Golden Protector

landin_marigold_web

I’ve always planted marigolds among my garden. I’ve heard these orange beauties have protective properties against herbivores. Is it true?

Hmm. Most researchers have found properties released from marigold roots inhibit bacteria, fungi, and/or nematodes (although this is extremely variable, depending upon the part of the plant used, how the marigolds are grown, and the pest species tested).

Most interesting sidetrack from my search… some research shows inhibition of Plasmodium, the microscopic organism that causes malaria (1).

Thanks to Charlie O’Shields of DoodleWash for the #WorldWatercolorMonth inspiration.

  1. Pankaj Gupta & Neeru Vasudeva (2010) In vitro antiplasmodial and antimicrobial potential of Tagetes erecta roots, Pharmaceutical Biology, 48:11, 1218-1223
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The Corpse Flower, a Botanical Marvel

corpseflower_lupin_thuIt’s rare to see a corpse flower bloom. If you ever have the opportunity, take it… especially if you get to visit Sumatra. Lucky for me, a corpse flower (Amorphophallus titanium) blossomed in the greenhouse next to my office last weekend at NC State University (https://cals.ncsu.edu/corpse-flower-at-nc-state/).

It took the corpse flower, dubbed Lupin, 13 years to save up enough energy to bloom.  It’ll probably be another five years before it does so again. So corpse flowers are rather special. Actually, fewer than 200 cultivars have been recorded since 1889. But now’s your opportunity. For some yet unknown reason, a bunch are flowering at once (1).

Lupin grew six feet tall in under two months! That tall, purple-grey phallic structure is called a spadix. At its base are about 700 vibrant orange and purple female flowers and thousands of male flowers (2). When the one giant petal (actually a bract known as a spathe) opens, the spadix releases a stench to attract carrion beetles and flies who pollinate all those female flowers.

So actually, the corpse flower isn’t a flower at all. It’s over a thousand flowers wrapped into one giant, stinky, gorgeous inflorescence.

corpseflowerfemales

  1. http://www.sciencealert.com/no-one-really-knows-why-but-america-s-corpse-flowers-are-all-blooming-at-once
  2. Gandawijaja, D, S. Idris, R. Nasution. 1983. Amorphophallus titanium Becc.: a Historical Review and Some Recent Observations. Ann. Bot. 51:269-278.

Wildflower Stories: The Final Chapter (Horsenettle)

ATwildflowers_horsenettlePlants are masterful chemists when it comes to defending themselves. Turns out, some plants build fortifications too. And these armories may even store deadly microbes for use as biological weapons.

Major defensive structures of plants include thorns, spines and prickles. Did you know they’re different? Thorns, officially, grow from the stem or shoot of the plant. They’re like miniature, pointy branches. Hawthorns and lemon trees, for example, have thorns. Spines grow from leaf tissues. Some leaves develop spinous points; some leaves fully convert into spines (like on cacti). Prickles grow from the plant’s outer surface of cells (the epidermis). Since the epidermis is found all over a plant, prickles can pop out of anywhere. “Thorns” on roses are actually prickles. And the spikes growing all over the leaves of this horsenettle (Solanum carolinense) are… prickles.

horsenettleBut these defensive structures may be more prickly (or thorny?) than we ever imagined. Preliminary research indicates that harmful (even deadly) microorganisms inhabit thorns, spines or prickles and cause further injury to herbivores who dare to challenge the awesome power of plants (1).

  1. Halpern M, Raats D, Lev-Yadun S. The Potential Anti-Herbivory Role of Microorganisms on Plant Thorns. Plant Signaling & Behavior. 2007;2(6):503-504.

Wildflower Stories: Ast(er)ounding!

asters_ATlFavorite flower? Daisy (an Aster, like these).
Not only is it humble and cute, it’s a bargain. For each daisy you buy, you get hundreds of flowers. The disk part of each “flower” is actually a composite of scores of tiny flowers. Look close – you’ll see.

aster_closeAnd the “petals” of a daisy? Each one is actually a whole flower too! The single petal plucked for “loves me” or “loves me not” is actually 5 petals fused over evolutionary time. If you look at the tips, you can still see some divisions.

Here’s another example of an aster – purple coneflower!

Educational Activity: dissect an aster and see all the mini-flowers for yourself!

Wildflower Stories – the Hercules of Plants

ATwildflowers_umbelCow Parsnip (Heracleum maximum) has a fascinating relationship with war, GMOs and sunscreen.

The plant’s scientific name probably points to its size – it’s taller than me (but that’s not saying much). It takes two years to grow that big. If you’re going to put that much time into growing, you’ll want to make sure nobody eats you; which leads us to the other possible reason for Cow Parsnip’s scientific name. Some claim Hercules used this plant medicinally.

Many plants contain chemicals to protect them from predators. This plant makes “furocoumarin”. In humans, furocoumarin combines with sunlight to cause a rash. This is where war comes in. During World War II, military organizations recruited plant and insect experts to investigate the defensive (or offensive) properties of these chemicals. Mustard Gas is similar in its blistering effect to furocoumarin.

Most plant predators, though, are not humans; they’re insects. As you can imagine, Cow Parsnip is very effective at deterring insect herbivores. So, the genes that will ultimately produce furocoumarin are prized. If you could insert those genes into another plant (how GMOs are made), the same protection will occur.

Beware the inevitable evolutionary “arms race” that results though. A few insects can eat Cow Parsnip, either due to mutations that let them break down the furocoumarins or behavioral shifts (like eating that plant only at night or when rolled in one of the plant’s leaves. Remember, the chemical has to be combined with sunlight to produce an effect.

And we get to sunscreens. A related chemical was used as a “tanning accelerator” up until 1996. Unfortunately, it caused rashes (“sun poisoning”), skin loss and even cancer. Turns out, furocoumarins can mutate DNA.

umbel

Cow Parsnip belongs to the Carrot family of plants. They tend to have hollow stems and flowers in “umbels” (like umbrellas). Some relatives are frequently on our dinner table (carrots, celery, parsley, dill, etc.); some, like hemlock (not hemlock), are deadly.

Wildflower Stories: Part 3 (Red Clover Symbiosis)

ATwildflowers_cloverImagine the extreme thirst of being stranded at sea, encircled by water you cannot drink.  Air is like that. Our bodies need nitrogen desperately to survive – and we’re surrounded by air full of Nitrogen (N2). But it’s all unusable. N2 needs to be converted to NO2 for us to use. Only bacteria can do that.

So what do bacteria and nitrogen have to do with this unassuming little plant? Red Clover (Trifolium pretense) is a member of the Legume Family of plants. Legumes cooperate with soil bacteria, giving them sugars and, in return, receiving “fixed nitrogen” (NO2). This fixed nitrogen inserts itself into all the living structures of the plant and, when eaten, passes the usable nitrogen on to animals.

clover_bee

Until the early 1900s, the only way we could get nitrogen in our bodies was through this route. Then, the Haber-Bosch process was developed. Not only did it save us from mass starvation (yay!), it served as a resource for making bombs (hiss!) and ultimately intensifying World War II.

For an AWESOME read about the Haber-Bosch process, read “The Alchemy of Air” by Thomas Hager. Now if someone would just write an exciting, gut-wrenching saga about legumes and soil bacteria.

Wildflower Stories: Part 2 (Tall Bluebell)

Bluebell_ATwildflowerslSee that Tall Bluebell (Campanulastrum americanum) flower? Is it red or is it blue?

Believe it or not, it’s kind of both!

The color pigment in plants that makes red is called anthocyanin. The pigment normally reflects red light waves. But if you raise the pH and add a couple metal atoms to anthocyanin, it changes the light waves reflected – and poof – blue!

bluebell_flower

Turns out, blue is a pretty rare color in nature. Dr. David Lee wrote a whole book about how colors in nature come to be, including the fairly complex steps to making blue in “Nature’s Palette: The Science of Plant Color”.

If you’d like to check out the color pigments in the flowers around your home, visit Scientific American for an easy, do-it-yourself pigment experiment.