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The Not-So-Secret Life of : In which the historical and experimental myths about emotional communication between animal and vegetable are put to rest Author(s): Arthur W. Galston and Clifford L. Slayman Reviewed work(s): Source: American Scientist, Vol. 67, No. 3 (May-June 1979), pp. 337-344 Published by: Sigma Xi, The Scientific Research Society Stable URL: http://www.jstor.org/stable/27849226 . Accessed: 06/01/2013 17:37

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This content downloaded on Sun, 6 Jan 2013 17:37:06 PM All use subject to JSTOR Terms and Conditions Arthur W. Galston The Not-So-Secret Life of Plants Clifford L. Slayman In which the historical and experimental myths about emotional communication between animal and vegetable are put to rest

In the troubled years of the late 1960s, Onto this scene, in 1973, burst a book, several book-club selections, made a wave of antiintellectualism swept The Secret Life ofPlants (1),which the book vastly popular. (Perhaps the success was through the United States, accom claimed formembers of the vegetable ultimate measure of its in panied by an antiscientism that still kingdom many mental capabilities the spate of cartoons it inspired the as to in persists in some measure. Some previously regarded limited New Yorker and the syndicated some public antipathy to the methods and gods, human beings, and higher strip Doonesbury.) Had the majority to products of science was understand animals. These included the ability of readers taken it in with the joy of able, because certain of the techno perceive and respond to human escape to fantasy that may be ac to a no logical applications of science had thoughts and emotions and distant corded good novel, damage failed to better man's condition and traumatic events, such as the injury would have been done. This was not indeed had perceptibly diminished or death of other organisms. Quoting what happened, however. The book ran the pleasure and grace of modern from uncontrolled experiments, catalyzed numerous claims of bizarre existence. Critics were quick to dom observations, and anecdotal re observations from "one-man" labo equate science with antihumanism, ports, the book fashioned a case for ratories; it led to a widespread lay and to call for reliance on alternate the ability of plants to count, to criticism of professional scientists for ways of arriving at an understanding communicate with each other, and to not taking account of the purported of the universe about us. This appeal receive signals from life forms else facts of existence; and it per were found receptive ears in a world wor where in the universe. Plants meated student arguments in uni ried about pollution, overpopulation, alleged to respond favorably to cer versity biology classes. unemployment, growing crime, tain forms of music (e.g. preferring and?perhaps most important?a Bach to rock); to display conditioned In response to this uncritical acclaim, nasty and persistent war in which reflexes; to predict storms, earth though perhaps after undue delay, even technology played a major role. quakes, and the like; and to several scientific reviews of the book transmute elements (in order to avoid appeared (2, 3, 4), and the American mineral starvation). Among the many Society of Plant Physiologists bizarre claims, the one that strains (ASPP) and the American Associa credibility the most is the assertion tion for the Advancement of Science that we can rid plants of insect pests, (AAAS) scheduled sessions to evalu or fertilize the soil inwhich they grow, ate some of the claims made. One of Arthur W. Galston is the Eaton Professor of simply by exposing photographs of the most tangible and also crucial at Yale. He has been president of the the growing plants to particular portions of Tompkins and Bird's Botanical the American Society of America, frequencies of electromagnetic ra book is a discussion of electrophysi Society of Plant Physiologists, and the Society diation. Throughout, the book in ological experiments on plants con for Social Responsibility in Science. His re mixed accounts of ducted Cleve search concerns the action of light and hor discriminately by polygraph expert mones in plant development. A former Sigma generally accepted phenomena with Backster (5). In June 1974, at the Phi Beta Xi National Lecturer and Kappa unsubstantiated and incredible re ASPP meeting, Dr. B. G. Pickard of Visiting Scholar, he was the first American ports. Washington University organized a scientist to visit the of People's Republic at which China, in 1971. Clifford L. Slay man is an As symposium independent of the Peter were sociate Professor in the Department of Phys The authors book, and well-controlled experiments iology at the Yale School ofMedicine, where Tompkins and Christopher Bird, are, described (6) that had attempted? he has since 1967. With his Caro taught wife without question, adept popularizers but failed?to reproduce Backster's lyn, a geneticist, he has probed the chemical of scientific and technological results. Following this, Galston or and physical mechanisms leading to the gen and are with a session at the AAAS meet eration of electrical potentials in living cells. certainly acquainted ganized some re This article will appear as a chapter in Science aspects of modern plant ing in January 1975, which brought and the Paranormal, ed. G. O. Abell and B. search. Moreover, the issuance of the Backster face to face with some of his to be later this year by Singer, published book was shrewdly timed to take ad critics, including the two scientists, E. Charles Scribner's Sons. Address: Arthur W. vantage of the malaise about L. and J. M. Kmetz, who Galston, Department of Biology, 904 Kline general Gasteiger noted above. These to to Biology Tower, Yale University, New Haven, science facts, plus had gone great lengths repro CT 06520. a lavish advertising campaign and duce Backster's experimental condi

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This content downloaded on Sun, 6 Jan 2013 17:37:06 PM All use subject to JSTOR Terms and Conditions tions. Subsequent to this meeting, a swelling, etc.) of plant materials. With observed that differences of electric number of national television and these instruments he was able to potential measured along plant stems radio confrontations were organized, demonstrate withdrawal movements and (we shall return to the but these eventually ceased when of plant tissues from sites of injury, methodology of these measurements scientist participants realized that the complementing for "ordinary" plants below) were acutely sensitive to hoped-for dialogue was replaced by the much more conspicuous move metabolic poisons (15), while Lun unbending restatements of previous ments displayed by various insecti degaardh found that the same dif positions. vorous and photoperiodically sensi ferences of potential, along with the tive plants (e.g. Venus's-flytrap, rate of oxygen consumption by the Since it is on the interpretation of sundew, and Mimosa). He also de tissues, were closely tied to cellular electrophysiological data that Back scribed events in aquatic higher uptake of anions from the medium ster's case and much of the Tomp plants that resembled action poten (16). The inference was drawn that kins-Bird case rests, the purpose of tials (8), while other investigators, metabolism could "pump" charges, the present essay will be to reexamine following the lead of Burdon-San both ionic and electronic, through the the published experiments and to derson in 1873 (9), demonstrated ac cell surface membranes, thus creating relate them?from the point of view tion potentials (and in some cases an electric-potential difference across of both philosophy and technical simple integration) in insectivorous the membranes. This idea came to procedures?to the body of controlled plants, mechanosensitive plants, and fruition in the late 1960s, after P. and reproducible electrophysiological giant algae (10,11). Since Bose's time, Mitchell (17) realized that it could experiments that have been carried events similar to action potentials account for numerous experimental out on plants. have been described in a wide variety data on the movement of ions and of plant cells (12) and even in fungi trapping of energy by mitochondria Electrophysiology of (13). Bose quite properly pointed out and chloroplasts, the subcellular or similarities between the for plants functional ganelles responsible conserving electrical/mechanical responsiveness, energy from the oxidation of sugar It is commonplace knowledge, or irritability, of plant and animal and from the capture of light, re reaching back to Galvani (7) in the tissues, but his data do not in any way spectively. eighteenth century, that variations of support Tompkins and Bird's con electric potential are an essential clusion that plants perceive their en The primary charge separation giving feature in the function of specialized vironment in the manner of human rise to bioelectric potentials takes animal cells and tissues, manifest beings and other higher animals. place across the bounding surface most conspicuously in the transient membranes of individual living cells, electric signals, called action poten While Bose's thought was very ad whence comes the familiar piece of nerves tials, found in and muscles vanced in some respects, itwas rather jargon "membrane potential.,, after stimulation. Judging from the primitive in others. His American Widespread verification of this fact lay response to the Tompkins-Bird contemporaries, chiefly the school of was delayed until the late 1940s and book, however, and from the queries W. J. V. Osterhout, were far closer to 1950s, following the development of of freshman biology students, a proper physical understanding of glass microcapillary electrodes that knowledge of related electrical phe electrical events in plants. Drawing on could be inserted into individual liv nomena in plant tissues has been re the emergent theory of electrolytic ing cells. Osterhout's work used a stricted almost entirely to profes solutions set forth by Nernst, Planck, macroversion of this insertion tech sional scientists. and other illustrious physical chem nique, taking advantage of giant algal ists of the late nineteenth and early cells, while the experiments of Bose, The impression left by the book, and twentieth centuries, Osterhout (11) Lund, Lundegaardh, and their other apparently accepted by a consider reasoned that differences of electric contemporaries (in both plant and able portion of its readers, is that the potential between the interior of animal electrophysiology) relied upon only important early work in plant (algal) cells and the external envi whole-tissue recording techniques. electrophysiology was that of the ronment must result from differential eminent Indian physicist J. C. Bose diffusion of ions (e.g. of sodium, po Typically, pairs of saline-bathed wick, and that that work was ignored for tassium, and chloride) through se wire, or capillary-suction electrodes forty to fifty years, until Backster's lective membranes at the cell surface. were used, one member of the pair was report published in 1968. We This was the firstmajor component of being placed at an "interesting" spot shall deal later on with the substance the modern theory of bioelectricity. on the tissue, and the other member of Backster's experiments, but we Osterhout even suggested that the at a distant?and presumedly "in need first to dispel this mistaken selectivity of cell surfaces might arise different"?spot. The most impor historical impression and to develop from the existence of carrier mole tant and familiar example of this some fundamental ideas in the mod cules residing within the surface, a technique is the recording of electro ern scientific view of "plant elec suggestion that presaged much of cardiograms via a skin electrode tricity." modern cell biochemistry (14). placed over the chest wall and an other electrode, for comparison, fas In retrospect, Bose certainly does The other major component of the tened to an arm or leg. The technique deserve great credit. With vast inge modern theory began to emerge in the is very much simpler than the intra nuity, he designed sensitive and ele 1930s, from experiments carried out cellular recording technique, but it is gant instruments to measure small by E. J. Lund at the University of also much more treacherous, since it changes in electric potential and Texas, by H. S. Burr at Yale, and by depends on many diverse features of small changes in shape (bending, H. Lundegaardh in Sweden. Lund the whole recording circuit: the

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This content downloaded on Sun, 6 Jan 2013 17:37:06 PM All use subject to JSTOR Terms and Conditions quality of the electrode-tissue con stalks can be polarized transversely, to the Central Intelligence Agency, tact, the size of the electrodes relative to 100 millivolts or more, by exposure where he developed the standard to the size of individual cells, the to light or gravitational fields. And polygraph examination methodology. on presence of "dead" space (cuticles, the polarization correlates with re From the C.I.A., he went to be a connective tissue), the constancy of distribution of the growth hormone, come director of polygraph institute potential near the indifferent elec auxin, and subsequent growth cur in Chicago, and in 1951 he founded trode, the relative magnitudes of vature (21). the Backster School of Lie Detection. electric resistance between cells as He claims to have served as a consul compared to around cells in the tis Electric currents accompanying tant to almost every government sue. Thus, whereas growth changes in single fertilized agency that has used the polygraph as to have numerous technical potentials vary only in the range of 10 eggs of marine algae, such Fucus and made to 300 millivolts, extracellular re and Pelvetia, have also been mea refinements, aimed at reducing the corded potentials range from a few sured, using ultrasensitive extracel number of inconclusive examinations. microvolts (as, for example, in elec lular electrodes (22). Early electric Within his field he iswell recognized, on troencephalograms) to hundreds of polarization of eggs, whether spon having served the Board of Direc volts (across certain fish electroplates, taneous or induced by external gra tors at the American Polygraph As 18). dients of light, temperature, etc., ac sociation and as chairman of the re curately defines the direction of search and scientific committee of the In both plant and animal electro growth and initial planes of division Academy for Scientific Interroga physiology, interpretation of data for the developing embryos. In this tion. from even the most careful and tech case -ion migration, rather on nically sophisticated measurements than hormone redistribution, is the When used human subjects, the re has often been vitiated by elementary chemical event most crucially linked polygraph records uncontrolled actions of the autonomie nervous biological mistakes; for example, cell to the electrical change (23). are damage during preparation of the system?chiefly sweating?which often associated with and other experiment can produce prolonged It should also be noted that various lying emotional disturbances. It this depolarization, with or without semi rhythmic "clock" functions manifest does are via what is called a periodic fluctuations. Typically, such in plant tissues associated with by measuring, Wheatstone a of damage response displays a rapid? changes in electric potential, which Bridge circuit, fall almost instantaneous?onset, but can readily be observed either with electrical resistance in the skin be tween two surface recovery can be delayed for periods of intracellular or extracellular elec independent elec tens of minutes to several hours. trodes. The best-known of these dis trodes (wire mesh or plate, in saline/ The is Owing to the natural impatience of a play roughly 24-hour (circadian) pe agar paste). phenomenon known as the reflex. scientist to "get on" with his work, riods, phase-locked to the normal psychogalvanic can this kind of artifact has permeated a day-night cycle, but they persist very considerable fraction of pub for long periods in the absence of light Backster's initial foray into plant or came almost lished experiments. stimulus, and can also be shifted physiology (5) evidently reset by pulsed light absorbed by a casually, as he wondered whether the surface resistance of Nevertheless, in careful hands, both specific pigment called phytochrome. plant be to human skin intracellular recording techniques As an example, diurnal opening might analogous varia and whole-tissue recording tech and closing in plants such as Sam resistance, and might reflect anea tions in the flow of niques can yield much important in (24) involve periodic depolar sap following routine It a rea formation, the whole-tissue tech ization and repolarization of different watering. seemed sonable and he attached a niques being particularly suitable groups of cells in the leafmotor organ. question, a common when scientific interest is focused on Although the precise causal rela polygraph to potted in his office. electrical gradients that extend long tionships have not been worked out houseplant, Dracaena, distances, over many cell diameters. for these systems, it is evident that Polygraph experience suggested that increased and water Growing regions of plants provide an both the cellular swelling and transpiration excellent terrain for such measure shrinking that produce the leaf flow through the leaf should decrease the transverse resistance of the leaf ments. Thus, the growing tip of the movements and the measured electrodes were attached to seedling leaf sheath of oat plants was changes of electric potential arise (the op foundby Lund (15) to be about 100 from periodic cellular uptake and posite leaf surfaces). millivolts negative to the base of the release of potassium chloride (25, As is often the case in new organ, and similar electric gradients 26). experi ments the have been observed along other plant by any electrophysiologist, initial records were rather organs, including roots, stems, and noisy. They The Backster report contained at least two unaccounted reproductive axes (19). Cleve Backster, whose experiments in for quasi-periodic variations, at about so 1 and 2 Furthermore, these longitudinal plant electrophysiology have been cycle/second cycles/minute, in the on a baseline drift that gradients can be altered by mechan handsomely reported Tomp superimposed if a ical distortion, and by changes in kins-Bird book, is a trained polygraph suggested, anything, progressive in increase of leaf resistance. There was temperature, light, and ambient salt (lie-detector) specialist, whose a concentration (15, 20). While nor troduction to the method came dur also segment (of the single record as an in that Backster that su mally no transverse electrical gradi ing service interrogation published) the slow rise ent exists across cylindrical plant or structor in the U.S. Army Counter perficially resembled occurs in gans, certain stems, roots, and leaf intelligence Corps; thence he traveled and-fall of resistance that

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This content downloaded on Sun, 6 Jan 2013 17:37:06 PM All use subject to JSTOR Terms and Conditions human polygraph records during Similar but undocumented experi laboratory. Sixth, he used a blind verifiedlying (Fig. 1). ments were subsequently carried out randomizer, along with controls of on other plant species, "frequently sterile brine (no shrimp), so the ex a At this point there took place totally serving to reinforce" Backster's hy perimental observer would not know unscientific discontinuity of logic. pothesis. No interpretation was given when or whether, during a particular Without investigating the recording of those experiments which failed to experiment, shrimp had actually been conditions to identify the sources of reinforce the hypothesis. The author killed.And seventh,he kept lightand unexpected noise and drift, Backster notes that the phenomenon "per temperature constant for all plants. jumped to the conclusion that be sisted when the plant leaf ... was cause in a the plant record resembled detached from the parent plant, and The analysis of data from seven ex ... single respect human records ob even when shredded and redis periments carried out in this manner tained during emotional reaction, the tributed between the electrode surr is as follows. All seven of the fixed must plant have been experiencing faces." In view of the known effects of resistor tracings were flat, giving no something like human emotion. This injury on electrical manifestations in indication of electronic disturbances a is classical semantic confusion of tissue, the latter claim is most re in the instruments. Of the twenty-one identity, roughly equivalent to argu markable. leaf records, two were discarded be ing that because the face of the full cause of failure in the pen recorders; moon displays dark patches resem Thereafter, Backster refined the three were discarded because of a must a bling human face, there be format of his experiments in several "gross overactivity"; and three were man in moon. real the ways. First, he devised a constant and discarded for "not displaying typical remote emotional stimulus in the fluidity."This lefta totalof thirteen to ex Backster thereupon decided form of scalding death of brine usable chart records. Each experi emotional plore further the possible shrimp (Artemia). Second, he se mental run was 2.5 minutes long and response of his plant by affronting it lected Philodendron cordatum as his was divided into 6 blocks of 25 sec in that evoke emotional ways strong recording species, its leaves being onds. During the first 10 seconds of reactions in human in beings?with optimally stiff, broad, and thick. each block a shrimp-killing could or threats of and death. He jury injury Third, he automated the experiments occur, but in only 13 blocks (desig reports finding that scalding a nearby and ran them in triplicate. Fourth, he nated stimulusblocks) out of the 78 leaf (with hot coffee!) was not suf connected a recorder to a 100,000 total did a killing actually take place. ficient to evoke a response on the ohm resistor, instead of a leaf, as a The remaining 65 blocks were desig polygraph, but that when he thought control against instrument noise. nated control blocks. A sudden de about burning the leaf with a match Fifth, he isolated the main recording viation of leaf resistance was scored as there was a "dramatic change in the instruments, each plant, and the a positive reaction, and this occurred tracing pattern" (Fig. 2). brine shrimp in separate rooms of the in 11 of the 13 stimulusblocks, but in

1. A Figure polygraph recording foi* the leaf of somewhat similar contours. While this fact tions, the plant record was probably made at a a one a houseplant and for human subject suggested to Cleve Backster, who performed stage when the testing system was unstable and undergoing verified emotional arousal exhibit the experiments, that plants experience emo may therefore be invalid. (From ref. 5.)

=

340 American Scientist, Volume 67 ^^^^^ ^'

This content downloaded on Sun, 6 Jan 2013 17:37:06 PM All use subject to JSTOR Terms and Conditions 8 of only the 65 control blocks. No is likely to be a very time-consuming tivating pulse was automatically re were positive reactions obtained in task, and one that, because of proba corded; videotape monitoring of the control runs with the sterile brine ble negative conclusions, seems un entire shrimp-killing operation; alone. Backster inferred that plant rewarding. We are indebted, there careful insulation and shielding of the must have cells "a primary sensory fore, to two serious and dedicated electrodes, plant preparation, and system." men, E. L. Gasteiger, of Cornell Uni electric cables; and use of high-gain, versity, and J.M. Kmetz, then of the capacity-coupled voltage amplifiers sum This is the total of published Science Unlimited Research Foun to measure microvolt changes of po experimental information underlying dation in San Antonio, Texas, who tential, rather than resistance, across the widely publicized claims. The eschewed expediency in order to the leaves. The latter modification in or report, appearing the Interna confirm reject the Backster report has substantial advantages, particu tional Journal of Parapsychology, from solid experimental ground. larly in its greater sensitivity and in Winter as 1968, stands today the only Verbal advice was given by Backster its lesser vulnerability to extrinsic report of such results, having appar to both researchers, so that the ex noise. ently not been reproduced, even by perimental conditions and layout Backster. It was supplemented, would be as nearly identical with the As befits the extreme care used in however, during the 1975 AAAS original circumstances as possible. arrangement of the electrophysio meeting. There Backster described Both sets of results have been pre logical apparatus, the resultant rec new experiments, in which the re sented to the public (in the 1975 ords were much "quieter" than those was cording organism Lactobacillus AAAS symposium), and one has been of Backster and displayed only one Pots of were (yogurt). yogurt said to published (6). feature that could possibly have been display changes of electric potential construed as a response to the emo upon addition of oxidizable substrate Gasteiger, working in collaboration tive stimulus. That feature was a brief to nearby pots. This, too, received with two undergraduate students, K. 10- to 45-microvolt deflection which extensive press coverage. A. Horowitz and D. C. Lewis, ar occurred spontaneously and at ir ranged experiments with all seven regular intervals, in about 30% of the features listed above in Backster's Experimental rebuttal plants studied. Horowitz, Lewis, and refined format. Some further im Gasteiger scored the deflections as When confronted with reports that provements of the procedure were positive, negative, or null, depending are as weak as and logically faulty also incorporated, including mainte on whether the amplitude of the one the nance this, professional scientist is of the plants in light-tight immediately following a shrimp tempted to dismiss them out of hand. rooms; ejection of the brine shrimp killing (or trial with water alone) was and Identifying cataloging all of the into the boiling water by solenoid larger than, smaller than, or equal to uncontrolled experimental variables driven pipettes, whose electrical ac the one (if any) occurring in the im

2. This onset a Figure recording suggested to Backster of thought, but the record certainly that plants can respond to human thoughts. No does become erratic. (From ref. 5.) methodology has been given for timing the

SeeOon of the February% 1966 plant monitoringchart showingthe reactionwhich occurred*t tfcesame time that the author thought

1979 May-June 341

This content downloaded on Sun, 6 Jan 2013 17:37:06 PM All use subject to JSTOR Terms and Conditions to evaporate from the agar gel, caus ing a change in concentration of so dium chloride in the gel. This change in turn causes a change in resistance, toGSR which appears as a pen deflection on amplifier the recorder. Since the evaporation process is not uniform, rather wide variations in resistance occur, and the system is thus extremely unstable just after it is set up.

After a period of time, a "skin" forms between the agar and the air. Al galvanic skin reflex experiment surface-potential change experiment though the skin does not completely 3. Backster's for the concentration of sodium chloride in Figure setups monitoring setups prevent the drying process, it retards galvanic skin reflex (left) and surface potential the agar gel took 20-30 minutes to stabilize; it sufficiently to make the electrode changes (right) in plants were reproduced and Backster's records were probably made before stable. Kmetz's ob somewhat refined by J. M. Kmetz. In both this point was reached. (From ref. 27.) system appear servations indicate that the equili bration time is 20-30 minutes. From the description given in his 1968 paper, it appears that most of Back ster's plant readings were taken dur the Kmetz mediately preceding control period. documenting, from a complicated ing equilibration period. that taken A total of 60 randomly sequenced experimental protocol, the probable suggested any readings then be invalid. shrimp-killings and 40 water trials source of Backster's results. We have might were conducted with 20 plants. Sta already noted that Backster's chart tistical analyses of the data were records from plants were noisy, much carried out in several different ways. noisier than the polygraph record he Sensory reception Under no identifiable criterion could produced from a human subject. It thus appears clear that Backster's either the shrimp-killings or the water When viewing, forexample, Figure 2, experiments do not support either his trials be associated with voltage from the 1968 article, anyone experi hypothesis or the Tompkins-Bird shifts. enced with practical electric circuits claims. Undoubtedly most of the (and particularly anyone experienced other experiments purported to re To be sure, the authors did find with bioelectric recording) would flect humanlike emotional or sensory Backster's reported data to be sig suspect an unstable electrical junc behavior in plants could be debunked nificant by the same kinds of statis tion somewhere; and even for the with the same precision. The cost, tical analyses; but, they stated, "we much cleaner record of Backster's however, would be unacceptably high matched, and in several instances fifth figure (not shown here), ob in both time and scientific distrac improved on, Backster's experimental tained from his refined experimental tion. techniques_We obtained no evi format, the low-level irregularity of dence of primary perception in the trace and the baseline blurs (me For this reason, and because the no plants. While the hypothesis will re chanically attenuated higher-fre tion of emotional plants admittedly main as an intriguing speculation, one quency oscillations?) raise suspicions. does have revolutionary implications, should note that only the limited The problem was to identify the exact the idea will surely float around on published data of Backster support point of the bad junction. the fringe of science for a long time to it." come. And, to be sure, both the logic Kmetz had noted that the plant rec and the require us Kmetz (27) was even more assiduous ords appeared "more active" imme to be alert to the possibility?however than the Cornell group in replicating diately after connecting the leaves to remote?that harder data may one Backster's experimental conditions, the recording system than they did day turn up. It therefore seems ap and in particular, he returned to the later on, and so he carried out one propriate to discuss briefly what Wheatstone Bridge method of re novel and crucial control measure identifiable features a bona fide sen cording leaf resistance (Fig. 3). But ment: instead of recording simply sory-communication process in plants after 168 trials on 42 plants, involving from a 100,000-ohm resistor as the might possess and how an experi 84 shrimp killings and an equal control against instrumentational menter might go about demonstrat number of water trials (Fig. 4), he noise, he included a pair of the ing the presence of such a process. We could find no significant correlation Backster electrodes (still without a address the problem only for small between resistance shifts and shrimp leaf) in that circuit. The resultant signal processes. Large signals are, by killing. He also delved into the "yo records were every bit as "active" as definition, easy to handle. gurt experiment" with the same when a leaf was included, and they thoroughness?and the same nega calmed down with time. All biological receptor phenomena tive result. that we know of, and certainly all that Kmetz studied the electrodes visually manifest themselves in electrical Perhaps more important, Kmetz inmany experiments and found that signals, can be described by five pa carried out the time-consuming and immediately after placing a set of rameters which should be relatively difficult task of ferreting out and electrodes in operation, Water begins constant in any given experimental

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This content downloaded on Sun, 6 Jan 2013 17:37:06 PM All use subject to JSTOR Terms and Conditions circumstance: waveform vialswith brineshrimp (shape), or sterile water amplitude, duration, latency, and? often most important?noise. The noise can play very nasty tricks, either by generating pseudophenomena (as implied by Kmetz's study) or by hiding real phenomena. These dan gers exist even when intracellular electrodes are used to record from individual cells, and they become a dominant problem in extracellular, massed recording. In many cases, experiments must be specifically de philodendron, to use am ex Backster a cor signed presumed latency, Figure 4. Kmetz reproduced Backster's reports having found positive or in relation in 11 out 13 cases a plitude, duration parameters periment on the effects of brine shrimp-killing of where killing order to extract real signals from on electrical responses in plants. Randomly actually occurred and in only 8 out of 65 cases and sterile-water where no took but Kmetz could background noise. sequenced shrimp-killings killing place, control tests were correlated through a recorder not reproduce Backster's results. (From ref. with changes in leaf resistance in a houseplant. 27.) Consider, for example, that most an imal sensory neurons discharge sig nals (action potentials) sponta neously, usually rather slowly?at rates on the order of a few per sec A related procedure is often used in section on electrophysiology of ond?without any known changes in massed-cell measurements, as in plants. their environment. On a time scale of studying brain signals (monitored by tens of seconds these spontaneous an electroencephalograph) triggered AU of these plant receptor processes discharges appear to be distributed by stimulation of sensory nerves from display simple and predictable be randomly, with some average fre the skin. In this case the experimenter havior of the first four physiologic quency, and some standard error (a may be looking for a signal ofmicro parameters listed above; noise has measure of variability), which can volt amplitude against a background generally not been analyzed, since easily be as large as the average fre trace 10 times larger. If the response only large signals have been exam quency. If a particular fiber in the has a fixed latency, computer tech ined. All of them also display two mammalian optic nerve discharged niques can be used to average tens, other essential characteristics: stim an average of 3 times per second, then hundreds, or even thousands of trac ulus specificity and anatomical lo over a period of time itwould display ings, each initiated by the stimulus to calization. Thus, light at 660 nm 1-sec intervals with any number of the skin. This maneuver has the effect triggers hyperpolarization and light action potentials between zero and, of amplifying the nonrandom at 730 nm triggers depolarization say, 10. Some intervals would have 3 event?i.e. the stimulus response? (26), these changes resulting from discharges, but most would not; many but of canceling the random reversible changes in form of the would have none, and an occasional events?the noise. For this latency pigment phytochrome, which is interval would contain 8-10. dependent extraction to work, it is probably embedded in the plasma obvious that the electrical signal must membrane of the cell (28). The question, now, is how an experi be of reasonably constant shape, with menter can detect a response to a the same sign (negative or positive) Another receptor system, which has low-level optic stimulus, one suffi and the same approximate duration been more extensively analyzed, is cient to increase the discharge by, say, on repeated trials. that mediating Chemotaxis in bacte as 1 impulse/sec, on the average. There ria. Motile bacteria, such Esche is no way other than to examine the There are, of course, a wide variety of richia coli, "swim" by means of fla neuronal discharge after numerous known receptor processes in plants, gella. In the absence of chemotactic repeated stimuli. In fortunate cir even when we rule out, as semantic agents, the bacteria move about ran cumstances, discharges due to the confusion, nonspecific biological re domly, tumbling erratically through stimulus would tend to appear at a sponses to excessive stimulation?i.e. the medium with individual flagella fixed interval?say 10 millisec destructive agents. Detection of and waving independently (29). When an as onds?following the beginning of a response to significant environmental attractive agent such a sugar or stimulus, such as the turning on of a changes are essential attributes of any amino acid is presented, the flagella a light, regardless of the frequency or living organism. The older literature amalgamate to form "tail," the timing of the background discharge. of botany and is full tumbling stops, and the bacteria move Reproducibility in this interval of of terms that inherently label recep efficiently toward the agent. latency is a very important criterion tor processes, though usually without Genetic and protein-chemical data by which to identify a causal rela distinguishing them from the resul exist to show that each agent that tionship between retinal illumination tant responses: , geo induces Chemotaxis must first react one or and electrical discharge within the , thermotropism, etc. The with two specific proteins in mem optic nerve. If reproducibility fails, easiest receptor processes to docu the bacterial wall and plasma then one must resort to long-term ment and study have proved to be brane. statistical analysis of the neuronal those related to light stimuli, some of ana discharge. which we have already noted in the It is the lack of any plausible

1979 May-June 343

This content downloaded on Sun, 6 Jan 2013 17:37:06 PM All use subject to JSTOR Terms and Conditions in tomical substratum, rather than any difficult. For instance, once you are sure 10. B. G. Pickard. 1973. Action potentials will it well higher plants. Bot. Reu. 39:172-201. single experimental fact or flaw, something happen, very may of which?in our view?drives the final not. I suspect that's because you are 11. W. J. V. Osterhout. 1929. Some aspects communicating to the biological material permeability and bioelectrical phenomena. nail into the coffin for the Backster, Bull. Nat. Res. Council 69:170-228. as long as you keep your consciousness Tompkins, and Bird view of plant in involved in the experiment. 12. T. Sibaoka. 1966. Action potentials plant "sensory perception." Perception, organs. Symp. Soc. Exp. Biol. 20:49-74. communication, and emotion are 13. C. L. W. S. Long, and D. Grad The proposition has been stated Slayman, properties of highly developed ner mann. 1976. "Action potentials" inNeu slightlydifferently by Marcel Vogel, crassa, a Bio vous systems (and perhaps in the near rospora mycelial fungus. another Tompkins-Bird hero (2, p. chim. Biophys. Acta 426:732-44. future will be properties of complex 27): 14. W. J. V. Osterhout. 1933. Permeability in computer circuits). Although intra large plant cells and in models. Ergeb. cellular complexity on a microscale u. Pharm. 35:967-1021. Hundreds of laboratory workers around Physiol. Exp. does exist in as well as animal plant the world are going to be frustrated and 15. E. J. Lund. 1947. Bioelectric Fields and nowhere in the is Growth. Univ. of Texas Press. cells, plant kingdom disappointed until they realize that em a 1954. Anion there gross anatomical structure pathy between plant and human is a key, 16. H. Lundegaardh. respiration: basis of a of ab that approximates the complexity of and learn how to establish it.No amount The experimental theory sorption, transport, and exudation of insect, or even worm, nervous sys of checking in laboratories is going to electrolytes by living cells and tissues. much less the prove a thing, until the experiments are tems, mind-boggling Symp. Soc. Exp. Biol. 8:262-96. intricacies of the cerebral cortex in done by properly trained observers. 17. P. Mitchell. 1963. Molecule, group, and Spiritual development is indispensable, higher primates. electron translocation through natural but this runs counter to the of philosophy membranes. Biochem. Soc. Symp. 22: many scientists who do not realize that 142-68. creative means that the Reflections: Science and experimentation 18. H. Grundfest. 1960. Electric fishes. Sei. the force experimenters must become part of their Am. 221:115-24. experiments. 19. G. E. Briggs and A. B. Hope. 1958. Elec Throughout this discussion, we have trical potential differences and the Donnan repeatedly invoked two essential op This is a no-lose proposition. Nega equilibrium in plant tissues. J. Exp. Bot. 9:365-71. erating principles of science: repro tive results must be discounted be 20. A. L. J.M. Ford, and A. B. Hope. ducible data collection and indepen cause the experimenter is not "in McAulay, 1951. The distribution of electromotive dent verification. Backster's conclu tune," and positive results are only forces in the neighborhood of apical mer as as in of sions, well many others the accepted. The operating principles istems. J. Exp. Biol. 28:320-31. are Tompkins-Bird book, collapse under science set aside, and the argu 21. A. R. Schrank. 1957. Bioelectrical impli the test of either principle. But for ments become removed from contact cations in plant . Symp. Soc. Exp. Biol. 11:95-117. tunately or unfortunately?depend with physical reality. The scientific 22. L. F. Jaffe. 1966. Electrical currents ing on your point of view?ideas, method is excluded, the questions the Fucus Proc. however often become irrelevant to through developing egg. illogical, prove very posed quickly Nat. Acad. Sei. 56:1102-09. tenacious in men's minds. Over the science, and we are left in the realm of 23. L. F. Jaffe, K. R. Robinson, and R. Nucci numbers of sci Ben Kenobi and Darth Vader. past century, large telli. 1974. Local cation entry and self entists, perhaps even a majority, have electrophoresis as an intracellular local ization mechanism. Ann. N. Y. Acad. Sei. clung to pet hypotheses long past the 238:372-89. time when data and other scientists 24. R. H. Racusen and R. L. Satter. 1975. have laid those to rest. hypotheses Rhythmic and phytochrome-regulated time erases at least Eventually, (or changes in transmembrane potential in blurs) our memory of such dead hy References Samanea pulvini. Nature 255:408-10. one will 25. R. L. Satter, M. Schrempf, J. Chaudhri, potheses, though occasionally 1. P. Tompkins and C. Bird. 1973. The Secret or even and A. W. Galston. 1977. Phytochrome and be resuscitated reincarnated Life of Plants. Harper and Row. circadian clocks in Samanea: Rhythmic in fruitful form at a later time. 2. L. T. Audus. 1974. Roots of New absurdity. redistribution of and chloride Scientist 64:207. potassium within the pulvinus during long dark pe or un 3. A. W. Galston. 1974. The unscientific But that corpus of fallacious riods. Plant Physiol. 59:231-35. method. Natural History 83:18-24. provable claims which comprise The 26. A. W. Galston and R. L. Satter. 1976. Light, 4. A. Hecht. 1974. Emotional Secret Life ofPlants is being kept responses by clocks, and ion flux: An analysis of leaf plants. Plant Sei. Bull. 20:46-47. movement. In and Plant alive in the popular literature by Light Develop 5. C. Backster. 1968. Evidence of a primary ment, ed. H. Smith, pp. 159-84. London: highly efficient mass-media tech perception in plant life. Internat. J. Par Butterworths. niques. The body has been kept 10:329-48. apsychol. 27. J.M. Kmetz. Unpubl. A study of primary the fact that its breathing despite 6. K. A. Horowitz, D. C. Lewis, and E. L. perception in plant and animal life. Lec brain is obviously dead. The rationale Gasteiger. 1975. Plant "primary percep ture presented at the symposium on for this was given by Backster in an tion": Electrophysiological unresponsive "Electrical Responses of Plants to External ness interview with the Christian Science to brine-shrimp killing. Science Stimuli," AAAS meeting, January 1975, 189:478-80. N.Y.C. Monitor (30): 7. L. Galvani. 1791. De Viribus Electricitatis 28. W. Haupt. 1965. Perception of environ inMotu Musculari Commentarius. mental stimuli orienting growth and The only problem in this kind of research movement in lower Ann. Rev. PL 8. J. C. Bose. 1924. The Physiology of Pho plants. is thatMother Nature does not want to 16:267-90. tosynthesis. London: Longmans, Green, Physiol. jump through the hoop ten times in a row, and Co. 29. D. E. Koshland. 1977. Bacterial Chemotaxis someone to. simply because wants her It 9. J. Burdon-Sanderson. 1873. Note on the and some enzymes in energy metabolism. is difficult to structure Soc. Gen. Microbiol. 27:317-31. repeatable exper electrical phenomena which accompany Symp. iments. There are some phenomena that stimulation of the leaf of Dionaea musci 30. C. L. Backster. 1973. Christian Science occur that make this kind of thing very pula. Proc. Roy. Soc. London 21:495-96. Monitor, 11 December.

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