Detection of Different Hosts From a Distance Alters the Behaviour and Bioelectrical Activity of Cuscuta racemosa

Abstract

In our study, we investigated some physiological and ecological aspects of the life of Cuscuta racemosa Mart. (Convolvulaceae) plants with the hypothesis that they recognise different hosts at a distance from them, and they change their survival strategy depending on what they detect. We also hypothesised that, as an attempt of prolonging their survival through photosynthesis, the synthesis of chlorophylls (a phenomenon not completely explained in these parasitic plants) would be increased if the plants don’t detect a host. We quantified the pigments related to photosynthesis in different treatments and employed techniques such as electrophysiological time series recording, analyses of the complexity of the obtained signals, and machine learning classification to test our hypotheses. The results demonstrate that the absence of a host increases the amounts of chlorophyll a, chlorophyll b, and β-carotene in these plants, and the content varied depending on the host presented. Besides, the electrical signalling of dodders changes according to the species of host perceived in patterns detectable by machine learning techniques, suggesting that they recognise from a distance different host species. Our results indicate that electrical signalling might underpin important processes such as foraging in plants. Finally, we found evidence for a likely process of attention in the dodders toward the host plants. This is probably to be the first empirical evidence for attention in plants and has important implications on plant cognition studies.

Fruit Herbivory Alters Plant Electrome: Evidence for Fruit-Shoot Long-Distance Electrical Signaling in Tomato Plants

“…For the generation of the features to feed machine learning (ML) algorithms, the Fast Fourier Transform (FFT), Spectral Power Density (PSD), Wavelets, and Approximate Entropy (ApEn) were calculated for each of the samples (Saraiva et al, 2017;Parise et al, 2021). For FFT, PSD, and Wavelets we calculate the average, the maximum value, the minimum value, the variance, skewness, and kurtosis.…”

“…For FFT, PSD, and Wavelets we calculate the average, the maximum value, the minimum value, the variance, skewness, and kurtosis. Moreover, in order to decrease the computational cost speeding the analysis, we decided to reduce these features by calculating a Principal Component Analysis (PCA) in the descriptive analysis calculated for FFT, PSD, and Wavelets (Parise et al, 2021). Thus, we obtained the first three PCA components (PCA1, PCA2, and PCA3).…”

“…To test our hypothesis, the groups GB × GA, RB × RA, RB × GB, and RA × GA were classified using the methods described above. The methodology used here has been previously described by Parise et al (2021). All the algorithms were running in Python.…”

“…Thus, plant electrome correspond to the plants' bioelectrical activity measured as micro-Voltage changes in stimulated or non-stimulated tissues (Saraiva et al, 2017;Toledo et al, 2019). Recently, plant electrome analysis has been shown as an efficient tool allowing diagnose of different plant stresses (both abiotic and biotic) since the electrome dynamic is sensitive to a plethora of stimuli, exhibiting specific pattern responses recognizable by standard time series analyzes techniques and, specially, by machine learning methods for data classification (Pereira et al, 2018;Simmi et al, 2020;Parise et al, 2021).…”

Influence of Local Burning on Difference Reflectance Indices Based on 400–700 nm Wavelengths in Leaves of Pea Seedlings

“…It can be expected that monitoring of electrical activity and ES-induced physiological changes is a potential tool for revealing the actions of stressors on plants. Investigations of plant electrical activity show that (i) the total electrical activity of plants (“electrome”) can be strongly dependent on abiotic and biotic factors [ 53 , 54 , 55 , 56 , 57 ], and (ii) analysis of the electrical activity can be used for the classification of stressors that act on plants [ 58 , 59 , 60 , 61 , 62 ]. However, direct measurements of electrical activity cannot be used for the remote sensing of ES-induced systemic responses because electrodes would need to be connected to the plant.…”