliciosa seems to fit the bill. From Wikipedia: This member of the arum family Araceae is an epiphyte with aerial roots... Wild seedlings grow towards the darkest area they can find until they find a tree trunk, then start to grow up towards the light, creeping up the tree.[6][dead reference link] Fruit The fruit of ...


3

There are no roses (that is, flowers of genus Rosa species) that naturally express a "true" blue color. Through cross-breeding, there are lilac-mauve rose horticultural varieties ("Blue Nile","Blue Moon","Lady X", etc.), and through genetic engineering (actually inserting delphinidin-producing genes) there are mauve-lavender varieties ("Applause"). The ...


3

I'd argue that this relates to species-specific strategies of seed dispersal, so the answer depends on which species you're asking about. Here's an answer for chili peppers, which I think illustrates how complex and idiosyncratic these strategies can be. As I mentioned in this answer, the seedsavers' manual Seed to Seed has great info on most plants, ...


3

As far as I know, the main challenges the plants have to face in cold environment are metabolism reduction and membrane fluidity. If the temperature is even lower, they may face freezing. Increasing the metabolism is quite hard, because plants usually are unable to increase their temperature by its own. Plant may produce more pigments in order to absorb ...



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