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The sounds of plants – Plants emit remotely-detectable ultrasounds that can reveal plant stress: Supplementary Materials
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Abstract
Plants communicate with their environment in many ways, using colors and shapes and secreting chemicals. Yet, the possibility that plants emit airborne sounds that reveal their condition has not been investigated. Here, we develop a novel method for remotely detecting plant sound emission. We use it to demonstrate, to our knowledge for the first time, that plants emit sounds that can be recorded from a distance. We recorded ~65 dBSPL ultrasonic sounds at 10 cm distance from tomato and tobacco plants, suggesting that these sounds could be detected by many animals from up to several meters. We further train machine learning algorithms to identify the physiological condition of tomato and tobacco plants based solely on the emitted sounds. We successfully classified the plant's condition - dry, cut, or intact - based on its emitted sounds. Our results suggest that animals, and possibly even other plants, could use sounds emitted by plants to gain information about the plant's condition. More investigation on plant bioacoustics in general and on sound emission in plants in particular may open new avenues for understanding plants, and their interactions with the environment.
... In fact, plants emit sounds through different organs and at different stages of growth or in response to different situations. Plants have been reported to emit low frequency sounds (50-120 Hz) from the xylem (Jung et al. 2018) or ultrasonic vibrations (20-100 kHz) in case of stress (Hassanien et al. 2014;Khait et al. 2018). This ability to emit, although not voluntarily, and perceive sounds led authors to think that there could be an underground communication channel between plants (Gagliano et al. 2012;Del Stabile et al. 2022). ...
... Another study has reported that plants emit SVs between 10 and 240 Hz (audible acoustic emissions) and 20 and 300 kHz (ultrasonic acoustic emissions) [19]. Previous studies have shown that plants emit SVs during wounding and drought stress, which may positively impact neighboring plants [38]. Gagliano et al. [39] reported that plant roots appear to move toward a water source in response to vibrations if their presence is detected. ...
Background
How plants emit, perceive, and respond to sound vibrations (SVs) is a long-standing question in the field of plant sensory biology. In recent years, there have been numerous studies on how SVs affect plant morphological, physiological, and biochemical traits related to growth and adaptive responses. For instance, under drought SVs navigate plant roots towards water, activate their defence responses against stressors, and increase nectar sugar in response to pollinator SVs. Also, plants emit SVs during stresses which are informative in terms of ecological and adaptive perspective. However, the molecular mechanisms underlying the SV perception and emission in plants remain largely unknown. Therefore, deciphering the complexity of plant-SV interactions and identifying bonafide receptors and signaling players will be game changers overcoming the roadblocks in phytoacoustics.
Aim of review
The aim of this review is to provide an overview of recent developments in phytoacoustics. We primarily focuss on SV signal perception and transduction with current challenges and future perspectives.
Key scientific concepts of review
Timeline breakthroughs in phytoacoustics have constantly shaped our understanding and belief that plants may emit and respond to SVs like other species. However, unlike other plant mechanostimuli, little is known about SV perception and signal transduction. Here, we provide an update on phytoacoustics and its ecological importance. Next, we discuss the role of cell wall receptor-like kinases, mechanosensitive channels, intracellular organelle signaling, and other key players involved in plant-SV receptive pathways that connect them. We also highlight the role of calcium (Ca²⁺), reactive oxygen species (ROS), hormones, and other emerging signaling molecules in SV signal transduction. Further, we discuss the importance of molecular, biophysical, computational, and live cell imaging tools for decoding the molecular complexity of acoustic signaling in plants. Finally, we summarised the role of SV priming in plants and discuss how SVs could modulate plant defense and growth trade-offs during other stresses.
... In fact, plants emit sounds through different organs and at different stages of growth or in response to different situations. Plants have been reported to emit low frequency sounds (50-120 Hz) from the xylem (Jung et al. 2018) or ultrasonic vibrations (20-100 kHz) in case of stress (Hassanien et al. 2014;Khait et al. 2018). This ability to emit, although not voluntarily, and perceive sounds led authors to think that there could be an underground communication channel between plants (Gagliano et al. 2012;Del Stabile et al. 2022). ...
Plants have been considered passive, static, and immutable organisms for a long time, but research shows that plants can perceive their environment and respond to stimuli by modifying their growth and development. Plants communicate with each other and with the world around them. This communication has been explained through the contact between mycorrhizae and volatile organic compounds, but recently, plant acoustic perception and communication have become a newline of research. The sounds produced by plants would contain information with ecological implications, which could be used in the management of crop fields or in the prevention of biodiversity loss. In addition, anthropogenic noise inflicts ultrastructural damage on various tissues of marine plants that could have implications at ecosystems level and in the planet’s biodiversity in general. This chapter provides an overview of the plants bioacoustics and aims to underline the need to develop criteria to assess the impact of sound on marine plants. Understanding how the intricate communication networks between the roots supplies vital information for individuals in marine ecosystems, the possible capacity to warn their peers of dangers and the root role on the sensory and communication capacities could be new research lines in marine plant bioacoustics.
... Can plants also communicate through sound? Hadany et al. [8] have recently shown that plants emit remotely-detectable ultrasounds, enabling the researchers to identify the plants' physiological condition through sound. Inspired by these findings, in Plantimus we envision a future in which we will be able to listen to a plant part and learn about it in many levels -its role in the plant life, its degree of health and its more abstract and emotional connotation. ...
... Through the use of small highly sensitive sound receivers, it has been shown that plants emit sound from the xylem 15 and faint ultrasound in case of stress. 16 Plants can hear caterpillar's chewing and set up the appropriate defenses 17 but they can also hear the moving close of a pollinator using flowers as "ears" and responding with minutes by sweetening the nectar. 18 From several years it has been demonstrated how plants can absorb and resonate specific sound frequencies 19 and how sound waves can change the cell cycle of the plant. ...
Life evolved in an acoustic world. Sound is perceived in different ways by the species that inhabit the Planet. Among organisms, also some algal species seem to respond to sound stimuli with increased cell growth and productivity. The purpose of this Short Communication is to provide an overview of the current literature about various organisms and sound, with particular attention to algal organisms, which, when subjected to sound applications, can change their metabolism accordingly.
Conventional plant disease detection approaches are time consuming and require high skills. Above all, it cannot be scaled down to smallholder farmers in most developing countries. Using low cost IoT sensor technologies that are gas, ultrasound and NPK sensors mounted next to maize varieties for profiling these parameters on a given period. Here we report an experiment performed under controlled environment to learn metabolic and pathologic behavioral patterns on healthy and NLB inoculated maize plants by generating time series dataset on profiled Volatile Organic Compounds (VOC), Ultrasound and Nitrogen, Phosphorus, Potassium (NPK). Dataset has been preprocessed with pandas and analyzed using machine learning models which are dickey fuller test and python additive statsmodel and visualized using matplotlib library to enable the inference of an occurrence of a disease a few days post inoculation without subjecting a plant to an invasive procedure. This enabled a deployment and implementation of noninvasive plant disease detection prior to visual symptoms that can be applied on other plants. With analyzed data, the IoT technology in this experiment has enabled the detection of NLB disease on maize disease within seven days post inoculation because of monitoring VOC and ultrasound emission.KeywordsNLBMaizeIoTtimeseriesVOCultrasoundNPK
Plants have long been considered passive, static, and unchanging organisms, but this view is finally changing. More and more knowledge is showing that plants are aware of their surroundings, and they respond to a surprising variety of stimuli by modifying their growth and development. Plants extensively communicate with the world around them, above and below ground. Although communication through mycorrhizal networks and Volatile Organic Compounds has been known for a long time, acoustic perception and communication are somehow a final frontier of research. Perhaps surprisingly, plants not only respond to sound, they actually seem to emit sound as well. Roots emit audible clicks during growth, and sounds are emitted from xylem vessels, although the nature of these acoustic emissions still needs to be clarified. Even more interesting, there is the possibility that these sounds carry information with ecological implications, such as alerting insects of the hydration state of a possible host plant, and technological implications as well. Monitoring sound emissions could possibly allow careful monitoring of the hydration state of crops, which could mean significantly less water used during irrigation. This review summarizes the current knowledge on sound perception communication in plants and illustrates possible implications and technological applications.
In a very recent book called Sensory Biology of Plants, published by renowned publisher Springer Nature, the authors stated that the scientific literature gathered so far regarding knowledge around the field of Plant Acoustics allows us to divert the focus from the question “whether plants perceive sound” toward the questions “how and why they are doing it” Some phenomena are well known: roots perceive the sound of flowing water and display a sound-mediated growth toward the water source, while the buzz pollination process allows plants to minimize the pollen lost and maximize which is collected by true pollinators. But plants are far more perceptive and responsive to their environment than we generally consider them to be, and they are communicating far more information than we realize if we only took all their signals (VOCs, sound, exudates, etc.) into a greater picture. Could Volatile Organic Compounds (VOCs) be involved in mediating more responses than we imagine? VOC synthesis and release is known to be elicited also by electrical signals caused by mechanical stimuli, touching and wounding being among these, serving as info-chemicals in the communication between plants (“eavesdropping”), and within the organs of the same plant, in order for it to get synchronized with its surroundings. This paper is an overview of the discoveries around plant perception with a focus on the link between mechanical stimuli, as sound vibrations are, and changes in plant physiology leading to VOC emission.
The hypothesis that information is the same attribute of the Universe as space, time and matter, which appeared after the Big Bang and its carrier is the dark energy, is proposed. We assume that along with the development of matter and space-time continuum the development of information took place, i.e. its accumulation and complication of forms of its realization in the Universe, and the formation of information field. The proposed concept is close to or coincides with the bio-centrism concept. They substantiate the connection between information and dark energy from philosophical and physical positions. including properties of "black holes" of the Universe.The rate of increase of knowledge and volumes of created information in the process of human evolution is very similar to the rate of increase of "mass" of dark energy of the Universe. They concluded that structured information in the information field, which forms the noosphere or thinking shell, plays a decisive role both in life of an individual and humanity. Comparison of quantum properties of information field of the Universe (noosphere) and dark energy may lead to new discoveries of the essence of life and the Universe. Studying and mastering of noosphere will mean the transition of humanity to a cosmic stage of its development.
Can plants sense natural airborne sounds and respond to them rapidly? We show that Oenothera drummondii flowers, exposed to playback sound of a flying bee or to synthetic sound signals at similar frequencies, produce sweeter nectar within 3 min, potentially increasing the chances of cross pollination. We found that the flowers vibrated mechanically in response to these sounds, suggesting a plausible mechanism where the flower serves as an auditory sensory organ. Both the vibration and the nectar response were frequency‐specific: the flowers responded and vibrated to pollinator sounds, but not to higher frequency sound. Our results document for the first time that plants can rapidly respond to pollinator sounds in an ecologically relevant way. Potential implications include plant resource allocation, the evolution of flower shape and the evolution of pollinators sound. Finally, our results suggest that plants may be affected by other sounds as well, including anthropogenic ones.
Sound is ubiquitous in nature. Recent evidence supports the notion that naturally occurring and artificially generated sound waves contribute to plant robustness. New information is emerging about the responses of plants to sound and the associated downstream signaling pathways. Here, beyond chemical triggers which can improve plant health by enhancing plant growth and resistance, we provide an overview of the latest findings, limitations, and potential applications of sound wave treatment as a physical trigger to modulate physiological traits and to confer an adaptive advantage in plants. We believe that sound wave treatment is a new trigger to help protect plants against unfavorable conditions and to maintain plant fitness.
We examined the responses of sound-treated arabidopsis adult plants to water deprivation and the associated changes on gene expression. The survival of drought-induced plants was significantly higher in the sound treated plants (24,8%) compared to plants kept in silence (13,3%). RNA-seq revealed significant up-regulation of 87 genes including 32 genes involved in abiotic stress responses, 31 involved in pathogen responses, 11 involved in oxidation-reduction processes, 5 involved in the regulation of transcription, 2 genes involved in protein phosphorylation/dephosphorylation and 13 involved in jasmonic acid or ethylene synthesis or responses. In addition, 2 genes involved in the responses to mechanical stimulus were also induced by sound, suggesting that touch and sound have at least partially common perception and signaling events.
Sound vibration (SV), a mechanical stimulus, can trigger various molecular and physiological changes in plants like gene expression, hormonal modulation, induced antioxidant activity and calcium spiking. It also alters the seed germination and growth of plants. In this study, we investigated the effects of SV on the resistance of Arabidopsis thaliana against Botrytis cinerea infection. The microarray analysis was performed on infected Arabidopsis plants pre-exposed to SV of 1000 Hertz with 100 decibels. Broadly, the transcriptomic analysis revealed up-regulation of several defense and SA-responsive and/or signaling genes. Quantitative real-time PCR (qRT-PCR) analysis of selected genes also validated the induction of SA-mediated response in the infected Arabidopsis plants pre-exposed to SV. Corroboratively, hormonal analysis identified the increased concentration of salicylic acid (SA) in the SV-treated plants after pathogen inoculation. In contrast, jasmonic acid (JA) level in the SV-treated plants remained stable but lower than control plants during the infection. Based on these findings, we propose that SV treatment invigorates the plant defense system by regulating the SA-mediated priming effect, consequently promoting the SV-induced resistance in Arabidopsis against B. cinerea.
Bioacoustic research of reptile calls and vocalizations has been limited due to the general consideration that they are voiceless. However, several species of geckos, turtles, and crocodiles are able to produce simple and even complex vocalizations which are species-specific. This work presents a novel approach for the automatic taxonomic identification of reptiles through their bioacoustics by applying pattern recognition techniques. The sound signals are automatically segmented, extracting each call from the background noise. Then, their calls are parametrized using Linear and Mel Frequency Cepstral Coefficients (LFCC and MFCC) to serve as features in the classification stage. In this study, 27 reptile species have been successfully identified using two machine learning algorithms: K-Nearest Neighbors (kNN) and Support Vector Machine (SVM). Experimental results show an average classification accuracy of 97.78% and 98.51%, respectively.
Being sessile, plants continuously deal with their dynamic and complex surroundings, identifying important cues and reacting with appropriate responses. Consequently, the sensitivity of plants has evolved to perceive a myriad of external stimuli, which ultimately ensures their successful survival. Research over past centuries has established that plants respond to environmental factors such as light, temperature, moisture, and mechanical perturbations (e.g. wind, rain, touch, etc.) by suitably modulating their growth and development. However, sound vibrations (SVs) as a stimulus have only started receiving attention relatively recently. SVs have been shown to increase the yields of several crops and strengthen plant immunity against pathogens. These vibrations can also prime the plants so as to make them more tolerant to impending drought. Plants can recognize the chewing sounds of insect larvae and the buzz of a pollinating bee, and respond accordingly. It is thus plausible that SVs may serve as a long-range stimulus that evokes ecologically relevant signaling mechanisms in plants. Studies have suggested that SVs increase the transcription of certain genes, soluble protein content, and support enhanced growth and development in plants. At the cellular level, SVs can change the secondary structure of plasma membrane proteins, affect microfilament rearrangements, produce Ca2+ signatures, cause increases in protein kinases, protective enzymes, peroxidases, antioxidant enzymes, amylase, H+-ATPase / K+ channel activities, and enhance levels of polyamines, soluble sugars and auxin. In this paper, we propose a signaling model to account for the molecular episodes that SVs induce within the cell, and in so doing we uncover a number of interesting questions that need to be addressed by future research in plant acoustics.
Acoustic emissions are frequently used in material sciences and engineering applications for structural health monitoring. It is known that plants also emit acoustic emissions, and their application in plant sciences is rapidly increasing, especially to investigate drought-induced plant stress. Vulnerability to drought-induced cavitation is a key trait of plant water relations, and contains valuable information about how plants may cope with drought stress. There is, however, no consensus in literature about how this is best measured. Here, we discuss detection of acoustic emissions as a measure for drought-induced cavitation. Past research and the current state of the art are reviewed. We also discuss how the acoustic emission technique can help solve some of the main issues regarding quantification of the degree of cavitation, and how it can contribute to our knowledge about plant behavior during drought stress. So far, crossbreeding in the field of material sciences proved very successful, and we therefore recommend continuing in this direction in future research.
This work has the objective to catalogue the information of auysodeixis includens (Walker, [1858]) (Lepidoptera: Noctuidae: Plusiinae) host plants. The list of plants comprehends new reports of host plants in Brazil and information from literature review around the world. It is listed 174 plants which are from 39 botanic families. The higher number of host plants of C. includens are in Asteraceae (29), Solanaceae (21), Fabaceae (18) and Lamiaceae (12). (C) 2015 Sociedade Brasileira de Entomologia. Published by Elsevier Editora Ltda.
To test the sound’s effect on plant and its contribution in drought tolerance, plants were subjected to various sound frequencies for an hour. After 24 h sound treatment, plants were exposed to drought for next five days. During the experiment it was observed that sound initiated physiological changes showing tolerance in plant. Sound frequency with ≥0.8 kHz enhanced relative water content, stomatal conductance and quantum yield of PSII (Fv/Fm ratio) in drought stress environment. Hydrogen peroxide (H2O2) production in sound treated plant was declined compared to control. ThermaCAM (Infra-red camera) a software which was used to analyze the plant images temperature showed that sound treated plant and leaf had less temperature (heat) compared to control. The physiological mechanism of sound frequencies induce tolerance in rice plants are discussed.
Sound waves technology has been applied to different plants. It has been found that sound waves were at different frequencies, sound pressure levels (SPLs), exposure periods, and distances from the source of sound influence plant growth. Experiments have been conducted in the open field and under greenhouse growing conditions with different levels of audible sound frequencies and sound pressure levels. Sound waves at 1 kHz and 100 dB for 1 h within a distance of 0.20 m could significantly promote the division and cell wall fluidity of callus cells and also significantly enhance the activity of protective enzymes and endogenous hormones. Sound waves stimulation could increase the plant plasma-membrane H+-ATPase activity, the contents of soluble sugar, soluble protein, and amylase activity of callus. Moreover, sound waves could increase the content of RNA and the level of transcription. Stress-induced genes could switch on under sound stimulation. Sound waves at 0.1–1 kHz and SPL of (70±5) dB for 3 h from plant acoustic frequency technology (PAFT) generator within a distance ranged from 30 to 60 m every other day significantly increased the yield of sweet pepper, cucumber and tomato by 30.05, 37.1 and 13.2%, respectively. Furthermore, the yield of lettuce, spinach, cotton, rice, and wheat were increased by 19.6, 22.7, 11.4, 5.7, and 17.0%, respectively. Sound waves may also strengthen plant immune systems. It has been proved that spider mite, aphids, gray mold, late blight and virus disease of tomatoes in the greenhouses decreased by 6.0, 8.0, 9.0, 11.0, and 8.0%, respectively, and the sheath blight of rice was reduced by 50%. This paper provides an overview of literature for the effects of sound waves on various growth parameters of plant at different growth stages.
Communication in plant–animal mutualisms frequently involves multiple perceivers. A fundamental uncertainty is whether and how species adapt to communicate with groups of mutualists having distinct sensory abilities.
� We quantified the colour conspicuousness of flowers and fruits originating from one Euro- pean and two South American plant communities, using visual models of pollinators (bee and fly) and seed dispersers (bird, primate and marten).
� We show that flowers are more conspicuous than fruits to pollinators, and the reverse to seed dispersers. In addition, flowers are more conspicuous to pollinators than to seed dispers- ers and the reverse for fruits. Thus, despite marked differences in the visual systems of mutual- ists, flower and fruit colours have evolved to attract multiple, distinct mutualists but not unintended perceivers. We show that this adaptation is facilitated by a limited correlation between flower and fruit colours, and by the fact that colour signals as coded at the photore- ceptor level are more similar within than between functional groups (pollinators and seed dispersers).
� Overall, these results provide the first quantitative demonstration that flower and fruit col- ours are adaptations allowing plants to communicate simultaneously with distinct groups of mutualists.
Xylem cavitation resistance has profound implications for plant physiology and ecology. This process is characterized by a 'vulnerability curve' (VC) showing the variation of the percentage of cavitation as a function of xylem pressure potential. The shape of this VC varies from 'sigmoidal' to 'exponential'. This review provides a panorama of the techniques that have been used to generate such a curve. The techniques differ by (i) the way cavitation is induced (e.g. bench dehydration, centrifugation, or air injection), and (ii) the way cavitation is measured (e.g. percentage loss of conductivity (PLC) or acoustic emission), and a nomenclature is proposed based on these two methods. A survey of the literature of more than 1200 VCs was used to draw statistics on the usage of these methods and on their reliability and validity. Four methods accounted for more than 96% of all curves produced so far: bench dehydration-PLC, centrifugation-PLC, pressure sleeve-PLC, and Cavitron. How the shape of VCs varies across techniques and species xylem anatomy was also analysed. Strikingly, it was found that the vast majority of curves obtained with the reference bench dehydration-PLC method are 'sigmoidal'. 'Exponential' curves were more typical of the three other methods and were remarkably frequent for species having large xylem conduits (ring-porous), leading to a substantial overestimation of the vulnerability of cavitation for this functional group. We suspect that 'exponential' curves may reflect an open-vessel artefact and call for more precautions with the usage of the pressure sleeve and centrifugation techniques.
Acoustic communication in plants lays an enticing vista of possibilities before us: new ways to test signalling hypotheses, exciting trophic interactions awaiting discovery, and unfamiliar mechanisms of signal production. But is this enthusiasm war-ranted? The review by Gagliano (2012) in this issue highlights some of the considerable hurdles to demonstrating acoustic communication in plants. Part of the excitement of plant communication is that the behavioral ecology community has a new opportunity to employ a rigorous research approach rooted in Tinbergen's ethological tradition (Tinbergen 1963). We propose that this approach needs to be identified clearly. To convincingly demonstrate that plant communication occurs as it is defined in the behavioral ecology literature, stud-ies must show that 1) plants produce and respond to sound, 2) both traits provide an adaptive benefit, and 3) they have been historically selected for their communicative functions (Williams 1966; West-Eberhard 1992; Autumn etal. 2002).
A scattering transform defines a locally translation invariant representation
which is stable to time-warping deformations. It extends MFCC representations
by computing modulation spectrum coefficients of multiple orders, through
cascades of wavelet convolutions and modulus operators. Second-order scattering
coefficients characterize transient phenomena such as attacks and amplitude
modulation. A frequency transposition invariant representation is obtained by
applying a scattering transform along log-frequency. State-the-of-art
classification results are obtained for musical genre and phone classification
on GTZAN and TIMIT databases, respectively.
In the coming decades, a crucial challenge for humanity will be meeting future food demands without undermining further the integrity of the Earth's environmental systems. Agricultural systems are already major forces of global environmental degradation, but population growth and increasing consumption of calorie- and meat-intensive diets are expected to roughly double human food demand by 2050 (ref. 3). Responding to these pressures, there is increasing focus on 'sustainable intensification' as a means to increase yields on underperforming landscapes while simultaneously decreasing the environmental impacts of agricultural systems. However, it is unclear what such efforts might entail for the future of global agricultural landscapes. Here we present a global-scale assessment of intensification prospects from closing 'yield gaps' (differences between observed yields and those attainable in a given region), the spatial patterns of agricultural management practices and yield limitation, and the management changes that may be necessary to achieve increased yields. We find that global yield variability is heavily controlled by fertilizer use, irrigation and climate. Large production increases (45% to 70% for most crops) are possible from closing yield gaps to 100% of attainable yields, and the changes to management practices that are needed to close yield gaps vary considerably by region and current intensity. Furthermore, we find that there are large opportunities to reduce the environmental impact of agriculture by eliminating nutrient overuse, while still allowing an approximately 30% increase in production of major cereals (maize, wheat and rice). Meeting the food security and sustainability challenges of the coming decades is possible, but will require considerable changes in nutrient and water management.
The effects of defoliation of alder (Alnus glutinosa) on subsequent herbivory by alder leaf beetle (Agelastica alni) were studied in ten alder stands in northern Germany. At each site, one tree was manually defoliated (c. 20% of total foliage) to simulate herbivory. Subsequent damage by A. alni was assessed on ten alders at each site on six different dates from May to September 1994. After defoliation, herbivory by A. alni increased with distance from the defoliated tree. Laboratory experiments supported the field results. Not only leaf damage in the field, but also the extent of leaf consumption in laboratory feeding-preference tests and the number of eggs oviposited per leaf in another laboratory test were positively correlated with distance from the defoliated tree. Resistance was therefore induced not only in defoliated alders, but also in their undamaged neighbours. Consequently, defoliation of alders may trigger interplant resistance transfer, and therefore reduce herbivory in whole alder stands.
We compared the ability of three machine learning algorithms (linear discriminant analysis, decision tree, and support vector machines) to automate the classification of calls of nine frogs and three bird species. In addition, we tested two ways of characterizing each call to train/test the system. Calls were characterized with four standard call variables (minimum and maximum frequencies, call duration and maximum power) or eleven variables that included three standard call variables (minimum and maximum frequencies, call duration) and a coarse representation of call structure (frequency of maximum power in eight segments of the call). A total of 10,061 isolated calls were used to train/test the system. The average true positive rates for the three methods were: 94.95% for support vector machine (0.94% average false positive rate), 89.20% for decision tree (1.25% average false positive rate) and 71.45% for linear discriminant analysis (1.98% average false positive rate). There was no statistical difference in classification accuracy based on 4 or 11 call variables, but this efficient data reduction technique in conjunction with the high classification accuracy of the SVM is a promising combination for automated species identification by sound. By combining automated digital recording systems with our automated classification technique, we can greatly increase the temporal and spatial coverage of biodiversity data collection.
Little is known about plant bioacoustics. Here, we present a rationale as to why the perception of sound and vibrations is likely to have also evolved in plants. We then explain how current evidence contributes to the view that plants may indeed benefit from mechanosensory mechanisms thus far unsuspected.
Recent evidence demonstrates that plants are able not only to perceive and adaptively respond to external information but also to anticipate forthcoming hazards and stresses. Here, we tested the hypothesis that unstressed plants are able to respond to stress cues emitted from their abiotically-stressed neighbors and in turn induce stress responses in additional unstressed plants located further away from the stressed plants. Pisum sativum plants were subjected to drought while neighboring rows of five unstressed plants on both sides, with which they could exchange different cue combinations. On one side, the stressed plant and its unstressed neighbors did not share their rooting volumes (UNSHARED) and thus were limited to shoot communication. On its other side, the stressed plant shared one of its rooting volumes with its nearest unstressed neighbor and all plants shared their rooting volumes with their immediate neighbors (SHARED), allowing both root and shoot communication. Fifteen minutes following drought induction, significant stomatal closure was observed in both the stressed plants and their nearest unstressed SHARED neighbors, and within one hour, all SHARED neighbors closed their stomata. Stomatal closure was not observed in the UNSHARED neighbors. The results demonstrate that unstressed plants are able to perceive and respond to stress cues emitted by the roots of their drought-stressed neighbors and, via 'relay cuing', elicit stress responses in further unstressed plants. Further work is underway to study the underlying mechanisms of this new mode of plant communication and its possible adaptive implications for the anticipation of forthcoming abiotic stresses by plants.
Precision agriculture has mostly emphasized variable-rate nutrients, seeding, and pesticide application, but at several research sites, variable-rate irrigation equipment has been developed to explore the potential for managing irrigation spatially. The modifications to commercial machines are relatively straightforward, but costly; thus economic analyses have not been positive at current grain price: water cost ratios. However, with increased attention to conservation of water during drought, with increased contention for environmental, recreational, municipal, and industry use, or with regulatory constraints, conclusions regarding profitability or desirability of variable-rate irrigation may change. The objectives of this paper are to: 1) define and describe site-specific irrigation, 2) discuss the opportunities for conservation using site- specific irrigation, 3) present case studies from production and research fields that illustrate these opportunities, and 4) discuss critical research needs to fully implement precision irrigation and thus realize these opportunities for conservation. The opportunities for conservation discussed include situations where non-cropped areas exist in a field for which irrigation can be turned completely off, situations where a reduced irrigation amount provides specific benefits, and finally, situations where optimizing irrigation amount to adapt to spatial productivity provides quantitative benefits. Results from the case studies provide estimates of the potential for water conservation using precision irrigation that range from marginal to nearly 50 percent in single years, and average from eight to 20 percent, depending on the previous irrigation management strategy employed. Critical research needs include improved decision support systems and real-time monitoring and feedback to irrigation control.
In spite of initial doubts about the reality of 'talking trees', plant resistance expression mediated by volatile compounds that come from neighboring plants is now well described. Airborne signals usually improve the resistance of the receiver, but without obvious benefits for the emitter, thus making the evolutionary explanation of this phenomenon problematic. Here, we discuss four possible non-exclusive explanations involving the role of volatiles: in direct defense, as within-plant signals, as traits that synergistically interact with other defenses, and as cues among kin. Unfortunately, there is a lack of knowledge on the fitness consequences of plant communication for both emitter and receiver. This information is crucial to understanding the ecology and evolution of plant communication via airborne cues.
The audiograms of two wood rats and three grasshopper mice were determined with a conditioned avoidance procedure. The wood rats were able to hear tones from 940 Hz to 56 kHz at a level of 60 dB (SPL), with their best sensitivity of -3 dB occurring at 8 kHz. The hearing of the grasshopper mice ranged from 1.85 kHz to 69 kHz at 60 dB (SPL), with their best sensitivity of 9 dB also occurring at 8 kHz. These results support the relation between interaural distance and high-frequency hearing and between high- and low-frequency hearing. The inability of the grasshopper mouse to hear low frequencies as well as other desert rodents such as kangaroo rats and gerbils demonstrates that not all rodents found in deserts have developed good low-frequency hearing. The degree to which general and specific selective pressures have played a role in the evolution of rodent hearing is discussed.
In coming decades, global climate changes are expected to produce large shifts in vegetation distributions at unprecedented rates. These shifts are expected to be most rapid and extreme at ecotones, the boundaries between ecosystems, particularly those in semiarid landscapes. However, current models do not adequately provide for such rapid effects-particularly those caused by mortality-largely because of the lack of data from field studies. Here we report the most rapid landscape-scale shift of a woody ecotone ever documented: in northern New Mexico in the 1950s, the ecotone between semiarid ponderosa pine forest and pinon-juniper woodland shifted extensively (2 km or more) and rapidly (<5 years) through mortality of ponderosa pines in response to a severe drought. This shift has persisted for 40 years. Forest patches within the shift zone became much more fragmented, and soil erosion greatly accelerated. The rapidity and the complex dynamics of the persistent shift point to the need to represent more accurately these dynamics, especially the mortality factor, in assessments of the effects of climate change.
I investigated the scaling of echolocation call parameters (frequency, duration and repetition rate) in bats in a functional context. Low-duty-cycle bats operate with search phase cycles of usually less than 20 %. They process echoes in the time domain and are therefore intolerant of pulse-echo overlap. High-duty-cycle (>30 %) species use Doppler shift compensation, and they separate pulse and echo in the frequency domain. Call frequency scales negatively with body mass in at least five bat families. Pulse duration scales positively with mass in low-duty-cycle quasi-constant-frequency (QCF) species because the large aerial-hawking species that emit these signals fly fast in open habitats. They therefore detect distant targets and experience pulse-echo overlap later than do smaller bats. Pulse duration also scales positively with mass in the Hipposideridae, which show at least partial Doppler shift compensation. Pulse repetition rate corresponds closely with wingbeat frequency in QCF bat species that fly relatively slowly. Larger, fast-flying species often skip pulses when detecting distant targets. There is probably a trade-off between call intensity and repetition rate because 'whispering' bats (and hipposiderids) produce several calls per predicted wingbeat and because batches of calls are emitted per wingbeat during terminal buzzes. Severe atmospheric attenuation at high frequencies limits the range of high-frequency calls. Low-duty-cycle bats that call at high frequencies must therefore use short pulses to avoid pulse-echo overlap. Rhinolophids escape this constraint by Doppler shift compensation and, importantly, can exploit advantages associated with the emission of both high-frequency and long-duration calls. Low frequencies are unsuited for the detection of small prey, and low repetition rates may limit prey detection rates. Echolocation parameters may therefore constrain maximum body size in aerial-hawking bats.
Herbivore attack is known to increase the emission of volatiles, which attract predators to herbivore-damaged plants in the
laboratory and agricultural systems. We quantified volatile emissions fromNicotiana attenuata plants growing in natural populations during attack by three species of leaf-feeding herbivores and mimicked the release
of five commonly emitted volatiles individually. Three compounds (cis-3-hexen-1-ol, linalool, and cis-α-bergamotene) increased egg predation rates by a generalist predator; linalool and the complete blend decreased lepidopteran
oviposition rates. As a consequence, a plant could reduce the number of herbivores by more than 90% by releasing volatiles.
These results confirm that indirect defenses can operate in nature.
The simple auditory system of noctuoid moths has long been a model for anti-predator studies in neuroethology, although these ears have rarely been experimentally stimulated by the sounds they would encounter from naturally attacking bats. We exposed the ears of five noctuoid moth species to the pre-recorded echolocation calls of an attacking bat (Eptesicus fuscus) to observe the acoustic encoding of the receptors at this critical time in their defensive behaviour. The B cell is a non-tympanal receptor common to all moths that has been suggested to respond to sound, but we found no evidence of this and suggest that its acoustic responsiveness is an artifact arising from its proprioceptive function. The A1 cell, the most sensitive tympanal receptor in noctuid and arctiid moths and the only auditory receptor in notodontid moths, encodes the attack calls with a bursting firing pattern to a point approximately 150 ms from when the bat would have captured the moth. At this point, the firing of the A1 cell reduces to a non-bursting pattern with longer inter-spike periods, suggesting that the moth may no longer express the erratic flight used to escape very close bats. This may be simply due to the absence of selection pressure on moths for auditory tracking of bat echolocation calls beyond this point. Alternatively, the reduced firing may be due to the acoustic characteristics of attack calls in the terminal phase and an acoustic maneuver used by the bat to facilitate its capture of the moth. Although the role of less sensitive A2 cell remains uncertain in the evasive flight responses of moths it may act as a trigger in eliciting sound production, a close-range anti-bat behaviour in the tiger moth, Cycnia tenera.
Green leafy volatiles (GLV), six-carbon aldehydes, alcohols, and esters commonly emitted by plants in response to mechanical damage or herbivory, induced intact undamaged corn seedlings to rapidly produce jasmonic acid (JA) and emit sesquiterpenes. More importantly, corn seedlings previously exposed to GLV from neighboring plants produced significantly more JA and volatile sesquiterpenes when mechanically damaged and induced with caterpillar regurgitant than seedlings not exposed to GLV. The use of pure synthetic chemicals revealed that (Z)-3-hexenal, (Z)-3-hexen-1-ol, and (Z)-3-hexenyl acetate have nearly identical priming activity. Caterpillar-induced nocturnal volatiles, which are enriched in GLV, also exhibited a strong priming effect, inducing production of larger amounts of JA and release of greater quantities of volatile organic compounds after caterpillar regurgitant application. In contrast, GLV priming did not affect JA production induced by mechanical wounding alone. Thus, GLV specifically prime neighboring plants against impending herbivory by enhancing inducible chemical defense responses triggered during attack and may play a key role in plant-plant signaling and plant-insect interactions.
Sound vibration (SV) is considered as an external mechanical force that modulates plant growth and development like other mechanical stimuli (e.g., wind, rain, touch and vibration). A number of previous and recent studies reported developmental responses in plants tailored against SV of varied frequencies. This strongly suggests the existence of sophisticated molecular mechanisms for SV perception and signal transduction. Despite this there exists a huge gap in our understanding regarding the SV-mediated molecular alterations, which is a prerequisite to gain insight into SV-mediated plant development. Herein, we investigated the global gene expression changes in Arabidopsis thaliana upon treatment with five different single frequencies of SV at constant amplitude for 1 h. As a next step, we also studied the SV-mediated proteomic changes in Arabidopsis. Data suggested that like other stimuli, SV also activated signature cellular events, for example, scavenging of reactive oxygen species (ROS), alteration of primary metabolism, and hormonal signaling. Phytohormonal analysis indicated that SV-mediated responses were, in part, modulated by specific alterations in phytohormone levels; especially salicylic acid (SA). Notably, several touch regulated genes were also up-regulated by SV treatment suggesting a possible molecular crosstalk among the two mechanical stimuli, sound and touch. Overall, these results provide a molecular basis to SV triggered global transcriptomic, proteomic and hormonal changes in plant
Tomato ( Lycopersicon esculentum Mill.) accessions were tested for hypersensitivity and rated for resistance following field inoculation with tomato race 3 (T3) of the bacterial spot pathogen Xanthomonas campestris pv. vesicatoria (Doidge) Dye (Xcv) in 1992 and 1993. Hawaii 7981, PI 126932, PI 128216, and selections of the latter two expressed hypersensitivity. Hawaii 7981, only tested in the field in 1993, was nearly symptomless and developed significantly less disease than any other accession. PI 128216 had a level of disease similar to susceptible `Solar Set' when tested in 1993. However, a selection from it (PI 126218-S) was significantly more resistant than `Solar Set' in both years. Although PI 126932 had a level of disease similar to `Solar Set' in both years, a selection from it (PI 126932-1-2) was significantly more resistant than `Solar Set' in 1993. Other accessions without hypersensitive responses but more resistant than `Solar Set' for two seasons were PI 114490, PI 126428, PI 340905-S, and PI 155372. Hawaii 7975 was significantly more resistant than `Solar Set' in the one season it was tested.
Environmental factors greatly influence the growth, development, and even genetic characteristics of plants. The mechanisms by which sound influences plant growth, however, remain obscure. Previously, our group reported that several genes were differentially regulated by specific frequenciesof sound treatmentusing a sound-treated subtractive library. In this study, we used a proteomic approach to investigate plant responses to sound waves in Arabidopsis. The plants were exposed to 250-Hz or 500-Hz sound waves, and total proteins were extracted from leaves 8 h and 24 h after treatment. Proteins extracted from leaves were subjected to 2-DE analysis. Thirty-eight spots were found to be differentially regulated in response to sound waves and were identified using MALDI-TOF MS and MALDI-TOF/TOF MS. The functions of the identified proteins were classified into photosynthesis, stress and defense, nitrogen metabolism, and carbohydrate metabolism. To the best of our knowledge, this is the first report on the analysis of protein changes in response to sound waves in Arabidopsis leaves. These findings provide a better understanding of the molecular basis of responses to sound waves in Arabidopsis.
Introduction to Audio Analysis serves as a standalone introduction to audio analysis, providing theoretical background to many state-of-the-art techniques. It covers the essential theory necessary to develop audio engineering applications, but also uses programming techniques, notably MATLAB®, to take a more applied approach to the topic. Basic theory and reproducible experiments are combined to demonstrate theoretical concepts from a practical point of view and provide a solid foundation in the field of audio analysis. Audio feature extraction, audio classification, audio segmentation, and music information retrieval are all addressed in detail, along with material on basic audio processing and frequency domain representations and filtering. Throughout the text, reproducible MATLAB® examples are accompanied by theoretical descriptions, illustrating how concepts and equations can be applied to the development of audio analysis systems and components. A blend of reproducible MATLAB® code and essential theory provides enable the reader to delve into the world of audio signals and develop real-world audio applications in various domains.
Examines aspects of the defensive value of both evasive flight and sound production. Defensive behavior in response to sound, light and touch is considered in the context of moth predator-prey relationships. Using the discovery that moth hearing is involved in mate calling, the review then emphasizes that calling moths must be able to generate sounds with unique characteristics and that receiving moths must have a diversity of hearing abilities to recognize mates and distinguish them from hunting bats. The possibility that techniques interfering with the sexual communication of stored product moths may be effective in pest detection and control is discussed. -from Author
Floral scent constitutes an ancient and important channel of communication between flowering plants, their pollinators, and enemies. Fragrance is a highly complex component of floral phenotype, with dynamic patterns of emission and chemical composition. The information content of specific volatile compounds is highly context dependent, and scent can function in direct and indirect ways from landscape to intrafloral scales. Floral scent promotes specialization in plant–pollinator relationships through private channels of unusual compounds, unique ratios of more widespread compounds, or through multicomponent floral filters. Floral scent also promotes outcrossing and reproductive isolation through floral constancy, via appetitive conditioning and discrimination on the basis of diverse mechanisms, including pheromone mimicry, odor intensity, complexity, composition, and synergy with visual stimuli. Finally, floral scent is a sexual signal and should be subject to the same selective pressures and modes of sig...
We investigated the diets of insectivorous bats (Chiroptera: Vespertilionidae) in forests with high densities of western spruce budworm (Choristoneura occidentalis, Lepidoptera: Tortricidae), in southern interior British Columbia, Canada. Caterpillars as potential prey were more common and widespread than previously reported. Caterpillar consumption by bats was more frequent where C. occidentalis larvae were more abundant, suggesting that the caterpillars being eaten were C. occidentalis. The frequency of caterpillar consumption was similar for Myotis evotis, which gleans prey from vegetation, and for other bat species that forage primarily by aerial-hawking. We suggest that caterpillars hanging by silk threads were captured by bats that foraged aerially.
The development, body weight, survivorship, and reproduction of the cotton bollworm, Helicoverpa armigera (Hübner), were evaluated in the laboratory at 27°C and photoperiod L:D = 14:10 on six host plants: cotton (Gossypium hirsutum L.), corn (Zea mays L.), tomato (Lycopersicon esculentum Mill), hot pepper (Capsicun frutescens L.), tobacco (Nicotiana tobacum L.), and common bean (Phaseolus vulgaris L.). Cotton bollworm larvae successfully survived on all six host plants, although mortality was very high on hot pepper and tomato. The developmental time of immature stages ranged from 26.6 d on corn to 35.1 d on tomato. Body weight of young fourth instar larvae ranged from 22.8 mg on corn to 5.9 mg on tobacco, while body weight of young last instar larvae and pupae ranged from 176.7 mg on cotton to 132.5 mg on tomato, and 285.2 mg on corn to 167.1 mg on tomato, respectively. Immature survival from egg to pupa varied from 33.1% on cotton to 1.7% on hot pepper. The average number of eggs oviposited by adults reared on cotton, corn, common bean, tomato, hot pepper, and tobacco were 708.4, 784.8, 778.1, 559.1, 562.5, and 314.3, respectively. The net reproductive rate of this species, measured from egg to egg, varied from 117.6 on cotton to 5.1 on hot pepper. We conclude that H. armigera can complete their life cycle on all six host plants, although tomato and hot pepper were relatively unsuitable.
We identified a set of sound-responsive genes in plants using a sound-treated subtractive library and demonstrated sound regulation
through mRNA expression analyses. Under both light and dark conditions, sound up-regulated expression of rbcS and ald. These are also light-responsive genes and these results suggest that sound could represent an alternative to light as a
gene regulator. Ald mRNA expression increased significantly with treatment at 125 and 250Hz, whereas levels decreased significantly with treatment
at 50Hz, indicating a frequency-specific response. To investigate whether the ald promoter responds to sound, we generated transgenic rice plants harboring a chimeric gene comprising a fusion of the ald promoter and GUS reporter. In three independent transgenic lines treated with 50 or 250Hz for 4h, GUS mRNA expression was up-regulated at 250Hz, but down-regulated at 50Hz. Thus, the sound-responsive mRNA expression pattern
observed for the ald promoter correlated closely with that of ald, suggesting that the 1,506bp ald promoter is sound-responsive. Therefore, we propose that in transgenic plants, specific frequencies of sound treatment could
be used to regulate the expression of any gene fused to the ald promoter.
An automatic frog sound identification system is developed in this work to provide the public to easily consult online. The sound samples are first properly segmented into syllables. Then three features, spectral centroid, signal bandwidth and threshold-crossing rate, are extracted to serve as the parameters for the frog sound classification. Two well-known classifiers, kNN and SVM, are adopted to recognize the frog species based on the three extracted features. The experimental results show that the average classification accuracy rate can be up to 89.05% and 90.30% for kNN and SVM classifiers, respectively. The effectiveness of the proposed on-line recognition system is thus verified.
Plants and carnivorous arthropods can interact mutualistically. A recent discovery is that such mutualisms can be mediated by volatile compounds — produced by plants in response to herbivore damage — that attract carnivores. However, after emission of these attractants, the plant has no control over their use. Thus, exploitation of the information may occur, to the detriment of the plant, leading to costs in addition to benefits. Although all plants studied to date become attractive to carnivorous arthropods after damage by herbivores, they do so in different ways and it is important to understand why this is so.
Population increase and the improvement of living standards brought about by development will result in a sharp increase in food demand during the next decades. Most of this increase will be met by the products of irrigated agriculture. At the same time, the water input per unit irrigated area will have to be reduced in response to water scarcity and environmental concerns. Water productivity is projected to increase through gains in crop yield and reductions in irrigation water. In order to meet these projections, irrigation systems will have to be modernized and optimised. Water productivity can be defined in a number of ways, although it always represents the output of a given activity (in economic terms, if possible) divided by some expression of water input. Five expressions for this indicator were identified, using different approaches to water input. A hydrological analysis of water productivity poses a number of questions on the choice of the water input expression. In fact, when adopting a basin-wide perspective, irrigation return flows often can not be considered as net water losses. A number of irrigation modernization and optimization measures are discussed in the paper. Particular attention was paid to the improvement of irrigation management, which shows much better economic return than the improvement of the irrigation structures. The hydrological effects of these improvements may be deceiving, since they will be accompanied by larger crop evapotranspiration and even increased cropping intensity. As a consequence, less water will be available for alternative uses.
What a plant knows: A field guide to the senses of your garden-and beyond
- D Chamovitz
Chamovitz, D. (2012). What a plant knows: A field guide to the senses of your garden-and
beyond. New York, Scientific American/Farrar, Straus and Giroux.
{PLP} and {RASTA}(and {MFCC}, and inversion) in {M} atlab
- D P Ellis
Ellis, D. P. (2005). "{PLP} and {RASTA}(and {MFCC}, and inversion) in {M} atlab."
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Green symphonies: a call for studies on acoustic communication in plants
- M Gagliano
Gagliano, M. (2012). "Green symphonies: a call for studies on acoustic communication in
plants." Behavioral Ecology: ars206.
How Some Insects Detect and Avoid Being Eaten by Bats: Tactics and Countertactics of Prey and Predator Evolutionarily speaking, insects have responded to selective pressure from bats with new evasive mechanisms, and these very responses in turn put pressure on bats to "improve" their tactics
- L A Miller
- A Surlykke
Miller, L. A. and A. Surlykke (2001). "How Some Insects Detect and Avoid Being Eaten by
Bats: Tactics and Countertactics of Prey and Predator Evolutionarily speaking, insects have
responded to selective pressure from bats with new evasive mechanisms, and these very
responses in turn put pressure on bats to "improve" their tactics." BioScience 51(7): 570-581.
Scatnet: a MATLAB toolbox for scattering networks
- L Sifre
- M Kapoko
- E Oyallon
- V Lostanlen
Sifre, L., M. Kapoko, E. Oyallon and V. Lostanlen (2013). "Scatnet: a MATLAB toolbox for
scattering networks."