Artificial and biological supports are different for pea plants

Abstract

Previous studies on the kinematics of pea plants' ascent and attach behavior have demonstrated that the signature of their movement varies depending on the kind of support. So far, these studies have been confined to artificial supports (e.g. wooden sticks). Little is known regarding the conditions under which pea plants could rely on biological supports (e.g. neighboring plants) for climbing toward the light. In this study, we capitalize on the 3D kinematic analysis of movement to ascertain whether pea plants scale their kinematics differently depending on whether they aim for artificial or biological support. Results suggest that biological support determines a smoother and more accurate behavior than that elicited by the artificial one. These results shed light on pea plants' ability to detect and classify the properties of objects and implement a movement plan attuned to the very nature of the support. We contend that such differences depend on the augmented multisensory experience elicited by the biological support.

Keywords: Pea plants; accuracy; circumnutations; climbing plants; kinematics; plant behavior; plant movement.

Figure 1.

In panel (a): Graphical representation of the experimental setup. A growth chamber with a controlled environment in terms of light and temperature and two infrared cameras recording the movement of the plants 24 hours per day. In panel (b): graphical representation of the experimental condition for the artificial support (AC condition). In panel (c): graphical representation of the experimental condition for the biological support (BC condition). In panel (d): graphical representation for the control condition (CC condition).

Figure 2.

Example of trajectories for the AC (a), the BC (b), and the CC (c) condition. The yellow and orange dots represent the stem of the tracked plant. The blue line represents the trajectory of the tendril. The black arrow in Panel (b) represents the end of the movement for the BC, culminating with the final grasping phase on the support plant.

Figure 3.

Graphical representation of the velocity profile for exemplar plants for the two conditions. The callouts represent the last 10% of the movement, emphasizing the number of zero-crossings on the velocity profile representing the amount of type 1 submovements for the AC condition (a) and BC condition (b). Note that the number of submovements is much higher for the AC condition than for the BC condition.