Present botanical orthodoxy holds that Plant germination is purely a mechanical process, entirely driven by the external environments, which acts as stimuli for the seed, i.e. a Plant seed has no role in the germination process. However, recent research published in PNAS, conducted by the scientists at the University of Birmingham, has changed this conception for good.
A Plant’s decision about when to germinate is one of the most important decisions a Plant makes during a lifetime. Scientists have revealed that the initiation of germination is the result of a ‘conscious’ decision-making process by the Plants – too soon, the Plant may be damaged by the harsh winter environment; too late, the Plant may face the highest competition.
Scientists have revealed that a group of cells function as a brain for Plant embryos, capable of assessing perfect environmental conditions, deciding when seeds need to germinate.
The study found that these seeds’ brains do not have the traditional gray matter, but they use the same information processing mechanism as human brains. According to the lead author of the study, Professor George Bassel from the School of Biosciences at the University of Birmingham, Plants operate surprisingly similar to humans in regards to decision-making.
As humans make decisions using a small region of specialized nervous system cells within their brain, similarly the microscopic cells are responsible for making decisions within a dormant seed of a Plant. Bassel indicated that these cells act in a similar way to the cells of the Human nervous system.
Structure of the brain of the seeds
The fact that Plants are alive, and can communicate, feel, hear, or even ‘see’ is not new. Jack C Schultz, Adjunct Professor of University of Toledo in the U.S. and a Plant researchers, says “Plants, are just very slow animals“. Numerous researches from various fields have proven Plants can communicate with each when danger is nearby, to share foods and other important information, as well as having ‘vision’. But the idea that ‘Plants can think or make decisions’ is also not as far-fetched as it may sound.
Accurately assessing the environmental information is crucial to a Plant’s survival during the period of seed’s germination. By being eaten by animals or being carried by the wind, seeds can travel a long distance and save travel time. By lying dormant in the ground until the environmental resources are available and the temperature is correct, seeds can optimize their chances of survival. The study’s lead author explained that the seeds make active decisions based on assessed information.
To understand the decision-making mechanism of the seeds, Bassel and his research team created a digital atlas of every single cell inside the seeds of the thale cress (Arabidopsis Thaliana), which enabled them to map where specific hormones tended to be localized within the seeds. They observed that two active hormones called gibberellin (GB) and abscisic acid (ABA) play a role in the germination process. These two hormones can be observed in high concentrations at the tip of the embryonic root.
Typically a seed is made up of about 3,000 to 4,000 cells. Among these cells, between 25 to 40 appeared to play the dominant role in signaling and processing these hormones. The researchers observed that one clump of cells produced GA, representing the germinate signal, while another clump of cells separated at some distance produced ABA, the stay-dormant-signal. The signals were being sent and received back and forth between the two regions.
The authors called this process a tug-of-war between these two signals, one clump of cells is saying ‘go’ and the other is saying ‘stop’. In the default state, the cells put out more ABA than GA signal. And as the cells of the seed collectively find out that the outside conditions are improving, the GA levels gradually increase until the seed’s decision center concludes that it is better to germinate than staying dormant.
Similarities between seeds brain and human brain
The lead author of the study exclaimed in surprise while showing the similarities between the human brain and the seeds brain. He explained that in the Plant seeds, the two opposing centers of the decision-making system are separated in the distance just like the human brain’s motor cortex, two separate regions that initiate a ‘go’ or ‘no go’ signal, either promoting or inhibiting the decision to move. Similarly, in animals, separating the two regions prevents random noise from forcing the body to make decisions that might not be right.
The study found that the separation between the two regions of the decision center is used to encourage germination in the Plant when the environmental temperature is fluctuating. It is still not clear why temperature fluctuations should be so crucial to the Plants, but one possibility is that it helps the Plants sense how deep they are in the soil. Another possibility is that wide temperature fluctuation often happens at the change of seasons, so temperature fluctuations can help the seed sense these transition periods.
The research team also altered the appearance or activity of the hormones in the seeds and revealed that by manipulating the levels and timing of the hormone signaling, they could control the timing of the germination. This means that scientists could one day use these insights to design seeds that all pop open at the same time each season or to engineer seeds to have a greater defense against climate change.
Conclusion
According to a study, the last common ancestor of Plants and animals was a single-celled, algae-like organism that lived 1.6 billion years ago. Yet despite this huge evolutionary gap, both animals and Plants seem to have evolved and arrived at a similar solution because it offered them some advantages in reacting to their environment in similar ways.
According to Bassel, the common information processing architecture between animal and Plant seeds’ brains is fascinating as they clearly did not evolve from the same anatomical structures.
One has only to wonder that if the Plant’s seeds can make ‘conscious’ decisions, then at what higher levels of decision making may be possible by not only Plants, but also a Forest ‘as a whole Tree’ – as has been found by the scientists over the recent years. The possibilities of ‘conscious’ activity, and thus influence and impact on ‘human’ consciousness are immense – which would only go to show how deeply Plants are integrated with human life, much more deeper than being the only source of survival of humans by being ‘oxygen’ providers. It is no wonder that the Holy and Divine Mother Ayahuasca is generous as She has provided the ability to ‘consciously’ access ‘deeper’ realms of consciousness through the Holy Medicine.
References
- Bassel, G. W., Topham, T. A., Taylor, E. R., et al. (2017). Temperature variability is integrated by a spatially embedded decision-making center to break dormancy in Arabidopsis seeds. Proceedings of the National Academy of Sciences, [online] Volume, 114(25), p. 6629-6634. Available at: https://doi.org/10.1073/pnas.1704745114 [Accessed 14th August 2021].
- Finkelstein R. (2013). Abscisic Acid synthesis and response. The Arabidopsis book, [online] Volume, 11, Available at: https://doi.org/10.1199/tab.0166 [Accessed 14th August 2021].
- Meyerowitz, E. M. (2002). Plants Compared to Animals: The Broadest Comparative Study of Development. Science, [online] Volume, 295(5559), p. 1482-1485. Available at: https://science.sciencemag.org/content/295/5559/1482.long [Accessed 14th August 2021].
- Simard, S., Perry, D., Jones, M. et al. (1997). Net transfer of carbon between ectomycorrhizal tree species in the field. Nature, [online], Volume, 388, p.579–582. Available at: https://doi.org/10.1038/41557 [Accessed 8th June 2021].
- http://www.bbc.com/earth/story/20170109-plants-can-see-hear-and-smell-and-respond
