We have learned much in our first season as neophyte vegetable gardeners.
Our experienced gardening friends have been generous in sharing their knowledge, tips and passionate enthusiasm as our guest bloggers this spring and summer, for which we are most appreciative and thankful. We have definitely caught “the bug” and are looking forward with excitement and anticipation to next year’s growing season!
Slowing down and moving to the rhythms of Nature has got us noticing and wondering about plant behaviour.
Turns out this is a contested arena among scientists.
What is plant behaviour? Is it even a valid notion?
In a delightfully informative article by W.C. Liu called, “Plant Behaviour,” the author says, first things first–
“Before digging into plant behaviour, let us define what a plant is. All plants evolved from the eukaryotic cell that acquired a photosynthetic cyanobacterium as an endosymbiont ~ 1.6 billion years ago. This event gave the lineage its defining trait of being a eukaryote that can directly harvest sunlight for energy. The cyanobacteria had been photosynthesizing on their own for a long time already, but this new “plant cell” gave rise to a huge and diverse line of unicellular and multicellular species….”
Liu recommends the Encyclopedia of Earth (EOE) at https://bit.ly/3jX689L and the Kew Gardens website at https://bit.ly/35j4J98 as good websites for exploring the enormity and diversity of the plant kingdom, citing from an article posted on EOE, “that there are more than 400,000 described species, a fraction of the estimated total number.” Helpfully, that EOE article also lays out the major plant groups and their characteristics as follows:
“The major divisions of Plantae are:
- Anthocerotophyta (Hornworts: Non vascular plants with one chloroplast per thallus cell)
- Bryophyta (Mosses: Non vascular plants with wiry stems that reproduce by spores)
- Cycadophyta (Cycads: Non flowering vascular plants with large pinnately compound leaves)
- Ginkgophyta (Gymnosperm with one extant tree species Ginkgo biloba)
- Gnetophyta (Woody plants having some angiosperm and some gymnosperm features)
- Lycopodiophyta (Vascular fern allies without seeds or flowers, having single microphyll leaf veins)
- Magnoliophyta (Flowering plants that have vascular systems and are seed producing)
- Marchantiophyta (Liverworts: Non vascular plants with one celled rhizoids)
- Pinophyta (Gymnosperm conifers that have vascular systems and cones, but no flowers)
- Pteridophyta (Ferns: Vascular plants lacking flowers and seeds, reproducing by spores)”
“Several groups of algae are under debate as to whether they should be included in Plantae; however, we will follow a definition of plants that excludes algae. Green plants, often termed Viridiplantae, derive the majority of their energy from sunlight via photosynthesis and are a subset of Plantae.” For the full Creative Commons licensed article on Plants by the Encyclopedia of Earth, go to: https://bit.ly/3i4ALtm.
Citation Plant. (2019, September 13). The Encyclopedia of Earth, . Retrieved 14:18, September 6, 2020 from https://bit.ly/3i63Wfj
Classification systems of any kind are often challenging, and sometimes challenged. Remember the ruccus when Pluto suddenly lost its status as a planet? So, too in plant world, apparently algae is ‘out’ as a member of the plant kingdom, at least for now.
Debates over plant “behaviour” are even more controversial, which Liu helps to orient us to –
“Plants do respond to changes in their environment, but is it fruitful or scientifically valid to say that they have behavior? They lack muscles and nerves, do not have mouths or digestive systems and are often literally rooted in place. A growing number of plant biologists have embraced the term behavior, as demonstrated by the journal devoted to the subject, Plant Behavior. Their resources page (https://bit.ly/2ReDWD3) is a good place to get oriented to the field.”
One of the links in Liu’s article took us to the Plants in Motion website at https://bit.ly/35dLmi4.
Plants in Motion
“Although our lives depend on plants for virtually everything that keeps us alive (oxygen, food, fibers, lumber, fuel, etc), the lives of plants remain a secret to many people. The reason is simple – plants live on a different time-scale from ours. Compared to the relatively hyperactive activities of humans, plants do not appear to do much but they are actually in constant motion as they develop, respond to enviromental stimuli, search for light and nutrients, avoid predators, exploit neighbors, reproduce, etc.”
“Time-lapse photography allows us to see the movements of plants and clearly demonstrates that plants are living organisms capable of some extraordinary things. Time-lapse photography is done by capturing a series of images at intervals ranging from seconds to hours apart. When the images are viewed in rapid succession the effect is to compress into a short period the changes that occurred over a relatively long period of time.”
“The movies on this site show a variety of plants living out their dynamic lives. The movies on this site will hopefully captivate the interest of budding plant biologists but many of them should also be of interest to the seasoned plant biologists. New movies will be added to the site occasionally but making time-lapse movies requires time, patience, and some luck so the rate at which new movies will appear is unpredictable. Hopefully you will enjoy the material that is available now.”
We were mesmerized by the many short videoclips offered, including the one of:
Morning glory vines twining: https://bit.ly/3h6zBMk
We end this Blog post by inviting our Readers to witness and wonder at Nature’s life force in the three-minute time-lapse video clip which captures the life of Arabidopsis thaliana. It is introduced below, and may be found by going to the plantsinmotion.bio.indiana.edu/ website, and selecting “Orchestrating” under the “Chapters” column, and then pressing play to start the videoclip.
Genes control the growth and development of all organisms—plants and people included. Many of the genes found in plants are also found in animals and other life-forms, providing even more insight into the most basic machinery that is required to be “alive.”
“Arguably the most-studied plant in the world is the mouse-eared cress, Arabidopsis thaliana. Its small size and rapid life-cycle (about 50 days) make it ideal for experimental investigation. Arabidopsis was the first plant to have all of its genes sequenced. Individual genes can now be linked with their biochemical functions, providing a road map to understanding plant development across all of plant-kind.”
“The movie, Arabidopsis thaliana: A Life shows a plant playing out its 6-week life from germination, through growth, flowering, and seed formation, to ensuing death. The background of color-coded visual data indicates the activation state of genes during each life stage.”
“The activity of many genes must be finely orchestrated for any individual—plant or human—to successfully grow and develop through all stages of life.”
Citation: W.C. Liu. Plant Behavior. (2014 Fall). The American Society for Cell Biology, CBE Life Sciences 13 (3): 363-368. Retrieved 14:18 September 6, 2020 from: https://bit.ly/3bwTBXs.
Last Word on Plant Behaviour
We conclude the plant behaviour debate (at least in this post) with these words from the sLowlife project, presented in The Herald (September 20, 2012) on the opening of the exhibit at the Montshire Museum of Science in Norwich, Vermont. (https://bit.ly/2GBjIkK)
“Many of us think of and treat plants as inanimate objects. However, a plant grows, reacts to changes in its environment, reproduces, responds to disease and injury, and undergoes a slow decline into old age and death—a saga that sounds hauntingly familiar. Contrary to our conscious perception, plants do move—be it ever so slowly.”
“By turning time on its head, the creators of ‘sLowlife’ have given us a whole new way to look at plants, their activities, their movement, and their lives.”
“sLowlife” is an exciting exhibition that uses science, art, and technology to provide alternative dimensions for experiencing plants. It presents unusual and sometimes unnerving perspectives on how a plant reacts, both short-term and long-term, to its inner and outer worlds.”
Save the Date!
This year National Tree Day is next week on Wednesday, September 23, 2020 in Canada. Check online for possible events in your community, and we will blog about National Tree Day next week.