Leaf Movement In Plants Research Articles

Rhythmic Leaf and Cotyledon Movement Analysis.

The first descriptions of circadian rhythms were of the rhythmic leaf movements of plants. Rhythmic leaf movements offer a sensitive, noninvasive, nondestructive, and non-transgenic assay of plant circadian rhythms that can be readily automated, greatly facilitating genetic studies. Rhythmic leaf movement is particularly useful for the assessment of standing variation in clock function and can be readily applied to a diverse array of dicotyledonous plants, including both wild species and domesticated crops.

Control of plant leaf movements by the lunisolar tidal force.

Background Investigations into the diurnal ascent and descent of leaves of beans and other species, as well as experimental interventions into these movements, such as exposures to light at different times during the movement cycle, led to the concept of an endogenous 'clock' as a regulator of these oscillations. The causal origin of leaf movement can be traced to processes that modulate cell volume in target tissues of the pulvinus and petiole. However, these elements of the leaf-movement process do not sufficiently account for the rhythms that are generated following germination in constant light or dark conditions, or when plants are transferred to similar free-running conditions. Scope To further unravel the regulation of leaf-movement rhythms, many of the published time courses of leaf movements that provided evidence for the concept of the endogenous clock were analysed in conjunction with the contemporaneous time courses of the lunisolar tidal acceleration. This was accomplished by application of the Etide program, which estimates, with high temporal resolution, local gravitational changes as a consequence of the diurnal variations of the lunisolar gravitational force due to the orbits and relative positions of Earth, Moon and Sun. To substantiate the results obtained in earthbound laboratories additional experiments were performed in the International Space Station (ISS). Tidal recurrence within the ISS exhibited a periodicity of 45 min. In all instances investigated, it was evident that a synchronism exists between the times of the turning points of both the lunisolar tide and of the leaftide when the direction of leaf movement changes. This finding of synchrony documents that the lunisolar tide is a regulator of the leaftide, and that the rhythm of leaf movement is not of endogenous origin but is an expression of an exogenous lunisolar clock impressed upon the leaf-movement apparatus. Conclusions A huge number of correlations between leaftide and Etide time courses were established for leaf movement rhythms in natural conditions of the greenhouse, in conditions of constant light or dark, and under the microgravity conditions of the International Space Station. Even the apparently spontaneous short-period, small-amplitude rhythms recorded from leaves under unusual growth conditions are consistent with the hypothesis of a lunisolar zeitgeber. Synchronism between leaftide and Etide is discussed in terms of classical and quantum mechanics.

Leaf Movements of Indoor Plants Monitored by Terrestrial LiDAR.

Plant leaf movement is induced by some combination of different external and internal stimuli. Detailed geometric characterization of such movement is expected to improve understanding of these mechanisms. A metric high-quality, non-invasive and innovative sensor system to analyze plant movement is Terrestrial LiDAR (TLiDAR). This technique has an active sensor and is, therefore, independent of light conditions, able to obtain accurate high spatial and temporal resolution point clouds. In this study, a movement parameterization approach of leaf plants based on TLiDAR is introduced. For this purpose, two Calathea roseopicta plants were scanned in an indoor environment during 2 full-days, 1 day in natural light conditions and the other in darkness. The methodology to estimate leaf movement is based on segmenting individual leaves using an octree-based 3D-grid and monitoring the changes in their orientation by Principal Component Analysis. Additionally, canopy variations of the plant as a whole were characterized by a convex-hull approach. As a result, 9 leaves in plant 1 and 11 leaves in plant 2 were automatically detected with a global accuracy of 93.57 and 87.34%, respectively, compared to a manual detection. Regarding plant 1, in natural light conditions, the displacement average of the leaves between 7.00 a.m. and 12.30 p.m. was 3.67 cm as estimated using so-called deviation maps. The maximum displacement was 7.92 cm. In addition, the orientation changes of each leaf within a day were analyzed. The maximum variation in the vertical angle was 69.6° from 12.30 to 6.00 p.m. In darkness, the displacements were smaller and showed a different orientation pattern. The canopy volume of plant 1 changed more in the morning (4.42 dm3) than in the afternoon (2.57 dm3). The results of plant 2 largely confirmed the results of the first plant and were added to check the robustness of the methodology. The results show how to quantify leaf orientation variation and leaf movements along a day at mm accuracy in different light conditions. This confirms the feasibility of the proposed methodology to robustly analyse leaf movements.

The discoveries of molecular mechanisms for the circadian rhythm: The 2017 Nobel Prize in Physiology or Medicine

Circadian clocks evolved to allow plants and animals to adapt their behaviors to the 24-hr change in the external environment due to the Earth's rotation. While the first scientific observation of circadian rhythm in the plant leaf movement may be dated back to the early 18th century, it took 200 years to realize that the leaf movement is controlled by an endogenous circadian clock. The cloning and characterization of the first Drosophila clock gene period in the early 1980s, independently by Jeffery C. Hall and Michael Rosbash at Brandeis University and Michael Young at Rockefeller University, paved the way for their further discoveries of additional genes and proteins, culminating in establishing the so-called transcriptional translational feedback loop (TTFL) model for the generation of autonomous oscillator with a period of ∼24 h. The 2017 Nobel Prize in Physiology or Medicine was awarded to honor their discoveries of molecular mechanisms controlling the circadian rhythm.

Control of plant leaf movements by the lunisolar tidal force.

Investigations into the diurnal ascent and descent of leaves of beans and other species, as well as experimental interventions into these movements, such as exposures to light at different times during the movement cycle, led to the concept of an endogenous 'clock' as a regulator of these oscillations. The causal origin of leaf movement can be traced to processes that modulate cell volume in target tissues of the pulvinus and petiole. However, these elements of the leaf-movement process do not sufficiently account for the rhythms that are generated following germination in constant light or dark conditions, or when plants are transferred to similar free-running conditions. To further unravel the regulation of leaf-movement rhythms, many of the published time courses of leaf movements that provided evidence for the concept of the endogenous clock were analysed in conjunction with the contemporaneous time courses of the lunisolar tidal acceleration. This was accomplished by application of the Etide program, which estimates, with high temporal resolution, local gravitational changes as a consequence of the diurnal variations of the lunisolar gravitational force due to the orbits and relative positions of Earth, Moon and Sun. To substantiate the results obtained in earthbound laboratories additional experiments were performed in the International Space Station (ISS). Tidal recurrence within the ISS exhibited a periodicity of 45 min. In all instances investigated, it was evident that a synchronism exists between the times of the turning points of both the lunisolar tide and of the leaftide when the direction of leaf movement changes. This finding of synchrony documents that the lunisolar tide is a regulator of the leaftide, and that the rhythm of leaf movement is not of endogenous origin but is an expression of an exogenous lunisolar clock impressed upon the leaf-movement apparatus. A huge number of correlations between leaftide and Etide time courses were established for leaf movement rhythms in natural conditions of the greenhouse, in conditions of constant light or dark, and under the microgravity conditions of the International Space Station. Even the apparently spontaneous short-period, small-amplitude rhythms recorded from leaves under unusual growth conditions are consistent with the hypothesis of a lunisolar zeitgeber. Synchronism between leaftide and Etide is discussed in terms of classical and quantum mechanics.

Diaheliotropic leaf movement enhances leaf photosynthetic capacity and photosynthetic light and nitrogen use efficiency via optimising nitrogen partitioning among photosynthetic components in cotton (Gossypium hirsutum L.).

Phototropic leaf movement of plants is an effective mechanism for adapting to light conditions. Light is the major driver of plant photosynthesis. Leaf N is also an important limiting factor on leaf photosynthetic potential. Cotton (Gossypium hirsutum L.) exhibits diaheliotropic leaf movement. Here, we compared the long-term photosynthetic acclimation of fixed leaves (restrained) and free leaves (allowed free movement) in cotton. The fixed leaves and free leaves were used for determination of PAR, leaf chlorophyll concentration, leaf N content and leaf gas exchange. The measurements were conducted under clear sky conditions at 0, 7, 15 and 30days after treatment (DAT). The results showed that leaf N allocation and partitioning among different components of the photosynthetic apparatus were significantly affected by diaheliotropic leaf movement. Diaheliotropic leaf movement significantly increased light interception per unit leaf area, which in turn affected leaf mass per area (LMA), leaf N content (NA ) and leaf N allocation to photosynthesis (NP ). In addition, cotton leaves optimised leaf N allocation to the photosynthetic apparatus by adjusting leaf mass per area and NA in response to optimal light interception. In the presence of diaheliotropic leaf movement, cotton leaves optimised their structural tissue and photosynthetic characteristics, such as LMA, NA and leaf N allocation to photosynthesis, so that leaf photosynthetic capacity was maximised to improve the photosynthetic use efficiency of light and N under high light conditions.

Introduction to Chronobiology.

A diverse range of species, from cyanobacteria to humans, evolved endogenous biological clocks that allow for the anticipation of daily variations in light and temperature. The ability to anticipate regular environmental rhythms promotes optimal performance and survival. Herein we present a brief historical timeline of how circadian concepts and terminology have emerged since the early observation of daily leaf movement in plants made by an astronomer in the 1700s.

The plant leaf movement analyzer (PALMA): a simple tool for the analysis of periodic cotyledon and leaf movement in Arabidopsis thaliana

BackgroundThe analysis of circadian leaf movement rhythms is a simple yet effective method to study effects of treatments or gene mutations on the circadian clock of plants. Currently, leaf movements are analysed using time lapse photography and subsequent bioinformatics analyses of leaf movements. Programs that are used for this purpose either are able to perform one function (i.e. leaf tip detection or rhythm analysis) or their function is limited to specific computational environments. We developed a leaf movement analysis tool—PALMA—that works in command line and combines image extraction with rhythm analysis using Fast Fourier transformation and non-linear least squares fitting.ResultsWe validated PALMA in both simulated time series and in experiments using the known short period mutant sensitivity to red light reduced 1 (srr1-1). We compared PALMA with two established leaf movement analysis tools and found it to perform equally well. Finally, we tested the effect of reduced iron conditions on the leaf movement rhythms of wild type plants. Here, we found that PALMA successfully detected period lengthening under reduced iron conditions.ConclusionsPALMA correctly estimated the period of both simulated and real-life leaf movement experiments. As a platform-independent console-program that unites both functions needed for the analysis of circadian leaf movements it is a valid alternative to existing leaf movement analysis tools.

Instrumentation and Software for Analysis of Arabidopsis Circadian Leaf Movement

This article is an addendum to the authors’ previous article (Kim, J. et al. (2008) Plant Cell 20, 307-319). The instrumentation and software described in this article were used to analyze the circadian leaf movement in the previous article. Here, we provide detailed and practical information on the instrumentation and the software. The source code of the LMA program is freely available from the authors. The circadian clock regulates a wide range of cyclic physiological responses with a 24 hour period in most organisms. Rhythmic leaf movement in plants is a typical robust manifestation of rhythms controlled by the circadian clock and has been used to monitor endogenous circadian clock activity. Here, we introduce a relatively easy, inexpensive, and simple approach for measuring leaf movement circadian rhythms using a USB-based web camera, public domain software and a Leaf Movement Assay (LMA) program. The LMA program is a semi-automated tool that enables the user to measure leaf lengths of individual Arabidopsis seedlings from a set of time-series images and generates a wave-form output for leaf rhythm. This is a useful and convenient tool for monitoring the status of a plant's circadian clock without an expensive commercial instrumentation and software.

Aquaporins and Plant Leaf Movements

Plant leaf movements can be mediated by specialized motor organs, the pulvini, or can be epinastic (i.e. based on different growth velocities of the adaxial and abaxial halves of the leaf). Both processes are associated with diurnally regulated increases in rates of membrane water transport, which in many cases has been shown to be facilitated by aquaporins. Rhythmic leaf movements are known from many plant species, but few papers deal with the involvement of aquaporins in such movements. Many details of the architecture and function of pulvini were worked out by Ruth Satter and co-workers using Samanea saman as a model organism. More recently a contribution of aquaporins to pulvinar movement in Samanea was demonstrated. Another model plant to study pulvinus-mediated leaf movements is Mimosa pudica. The contribution of both plasma membrane- and tonoplast-localized aquaporins to the seismonastic leaf movements in Mimosa was analysed. In tobacco, as an example of epinastic leaf movement, it was shown that a PIP1 aquaporin family member is an important component of the leaf movement mechanism.

Chemical Basis of Plant Leaf Movement

Nyctinastic plants open and close leaves with a circadian rhythm. Here we discuss chemical aspects of the mechanism of nyctinastic leaf movement. Nyctinastic plants from five different genera are known to contain species-specific leaf-opening and leaf-closing factors. The relative concentrations of leaf-closing and leaf-opening factors of the nyctinastic plant Phyllanthus urinaria change circadianly, suggesting that nyctinastic movement is regulated by two classes of circadianly regulated factors with opposing functions. A closing and an opening factor of Albizzia, when linked to a fluorescent dye, both specifically labeled motor cells of pluvini. A membrane fraction of pluvini contains proteins of 210 and 180 kDa that bind to a leaf-opening factor of Cassia mimosoides. The molecular identification of these proteins is underway.

Osmoregulation of leaf motor cells

“Osmotic Motors” – the best-documented explanation for plant leaf movements – frequently reside in specialized motor leaf organs, pulvini. The movements result from dissimilar volume and turgor changes in two oppositely positioned parts of the pulvinus. This Osmotic Motor is powered by a plasma membrane proton ATPase, which drives KCl fluxes and, consequently, water, across the pulvinus into swelling cells and out of shrinking cells. Light signals and signals from the endogenous biological clock converge on the channels through which these fluxes occur. These channels and their regulatory pathways in the pulvinus are the topic of this review.

Biological Rhythms Workshop I: Introduction to Chronobiology

In this chapter, we present a series of four articles derived from a Introductory Workshop on Biological Rhythms presented at the 72nd Annual Cold Spring Harbor Symposium on Quantitative Biology: Clocks and Rhythms. A diverse range of species, from cyanobacteria to humans, evolved endogenous biological clocks that allow for the anticipation of daily variations in light and temperature. The ability to anticipate environmental variation promotes optimal performance and survival. In the first article, Introduction to Chronobiology, we present a brief historical timeline of how circadian concepts and terminology have emerged since the early observation of daily leaf movement in plants made by an astronomer in the 1700s. Workshop Part IA provides an overview of the molecular basis for rhythms generation in several key model organisms, Workshop Part IB focuses on how biology built a brain clock capable of coordinating the daily timing of essential brain and physiological processes, and Workshop Part IC gives key insight into how researchers study sleep and rhythms in humans.

Concise synthesis of glyconoamidines as affinity ligands for the purification of β-glucosidase involved in control of some biological events including plant leaf movement

Glycosidases are involved in deactivation or storage of some endogenous bioactive substances through biologically intriguing processes. For example, nyctinastic leaf movement is controlled by a biological clock through the regulation of β-glucosidase activity. Ganem’s glyconoamidine ( 1 ) is used as a micromolar inhibitor of glucosidase in biochemical studies and would be useful as an affinity ligand for purification of glycosidase. However, its use for the specific inhibition of glucosidase which is highly specific to a glycoside with voluntary aglycon is seriously restricted because no universal method for the synthesis of N-alkylated glyconoamidine has been reported. Here, we report a concise synthesis of N-alkylated Ganem’s glyconoamidine with voluntary aglycon using a non-protected sugar derivative.

Detection of potential membrane receptor proteins concerning circadian rhythmic leaf movement of legumes using novel photoaffinity probe compounds

Circadian rhythmic plant leaf movement, called nyctinasty, is controlled by a time-course change in the internal concentration of the leaf-movement factor in the plant body. We report that specific binding protein (210 and 180kDa) for a leaf-movement factor, potassium lespedezate, is contained in the plasma membrane of the plant motor cell. These proteins would be potential receptors for leaf-movement factor to control the leaf movement.

Chemical studies on plant leaf movement controlled by a biological clock

Abstract Most leguminous plants close their leaves in the evening, as if to sleep, and open them early in the morning according to the circadian rhythm controlled by a biological clock. Extensive studies on nyctinastic plants led to the isolation of a variety of leaf-closing and -opening substances. And we found that the biological clock regulates the balance of concentration between leaf-opening and -closing substances in the plant body during the day.

Chemistry and Biology of Plant Leaf Movements.

The leaves of Mimosa pudica L. are well known for their rapid movement when touched. Recently, we were able to isolate an excitatory substance in small quantities from this plant, which consists of three different components (potassium L-malate, magnesium trans-aconitate, and dimethylammonium salt). Many plants close their leaves in the evening, as if to sleep, and open them early in the morning (nyctinastic leaf movement). This circadian rhythm is known to be controlled by the biological clock of such plants. Extensive studies on other nyctinastic plants led to the isolation of a variety of leaf-opening substances (LOSs) and leaf-closing substances (LCSs). Based on our experiments on these bioactive substances, we found that the circadian rhythmic leaf movement of these plants is initiated by the regulated balance of LOSs and LCSs. The balance of concentration between the two leaf-movement factors (LMFs) is inversed during the day. The glycoside-type LMF is hydrolyzed with beta-glucosidase, the activity of which is regulated by the biological clock. The circadian rhythm observed in the leaf movement is introduced by activation of beta-glucosidase regulated by the biological clock.

The diversity of chemical substances controlling the nyctinastic leaf-movement in plants

Leaf-movement in nyctinastic plants has long been believed to be controlled by plant hormones that are common among all nyctinastic plants. We have identified several bioactive substances for nyctinasty, whose bioactivities were highly specific to the original plant, based on the bioassay using the original plant leaf, and have shown that nyctinastic leaf-movement is not regulated by plant hormones. Our present results are in accordance with Umrath et al. physiologically significant opinion.

Photoelectric device for recording of leaf movements.

A photoeletric device is described that may have usefulness for sensing rhythmic leaf movements of plants in space experiments. The system provides an instantaneous record of the precise angular change in position of the leaf blade and avoids physical attachment or disturbance of the plant. This system has been utilized to record leaf movements for several weeks. The device is sufficiently sensitive to record small rapid oscillations by the leaf of only 2° angular movement.