Lungs and Plants

As a third grader I distinctly remember my teacher telling our class about how it was bad to smoke because the smoke would make your lungs filthy.  She used her aunt as an example.  It seems that this aunt was a heavy smoker.  One day this aunt was eating popcorn and accidently inhaled a piece.  About 6 months or so after she inhaled it she coughed it up and it looked like a little piece of tar.  Funny how some stories stay with you.

The interesting thing to me is that my third grade teacher’s aunt isn’t the only one who has inhaled a seed, and that the inhilation of the seed needen’t mean curtains for the plant.  Recently a gentleman inhaled a pea (or bean, the exact type of plant still appears to be a bit up in the air — ) which sprouted in his lung and last year there was a gentleman from Russia who apparently had a fir growing in his lung (though it seems more likely that the man actually inhaled the tip of a more mature tree — too much vodka? — My question is whether there were roots, and if so, does that make this a novel way to root a fir cutting?)–FIR-TREE-inside-lung.html

After doing a quick search I also found a case where a child had a germinating seed of an apple in his lung, a case where a germinating bean caused a young girls right lung to collapse. And, apparently, both children and adults inhale grass seeds now and again though I couldn’t find much information on how frequently these seeds actually germinate in the lungs.

I wonder, is this the beginning of an interesting coevolution between plants and people?  Could a plant evolve so that the seeds were inhaled by humans, grew in our lungs, and then, later were expelled to be inhaled by other humans?  Just a random thought on a slow Thursday.

A ground cover I just love

I’m a particular fan of ground covers, especially those that replace bare soil or synthetic mulches (plastics, fabrics, and the sciency-sounding “geotextiles”).  That enthusiasm is tempered, however, by those invasive species, like members of Hedera, that seem to take over the world (or at least my little corner of it).  So while logic might dictate a preference for native species, I can’t help but love Rubus hayata-koidzumii (often mislabeled as Rubus calycinoides), and commonly called creeping raspberry.

When it comes to ground covers, I prefer species that stay on the ground; I like them low, tough, and dense enough to keep weeds out.  Of course they need to have attractive foliage and/or flowers.  But the icing on the cake, quite literally, is when they have edible fruits.

That’s why I love Rubus hayata-koidzumii, a high-elevation species native to Taiwan.  This USDA Zone 7 plant prefers sun to part shade (as you can see in the photo above), thriving in hot, dry conditions.  Not only does it do yeoman’s work in covering and protecting slopes, it bears abundant white flowers which morph into tasty fruits that practically beg to be baked into a cobbler or crisp.

But have I let my heart overrule my head?  Are there places where this species has become a problem?  I haven’t found anything in the literature to suggest it’s invasive, but am curious to hear from others.

Pigmented Mulch in Paradise

Just back from a quick vacation to Little Cayman island.  Truly a dot on the map – the whole island is about 7 miles long and a mile wide. Only 150 locals and a couple hundred tourists are on island at any one time.  It’s beyond laid back, with few attractions other than the resident iguanas and red-footed boobies (booby jokes abound).

Airport terminal/post office/fire station.

The big draw is diving – LC is the home to Bloody Bay Wall, one of the most famous dives in the Caribbean.  The reef drops off like a sheer cliff, from 40-60′ to more than 1000′.

All the action is underwater!
(Let me know if you want to see more slightly blurry diving photos.)

“Fascinating, Holly.  But what does this have to do with painted mulch?”

The extent of the landscaping for most yards: conch shells arranged in interesting designs and/or piles. But as we pedaled past a rather upscale condo, I came to a screeching halt. A gorgeous Bismarckia nobilis had caught my eye, but then I saw what was under it. Egad.

Everything comes to Little Cayman by a weekly barge or little prop plane and is wildly expensive. Four-pack of batteries? $15. A six-pack of beer is $20. TWENTY DOLLARS!!!

So, good readers, what we have here is possibly the most expensive mulch on the face of the earth. I can’t even imagine.


Need a lift?

One of the topic groupings for our posts is titled ‘Cool research’.  The subject of today’s post has actually been around for a few years but I still think it’s pretty cool.


When we think of interactions between plants we usual think of negative interactions such as competition for water and nutrients or maybe allelopathy.  But there are cases where plants can benefit each other.  One of these is a phenomenon known as hydraulic lift.    Hydraulic lift is the passive movement of water from roots into soil layers with lower water potential, while other parts of the root system in moister soil layers, usually at depth, are absorbing water.  In essence, plants will large, deep root systems (usually trees) bring soil water from depth to the surface where it can be used by other plants.  Hydraulic lift has largely been observed in arid and semi-arid ecosystems, though it can occur in wetter systems as well.  For me, the research that went into discovering hydraulic lift is as fascinating as the process itself.


One of the key lines of evidence for hydraulic lift comes from studies of stable isotopes.  As you may recall from college or high school chemistry, atoms of each chemical element have a certain number of protons and neutrons, which give it its mass.  A small portion of each element has extra neutrons resulting in a ‘heavy isotope’.  In the case of hydrogen, approximately 1 in 6400 atoms is heavy hydrogen or deuterium (2H).  Interestingly, the amount of 2H in water can vary depending on the source of the water; this ratio is termed an isotopic signature.  By comparing the isotopic signature of ground water and rain water in a given location, researchers can actually tell where certain plants are getting their water.  One of the classic studies in this area was conducted by Todd Dawson at Cornell in the early 1990’s.   Dawson analyzed isotopic signatures of groundwater, rainwater, and water in various plants around sugar maple trees and determined that many herbaceous plants contained a high proportion (up to 60%) of groundwater.  But how do shallow-rooted plants obtain groundwater?  The neighboring maple trees bring it to the surface from ground water as they are hydrating overnight.  An efflux of water from the maple roots results in a localized increase in soil, which can be utilized by other plants: hydraulic lift.


How important in hydraulic lift in most landscapes?  Probably not very.  Demonstrating significant hydraulic lift requires the proper hydrology (shallow ground water accessible to trees or shrubs but not smaller plants) and limited rainfall.  But the importance goes deeper (no pun intended!).  Prior to the advent of stable isotope techniques, many would have been dismissive of the concept of hydraulic lift.    Since 1993 over 100 papers have now been published on the subject.  To me, the ultimate value of Dawson’s work and related studies is showing the importance of keeping an open mind and being receptive to new ideas. 


Why bother having trees?

Sorry to be late with my post this week – I was away reviewing grant proposals.  It was interesting and useful work, but really drains your brain.  So with that being said, my post is long on pictures and short on words.

One of the things that bugs us GP types is poor plant placement.  Why bother planting a tree if you’re not going to allow it to grow naturally?  Here are some photos to mull over the weekend.  While I have lots of bad pruning pictures, these ones are chosen specifically because the trees were obviously poor choices for either site usage or size.

Because my sense of humor seems to have been left at the grant reviewing venue, I can’t think of amusing captions for these pictures.  But I’ll bet you can!  Just submit them in the comments sections, and I’ll repost the photos later next week with your contributions.

Photo #1

Photo #2

Photo #3

Photo #4

Photo #5