Confronting Vegetal

Otherness

Špela Petrič

Slovenia

HOW DO HUMANS RELATE TO PLANTS?

UTILITYagriculture/food

medicine

materials

fuel

nature conservation

(“lungs of planet”, habitat

conservation)

EMPATHY (?)nature conservation

(pity)

antropomorphism (plant neurobiology)

gardening (aesthetic pleasure)

WHERE LIES AT THE ROOT OF TOTAL OBJECTIFICATION?

WESTERN PHILOSOPHICAL TRADITION UNDERSTANDS PLANTS AS

LACKING

autonomy

individualization

self-identity

originality

and essentiality

TIME-SCALE AND ASSIMILATION

SEDENTARY

PLURIPOTENCY AND VEGETATIVE REPRODUCTION (“body without organs”)

PLANT NEUROBIOLOGY

GROWTH IS THE MAIN MODALITY OF MOVEMENT

the crescograph, Sir Jagadis Chunder Bose, 1919

PLANT COMMUNITES FORM A CONTINUUM

THEY ALSO FORM (NATURAL) GRAFTS

SEXUAL REPRODUCTION

PUTTING THEORY INTO PRACTICE: WHAT OF THE ‘NEW’ SUBJECTIVITY?

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BRASSINOLIDE ESTRADIOL

pick up vibrations from its environment. Noteworthy is thefact that in dense environments, such as water and soil, thecoupling of such structures is more efficient than in air,obviating the need for complex mechanisms providingimpedance matching.

The existing evidence: plants detect and react todifferent soundsThe proximate and ultimate mechanisms used by animalsto sense their environment and communicate with eachother have long been the subject of intense scientific inter-est. In plants, sensory and communication research exists,yet is not as advanced and recognised. Existing evidence isenticing and calls for further investigation on the proxi-mate, mechanistic question of how plants acquire andrespond to acoustic information and further, demandsthe examination of ultimate, functional questions as to

why such information bears adaptive value. In plants, bothemission and detection of sound may be adaptive, aspreliminary investigations of both processes (in particularreception) suggest (Figure 1a and b). Whilst receptormechanisms in plants are still to be identified, there isearly, yet tantalising, evidence about plants’ ability ofdetecting vibrations and exhibiting a frequency-selectivesensitivity that generate behavioural modifications(Figure 1b and c). At both proximate and ultimate levels,sound production in plants is only rarely documentedand still poorly understood. We are growing increasinglydoubtful of the idea that all acoustic emissions by plantsare the mere result of the abrupt release of tension in thewater-transport system [5]. We anticipate that plantacoustic radiation is not simply an incidental mechanicalby-product attributable to cavitation alone; recent evi-dence illustrates that the young roots of corn generate

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TRENDS in Plant Science

Figure 1. Root bioacoustics. Behavioural response to incident sound, frequency selective response and acoustic emissions by roots in Zea mays. (a) Behavioural responseof young roots to a continuous 220 Hz sound coming from left field (white arrow). Root tip clearly bend towards sound source. (b) Phonotropic assay assessing the responseof young roots to water-borne vibrations (ca. 10 mm/s sound velocity level) at different frequencies. Best response is measured between 200 and 300 Hz. (c) Acousticemissions of young roots measured optically with microscanning laser Doppler vibrometer. Vibrations were measured at the elongation zone of root tip (red star in panel a).Roots generate structured acoustic emissions in the form of loud (ca. 2 cm/s) and frequent clicks, which can also be measured at some distance into the fluid medium. (M.Pagano, PhD thesis, University of Firenze, in press).

Spotlight Trends in Plant Science xxx xxxx, Vol. xxx, No. x

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