Weird Plants

[Condraz23]

Hi everyone. A few months ago, I had two lemons that I kept in my fridge. Three months passed and the lemons were slightly smaller and harder. I sliced one of the lemons open and everything seemed normal inside. So I ate it. Three more months passed and the second lemon wasn't showing any signs of rotting. It looked exactly the same everyday, while the other fruits that inhabited the same area had to be periodically removed and replaced because they were always growing mouldy. Then one day, the lemon suddenly disappeared. I have no idea how this happened, although I suspect my parents ate it. But that's not the issue here. Now, my real question is, is it true that lemons are resistant to rotting? If so, then why?

Another weird plant of mine is a leaf from a sweet potato. Two weeks ago, our sweet potato plant was dying so I chopped off some of the living leaves and I placed them in a bowl of water. They're still alive right now and they show no signs of dying, although they seem to be growing at an unusually slow rate. One of the cuttings is just a big leaf. No shoot, no stem, nothing. Unlike the others, it isn't growing any roots. But for some weird reason, it still manages to survive. I thought plants needed roots! So as an experiment, I took the leaf out of the water. It became all floppy and wrinkled. At the end of the day, I placed it back in the water and it was back to normal the next morning like as if nothing had ever happened.

The perpetual lemon and the plant with no roots. What's happening?

[Apostate1970]

i don't know about the lemons but i strongly suspect that it has to do with the extreme acidity inhibiting bacterial and even fungal growth.

this is sort of the same reason that jams and peanut butter and honey are naturally resistant to spoiling, except in those cases it's not acidity but very high tonicity that's at work... in essence those substances compete for water with any living cells that land on them, so the cells can't grow. of course honey also has some other natural antibiotic properties but the tonicity has a very large part to do with it. they have actually compared honey with silver sulfadiazene (the medical standard) for treatment of severe burns and certain other wounds and some studies have shown that honey works just as well if not better.

as for the leaf issue. the fact is that plant tissue is relatively undifferentiated. all roots are are just mineral collection mechanisms, and all stems are are just transport mechanisms. they also both serve a food storage/reserve function so that new leaves can be grown quickly if existing ones are lost. but an individual leaf doesn't need food storage since it produces its own. also, a plant's xylem (water carrying tubes) work primarily by capillary action (passive transport) and are present in the leaf itself. in other words, stems and roots, at least of most plants, don't serve much of any life-supporting function for an individual leaf other than water collection, and this leaf has plenty of water so long as it remains in the jar. sooner or later the leaf will die as a result of inability to regulate water concentrations &/or as a result of mineral exhaustion. it would be sort of as if you fed a human nothing but water and sugar... they could live a real, real long time on that but sooner or later they'd die (from salt depletion, etc). the difference in this case is that you're only feeding the leaf water.

all this talk about water and salt and life reminds me of something... i hope you listen to the lyrics carefully and enjoy it...

www.youtube.com/watch?v=QENH_FN5Bys

[dalehileman]

Behavior of vegetables attributed to their reasoning power

http://www.wordwizard.com/phpbb3/viewtopic.php?f=21&t=20044&hilit=zen+osho

[Apostate1970]

if you got the right nutrients into the water in the right concentrations the leaf should theoreticaly last a long while. i don't think that there's any reason it shouldn't last as long as any other leaf on the same plant normally would, maybe even longer if you exposed to to the right amount of light, etc. etc.

you'd have to get sodium, potassium, magnesium, nitrogen, phosphorus, and pretty much all the other things that we need ourselves. they've got those little packets of nutrients for flowers you can buy to help keep them fresh... that probably has a lot of the stuff in it.

[crispy]

Another weird thing about plants are really big really old trees - you might have one branch at one end of the tree with DNA1 and a branch in the opposite end with DNA2 :)

[WCH]

Weirdest plant I know is Salvia divinorum. Chemically speaking, there's no known explanation for why the hell it does what it does when smoked.

[premjan]

Another weird thing about plants are really big really old trees - you might have one branch at one end of the tree with DNA1 and a branch in the opposite end with DNA2 :)How does that happen? Mutations? Or maybe splicing of tissue from two individuals.

[Apostate1970]

Another weird thing about plants are really big really old trees - you might have one branch at one end of the tree with DNA1 and a branch in the opposite end with DNA2 :)How does that happen? Mutations? Or maybe splicing of tissue from two individuals.

i don't know exactly what he's refering to but i do know that many plants are hermaphroditic (in fact they do all kinds of crazy things), and that others can go back and forth between tetraploid and diploid states between generations.

i studied forestry for a few years is where i get this all from.

http://en.wikipedia.org/wiki/Plant_sexuality

http://en.wikipedia.org/wiki/Tetraploidy

[ahdenai]

WCH: Weirdest plant I know is Salvia divinorum.

there's a general answer and a specific answer.

the specific answer is that Salvia contains a chemical which activates the kappa-opiate receptor. This receptor recognizes the endogenous compound dynorphin, which is involved in pain sensation and reward mechanisms.

the general answer is that many plants evolve to express chemicals that alter mammalian neurotransmitters. The plants gain evolutionary advantage either by encouraging animals to eat their seed pods, thereby spreading the seeds in the animals droppings, or by discouraging the wrong animals from eating their leaves by inducing unpleasant experiences in the eater.

[WCH]

WCH: Weirdest plant I know is Salvia divinorum.

there's a general answer and a specific answer.

the specific answer is that Salvia contains a chemical which activates the kappa-opiate receptor. This receptor recognizes the endogenous compound dynorphin, which is involved in pain sensation and reward mechanisms.You misunderstood completely. I know what the chemical is and what receptors it binds to; my point is that chemicals which bind to those receptors aren't "supposed" to cause the kind of effects this particular chemical apparently does. K-Opiod agonists are dysphorics... Salvinorum A induces visionary states. No other drug which attaches at K-Opiod sites does anything remotely similar.

and... it's believed to be a cultivar, normally doesn't survive if not tended. And it's the leaves which contain the drug, not the seeds, not that that matters. So there's no clear evolutionary explanation for its development, more likely a freak occurance due to cross-breeding or some such (note that it's a species of sage; the sage used in cooking does contain quite a few psychoactive chemicals in low concentrations, Salvia divinorum just happens to contain a particularly strange chemical in high enough concentrations that it can be used as an entheogen, which makes it a pretty weird plant).

[ahdenai]

plant alkaloids can be agonists, mixed agonist-antagonists, or partial agonists or allosteric modulators. so there's a lot of variability in what a ligand does when it binds to a receptor. the action of salvia is overall consistent with known kappa-opioid pharmacology.

as for evolutionary advantage, it's pretty clear. Most grazing animals avoid plants with psychoactive substances in them. So that protective mechanism has evolved in numerous kinds of plants, from peyote cactus to cannabis.