Real-time imaging of pulvinus bending in Mimosa pudica

Abstract

Mimosa pudica is a plant that rapidly shrinks its body in response to external stimuli. M. pudica does not perform merely simple movements, but exhibits a variety of movements that quickly change depending on the type of stimuli. Previous studies have investigated the motile mechanism of the plants from a biochemical perspective. However, an interdisciplinary study on the structural characteristics of M. pudica should be accompanied by biophysical research to explain the principles underlying such movements. In this study, the structural characteristics and seismonastic reactions of M. pudica were experimentally investigated using advanced bio-imaging techniques. The results show that the key factors for the flexible movements by the pulvinus are the following: bendable xylem bundle, expandable/shrinkable epidermis, tiny wrinkles for surface modification, and a xylem vessel network for efficient water transport. This study provides new insight for better understanding the M. pudica motile mechanism through structural modification.

GmILPA1, Encoding an anaphase-promoting complex-like Protein, affects Leaf Petiole Angle

“…Legumes both track and avoid the sun, thereby exhibiting nyctinastic movements. Pulvini show nyctinastic and thigmonastic movement through waterdriven volume changes in their motor cells (Chen et al, 2012;Song et al, 2014). Two functionally different parts of motor cells, the adaxial flexor and the abaxial extensor, undergo rhythmic swelling and shrinking, causing volume changes of motor cells, and inducing petiole rising and falling (Volkov et al, 2010).…”

“…LPA is mainly controlled by the structure of a motor organ, termed the "pulvinus" (Volkov et al, 2010;Song et al, 2014), which is a jointlike thickening at the base of a leaf petiole, leaf, or leaflet. Typically, a pulvinus consists of a core of vascular tissues surrounded by a flexible, bulky cylinder of thin-walled parenchyma cells (Satter et al, 1990).…”

Mechanical basis for thermonastic movements of cold-hardy Rhododendron leaves

“…Mechanical instabilities often become important in triggering these movements. Some recent examples include touch sensitivity in Venus flytraps [8] and Mimosa leaves [9], edge and in-plane growth during blooming of flowers [10,11], rolling of doubly curved grass blades [12], fluttering of growing leaves [13], and mechanical instabilities that drive seed dispersal [14]. Characterization of the differential strains effected through cellular-scale growth and/or changes in turgor pressure as well as their relation to the movements serve as a gateway for understanding the biological design principles and the biosignalling pathways, aspects that are important for comparative and evolutionary studies [15,16] and for (genetic) engineering of environmental robustness such as drought resistance [17] and cold-hardiness [18,19].…”

Toward Energy Autonomy in Heterogeneous Modular Plant-Inspired Robots through Artificial Evolution

“…Some other species of plants can adjust their leaves or flowers to bend toward the light with a structure called the pulvinus. The pulvinus is a structure below the leaves and flowers that twists and pivots them through adjusting turgor pressure (Song et al, 2014). In general, leaves adjust their angle and move their surface perpendicular to the sun when conditions are optimal in a process called diaheliotropism.…”