What is intelligence?
Intelligence can be defined as the ability to perceive changes in one’s environment, to apply knowledge to manipulate one’s environment to suit oneself, and to think abstractly. If I were to ask if you thought plants were intelligent, most likely your response would be no. And if we are comparing them to animals then I would be inclined to agree with you. After all, it is much easier for us to prove that animals can be intelligent because they have obvious structures that we associate with intelligence, i.e., brain, nervous system. But when considering plants, the criteria for intelligence are less clear. This raises the question —
…if plants are not considered intelligent, what has allowed plants to adapt, survive and flourish in their ever-changing environment?
The question of plant intelligence raises the issue of whether plants are capable of feeling and adapting to their environment, and to some extent manipulate it to suit themselves, which has led to the idea of plant neurobiology. This concept of plant neurobiology allows us to understand how plants perceive their environment and how they respond to those stimuli. This has given us tools to know how to manipulate the growing environment, either by changing temperature, light, water, or nutrient levels. For example,
one study showed that by growing basil and kale under an increased proportion of blue light plus red light, the relative chlorophyll concentration increased². This allowed better photosynthesis overall by increasing the density and size of stomata, therefore boosting CO2 uptake.
However, the trade-off with this increase in blue light is the inhibition of stem elongation and leaf expansion. The floriculture industry has actually used this to their advantage to grow more compact roses and chrysanthemum plants³, as well as induce greater numbers of flowers⁴. Another benefit of increasing percentage of blue light is the encouragement of secondary metabolite production. For example,
glucosinolates — a group of important “superfood” nutrients in broccoli — increased with higher blue light levels, suggesting that the nutritional content of broccoli could be manipulated⁵. Therefore, not only does fine-tuning ratios of wavelengths effectively manipulate plants to perform in various ways, but species may also respond differently from each other under the same ratios.
Scientists have also hit on another strategy that plants use to respond to their environment. Grasses produce crown roots, which are roots originating from nodes at the base of shoots. Crown roots are the major channel for water uptake, and they develop relatively early in the growth cycle. Plants use crown roots to sense water availability in the surrounding soil and subsequently stimulate further crown root growth. Research showed that it is possible to induce changes in the root architecture, specifically the crown roots, when in drought. By subjecting a model grass Setaria viridis to drought, crown root growth was suppressed, with plants maintaining a more limited root system under limited water conditions⁶.
Scientists concluded that this species did this as an austerity measure — slowing down their water uptake ultimately means less energy is utilised and so more of the water can be conserved in the plant shoots and not lost through transpiration. What is even more incredible is that the fate of the roots can be reversed.
When these droughted plants were re-watered from the base of the pot, they could resume a healthier root growth. In comparison, when the plants were re-watered from the top of the pot, the crown roots revived, and development was reactivated. This suggests that the crown of the plant can sense local water availability to induce or pause crown root growth.
What does this all mean for agriculture?
Plants have shown resilience against extreme environmental conditions for centuries, because ultimately their ability to survive maximises their chances for successful reproduction. The concepts of plant intelligence and neurobiology raises more awareness of what plants are capable of when placed into challenging situations. Using this knowledge, it could change how plant breeders, researchers, and farmers tackle agriculture in a changing environment.
At Gardin, we have created a remote phenotyping SaaS (Software as a Service) platform, which monitors and provides insight into plant health and behaviour.
Using certain photosynthesis parameters, we can detect stress in advance of human eye or camera, thus helping to improve yields, crop uniformity, and optimise resource application within the indoor agriculture space. Generating these insights into plant-environment interactions will undoubtedly allow us to guide breeding practices and develop tailored crop management strategies. And with climate uncertainty and global pandemics, we don’t just need plants, we need clever plants.
Gardin believe in a world where everyone has the right to eat food with the highest nutritional content, grown sustainably. If you are an indoor grower and are interested in learning more about how Gardin can help manage your vertical farm or greenhouse, please contact us.
1. BBC. Do we underestimate the power of plants and trees? [Internet]. 2015 [cited 2022 Sep 28].
2. Dou H, Niu G, Gu M, Masabni J. Morphological and Physiological Responses in Basil and Brassica Species to Different Proportions of Red, Blue, and Green Wavelengths in Indoor Vertical Farming. Journal of the American Society for Horticultural Science [Internet]. 2020 Jul 1 [cited 2022 Sep 21];145(4):267–78.
3. Ouzounis T, Fretté X, Rosenqvist E, Ottosen CO. Spectral effects of supplementary lighting on the secondary metabolites in roses, chrysanthemums, and campanulas. J Plant Physiol. 2014 Oct 15;171(16):1491–9.
4. Park YG, Jeong BR. How Supplementary or Night-Interrupting Low-Intensity Blue Light Affects the Flower Induction in Chrysanthemum, a Qualitative Short-Day Plant.
5. Langston FMA, Monaghan JM, Cousins O, Nash GR, Bows JR, Chope G. Manipulation of the Phytochemical Profile of Tenderstem ® Broccoli Florets by Short Duration, Pre-Harvest LED Lighting. Molecules [Internet]. 2022 May 1 [cited 2022 Sep 21];27(10).
6. Sebastian J, Yee MC, Viana WG, Rellán-Álvarez R, Feldman M, Priest HD, et al. Grasses suppress shoot-borne roots to conserve water during drought. Proc Natl Acad Sci U S A [Internet]. 2016 Aug 2 [cited 2022 Sep 21];113(31):8861–6.