Plant knowledge: 5 facts found this week

This fortnight I thought I would write something a little different. One of my favourite podcasts to listen to is No Such Thing as a Fish, a podcast from the QI elves and so I’ve decided to detail my five favourite plant (or plant related) facts that I’ve found this week.

  1. Caffeine acts as a pesticide for coffee plants.

The presence of caffeine is not uncommon in plants with examples found in tea, cacao and coffee (Coffea canephora & Coffea robusta). The occurrence of caffeine biosynthesis has evolved independently in many lineages of plants. This process is termed convergent evolution and is often an indicator that this characteristic has a useful or vital function. It has been discovered by the team that published the coffee plant genome that in Coffea canephora, caffeine is used as a pesticide [1]. When coffee plants shed leaves, other plants experience suppressed growth or struggle to grow entirely. In the same manner, caffeine is used to deter pest insects from devouring plant leaves.

An article in the NY Times by one of my favourite popular science writers, Carl Zimmer, summarised the findings of the Science paper [2]. The evolution of caffeine production in coffee is very complex with multiple enzymes, pathways and gene mutations involved. These enzymes have multiple functions such as defense against attack, e.g. the basis of aspirin originated in willow trees.Coffee beans

  1. Plants can talk to one another through their roots.

Plants use their roots to communicate, both listening and talking to their neighbours. Plants are sessile and require abilities to tolerate unruly neighbours so have adapted signals to avoid competitive situations. These communication techniques are sophisticated enough to allow plants to recognise their siblings, giving them preferential treatment. Conversely, if growing next to a stranger, plants will compete more aggressively for valuable resources such as root space [3,4].

Plant communication
Edited from The Scientist Magazine
  1. The first product barcode to be scanned was that of Wrigley’s chewing gum.

Although perhaps a little stretch from the plant based theme, the gum in question, Wrigley’s Juicy Fruit chewing gum contains several plant based ingredients e.g. corn syrup, dextrose, soy lecithin and the gum base (jelutong, loquat). At 8am on 26th June 1974, the first Universal Product Code (UPC) was scanned in a supermarket in Ohio, USA. The shopper to make this purchase, Clyde Dawson, is said to have picked the item from his basket as it was thought that a barcode could not be printed on something as small as a pack of chewing gum [5].

Joe Woodland, the designer of the barcode, drew his first design in the sand of Miami Beach and was inspired by Morse code. The design was granted a patent in 1952 but they weren’t yet functional due to the lack of a barcode scanner. In 1960, research scientist, Theodore Maiman, announced he had created a “laser brighter than the centre of the sun”. The design for this laser was then used to create the first barcode scanner [6].Barcode

  1. Of the 400,000 plant species on Earth, humans eat just 200.

There are an estimated 400,000 species of plants on Earth with the majority of these being flowering plants. Of these 400,000 species, 300,000 are thought to be edible in some capacity. However, according to John Warren’s The Nature of Crops: How we came to eat the plants we do, only 200 species are regularly eaten [7]. These include most often maize, rice and wheat which accounts for 50% of the global plant based diet [8]. Currently 95% of the world’s calorie intake comes from less than 50 plant species.Fruit and veg

  1. Scientists have advised people that are stressed to mow the lawn.

Recent research suggests that chemicals released when a lawn is mowed can help relieve stress, making the mower happier and more relaxed. These chemicals have also been associated with prevention of mental decline in older age. The scientists produced a perfume based on the chemical composition of cut grass, termed “eau de mow”. They then demonstrated that animals became more relaxed after being in contact with the scent whilst also avoiding brain damage [9]. The product officially called SerenaScent is available to purchase. Cutting grass

If you want to learn more:

  1. Denoeud, F. et al. 2014. The coffee genome provides insight into the convergent evolution of caffeine biosynthesis. Science, 345(6201). 1181-1184.
  2. Zimmer, C. 2014. How caffeine evolved to help plants survive and help people wake up.
  3. Devlin, H. 2018. Plants ‘talk to’ each other through their roots.
  4. Elhakeem, A. et al. 2018. Aboveground mechanical stimuli affect belowground plant-plant communication. PLOS ONE, 13(5).
  5. Weightman, G. 2015. The History of the Bar Code.
  6. Weightman, G. 2015. Eureka: How Invention Happens. Yale University Press.
  7. Barnett, A. 2015. The Nature of Crops: Why do we eat so few of the edible plants?
  8. Warren, J. 2015. The Nature of Crops: How we came to eat the plants we do. CABI.
  9. Alleyne, R. 2009. Feeling stressed? Then go mow the lawn, claims research.

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