How do plant cells communicate with each other?
Written by
Tina Carter
Reviewed by
Prof. Samuel Fitzgerald, Ph.D.Cellular communication in plants requires complex biochemical systems that ensure that information conveyed by environmental stimuli or developmental responses is integrated in a coordinated manner. The major pathways of communication are based on the existence of plasmodesmata, which are cytoplasmic strands through the cellulose wall permitting continuity between adjacent cell cytoplasm. In this way, organic ions, small metabolites, or signals like transcription factors can be exchanged very rapidly without the need for transport across membranes. However, plants utilise hormonal communication in specialised forms such as Auxins or Abscisic acid. These substances also move through the plasmodesmata or via the vascular system. They are responsible for regulating processes such as phototropism, seed germination, and stress responses over distances within the plant system.
Electrical signaling is another major communication pathway in plants, where waves of membrane depolarization operate similarly to animal nerve impulses. When certain specialized receptors detect stimuli such as herbivory or pathogen infection, ion channels open, altering the membrane potential, this produces voltage-gated calcium channels that relay signals via secondary messenger systems. The resultant calcium signatures propagate electrical signals to neighboring cells that travel at 1 cm/second. These signals are capable of traveling distances from roots to leaves, or vice versa, which coordinate defense mechanisms, such as the production of nicotine in tobacco or proteinase inhibitors. This long-distance signaling suggests remarkable parallel evolution with the communication mechanisms of animal nervous systems.
Plasmodesmata
- Cytoplasmic channels traversing secondary cell walls
- Permit transport of molecules up to 10-20 kDa
- Regulated by callose deposition and plasmodesmatal-associated proteins
- Enable symplastic movement of nutrients and signaling molecules
Hormone Signaling
- Systemin peptides activate defensive protein production
- Auxin gradients establish apical-basal polarity during development
- Abscisic acid closes stomata during drought conditions
- Brassinosteroids mediate cell elongation responses to light
Electrical Signaling
- Action potentials generated by glutamate receptor-like channels
- Propagate through voltage-gated ion channel cascades
- Trigger calcium waves activating gene expression changes
- Enable rapid wound responses across multiple cells
The ecological importance of these modes of communication is illustrated in the context of plant-microbe interactions. The binding of pathogen-associated molecular patterns to plant receptors triggers a chain of events that includes plasmodesmatal callose deposition and electrical impulse transmittance. This consolidates adjacent cells so that they can reinforce the plant cell walls and synthesise toxic compounds. Similarly, mycorrhizal fungi make use of plasmodesmata to transmit nutrients from plant cells into fungal hyphae. These communicatory systems allow the plant to operate as an integrated superorganism rather than a collection of isolated cells. The elucidation of these mechanisms is helping to bring about advances in sustainable agriculture, including the breeding of varieties with an improved capacity for symbiotic communication or more rapid activation of their defensive capabilities.
Read the full article: Plant Cell Structure: A Comprehensive Guide
