Unidirectional versus bidirectional brushing: Simulating wind influence on Arabidopsis thaliana

Abstract

Plants acclimate to various types of mechanical stresses through thigmomorphogenesis and alterations in their mechanical properties. Although resemblance between wind- and touch-induced responses provides the foundation for studies where wind influence was mimicked by mechanical perturbations, factorial experiments revealed that it is not always straightforward to extrapolate results induced by one type of perturbation to the other. To investigate whether wind-induced changes in morphological and biomechanical traits can be reproduced, we subjected Arabidopsis thaliana to two vectorial brushing treatments. Both treatments significantly affected the length, mechanical properties and anatomical tissue composition of the primary inflorescence stem. While some of the morphological changes were found to be in line with those induced by wind, changes in the mechanical properties exhibited opposite trends irrespective of the brushing direction. Overall, a careful design of the brushing treatment gives the possibility to obtain a closer match to wind-induced changes, including a positive tropic response.

The Quantitative Biotinylproteomics Studies Reveal a WInd-Related Kinase 1 (Raf-Like Kinase 36) Functioning as an Early Signaling Component in Wind-Induced Thigmomorphogenesis and Gravitropism

“…Consequently, the reorientation of plant organs against the gravity vector above a certain angle is able to trigger gravity force signaling ( 135 ). The negative anemotropism is the very term used to describe such reorientation of plants, in which the inflorescence stem orients itself toward the direction of wind under the constant and unidirectional wind treatment ( 16 ). However, if younger Arabidopsis plants were observed in a wind tunnel, the primary growth region bend themselves toward the source of wind probably due to the influence of gravitational force ( 16 ).…”

“…Given that both wind and flexing produced plants of shorter stem and reduced biomass ( 9 ), and the periodic mechanical stimulations of plants generate dwarf plants of delayed flowering phenotypes ( 10 , 11 , 12 , 13 ), it is therefore hypothesized that the wind drag force, as one of the most direct effects of wind on the plant response, might share a common signaling network with the touching, brushing, robbing or flexing-induced plant mechano-responses or called thigmomorphogenesis ( 13 , 14 , 15 , 16 ). Other than the intermittent, turbulent, and constant (or sporadic) wind-evoked thigmomorphogenesis, plants often exhibit negative anemotropic response, a unique type of thigmotropic response (or force-triggered directional growth), under constant and unidirectional wind application ( 1 , 16 ), in which plants flex in parallel with the wind direction. Interestingly found in Arabidopsis was that the primary growth region of the inflorescence stem bends windward opposite to the wind direction, exhibiting a positive anemotropism under the constant influence of unidirectional wind ( 17 ).…”

Biochemical and Physiological Responses of Arabidopsis thaliana Leaves to Moderate Mechanical Stimulation

“…Acclimation of plants to disturbances caused by mechanical stimuli is based on developmental responses that modulate the mechanical properties of exposed tissues and organs [4,[11][12][13]. It was shown that A. thaliana acclimates to mechanical stimulation in the form of brushing by inhibiting the length of the inflorescence stem and altering its mechanical properties [14,15]. When plants successfully recover from mechanical stress, they can maintain agronomically beneficial characteristics.…”

“…Wheat and barley sown in the fall were subjected to treading in winter period, which induced morphological changes such as strengthening of roots and shortening of plant height, resulting in higher grain yields. Nowadays, mechanical stress is the focus of much research that continues to expand our knowledge of morphological changes in plants exposed to mechanical stimuli [6,9,11,[15][16][17]. Moreover, mechanically-induced stress can increase the content of specialized metabolites and antioxidant capacity of leafy vegetables [13].…”

“…The studies conducted so far included different types of mechanical stimuli, however they were rarely quantified, making it difficult to compare data from different studies as pointed out by Coutand [65]. In most cases, mechanical stimuli have been quantified as the number of rubbing [22], touching [21], bending [66], and brushing treatments [15], and these studies have focused mainly on the effects on growth, morphological, and developmental changes [18,67]. Unlike these long-term effects, mechanical stimulation triggers numerous physiological and biochemical changes that can be detected in a much shorter time than phenotypic modifications.…”