This chapter aims to explore and describe the physiological aspects of oscillating growth patterns in rapidly elongating plant organs, such as roots, hypocotyls, shoots, branches and flower stalks. After a brief description of the phenomena, the theories and models proposed to explain circumnutation are reported, focusing largely on the internal oscillator model and the gravitropic overshoot model. The former is derived from the intuition of Charles Darwin, the first to suggest that circumnutatory movements are mediated by an endogenous oscillator, i.e. the driving and regulating apparatus responsible for circumnutation is internal. By contrast, the latter theory proposes a gravity-dependent model to account for circumnutations, essentially consistent with the Cholodny-Went theory, thus interpreting oscillations as being a continuous series of over-compensatory responses of the plant to the changing orientation of its gravisensory apparatus relative to the Earth’s gravity vector. A revised two-oscillator model is also reported, which is based on a combination of the above-mentioned two models. In this combined model, circumnutational movement involves a gravitropic reaction acting as an externally driven feedback oscillator, together with an endogenous or intrinsic oscillator which sends a rhythmic signal to the feedback system. The role of hormones will be finally discussed, with particular attention to the effect of ethylene in controlling nutation. 2.1 Overview of Nutations: Definition and Kinematic More than a century ago, plant physiologists were already aware that rapidly elongating plant organs—roots, hypocotyls, shoots, branches, flower stalks—rarely grow in only one direction. Mean growth direction may be maintained for long S. Mugnai E. Azzarello E. Masi C. Pandolfi S. Mancuso (&) LINV–International Lab for Plant Neurobiology, Dipartimento di Scienze delle Produzioni Agroalimentari e dell’Ambiente, University of Florence, viale delle idee 30, 50019 Sesto Fiorentino, FI, Italy e-mail: stefano.mancuso@unifi.it © Springer International Publishing Switzerland 2015 S. Mancuso and S. Shabala (eds.), Rhythms in Plants, DOI 10.1007/978-3-319-20517-5_2 19 intervals, but the organ’s instantaneous growth direction usually oscillates slowly around that mean. From a distal viewpoint, the plant organ tip, or an elongating cylindrical plant organ, describes an ellipse, a circleor pendulum-like movements about the plumb line, which can alternate between a clockwise and counterclockwise direction. The axes of the ellipse can vary: at one extreme, the ellipse approximates a line and, at the other, a circle. As the organ grows, its tip advances and (in three dimensions) traces an irregular helix (Migliaccio et al. 2009). This oscillating growth pattern was well known to nineteenth-century plant scientists as ‘revolving nutation’ until the Darwins (father and son, Darwin and Darwin 1880) introduced the term ‘circumnutation’, used to this day (Fig. 2.1). Thus, circumnutational oscillations are manifestations of the radially asymmetric growth rate typical of elongating plant organs (Fig. 2.2). These do not include tropic processes occurring in response to a directional cue, such as gravity or light, or nastic movements, which occur in response to external factors but are independent of the position, i.e. the closing of leaves at night. These various forms of movements usually occur together; for example, it has been shown that gravity amplifies the circumnutatory response in Arabidopsis thaliana (Johnsson et al. 2009). Darwin’s (1875) close observation of the behaviour of ‘climbing plants’, which tendrils appeared to ‘search’ for some upright support, led him to widen his investigation to a large variety of species in which, however, he found no exception to his generalization that circumnutations must be a universal kind of plant movement (Darwin and Darwin 1880). Indeed, today we know that the widespread occurrence of circumnutations is even greater than Darwin had ever suspected. It not only occurs in dicots and monocots (Brown 1993) but also is well established for gymnosperms, fungi (Basidiomycetes), bryophytes (Ceratodon purpureus, Kern et al. 2005) and algae (Spirogyra, Kim et al. 2005). Even some colonial forms of bacteria (Acetobacter xylinum) exhibit oscillating growth patterns which kinematically resemble higher plant circumnutations (Hoiczyk 2000). Although circumnutatory movements are of obvious use to twining plants seeking mechanical support, in other cases the movements appear to have no useful purpose. The amplitude, period and shape of circumnutation depend on the plant Fig. 2.1 Some sketches illustrating Darwin’s close observation of the behaviour of ‘climbing plants’ (extracted from Darwin 1875) 20 S. Mugnai et al.

The morpho-chemical and aromatic characteristics of four sweet cherry cultivated varieties (Prunus avium L.) grown in the area of Lari (Pisa, Central Italy) were evaluated with the aim to investigate their properties, mainly concerning volatile organic compounds (VOCs). Of these, three cultivars (‘Di Giardino’, ‘Di Nello’, and ‘Marchiana’) represent ancient sweet cherries recovered through a private cultivation program (belonging to the group of the so-called ‘Ciliegia di Lari’); their evaluation was compared with the commercial cultivar Ferrovia, highly-prized variety marketed in Italy and abroad. Morpho-chemical analyses highlighted statistical differences among the cultivars under study, mainly on total soluble solids (TSS) and tritatable acidity (TA). Aroma investigation was performed with PTR-ToF-MS (proton transfer reaction - time of flight - mass spectrometer) approach, employed here for the first time in cherry fruits. About 50 VOCs were detected; among them, those belonging to the chemical classes of aldehydes and alcohols were the most represented although with different intensities between samples. Tentative identification of some key VOCs for cherry fruit was also performed and preliminary conclusions on the characterization of ancient and wide spread Italian cultivars were given.

Gas chromatography-mass spectrometry (GC-MS) is one of the most common techniques used to measure and to characterize volatile organic compounds (VOCs). At the same time, the proton transfer reaction time-of-flight mass spectrometry (PTR-ToF-MS) represents a recent innovative tool that allows the on-line monitoring of VOCs providing the whole mass spectra with short response time, high mass resolution and without sample preparation. We reported as major constituents of headspace in spearmint dried leaves the monoterpenes carvone, followed by dihydrocarvone, limonene and 1,8-cineole (eucalyptol) although other monoterpenes such as a-pinene, 3-carene, terpineol and neodihydrocarveol, alcohols (3-octanol, 1-octen-3-ol and 3-methyl-1-butanol), esters and ketones (3-octanone) were detected in low concentrations. In this study, the analytical GC-MS and PTR-ToF-MS techniques allowed to characterize the entire volatile profile of the sample bypassing the limitations of each tool.

To date, the chemical composition and the amount and diversity of volatile organic compounds (VOCs) released by different woody plants samples have been measured and characterized through one of the most common techniques, the gas chromatography–mass spectrometry. However, this technique is very time-consuming and requires sample preparation. By contrast, the Proton-Transfer-Reaction Time-of-Flight Mass spectrometry (PTR-ToF-MS) represents an innovative tool able to provide the whole mass spectra of VOCs with short response time, high mass resolution and without sample preparation. This technique is fast, non-invasive, highly sensitive with a rapid detection system and a very low mass fragmentation of the volatile molecules. The goal of this study was to characterize the VOCs profile of different wood sample cores using a PTR-ToF-MS tool and thereafter to assess whether VOC emissions were specific for some groups of trees. VOCs released from core wood samples belonging to 14 different species were analyzed and subsequently, using an advanced multivariate class-modeling approach, the groups (softwood and hardwood) and the different tree species were discriminated. PTR-ToF-MS was able to detect VOCs from wood and to discriminate between hardwood and softwood and among different species. The great potential and the rapidity of this analysis method allow the PTR-ToF-MS to become a commercial standard tool for monitoring VOCs emitted by wood.

Saffron samples from Italy and Iran were analyzed for their content in aroma and bioactive compounds with different analytical techniques. HPLC was used for the identification and quantification of crocins, picrocrocin, safranal and flavonoids content, while the novel proton transfer reaction time-of-flight mass spectrometer was employed for the aroma compounds analysis. Italian saffron turned out to be richer in total crocins and safranal contents. Sample characterization was performed with an unsupervised statistical approach; tests involving different numbers of parameters deriving from the two analytical techniques were performed. The results achieved showed that the best samples classification was obtained by joining the information acquired from both techniques; following such an approach, a sharper separation between Iranian and Italian samples was achieved. Finally, among the variables that most contribute to the description of variability, isophorone, safranal and picrocrocin were identified to be the most significant.

The electrical activity signals in plants can provide useful information to monitor environmental conditions, such as atmospheric pollution. Nonetheless the study of the relationship between environmental stimuli and electrical responses of plants is still a critical step in developing technologies that use plants as organic sensing devices. In this paper an automatic method of analysis of plant electrical signals for ozone critical levels detection is proposed, based on the fundamentals of correlation theory. In order to classify the morphology characteristics of plant response to ozone exposure we used a segmentation of time series measurements of the electrical activity of plants before, during and after the stimulation. Then, we extracted the significant deviations from the baseline trend to detect and identify the response to a known stimulus, in terms of correlation coefficient. As a result, the proposed detection algorithm represents a novel monitoring method for detecting critical levels of ozone concentrations.

This paper describes an innovative monitoring technology that is used to detect ground-level ozone pollution and is based on the deployment of a network of wireless devices which are connected to a collection of plants and are used as biosensors. Such devices retrieve and transmit the electrical activity signals, which are generated within the plants, and use them to monitor environmental conditions. The distributed plants act as wireless sensors which communicate with a weather station, that equipped with meteorological sensors as well as data logging and both wireless and wired communication capabilities. A back end server collects and analyzes the real-time data from the station and delivers environmental and ozone pollution information to the users through a web portal. In order classify the level of ozone exposure, a correlation-based approach has been used. A pilot system has been implemented with a sensing infrastructure that is composed of four plants and started operating in November 2014. As the data collection volume increases, more accurate classification techniques can be adopted.

Abstract Trees can be successfully used in phytoremediation because of their ability to grow on nutrient-poor soil, deep root system, fast rate of growth, metal-resistance traits and economically viable secondary use. Thanks to these features, trees are able to stabilize, extract, degrade or volatilize soil contaminants. The paper offers a comprehensive review of the role of trees in the phytoremediation of soils contaminated by heavy metals or organic pollutants. Transgenic approaches to enhance the aforementioned processes, together with the use of chelating agents to improve the bioavailability of pollutants for plants uptake, are also reviewed and discussed.

Field experiments with Sangiovese vines were carried out in the Chianti Classico region over a period of two years to examine the effect of molybdenum (Mo) foliar sprays on nutrient composition of leaves, petioles and berries, leaf gas exchanges, must composition, total yield, bunch size and pruning weight. Two Mo foliar doses and time sprays (Mox1: one application in early flowering; Mox3: three applications in early flowering, early fruit set and veraison) were applied. Basal sample of petioles, leaves and berries collected at fruit set (except berries), veraison and harvest for mineral analyses showed not relevant interactions between Mo and the main macro and micronutrients. Leaf gas exchanges monitored after the applications, as well as SPAD units, showed a higher activity in the Mox3-treated vines. Increased vigour was also confirmed by the slightly higher total yield, bunch size and pruning weight, as well as the delay in fruit maturation (lower sugar and polyphenol contents at harvest). No relevant discrepancy between Mox1 and the control was found, except for higher soluble solid and yeast-assimilable nitrogen contents (YANC) in the treated vines. YANC was positively influenced also in the Mox3 vines, however with no significant differences towards the Mox1 treatment. The application of Mo as a useful tool to stimulate nitrogen metabolism, as well as indications about dose and time of Mo application, are discussed.

The study of electrical network systems, integrated with chemical signaling networks, is becoming a common trend in contemporary biology. Classical techniques are limited to the assessment of signals from doublets or triplets of cells at a fixed temporal bin width. At present, full characteristics of the electrical network distribution and dynamics in plant cells and tissues has not been established. Here, a 60-channels multielectrode array (MEA) is applied to study spatiotemporal characteristics of the electrical network activity of the root apex. Both intense spontaneous electrical activities and stimulation-elicited bursts of locally propagating electrical signals have been observed. Propagation of the spikes indicates the existence of excitable traveling waves in plants, similar to those observed in non-nerve electrogenic tissues of animals. Obtained data reveal synchronous electric activities of root cells emerging in a specific root apex region. The dynamic electrochemical activity of root apex cells is proposed to continuously integrate internal and external signaling for developmental adaptations in a changing environment.

The potential application of phyllometric and fractal parameters for the objective quantitative description of leaf morphology, combined with the use of Back Propagation Neural Network (BPNN) for data modelling, was evaluated to characterize and identify 25 Camellia japonica L. accessions from an Italian historical collection. Results show that the construction of a BPNN based on phyllometric and fractal analysis could be effectively and successfully used to discriminate Camellia japonica genotypes using simple dedicated instruments, such as a personal computer and an easily available optical scanner.

Lethal low temperatures were examined in two species of Grevillea and four species of Callistemon, two taxa originating from Australia. The demand in Europe and America for Australian plants is increasing both as cut flowers and as potted or landscape plants, but there is little information available on the cold hardiness of these species. LT50 (lethal temperature at which 50% of damage occurs) was determined by measuring electrical conductivity (electrolyte leakage), impedance spectroscopy and fractal spectrum of leaf colour. All the experiments were conducted on non-acclimated and cold-acclimated plants. LT50 calculated on non-acclimated plants were about 2-3degreesC higher than in acclimated plants, except for G. olivacea. In every case, the LT50 estimated by the three methods were very similar and ranged from -4.6degreesC for G. olivacea, the species most sensitive to freezing, to about -9.5degreesC for C. salignus, the most resistant to freezing among the species tested.

Microsatellite (MS) VVMD21 (Bowers et al. 1999) was taken as a model to explore the molecular basis of polymorphism in a panel of 6 grapevine accessions (Vitis vinifera L.), consisting of Sangiovese and Cabernet Sauvignon and 4F(1) plants derived from crossing both varieties. The 12 alleles of both parents and the progeny were cloned and sequenced. The microsatellite repeat (AG)(n>6) was found in each sequence, together with a poly-T rich region that showed irregularity. Furthermore, single nucleotide deletion or exchange (point mutations) were found in the microsatellite flanking regions.

Amplified fragment length polymorphism (AFLP) analysis was used to evaluate the genetic biodiversity and variability present in some Italian varieties of cultivated olive. A group of 12 genotypes belonging to three varieties was screened using six different AFLP primer combinations. A total of 274 loci (59.8% of which were polymorphic) were investigated. The number of polymorphic loci detected by single primer combination for each variety was calculated. AFLP banding patterns were transformed into binary data of presence–absence and matrices were processed with NTSYS-pc and Arlequin software programmes. Similarity relationships were described graphically by a dendrogram which clustered accessions of the same cultivar. Analysis of molecular variance (AMOVA) revealed greater variation among cultivars than within them, but significant intra-cultivar differentiation was found. For the varieties analysed, the data revealed significant genetic diversity in the cultivated olive tree, despite the fact that they come from a limited geographical area. The DNA fingerprinting technique used was confirmed to be a reproducible and sensitive tool for the study of population genetics of olive trees. The high genomic polymorphism observed suggests a more complex genetic population structure than the conventional variety or cultivar level. The present study confirms the importance of considering the degree of genetic relatedness and variability within populations during clone and variety selection programmes.

SUMMARY Spectrographic analyses of the vocal repertoire of viverrids are scarce, and lacking altogether for the banded mongoose, Mungos mungo (Gmelin), a species whose acoustic communication is rich and which displays an interesting social behaviour. In this study we give a spectrographic and quantitative description, by means of a Kay Elemetrics 7800 Sonagraph, of the more frequent vocalizations in a captive group of banded mongoose, with a description of the related behaviours. A series of playback experiments of the recorded vocalizations allowed us to study the responses elicited by the different signals and the relevance of the context in which the call is given. We report here on (1) contact call type A and B; (2) alarm call; (3) distress call; (4) young call; (5) rally call, type A and B; (6) threat call; (7) aggression call; (8) «grooming» call; (9) «water» call. The importance of the physical variables of the environment in which the banded mongoose lives is also discussed in relation to sound transmission.