Mimosa pudica,Dionaea muscipula and anesthetics

Some studies showed that anesthetics reduce the response of physical stimuli in Mimosa pudica and in Venus Flytrap (Dionaea muscipula), peculiar plants that have the ability to respond to touch stimuli. In this research we tested the effects of ketamine, lidocaine, diethyl ether, and amlodipine on the movements of Mimosa pudica and Venus Flytrap. With a literature review, we tried to bring elements to theorize about the interaction of these substances with these plants. The angular displacement in Mimosa´s petiole and in Dionaea leaves is what was measured to compare the drugs group with control groups.     

Mimosa pudica apyrase requires polysaccharide and Ca2+ for the activity

Mimosa pudica Linn leaves with pulvini contain unique isoforms (I and II) of apyrase enzyme (EC 3.6.1.5). The activity of isoform I depends on divalent cation Mn²⁺. This isoform is associated noncovalently with the polysaccharide, containing mainly of galactose and arabinose sugars. The apparent molecular mass of these 2 isoforms are 36 and 34 Kd respectively. The association of the polysaccharide with the isoform I has been found to be Ca²⁺ dependent which is endogenously present in this isoform. Removal of Ca²⁺ and polysaccharide from the enzyme (isoform I) leads to an inactivation. The enzyme activity can be restored when both Ca²⁺ and endogenous polysaccharide fraction were added at an optimal molar ratio of Ca²⁺:protein of 7:1. The endogenous polysaccharide can be replaced by the standard arabinogalactan. No other sugar or polysaccharide except the arabinogalactan can restore the apyrase activity. Calcium mediates a conformational change in the protein which helps in association of polysaccharide as evidenced from fluorometric and far UV-CD studies to restore the enzymic activity. Neither any interaction of the polysaccharide with the protein is detected in absence of Ca²⁺ nor the enzyme activity could be recovered under such condition.     

含羞草(Mimosa pudica L.)叶片匀浆悬浮液的滞后环

由于受力后叶子立即发生运动 ,含羞草是一个研究力对于生物细胞作用的良好模型。在以往的研究中 ,人们认为此种现象与受力后渗透压改变、离子通道被激活、细胞骨架的动态变化有关。该文旨在通过观察含羞草叶片和叶柄匀浆悬浮液的应力 切变率滞后环变化 ,揭示含羞草的力学性质。在用于比较的含羞草、叶下珠和猪骨骼肌匀浆悬浮液以及水 4个系统中 ,只有含羞草系统具有明显的逆时针滞后环轨迹 ,而其它的 3个系统均不存在。以上结果提示 ,在含羞草的匀浆悬浮液系统中 ,有一种或多种物质 (可能是蛋白质和细胞骨架 )在剪切应力作用过程中由颗粒状结构向网状结构转变 ,由无序结构向有序结构转变 ,由液体结构向黏弹性状态转变 ,而当力撤除以后再缓慢恢复。     

Quantification of Phytochemicals and Metal Ions as well as the Determination of Volatile Compounds,Antioxidant, Antimicrobial and Antacid Activities of the Mimosa pudica L. Leaf: Exploration of Neglected and Under-Utilized Part

Mimosa pudica L. (MP) is well-known plant in traditional medicinal system, especially in India. Unfortunately, leaves of MP are less explored. To determine the food and nutritional value of the neglected part of Mimosa pudica L. (MP), that is MP leaves, phytochemicals and metal ions of MP were quantified by newly developed HPLC and ICPOES-based methods. The content of phytochemicals observed using HPLC analysis for chlorogenic acid, catechin, and epicatechin was 141.823 (±8.171), 666.621 (±11.432), and 293.175 (±12.743) μg/g, respectively. Using GC/MS/MS analysis, fatty acid like oleic acid were identified. In ICP-OES analysis, a significant content of Na, K, Ca, Cu, Fe, Mg, Mn, and Zn was observed. The observed TPC and TFC for MP leaf extracts was 44.327 (±1.041) mg GAE/ g of wt. and 214.217 (±4.372) mg QCE/ g of wt., respectively. The DPPH assay depicted a strong antioxidant activity of MP leaf extracts with IC₅₀ values of 0.796 (±0.081) mg/mL and a TEAC value of 0.0356 (±0.0003). A significant antacid activity (666 mg MP+400 mg CaCO₃ >400 mg CaCO₃ ≫666 mg Gelusil) of MP leaves was noticed. The methanolic extract of MP leaves demonstrated anti-microbial activity against Staphylococcus aureus (15±2mm), Pseudomonas aeruginosa (12±2mm) and Escherichia coli (10±2mm). In silico studies confirmed the in vitro results obtained for antioxidant, antiacid, and anti-microbial activities. In addition, in silico studies revealed the anti-cancerous and anti-inflammatory potential of the MP leaves. In summary, this study demonstrated the medicinal significance of MP leaves and the conversion of agro-waste or the under-utilized part of MP into pharmaceutical potent materials. Consequently, the present study highlighted that MP leaves alone have medicinal importance with good nutritional utility and possess large promise in the pharma industry along with improving bio-valorization and the environment.     

Indoleamines and calcium channels influence morphogenesis in in vitro cultures of Mimosa pudica L.

The present article reports the interplay of indoleamine neurohormones viz. serotonin, melatonin and calcium channels on shoot organogenesis in Mimosa pudica L. In vitro grown nodal segments were cultured on MS medium with B5 vitamins containing Serotonin (SER) and Melatonin (MEL) at 100 µM and indoleamine inhibitors viz. serotonin to melatonin conversion inhibitor p-chlorophenylalanine (p-CPA) at 40 µM, serotonin reuptake inhibitor (Prozac) 20 µM. In another set of experiment, calcium at 5 mM, calcium ionophore ({"type":"entrez-nucleotide","attrs":{"text":"A23187","term_id":"833253","term_text":"A23187"}}A23187) 100 µM, and calcium channel blocker varapamil hydrochloride (1 mM) a calcium chelator EGTA (100 µM) were administered to the culture medium. The percentage of shoot multiplication, endogenous MEL and SER were monitored during shoot organogenesis. At 100 µM SER and MEL treatment 60% and 70% explants responded for shoot multiplication respectively. Medium supplemented with either SER or MEL along with calcium (5 mM) 75%–80% explants responded for organogenesis. SER or MEL along with calcium ionophore ({"type":"entrez-nucleotide","attrs":{"text":"A23187","term_id":"833253","term_text":"A23187"}}A23187) at 100 µM 70% explants responded for shoot multiplication. p-CPA, prozac, verapamil and EGTA, shoot multiplication was reduced and endogenous pools of SER, MEL decreased by 40–70%. The results clearly demonstrated that indoleamines and calcium channels positively influenced shoot organogenesis in M. pudica L.     

Transport processes in stimulated and non-stimulated leaves of Mimosa pudica

Summary Using energy-dispersive X-ray microanalysis, the concentrations of ions, especially potassium and chlorine, were determined in different tissues of primary and tertiary pulvini of Mimosa pudica. It was shown that stimulating the leaf was followed by ion displacements which were most striking in the outer extensor cells, resulting in turgor loss. Since Ca concentration remains relatively constant in cell walls of collapsed cells, the changes of K concentration are best described by the K:Ca ratio. After stimulation the K:Ca ratio dropped in the outer extensor of the primary pulvinus from 775.3 to 2.37 in the cytoplasm, and from 542.2 to 9.25 in the cell wall. Changes in chlorine content were less striking in the primary pulvinus. The KCl ratios in some cases were lower than 1.0, which indicates that Cl content can increase, while K content is diminished. In the non-stimulated tertiary pulvini the outer extensor cells show high concentrations of Cl, but much lower Cl concentrations were found after stimulation. In contrast to the primary pulvinus the K content of the tertiary pulvini is very low. In the vascular tissues of both primary and tertiary pulvini stimulation is followed by a release of K and Cl out of the sieve element cytoplasm into the apoplast. K then appears accumulated in the cell walls of the collenchymatous tissue. These displacements lead to the assumption that the collenchymatous apoplast temporarily functions as a reservoir for K and to a lesser extent for Cl. With regard to the mechanism of leaf movement after stimulation, the accumulation of ions in the apoplast seems to be initiated by the decrease of water potential triggered by an apoplastic accumulation of unloaded sucrose (Fromm and Eschrich 1988a). The resulting turgor release in the outer extensor is accompanied by an efflux of ions.Supported by the Deutsche Forschungsgemeinschaft     

The relationship between wound-induced proteinase inhibitors and hydraulic signals in tomato seedlings

Localized wounding is known to induce systemic proteinase inhibitors (PI) in seedlings of tomato (Lycopersicon esculentum L.). Inhibitors of elastase (EC 3.4.21.36) were shown here to be among those systemically induced by wounding, and a simple rapid assay for PI based on elastase was developed. Using this assay, the nature of the systemic signalling system (‘PIIF’) was investigated. Hydraulic signals were shown to be induced in tomato by localized wounds. These signals travelled throughout the plant well within the lag time before appearance of systemic wound-induced PI. A number of correlations were drawn between the occurrence of the hydraulic signals and induction of systemic PI, suggesting that hydraulic signals might be the PIIF, or a component of it. It was shown that systemic hydraulic signals could be triggered, without significant wounding, by excision of a single leaflet through the submerged petiole. These hydraulic signals were similar in both kinetics and magnitude to those induced by localized wounding. However, they did not induce systemic PI. In addition, it was shown that systemic events almost as rapid as wound-induced hydraulic signals could be induced without wounding, under certain environmental conditions. This indicates that rapid hydraulic signals do not provide a specific signal of wounding. These findings demonstrate that hydraulic signals per se are not the PIIF.     

Ultrastructural features of the starch sheath cells of the primary pulvinus after gravistimulation of the sensitive plant (Mimosa pudica L.)

Summary InMimosa pudica the primary and secondary motor organs (pulvini) of fully grown leaves are capable of graviresponse. These organs possess sedimentable amyloplasts in their starch sheath cells.In the primary pulvinus these cells are characterized by a structural polarity induced by the localization of nucleus at their (morphologically) apical part and the localization of amyloplasts at their (physically) basal part. These cells also display structural peculiarities including plasmodesmatal disposition, little development of the endoplasmic reticulum and an absence of vacuolar tannins; moreover, the sedimentation of the amyloplasts, induced by gravistimulation, is accompanied by the variation of localization of the cytoplasm, vacuole and mitochondria and by structural modifications of the nucleus and endoplasmic reticulum.     

Control of phloem unloading by action potentials in Mimosa

In the sensitive plant, Mimosa pudica , action potentials arise when the leaves are touched and they trigger a sudden decrease in turgor of the pulvinar motor cells, which causes the leaf to close. These potentials may travel through the phloem and they appear to influence pulvinar phloem unloading after stimulation. Mature leaves were exposed to ¹⁴CO₂ and phloem translocation was observed by autoradiography. In unstimulated pulvini, labeled photoassimilates were restricted to the phloem. However, after stimulation, the ¹⁴C-label appeared to be concentrated in the extensor region of the motor cortex. Since stimulation elicits an action potential, it is suggested that it also triggers phloem unloading of sucrose in the pulvini.     

Memory elements in the electrical network of Mimosa pudica L.

The fourth basic circuit element, a memristor, is a resistor with memory that was postulated by Chua in 1971. Here we found that memristors exist in vivo. The electrostimulation of the Mimosa pudica by bipolar sinusoidal or triangle periodic waves induce electrical responses with fingerprints of memristors. Uncouplers carbonylcyanide-3-chlorophenylhydrazone and carbonylcyanide-4-trifluoromethoxy-phenyl hydrazone decrease the amplitude of electrical responses at low and high frequencies of bipolar sinusoidal or triangle periodic electrostimulating waves. Memristive behavior of an electrical network in the Mimosa pudica is linked to the properties of voltage gated ion channels: the channel blocker TEACl reduces the electric response to a conventional resistor. Our results demonstrate that a voltage gated K⁺ channel in the excitable tissue of plants has properties of a memristor. The discovery of memristors in plants creates a new direction in the modeling and understanding of electrical phenomena in plants.     

Rapid hydropassive opening and subsequent active stomatal closure follow heat-induced electrical signals in Mimosa pudica

In Mimosa pudica L., heat stimulation triggers leaflet folding in local, neighbouring and distant leaves. Stomatal movements were observed microscopically during this folding reaction and electrical potentials, chlorophyll fluorescence, and leaf CO(2)/H(2)O-gas exchange were measured simultaneously. Upon heat stimulation of a neighbouring pinna, epidermal cells depolarized and the stomata began a rapid and pronounced transient opening response, leading to an approximately 2-fold increase of stomatal aperture within 60 s. At the same time, net CO(2) exchange showed a pronounced transient decrease, which was followed by a similar drop in photochemical quantum yield at photosystem (PS) II. Subsequently, CO(2)-gas exchange and photochemical quantum yield recovered and stomata closed partly or completely. The transient and fast stomatal opening response is interpreted as a hydropassive stomatal movement caused by a sudden loss of epidermal turgor. Thus, epidermal cells appear to respond in a similar manner to heat-induced signals as the pulvinar extensor cells. The subsequent closing of the stomata confirms earlier reports that stomatal movements can be induced by electrical signals. The substantial delay (several minutes) of guard cell turgor loss compared with the immediate response of the extensor and epidermal cells suggests a different, less direct mechanism for transmission of the propagating signal to the guard cells.     

Calcium-sensitivity of the plasmalemmal delayed rectifier potassium current suggests that calcium influx in pulvinar protoplasts from Mimosa pudica L. can be revealed by hyperpolarization

Isolated protoplasts from pulvinar motor cells of Mimosa pudica were studied using conventional whole-cell patch clamp techniques. With internal solutions weakly buffered for Ca²⁺ (0.2 mm EGTA), a run-down of the outward delayed rectifier K⁺ current was induced by hyperpolarizing the holding potential, and this effect was strongly promoted by high external Ca²⁺ concentrations. This rundown could be reversed by coming back to less hyperpolarized holding potentials or by lowering the external [Ca²⁺]. Such rundown was absent when pipette internal solutions strongly buffered (10 mm EGTA) for Ca²⁺ were used. Ionomycin induced run-down of the K⁺ current with internal solutions containing 0.2 mm but not 10 mm EGTA. The hyperpolarization-associated rundown was reversibly blocked by Gd³⁺ and La³⁺.We thank Christophe Untereiner and Denis Wagner for expert technical assistance in facilitating the experiments and data acquisition and analysis.     

Comparative Structure of Companion Cells and Phloem Parenchyma Cells in Mimosa pudica L.

The phloem of Mimosa pudica L. furnishes an example of definablediversification of the parenchymatic members of the tissue intocompanion cells and parenchyma cells. The companion cells havedense protoplasts which contain the typical organelles of plantcells, including chloroplasts and many ribosomes. The sieveelements and companion cells are interconnected by numerousbranched plasmodesmata. The companion cells degenerate whenthe associated sieve elements cease to function. The parenchymacells have less dense protoplasts than the companion cells.In many parenchyma cells the rough endoplasmic reticulum assumesa tubular form, and bundles of microfilaments are present. Thecytoplasmic ribosomes occur in groups apparently held togetherby fibrils. Chloroplasts, mitochondria (some are exceptionallylong), dictyosomes, microbodies, and microtubules are the othercell components. Whether the parenchyma cells are ontogeneticallyrelated to the sieve elements or not, they do not degeneratewhen the sieve element ceases to function.     

Comparative Histocytology of the Petiole and the Main Pulvinus in Mimosa pudica L.

In Mimosa pudica, the main pulvinus, which brings about leafmovements, presents unusual structural characteristics in comparisonwith the petiole. Peculiar cellular features which exist inthe cortex, epidermis, parenchyma and endodermal regions includethe shape of the cells, their disposition and the location ofthe organelles. The central cylinder of the petiole is surrounded only by afew parenchyma layers whereas the central cylinder of the pulvinusforms a narrow central core enclosed in numerous cortical parenchymalayers. The phloem of the pulvinus contains collenchymatouscells towards the outside and possesses companion cells withwall ingrowths; these phloem members do not exist in the petiole.Xylem and protoxylem parenchyma cells of the petiole possesswall ingrowths which do not occur in homologous cells of thepulvinus. Moreover the pith of the pulvinus is composed of smallfibriform elements similar to the xylem fibriform elements ofthe organ. The structures observed may facilitate exchanges between cellsin the petiole and in the pulvinus. The predominant functionsof the organs relative to lateral and longitudinal transferof nutrients and conduction of stimuli are discussed. Mimosa pudica L., sensitive plant, pulvinus, ultrastructure, conduction of stimuli, leaf movement     

Involvement of respiratory processes in the transient knockout of net CO2 uptake in Mimosa pudica upon heat stimulation

Leaf photosynthesis of the sensitive plant Mimosa pudica displays a transient knockout in response to electrical signals induced by heat stimulation. This study aims at clarifying the underlying mechanisms, in particular, the involvement of respiration. To this end, leaf gas exchange and light reactions of photosynthesis were assessed under atmospheric conditions largely eliminating photorespiration by either elevated atmospheric CO₂ or lowered O₂ concentration (i.e. 2000 μmol mol^?1 or 1%, respectively). In addition, leaf gas exchange was studied in the absence of light. Under darkness, heat stimulation caused a transient increase of respiratory CO₂ release simultaneously with stomatal opening, hence reflecting direct involvement of respiratory stimulation in the drop of the net CO₂ uptake rate. However, persistence of the transient decline in net CO₂ uptake rate under illumination and elevated CO₂ or 1% O₂ makes it unlikely that photorespiration is the metabolic origin of the respiratory CO₂ release. In conclusion, the transient knockout of net CO₂ uptake is at least partially attributed to an increased CO₂ release through mitochondrial respiration as stimulated by electrical signals. Putative CO₂ limitation of Rubisco due to decreased activity of carbonic anhydrase was ruled out as the photosynthesis effect was not prevented by elevated CO₂.     

Effects of Jasmonic Acid on Motor Cell Physiology in Mimosa pudica L. and Cassia fasciculata Michx

When applied to pulvini of Mimosa pudica, jasmonic acid (JA)affected neither proton fluxes nor the membrane potential ofthe motor cells. When added to leaflets of Cassia fasciculata,JA increased the rate of dark-induced pulvinar movements ina concentration-dependent manner. This effect was observed withinas little as 15 min after a 1-h treatment that preceded theinducing signal. Treatments in buffered media at acidic pH resultedin the greatest physiological responses. Light-induced pulvinarmovements were considerably reduced under the same conditions.With continuous illumination, JA induced a closing movementof the leaflets in a concentrationdependent manner. These resultsare discussed in relation to the ionic changes in the pulvinarmotor cells and in relation to results obtained previously upontreatment of Cassia plants with ABA. Although ABA and JA havesimilar physiological effects on the dark-induced closure, theydiffer in the type of response elicited by brief treatment andwith respect to light-induced opening. (Received September 27, 1993; Accepted January 15, 1994)     

Changes in the Nucleus and the Endoplasmic Reticulum during Differentiation of a Sieve Element in Mimosa pudica L.

The differentiating sieve element in stem and leaf phloem ofMimosa pudica L. was examined with the electron microscope.The nucleus of a sieve element at first resembles that of acompanion cell, except that its nucleolus is smaller. The firstindication of approaching disintegration is a change in theappearance of the nuclear envelope. With the fixatives used,its profile becomes wider and clearer, giving the impressionof having been dilated. Subsequently, the nuclear contents disintegrateand the envelope breaks apart. No nuclear remnants are discerniblein mature sieve elements. The endoplasmic reticulum (ER) ofyoung sieve elements consists of cisternae-bearing ribosomes.At the beginning of nuclear disintegration ER cisternae becomestacked, with electron-dense material accumulating between thecisternae. The stacking assumes various forms. Some of the stackedER is independent of cell organelles and occurs next to theplasmalemma along the cell wall. Part of the ER becomes stackedagainst the plastids or the nucleus. There is also unstackedER which forms an anastomosing system along the plasmalemma.All of the modified ER bears no ribosomes. The anastomosingER appears to persist longer than the stacked ER.