Quantitative Biosciences Thesis Proposal

Aradhya Rajanala

School of Physics
Advisor: Dr. Daniel Goldman (School of Physics)

Open to the Community

Modeling Plant Root Circumnutation as an Emergent Behavior

Thursday, November 17, 2022, at 2:00 pm

Location TBD

Committee Members:

Dr. Jennifer Curtis (School of Physics)

Dr. James C. Gumbart (School of Physics)

Dr. Peter Yunker (School of Physics)

Abstract:

Despite their lack of central nervous systems, plant roots are able to navigate substrates with arbitrarily complex terradynamic interactions to find nutrients and anchor themselves in the ground. To accomplish this, plants utilize a combination of active and passive growth strategies. Plant root circumnutation, the helical motion of a plant root tip, is a one example of a passive behavior of plant roots. It is hypothesized that circumnutation is important to allow for anchoring and obstacle avoidance. Understanding the mechanisms and coordination that are required to generate circumnutation could lead to unique strategies to traverse unknown terrain and provide a novel method of anchoring, creating high pullout forces with relatively low intrusion forces.

Circumnutation has been studied from an organismal level, but it is not well known how this behavior is regulated on a cellular level or how it interacts with local environments. Ultimately, circumnutation is generated and sustained as plant cells modify their growth and elongation based on strategies relying on local communication. Simulations can allow us to understand how plant cells coordinate to create this behavior. To bridge the gap between cellular behaviors and the organismal level phenomenon of circumnutation, I will use Discrete Element Method (DEM) simulations in which each particle represents a cell to model the plant root.

First, I will implement a DEM simulation to model circumnutation in O. Sativa rice roots, which will be validated through quantitative comparison with live growth experiments. I will then investigate physical characteristics of the biological root to allow parameter matching in the simulation, thus allowing for interrelation between properties of individual cells and those of the organism. Finally, I will test this model in complex heterogeneous environments to compare circumnutating and non-circumnutating roots and quantify the benefits of circumnutation through observation of stresses on the simulated root and the environment.