Most plants in the wild are interconnected via common mycorrhizal networks (CMN) .
The “Wood-Wide-Web” and Plant “Social Networks” are two previous posts that explore one of the most intriguing – and frustrating – subjects in plant biology. Intriguing, because vascular land plants likely owe their existence to mycorrhizae. Frustrating, because these plant-fungal relationships are very difficult to study experimentally.
That CMN’s exist among plants has been long-known. And biologists have long-wondered whether or not substances travel from plant-to-plant via these fungal networks (e.g., see refs. 2 & 3 below). But unequivocal and reproducible evidence has been difficult to obtain.
A paper published in 2010 (see ref. 1 below), reported evidence that chemical signals that elicit plant defensive responses can travel between tomato plants via CMN’s.
Volatile plant chemical signals are known to travel from plant-to-plant through the air to trigger plant defense responses. (Please see previous post on airborne chemical signals.)
A paper published online 9 May 2013 in Ecology Letters (see ref. 4 below) has added to the scientific evidence in favor of the idea that interplant communication via CMN’s exists. (For a summary of this paper, please see plants use underground networks to warn of enemy attack.)
Like ref. 1, this study used plants of the same species, grown under controlled conditions in the greenhouse. Though much more difficult, it will be interesting to see if experiments using plants in natural environments yield similar results. Especially when considering that different plant species are inter-connected via CMN’s.
Are defensive signals traveling through the CMN’s plant-species-specific, or do such signals activate all the plants “on the network”?
1. Song, Y. Y., et al. (2010) “Interplant Communication of Tomato Plants through Underground Common Mycorrhizal Networks.” PLoS ONE, 5, e13324. (Full Text)
2. Barto, K.E., et al. (2011) “The Fungal Fast Lane: Common Mycorrhizal Networks Extend Bioactive Zones of Allelochemicals in Soils.” PLoS ONE, 6, e27195. (Full Text)
3. Barto, K. E. (2012) “Fungal superhighways: do common mycorrhizal networks enhance below ground communication?” Trends in Plant Science, Vol. 17, pp. 633–637. (Abstract)
4. Babikova, Z., et al. (2013) “Underground signals carried through common mycelial networks warn neighbouring plants of aphid attack.” Ecology Letters, published online 9 May 2013. (Abstract)
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