Can plants make themselves invisible to their neighbours?

Plants are capable of shaping their developmental pattern to the competitiveness of the environment. For example, plants growing at a high population density can divert resources towards height growth to prevent being shaded by their neighbours.

To be able to do so, plants make use of light signals they perceive through light-sensitive molecules such as phytochrome. Such light signals can already be perceived before the actual shading takes place. A well-known example of such a light signal is the ratio between red and far-red light (R:FR). The value of R:FR of the light reflected off neighbouring plants is relatively low compared to light coming from the sky. The reason for this is that plants absorb red light for photosynthesis, but reflect far-red light. The decreased ratio between the two reveals their presence to neighbours.

Research aim

The aim of this thesis project is to find out to what extent plants may exploit this mechanism, by weakening or masking the light signals that give away their presence. Such ‘cheating’ behaviour by plants is well known to occur, for example orchids deceiving their pollinators by the morphology of their flowers, but has not been reported for light signals. If a plant would be able to manipulate the spectrum of the light it reflects, it would gain a competitive advantage over neighbouring plants who do not.

Operational objectives

  • To screen a range of plant genotypes for the spectral properties of their leaves, to get a quantification of the variation in the composition of the light they reflect;
  • To apply an FSP model to explore potential benefits of stealth behaviour by modifying light signals, and to find out what the level of signal masking should be in order for it to make a difference for competitive outcomes.

Type of research

Preferably the student combines experiments and modelling. However, only modelling or experiments are possible depending on the learning goals of the student.