Biology subjects

Burri, J. T.

Publications and source records attributed to Burri, J. T..

3 recordsLinked to original sources

bioRxiv2021

Cell Wall Biochemistry Drives Pollen Tube Mechanics and Affects Growth Rate

Pollen tubes maintain cell wall integrity as they rapidly grow towards the ovule, yet need to rupture at a precise moment to release the sperm cells. This biomechanical balance is critical for fertilization and relies on the interplay between turgor pressure and cell wall rigidity. How cell wall composition affects its mechanical properties is, however, not well understood. In this study, we combine experimental and simulation techniques to determine key mechanical parameters using Arabidopsis cell wall mutants. We integrated cellular force microscopy with a Finite Element Method-based model to predict growth rates of different mutant pollen tubes. The Finite Element Method-based model allowed us to quantify the effects of cell wall mutations on the time-independent turgor pressure and cell wall elasticity, while cellular force microscopy enabled determination of time-dependent viscoelastic properties of the cell wall. This novel approach can be applied across biological systems and advances mechanical studies of cell and tissue morphogenesis.

systems biology↗

bioRxiv2019

The mechanical basis for snapping of the Venus flytrap, Darwin’s ‘most wonderful plant in the world’

The carnivorous Venus flytrap catches prey by an ingenious snapping mechanism. Based on work over the past 190 years, it has become generally accepted that two touches of the traps sensory hairs within 30 seconds, each one generating an action potential, are required to trigger closure of the trap. We developed an electromechanical model which, however, suggests that under certain circumstances one touch is sufficient to generate two action potentials. Using a force-sensing microrobotics system, we precisely quantified the sensory hair deflection parameters necessary to trigger trap closure, and correlated them with the elicited action potentials in vivo. Our results confirm the models predictions, suggesting that the Venus flytrap may be adapted to a wider range of prey movement than previously assumed.

plant biology↗

bioRxiv2018

Feeling the force: how pollen tubes deal with obstacles

HighlightPollen tubes literally feel their way through their environment to avoid obstacles as they deliver male gametes to the ovule. We measured their force sensitivity to understand this remarkable behavior.\n\nAbstractPhysical forces are involved in the regulation of plant development and morphogenesis by translating mechanical stress into the modification of physiological processes, which, in turn, can affect cellular growth. Pollen tubes are tip-growing cells that provide an ideal system to study processes induced by exposure to mechanical stress. We combined a lab-on-a-chip device with cellular force microscopy to mimic and quantify the forces that are involved in pollen tube navigation upon confronting mechanical obstacles. Several stages of obstacle avoidance were identified, including force perception, growth adjustment, and penetration. We have experimentally determined the perceptive force, which is the force threshold at which the pollen tube senses the obstacle, for Lilium longiflorum and Arabidopsis thaliana. In addition, we provide evidence that pollen tubes are capable of penetrating narrow gaps by increasing turgor pressure. Taken together, our data indicate that pollen tubes sense physical barriers and actively adjust their growth behavior to overcome them.

plant biology↗