AGRICULTURAL BOTANY. 317 



AGRICULTURAL BOTANY. 



Report on metabolism in Anim spadices and the electrical response of 

 vegetable tissues, A. D. Waller (Rpt. Brit. Assoc. Adv. Sci., 1908, pp. J/dS-Jp'S, 

 ji<js. i6').— An account is given of work done by Miss Siinders ou the metabo- 

 lism of Arnm spadices and by Miss Kemp ou the occurrence in certain vegetable 

 tissues of a propagated electrical response to stimulation. 



In the first investigation, which was conducted to determine the changes goiug 

 on \^ Arum spadices during inflorescence, but little advance was made, owing to 

 the ditticulty of securing flowering material. It was possible, however, to ex- 

 tend observations on the enzym activity of the plants and on the nuclear 

 changes taking place. 



It was found that the active spadices of A. italicum, A. crinoides, A. crinitum, 

 and Dracunciiliis vulgaris secrete a proteolytic enzym or enzyms comparable 

 with trypsin in attacking proteids and peptones, but carrying the process of 

 splitting to a further stage in which tryptophane can no longer be detected. 

 Experiments are still in progress relating to the splitting up of sugars by plant 

 enzyms. and from the fact that the author was not able to ascertain which 

 sugars resulted by the ordinary methods, it is suggested that possibly there is a 

 further stage in carbohydrate metabolism parallel to the complete breaking 

 down of proteids. 



In the experiments on electrical response, observations were made ou seedling 

 plants of the mustard, pea, and bean, and upon the adult petioles of the maiden- 

 hair fern. With the exception of a few cases where the nature of the stimulus 

 was mechanical, the thermo-electric method of stimulation was used. 



The data presented are insufficient to determine the true nature of the change 

 by transmission of which an electrical disturbance is set up at points distant 

 from that of the exciting stimulus. It appears that the transmission is essen- 

 tiallj' a physiological process, as shown in the character and extent to which 

 the propagation varies in accordance with the general character of the tissue 

 tested, and by the fact that a very slight etiolation or unhealthiness of a plant 

 destroys its power of propagating a stimulus, as seen with seedlings grown in 

 the laboratory under improper conditions of nourishment and light. It is 

 further shown that the tissues quickly become fatigued unless in optimum condi- 

 tion and that on altering tlie state of the tissue in such a way as to annul its 

 power of response while at the same time increasing its electrical conductivity, 

 no propagation of an excitatorj^ stage can be obtained. 



The investigations lead to the conclusion that the i)ower of propagating ex- 

 citation, instead of being a rare and specialized phenomenon in vegetable 

 tissues dependent upon si)ecial fibrillar structures, as claimed by Bose, is innate 

 in every normal cell and occurs freely wherever the protoplasmic continuity 

 I)etween cell and cell is at all considerable. 



Mechanical and electrical response of plants, J. C. Bose (Bpt. Brit. Assoc. 

 Adv. Hci., .1!)0S, PI). 'Jit.';, :>(J'i). — The author briefly desciibes a method by which 

 he has been able to make accurate studies of the effect of external stimulus on 

 plants. He claims to have shown that all organs of all plants are sensitive to 

 excitation. Further he claims that the fibrovascular elements provide prefer- 

 ential channels through which waves of excitation are conducted. 



The influence of electricity on plant growth, M. Breslauer (Electrochem. 

 Ztschr., 16 {WOO), Nos. 1, pp. 1-5; 2, pp. 35-3U, figs. //; 3, pp. 72-75, figs. 3).— A 

 descripfion is given of investigations of various individuals relating to the 

 application of electricity as a stinuilus of plant growth, particular attention 

 being given to the experiments of Lemsti'om (E. S. R., IG, p. G4G), Sir Oliver 

 Lodge (E. S. R., 20, p. G30), aud others. 



