Plant Chemical Out Posts

Flower of Garden Strawberry (Fragaria ×ananassa)
Image via Wikipedia

The search for chemical mediators in plant root rhizosphere interactions with symbiotic and pathogenic organisms found in the soil continues to generate interesting research. Martha Hawes group at the University of Arizona reported on the role of sugars, proteins and small molecules found in root cap secretions – a mucilaginous mixture that covers the growing root tip and “converses” with the surrounding matrix of living organisms. The cap is rich in root border cells, which detach from the growing root tip. Curlango-Rivera et al (2010) provides us a bit more detail about which metabolites are biologically active. Neither sugars nor amino acids triggered root growth or border cell production. Transient exposure to biologically active concentration levels of the isoflavonoid pisatin, a phytoalexin, stimulated root border cell production but not root tip growth. I wonder if inhibition of root elongation may “reset” plant growth patterns as root border cells, acting as chemical sense organs, define the nature of the environment?

A second paper used histochemcial methods to profile root metabolites in plants from the Rose family (Hoffman et al., 2010). They found flavan-3-ol molecules in the root tip and border cells. Their findings suggest that the distribution of flavan-3-ols in Fragaria and Malus is under tight developmental control. These molecules are found in plants as catechin and epicatechin derivatives and in long chain (polymeric) form. They influence the taste and medicinal potential of green tea and wine, to name a few well-known plants. Previous researchers summarized their role in chelating toxic cations (metals) in the soil, establishing mycorrhizal interactions and priming plant root defense. This paper suggests a role in the transport of the long distance plant hormone auxin, which would link the chemical cross talk at root border cells with responses that occur in tissue distal to root tips. Hoffman’s research lacked a clear distinction of whether the monomeric or polymeric flavan-3-ol forms where the active species. This has plagued plant research for some time, since the analytical methods for detecting the polymeric forms have been crude and ineffective. All of their samples were from a botanical garden. I wonder if the flavan-3-ol profile would differ compared to native wild grown species?


  1. Curlango-Rivera, G. et al. (2010) Plant Soil 332:267-275
  2. Hoffmann, T. et al. (2011) Plant Biology, 13: no. doi: 10.1111/j.1438-8677.2011.00462.x

Mining the World of Science for Ideas and Language to Expand Your Poetry

This is based on a talk I’m giving at the 2019 Bay to Ocean Writers conference Saturday, March 9th.

Much like ekphrasis, which uses visual art as a jump off point, science articles offer both unique phenomena and highly specific vocabulary to build the scaffolding of poetry.  And the substructure of ideas provides space for more esoteric, even spiritual explorations that link questions about grand design with the granularity of a narrator’s voice.

In general, science articles provide examples of deep, underlying, non-linear patterns found in nature that can be mined for the bones of ideas that allow space for authentic emotional voice to emerge. And the observational phenomena appeals to the Imagist Poet in me. Scientific vocabulary and the specificity of meaning can be a barrier and a benefit. There’s a fine line between expecting readers to look up words and to learn ideas as part of their engagement with the poem, and locking them out with material that does not invite them into the poem.

During the rewriting and shaping process, I keep returning to the question of accessibility. I often turn to intelligent lay readers for feedback on whether they felt left out of or included in  the poem. I look for unique language and phenomena to weave interesting lines and phrases.

The poem in the example below, published in the The Syzygy Poetry Journal 2015, was sourced from several articles about the science of weather in the upper atmospheric layers. We live with our head down or lack awareness of events beyond the cloud layer. The poem asks what if we were creatures of air? And what does it mean to return to being human by falling to earth? The question has been asked before without the aid of scientific knowledge. The lineation and rhythmic structure supports the sense of being airborne and falling:

A Theory of Air

Gaia’s magnetic field snaps back
displeased at being rubbed
the wrong way.
An aurora borealis pungent
and teeming spills over
the invisible edge.

We are all creatures of air.

Hurricane speed currents plunge
ice crystals down to earth’s surface
as electrostatic discharge
organized in previously unexplored
directions, seeding nimbus dust
with reproducing bacteria
on the troposphere mist.

Our cellular progenitors, we carry
their imprint of sky, engulf
other ephemeral bodies
in symbiont desperation, a reverse
sublimation into mutlicellularity,
Gaia intending our existence
to be a lighter resurfacing
less of the organized, arrogant
tissue we now drag through air.

Another example, published in The Broadkill Review 2015, originated as an investigation into the developmental pattern found in Boneseed lilac (Osteospermum spp.) flowers, and how the elaboration of biological function was tied to a Fibonacci sequence (each number is the sum of the previous two numbers, geometrically creating a nautilus-like shape).

It became a bit of a rabbit hole, pursuing Fibonacci, the mathematician and his effort to popularize Hindu–Arabic numeral system in West, which advocates numeration using digits 0–9 and place value. The math in those cultures had far surpassed western thinkers. Adoption of the new numbering system was transformational.

The worm hole eventually took me into researching Pascal’s contribution to probability theory, specifically, Pascal’s wager – An infinite gain will always outweigh even a finite loss or gain. Therefore, it’s always more rational to bet that God exists.

At some point the poem forced me to pull back so I could understand what I was actually seeing and to create the physical phenomena that would become the structure for the personal narrative to unfold.

Bone Seed Lilac

Poised on this final cusp
of summer, florets settle
into opposing spirals,
bleed magenta.

A Fibonacci sequence floats
outward from the zero point,
and counting itself into existence.

one of the smaller daisy tribes,
reminds us of how
Hindu numbering emerged
elegant and bathed in spectral
light, its wind sway
establishing resonance,
a field pattern negative
of wrens in flight.
The hard decay of its seed
will hint at dark matter,
Pascal’s wager of infinite
loss, our reliance on small
gods of fixed dimension, ignoring
the rhythm of deeply
repeated patterns,
fractal emanations
altering topography so life
might begin again.

At the end of the day, the creative process allowed me to push away from ensuring that everything was scientifically accurate. The song found in the structure and rhythm of the language, the sense of entering into new and potentially sacred space, all this needed to be present, to invite the reader into the adventure of finding out what poem was waiting to emerge.


Both of these poems can be found in my book, The Acoustic Properties of Ancient People, published by Finishing Line Press.

Ecological Rational for Multiple, Plant Secondary Compounds

(Gossypium L.)
Image via Wikipedia

As I’ve studied medicinal plants, one intriguing question keeps cropping up – what is the biological rationale for plants investing in several classes of structurally varied plant secondary metabolites?. Certainly this question drives a number of researchers in the field of plant chemical ecology. Edwards et al (2008) provided some striking evidence from their study of bacteria resistant cotton (Gossypium hirsutum).

They detected flavonoid pigments, chrysanthemin and isoquercitin, at unusually high levels in epidermal tissue of young leaves in response to Xanthomonas infection. These cells clustered around infected cells that had died because of the plant’s hypersensitive resistance response.

A very different chemical, a  sesquiterpene, 2,7-dihyroxycadalene, acted as a light activated phytoalexin, destroying both bacteria and the infected plant cell. So what were the flavanoids doing to help out? The presence of the flavanoids in surrounding cells appeared to filter sunlight, limiting the generation of free radicals resulting from light activation of 2,7-dihyroxycadaline. How’s that for compartmentalizing your response to friends and enemies?