what is the phytotoxin?type of it , and mode of action of it?
596440
phytotoxin is a poison.  It's mainly in plants.  Ricin is one of the major phytotoxins.. it's a protein poison. It's made from the waste left over from processing castor beans.\n\nAlso it's aerosol.  So if a human inhales it, major changes will happen within hours effecting the respitory system.   \n\nIf eaten, ricin causes severe pains int he stomach and can cause a person to collapse and die.
598357
Phytochrome is a chromoprotein whose state is influenced by light. It is mainly produced in darkness and exists first of all as PR (or P660; P is the abbreviation of phytochrome, R means reduced). \nPhytochrome is the photoreceptor that activates the de-etiolation (and many other) responses to red light and Phytochrome is a protein with a pigment molecule covalently bound
27191
Chlorophyll is the molecule that traps this 'most elusive of all powers' - and is called a photoreceptor. It is found in the chloroplasts of green plants, and is what makes green plants.\n\nAnd both questions are good ones ...
578449
The absolutely most poisonous plant-like organisms are any number of mushrooms (yes, I know they're fungi, but they look like plants) that grow wild-many of them are fatally toxic with nothing more than a lick.  The greatest number of deaths occur from bee stings (anaphylactic shock)- Botulinum toxin is the most toxic substance on Earth, as mentioned.  Copperheads are more venomous ounce for ounce, but rattlesnakes are more dangerous because of the amount injected.  But you are asking "lethal", so- The cyanogenic plants, such as wild cherries, peaches, etc- If the leaves are cut correctly, or frozen on the vine, they generate high levels or hydrogen cyanide.  A handful of these leaves can kill a cow or horse, so I would say that those are the most lethally toxic.
876160
The differences between short-day and long-day plants in view of the effect of phytochrome can be summarized as follows (according to H. MOHR and P. SCHOPFER, 1978): \n\nlong-day plants: short day + enough PFR (during the middle of the skotophile phase) > production of flowering hormones \n\nshort-day plants: short day + enough PFR (during the middle of the skotophile phase) > no production of flowering hormones \n\nThe qualitative difference in the reaction to the same signal is genetically fixed. \n\npl. visit:\nhttp://www.biologie.uni-hamburg.de/b-online/e30/30c.htm
873032
Bacteriocins are toxins that are produced by bacteria to kill  similar types of bacteria. Just as there is competition between different species of bacteria, there is also competition between different strains of the same species. They have similar mechanisms to most antibiotics. Many types of bacteria produce bacteriocins including Baccilli, Enteric bacteria (e.g. E.coli), and most gram-positives.
337412
The answer you are looking for is in the soil-plant-atmosphere continuum.  I'm too tired to give a full answer now so I will come back to this.\n\nIt basically works on negative pressure.  Air is the driest in the continuum and pulls water through the stomates from the xylem (not the phloem) up the stem from the roots, from the soil.\n\nI'll come back later.
453688
http://en.wikipedia.org/wiki/Spores\nor \n\nhttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=5765338&dopt=Abstract\n\nhttp://www.healthscout.com/ency/1/002307.html\n\nand you must try this one\nhttp://www.pesticideinfo.org/Detail_ChemUse.jsp?Rec_Id=PC35733
568892
If i remember my plant physiology lessons correctly, yes, they can.  An example is that of a plant wounding hormone that i think is called methyl jasmonate.  When a plant is wounded or under attack the hormone is released inside the plant to trigger an immune response (produce or increase concentration of chemical defenses).  The homone is also released into the air and is picked up by neighbouring plants of the same species or related species, which triggers their immune response before they're attacked as well.
578388
Lipid peroxidation .\nTry this link for more:\nhttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=3319227&dopt=Abstract\nAND:\nhttp://www.answers.com/Organelle+Dysfunction?gwp=11&ver=1.1.2.381&method=3\n Hope that helped ;-)
116416
It kills the microorganisms.  It also tends to remove air from the soil making it harder for larger organism (like insect grubs and earthworms) to breathe.\nIn addition it upsets the natural chemistry or the soil.
1174018
Anthrax is a bacteria that releases a toxin.  The toxin forces macrophages to release huge amounts of interleukin 1, a signaling molecule that causes shock and death in excessive amounts by lowering the blood pressure way too much.
325112
Neuro-motor system, no way.  That would involve neurons and neurotransmitters.  None of these have been found in plants.\n\nHowever, there is definite physiologic responses that could be defined as behaviour in plants.  These responses and stimuli are much simpler than we can appreciate.
19705
One common name for this is "nutrient overload" and it is responsible for things like algal blooms and eutrophication of the water. \nI think  it's the term "eutrophication" you are after:\nhttp://toxics.usgs.gov/definitions/eutrophication.html\n\n"Eutrophication is a process whereby water bodies, such as lakes, estuaries, or slow-moving streams receive excess nutrients that stimulate excessive plant growth (algae, periphyton attached algae, and nuisance plants weeds)."
353901
Plant communication is all based on chemicals.\n\nThe idea that plants communicate chemically with one another has been around for a couple of decades, but it's only been in the last few years that solid scientific evidence has been accumulated to support the notion.\n\nOver three seasons spanning 1996 through 1998, researchers from the University of California in Davis monitored wild tobacco plants growing near sagebrush. They clipped the leaves of some of the sagebrush plants to mimic the damage caused by insects. The sagebrush plants responded with a puff of a chemical called methyl jasmonate. In response, tobacco plants downwind immediately begin boosting the level of an enzyme called PPO that makes their leaves less tasty to plant-eating insects. Within minutes of the clipping of the sagebrush, the plants' PPO levels quadrupled.\n\nIt worked, too. Tobacco plants next to the clipped sagebrush suffered sixty percent less damage from grasshoppers and caterpillars than tobacco plants next to unclipped sagebrush.\n\nThen, last fall, scientists at Kyoto University in Japan let spider mites loose on lima-bean plants and tracked the plants' responses. They found five different defense mechanisms. First, each injured plant released a chemical that changed its flavor, making it less attractive to the mites (although I personally nd it hard to imagine anything less attractive than the taste of a lima bean to begin with).\n\nThen the plants released other chemicals that drifted away. Other lima bean plants received the chemical and immediately begin giving off the same chemicals, making themselves less tasty and warning still more lima bean plants, before the mites even reached them.\n\nMost amazingly, some of the released chemicals had the effect of summoning a whole new batch of mites--mites that, rather than eating lima bean plants, preferred to eat the spider mites attacking the lima bean plants.\n\nThe Japanese researchers even found that the plants could distinguish between insect damage and crushing damage. They crushed some leaves and stems and found that although the injured plants released chemicals, the surrounding plants ignored them, somehow recognizing no real danger existed. (It appears that substances in the attacking insects' saliva are required to trigger the anti-insect chemical response in the plant.)\n\nOther examples from agriculture are also known. Corn under attack from armyworms, for instance, puts out a chemical signal that attracts a predatory wasp. The wasp lays its eggs inside the armyworm; when they hatch, the wasp larva eat the armyworm.\n\nAnd a study released last week shows that this kind of signaling exists not only in agricultural situations and in labs, but in the wild--which means it is likely widespread throughout the plant kingdom.\n\nResearchers from the Max Planck Institute for Chemical Ecology in Jena, Germany, discovered that when a species of wild tobacco plant that grows in the southwestern United States is damaged by hornworms (the larva of the hawkmoth) it releases chemicals that attract predatory insects that kill the larva.\n\nSuch chemical calls for helps benefit both the plant being attacked and the predators, who would otherwise find it very difficult to find the larva, which are camouflaged and also tend to feed on the underside of leaves, where they can't be seen. Most likely the plant developed a chemical defense that predators evolved to take advantage of, but the result is the same as if the plant consciously sent out a cry for help.\n\nAgricultural scientists are already looking for ways to use this new understanding of plant communication to improve the way farmers fight pests. For example, these kind of indirect defenses could be genetically engineered into crops so that they could more effectively summon natural predators. That could reduce the need for chemical pesticides--in fact, you'd want to avoid chemicals, because they would kill the predator
558469
The extensive researches of scientists at the plant industry station at Beltsville,yale and Duke university and at several research institutes have culminated in the isolation of a blue or yellow green proteinaceous pigment, called phytochrome which is the primary receptor of the visible radiation. These are photosensitive photoreceptor found in almost all flowering plants.It was discovered by Borthwick et al (1952) and isolated by Butler et al (1959) from etiolated seedlings of maize.It exists in two interconvertible states, blue and yellow green,Pr and Pfr. Pfr is associated with cellmembrane while proccurs diffused in cytosol.It causes germination of seeds, inhibit flowering in SDP and in LDP plants.Pr absorbs light at 660nm and is changed to Pfr or P730. The latter absorbs light of 730nm and is changed back to Pr quickly.It is required in seed germination of some olants, bud dormancy, leaf abscisson,synthesis of gibberellins and etylene,prevention of photooxidation,photoperiodism and morphogenesis.Pfr is essential for seed germination.Pr is inactive form whil Pfr is active form.
599444
Aflatoxin is a naturally occurring toxic chemical by-product from the growth of the fungus Aspergillus flavus on corn and other crops such as peanuts and ...\nmsucares.com/pubs/infosheets/is1563.htm - 17k - Cached - Similar pages