Which of these causes leaves to turn purple or red?

Woohooo!

That was a slightly educated guess. Narrowed it to two and clicked. Got lucky it seems.

Dang got it wrong. Well, now I know!
Barb

Didn't we have this same question last fall?

Yes, but our score wasn't very good, so this is the retest.

Hhmm, seems like we're not doing any better!

70% correct is pretty good!

Resin

It's a 'C', but it's sufficient for a Bachelor's Degree.

Woo-hoo! I got it right with a semi-educated guess!

hahaha

I wanted to say S U G A R !!

Or loss of chlorophyll-- ANTI chlorophyll

I have to confess I didn't vote because I was clueless on this one. I just tuned in to see what the correct answer was so I could see what people were guessing.
It was nice to learn something new.

Not sure if this question is applicable to cacti since they really don't turn any colors other than green, yellow or brown . Green = good. Yellow = over watered. Brown = rotten or fried from too much sun. (eye roll on yellow and brown)

I know Aloes and Agaves and other succulents like Sedums, Sepervium, etc.can turn shades of red and orange, purple and black so I'm thinking this answer may apply here.
Is this a correct assumption?

Yes, we had this same question last fall...I wanted to see who was paying attention to that lesson!

Has our score improved at all?

I know I got it wrong last year and right this year. I remembered the question but actually didn't remember the answer. This year I did a better job of reasoning to determine the most likely answer. Both times I correctly eliminated green, orange, and brown and correctly associated cyan with blue, due to my art training and knowledge of printer ink. Last year I reasoned, incorrectly, eliminating cyan/blue as not red or purple and thus chose Xanthophyl as the winner by default. This year, realizing that cyan/blue and red are both components of purple, I chose Anthocyanin, the correct answer.

Regrettably, had the question been stated differently, perhaps adding a 2nd wrong answer not color related, I might have missed it again. If you had asked for the name of the purple/red component without giving me options from which to choose (e.g., not multiple choice), I would definitely have failed. Now if you should repeat this question again next year, there is some slight chance I might, after 2yrs of 'lessons', actually remember the answer straight out.

Last time we finished with 42% correct answers by the end of the week. We're running at 45% now, so that is an improvement.

Sheesh not much of one :-)

Should I re-run it again next year?

Yes.

Ok, this will be an annual autumn question...just remember the lesson and let's get that percentage up next year.


(this question inspired my Saturday article that I'm working on right now, so maybe that will help)

Melody,
Would you be so kind as to answer my cactus question?
Thanks,
A.G.

IMO, it is simple logic, once you know a few things, that is. Cholor. is about green, carrot is about orange. Anyone working with leather knows tannin is brown. Xanth. In the world of paints is yellow. "Leaves" just one answer. Gene

I'm not really well versed in succulents, but the few I have do tend to take on a reddish tinge when the weather turns cold. I'm told that is is the same thing as leaves. The Anthocyanin and the sugars formed cause the red tints. Some plants do not form Anthocyanin, so do not turn red.

The Santa Rita cactus has a red tone all the time. I don't know if the Anthocyanin is the cause, but it has the same appearance. http://davesgarden.com/guides/pf/showimage/14345/

Hi,
This may be a good article! Why don't cacti change colors in the Fall?

Here's the best info I found...PLEASE CORRECT ME if I'm inaccurate. I'm no expert and still learning. I hate to misspeak or sound like I know more than others, especially if my info isn't right.

Best I can gain is that cacti, Agaves and Aloes, Barrels, etc. are evergreen plants who use their body to store water and has a system internally that feeds them and helps with photosynthesis (CMS..or is it CSM) that is different than plants with "leaves" . Since they are evergreens they don't turn colors.

The colors that they do have, like the Santa Rita Opuntia, (link above) which shows purple are natural variations from the breeding of species and hybrid varieties. Usually this color pales or deepens depending on how much water and sunlight they get rather than cold and the seasons. Could also depend on age/maturity of plant.

You can deliberately 'stress' some Aloes and Agaves and prickly pear into changing color by limiting their water or increasing their sun exposure but changing color it isn't something they would do naturally every season like leaves.

All cacti are succulents BUT not all succulents are cacti. Has to do with the way the spines grow out of the areoles. This is why Sedums, Sepervium, etc. are succulents but not cacti. It may be also why they change colors more readily. Their photosynthesis is different somehow. Sauguaro and Prickly pear with areoles really don't change colors.

Best I can come up with.
If anyone has more concise info...PLEASE share.

My Santa Rita p.pear. Gets partial shade all year long and is tended to by me so it also gets regular water.

My Beaver tail p.pear. It never changes color all year long regardless of 110 degree heat and full sun.

An A. ferox. Normally the leaves are green. This was taken in the Summer when it was very hot. This plant was in public landscaping and in full sun so it probably wasn't getting watered regularly. Wish it was mine! Pretty when 'stressed' isn't it!

This message was edited Nov 6, 2015 7:33 AM

I just found something else while researching tomorrow's article. (it is about 2/3 done at the moment)

"Not all land plants contain anthocyanin; in the Caryophyllales (including cactus, beets, and amaranth), they are replaced by betalains. Anthocyanins and betalains have never been found in the same plant"

So my earlier theory on cactus is incorrect. They do not produce Anthocyanins.

Agavegirl1, you are correct about the differences in cacti and succulents...my houseleeks and sedums change color with cooler temperatures, but they are not cacti. Love the A.ferox!

Here's a Santa Rita that I photographed in Santa Barbara last year...loved this plant!

Boo Hoo, I shoulda known!

This is why purple beans turn green when cooked and red cabbage "bleeds" and the green shows in days old slaw. It's the anthocyanin which is not very heat or liquid stable if the cell walls are damaged. Honorary degrees awarded. Send ten bucks and a SASE. lol

This is a great topic and very educational to all of us it seems, especially those like me that don't grow "typical" foliage plants that do change colors.

I don't know about everyone else but I do think this would make a great article...If you wanted to put the time, research and explanations into it Melody!

BTW gorgeous cactus you photographed. They're sloooooow growing. Mine is almost 7 months old and all it has done was get a little bigger and more glochids on it. It hasn't gotten any new pads yet. :( By contrast those Beaver Tail p.pears were about 4 inches tall each when I bought them at the same time and only a branch or two. Now they're over a foot and you can see them go!

I don't know how fascinating everyone would find the colors of plants and why they change or don't but I know I sure would! It seems to me I can never find enough S.W. plant/gardening articles dealing with cacti and cacti varieties.

O.K. here's another lovely that looks even prettier when stressed. The whole thing will turn yellow, orange and red. Fire sicks. The second plant is an Austrocylindropuntia subulata monstrose. Gets really cute red tips on it. Easy to grow, fast grower, clumper and you can break pieces off to keep it spreading.

This is an interesting tangent we've gone on...the article is really landscaping around fall color and a bit of the science behind it, but I can see where there's a whole different aspect to why plants change color.

The cactus was at a Garden Watchdog vendor's nursery that I visited...there were some splendid examples of drought tolerant plants there...and given the southern California drought, they were surprisingly gorgeous. This agave was the size of the car we were driving.

To do kitchen science projects with kids I wanted to know why purple "green" bean varieties turned green when cooked. One thing led to another and so forth. There is speculation that certain vegetables have evolved to purple coloration because the color is not attractive to insects. Reds fit in this group and some, but not all, oranges.

Also many animals can't see the red spectrum either.

Yes, should have mentioned that. But isn't it fortuitous that this spectrum is so eye-catching to humans? Think about all those red, orange and purple vegetables we love to grow and eat.

Beautiful majestic Agave!!
Some spectacular 'monster' plants out here.

I do find color just amazing. The various reasons why even more so.

They are camouflage, signs of health or illness and even protection. Think of Lithops, the 'living stone' plants.

May be incorrect on this but I think originally nightshades were considered poisonous by many people. Tomatoes and eggplants
were thought of as lethal.

The birds, rabbits and other little critters out here don't seem to have a problem with red, orange or peach. They looooove those prickly pear fruit. They have a field day with the stuff before most people can get to it!

I did read somewhere once that nocturnal animals see more shades or red and orange while animals active in the day see more shades of blue, and green. It has something to do with the amount of rods and cones in their eyes and what type of hunting and/or food they depend on to eat.

I might be way off topic here but one of my favorite trees that I have is Stripped Bark Maple. IMO, a beautiful and unusual Maple. The bark has vertical white stripes against the green bark in summer and white stripes against red bark in winter. I always wondered how the bark could change color. Most logical explanation I have read (so far) is that the trees do not have a normal outer bark, just inner bark and that bark contains (is made of?) the same substances as the leaves. If someone here could provide a better explanation, I would really appreciate it. Gene

Looks like we ended up right were we did last year. I'll put the question on the schedule for next fall too.

Consistency is often viewed as a valuable characteristic.

^^^^ I wish we had a 'like' button for that one!