StarTalk Radio: Astrobotany & Plant Intelligence with Simon Gilroy
Host: Neil deGrasse Tyson
Guest: Professor Simon Gilroy, Astrobotanist at the University of Wisconsin
Release Date: April 4, 2025
Introduction
In this special edition of StarTalk Radio, astrophysicist Neil deGrasse Tyson delves into the fascinating world of astrobotany with Professor Simon Gilroy, a leading expert in plant intelligence and space-based botany. Joined by co-hosts Gary O'Reilly and Harrison Greenbaum, the episode explores the intricate awareness of plants, their defense mechanisms, communication strategies, and the challenges of growing them in extraterrestrial environments.
Understanding Plant Awareness and Intelligence
Neil DeGrasse Tyson opens the discussion by questioning the depth of plant awareness:
“We know plants are alive, but how aware are they? Do we have to loosen our definition of the word aware to include everything they do?” [05:09]
Professor Simon Gilroy responds by broadening the concept of awareness to encompass any organism's ability to monitor and respond to environmental changes, essential for survival:
"All biology is aware. If we use awareness as monitors, the environment around it and deals with it whatever the appropriate dealing with is." [05:30]
Gary O'Reilly adds humorously, highlighting the complexity of plant life:
"There's a lot more going on in plants than we realized." [01:03]
Plant Defense Mechanisms
The conversation shifts to how plants defend themselves when their environment is hostile. Gilroy explains that plants employ both physical and chemical defenses:
"Plants make nasty stuff. There are an enormous number of poisonous plants. They are chemical defenses to deter herbivores." [09:39]
Neil quips about the Venus flytrap, a commonly recognized aggressive plant:
"Oh, okay, of course." [09:39]
Gilroy elaborates on the Venus flytrap's ability to count stimuli before closing its traps, demonstrating a rudimentary form of intelligence:
"In order to get the trap to shut, the plant has to count to two." [21:22]
"There's a chemical signal memory that's built up. When you get down to the machinery of it, it doesn't sound quite so magic." [22:30]
Plant Communication and Memory
The discussion deepens into how plants communicate and possess memory. Gilroy describes chemical signaling and the role of mycorrhizal fungi in inter-plant communication:
"If you treat a completely intact plant with the chemical signals from a damaged plant, it will switch on defense responses." [27:22]
"There are fungal bridges between plants that work underground. These mycorrhizal fungi help the plants." [29:22]
Gilroy also touches on the concept of memory in plants, using seed germination as an example:
"Seeds have to accumulate a long freezing cold period. They remember that it's been cold for a long time before germinating in spring." [22:37]
Challenges of Growing Plants in Space
A significant portion of the episode focuses on the complexities of cultivating plants in space. Gilroy discusses the impact of microgravity on water behavior, crucial for plant growth:
"In space, water is creepy and sticky. It sticks to surfaces and creeps over them." [34:05]
"Overwatering encases the plant. Sticky water interacts with plants in unique ways." [35:56]
Neil probes into the practicality of growing plants on the Moon and Mars:
"How does a plant know which direction to send a root versus a leaf in zero gravity?" [39:42]
Gilroy responds by explaining that plants rely on light direction rather than gravity for growth orientation:
"Shoots grow in the direction of light. Roots have a random distribution in space." [40:16]
Genetic Modification and Future Prospects
The conversation explores the potential of genetically modifying plants to thrive in extraterrestrial environments. Gilroy acknowledges the feasibility of engineering plants with altered photosynthetic pigments to utilize different light spectra:
"We might be able to take the basic machinery of photosynthesis and hook some different pigments into it." [53:12]
"That's called genetically modifying organisms (GMOs). It’s real modern plant biology." [53:41]
Neil highlights the role of microbes in supporting genetically modified plants:
"What prevents us from creating a life form that can eat the regolith and thrive without UV?" [53:03]
"We still rely on ecosystems where microbes and plants work together for stability." [54:06]
Psychological Benefits of Plants in Space
Gilroy emphasizes the psychological importance of plants for astronauts:
"Growing plants is calming and nurturing. It provides psychological benefits in the confined and stressful environment of space." [38:26]
Harrison Greenbaum humorously interjects, expressing his disdain for the idea of only cultivating kale in space:
"Nobody wants to go to space just to eat kale." [57:17]
Conclusion
The episode wraps up with a hopeful outlook on the future of astrobotany. Gilroy asserts that leveraging Earth's evolutionary knowledge is essential for developing space crops:
"Biology is an immensely powerful force. We should capitalize on what we've got to develop crops that are familiar and comforting to humans." [56:00]
"Kale might be a target crop, but we aim to engineer plants that astronauts can enjoy and find nourishing." [57:13]
Neil DeGrasse Tyson concludes with an inspiring note on humanity's quest to explore the cosmos:
"Earth's surface is the shoreline of the cosmic ocean." [58:13]
"Keep looking up." [58:35]
Notable Quotes
- Neil DeGrasse Tyson: “All biology is aware.” [05:30]
- Simon Gilroy: “Photosynthesis is going to be photosynthesis. It's a highly successful way to convert light into all of your energy needs.” [52:17]
- Gary O'Reilly: “There's a lot more going on in plants than we realized.” [01:03]
- Harrison Greenbaum: “Nobody wants to go to space just to eat kale.” [57:17]
Final Thoughts
This episode of StarTalk Radio offers a deep dive into the intelligence and adaptability of plants, especially in the context of space exploration. Professor Simon Gilroy illuminates the sophisticated mechanisms plants use to interact with their environment, defend themselves, and communicate, challenging our traditional views of plant life. As humanity looks towards expanding its presence beyond Earth, understanding and harnessing plant intelligence becomes not just fascinating, but essential for sustainable living in space.
Keep Looking Up!