Leaf lamina. The leaf architecture probably ar...
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In an issue of New Phytologist, Claire Belcher provides a wonderful summary about work by Bond and Scott (from same issue) on the ecological role of fire in the spread of angiosperms (flowering plants). During the Cretaceous (145.5 to 65.5 mya, ending with extinction of dinosaurs), angiosperms were fast growing, weedy and largely understory herbs, shrubs and small trees more likely to colonize edge or disturbance sites. An improved plant vascular system, including a large increase in leaf vein density, doubled the photosynthetic rate and increased leaf mass in comparison with ferns and gymnosperms, which were the dominant land plants at the time. This adaption allowed angiosperms to work more efficiently fixing carbon from falling CO2 levels of the period. Fire also appeared to play a vital ecological role in the spread and ultimate dominance of flowering plants on earth.

Fossil charcoal demonstrated the presence of fire in the early ecosystem. The combination of  highly flammable detritus from weedy angiosperms and increasing atmospheric oxygen levels created an angiosperm-fire cycle equivalent to modern prairie fire cycles. Once an ecosystem was fire damaged, the faster growing angiosperms out-competed both gymnosperms and ferns. The early fossil records indicate that fire activity was greater during the Cretaceous than in previous epochs. However, when oxygen levels dropped about 56 mya, fire-cycles decreased and angiosperm-dominated forests, such as tropical forests, expanded.

In fact, the resulting layers of charcoal helped preserve the fossil record of dinosaurs’ last days. Researchers were then able to predict what the Cretaceous forests looked like.

Sister Morphine

Although I’ve met and friended folks who claim they’ve seen it, I’ve never witnessed a plant that could run. Instead, they engage in chemical warfare or communication. The chemicals are the result of multi-step metabolic networks that provide the chemical apparatus to change the staring material into a bioactive substance. Such a chain of chemical reactions is controlled by a series of proteins, called enzymes. Each protein is coded for by a gene.Poster_papaver_3a

This research identified a large cluster of 15 genes that encode enzymes in the metabolic pathway with morphine as an endpoint. Approximately 50 alkaloids are found in Opium poppy (Papaver somniferum), with morphine the largest in concentration.

According to the study, the pathway for the painkilling drugs evolved around 7.8 million years ago (mya). Primates are presumed to have appeared 63 mya, Hominidae (precursors to modern humans) 15 mya, and humans 1.3-1.8 mya. First recorded humans use appears in 5000 BCE in the Neolithic age. The PBS show Frontline provides a timeline of human use. It’s history shows that Morphine has been a “wonder” drug for pain, and a bane for those addicted to it and it’s derivatives

The mechanism responsible for euphoria also kills. Morphine binds to receptors in the brain, inhibiting neurotransmitter release and resulting in among other physiological changes, pain relief, but also slowed breathing.  Overdose victims often stop breathing.

Since the plant has been around for quite some time, I wondered if there were any histories to show animals consuming this or other plants to reduce pain or to  give pleasure? A brief review showed the following:

  • Researchers discovered it was chili peppers. Next, they studied tree shrews in the wild and discovered they ate one particular pepper, the Piper boehmeriaefolium, and actually preferred to eat it over other plants and vegetation.
  • Scientific Reports provides evidence that Borneo based apes chew leaves of the Dracaena cantleyi plant to create a white lather, which they then rub onto to their bodies
  • A study of chimps found that they roll Aspilia leaves for a period of time (they are very bitter to chew). This plant material contain thiarubine A , which kills harmful bacteria, and fungi because they contain thiarubine A, a powerful antibiotic. Research also suggests these leaves act as a stimulant, since chimps ingest them first thing in the morning.

What’s more compelling is the rich association of the opium poppy with war.  with a few examples below. One aftermath of each – the trail of addiction that followed either the imposition of trade or the use of morphine on the battlefield to reduce pain from horrible damage.

  • During the 18th century, forcibly exported opium to China, even while it was banned in Britain because the government and industry knew it was not good for the populace in general. It took two opium wars, eventually disrupting the country and leading to the  collapse of the Qing Dynasty.
  • After World War I in remembrance of the fallen soldiers, the living commemorate the sight of thousands of blood-red poppies appearing on the battle-scarred fields of Flanders, in Northern France.
  • US wars in Vietnam and Afghanistan have been greatly affected by opium production supporting the opposing militaries ability to pay for the fighting.

Now America is facing a public health crisis of opioid addiction.  In an interesting turn, last November, President Donald Trump asked Chinese President Xi Jinping to help stop the “flood of cheap and deadly” fentanyl from China into the United States.  Fentanyl is a synthetic opioid, 50 to 100 times stronger than morphine.

For better or worse, this is an example of co-evolution – humans identifying and applying a plant to alleviate the pain they, themselves create.

Listening in on someone else’s conversation

This paper in Science, investigated molecular conversation between a parasitic plant, dodder (C. pentagona), and two host plants, by sequencing all three transcriptomes.


Genes, defined segments of DNA (deoxyribonucleic acid), must be “read” and copied (transcribed) into RNA (ribonucleic acid). These gene readouts are called transcripts, and a transcriptome is a collection of all the gene readouts present in a cell, The major type, of gene readout is called messenger RNA (mRNA), which plays a vital role in making proteins that can have a profound impact on an organism. The production of these proteins can vary, depending on both environmental and genetic influences.

The researchers found thousands of mRNAs moving in a bidirectional manner between species. These transcripts represented thousands of different genes. Researchers think this molecular conversation might allow the parasitic plant to direct the host plant to dampen its defense responses.

Since we also contain ancient, and potentially active viral or bacterial transcriptomes in our genes, at least some of the voices we hear are real.