I I.KMI \ I \ riON WD RESPIE \ I K»\ 



- 7 'л 



Zaliesskii 1 found that if the bulbs of Gladiolus are immersed in water for л 

 short time their respiratory activity is considerably increased. 



Changes in concentration of the nutrient solution affect the value of tin- 

 respiratory ratio. Purievich 2 obtained the following values of this ratio for 

 Aspergillus niger with different concentrations of cane-sugar solution. 



Concentration of the medium, per cent 1 5 10 20 25 



Respiratory ratio 



*m 



0.85 0.96 



1.04 0.93 0.73 



Respiration is influenced by various toxic substances. 3 Morkovin 4 studied 

 this effect in the case of various alkaloids, glucosides, alcohols and other sub- 

 stances, such as ethyl ether, formaldehyde and paraldehyde, and found thai 

 these increase respiratory activity when present in very weak concentration. 

 For example, of two similar groups of shoots of etiolated bean seedlings one 

 group was grown in cane-sugar solution, and the other in the same solution with 

 the addition of 1 per cent, of isobutyl alcohol. Without the poison, 100 g. 

 of shoots produced 65.0 mg. of carbon dioxide per hour during the first twenty- 

 four hours of the experiment, and 72.4 mg. per hour during the fust t hirt y-seven 

 hours. With the poison, 191. 7 mg. of carbon dioxide was produced per hour for 

 the first twenty-four hours and 124.5 mg. per hour for the first thirty-seven 

 hours. Isobutyl alcohol, in this concentration, is thus seen to exert a definitely 

 accelerating effect upon respiration. Zaliesskii 5 has shown thai ether accelerates 

 respiration in resting plant organs to a marked degree; in the case of Gladiolus 

 bulbs exposed to an atmosphere containing ether, respiration is first increased, 

 but later decreases to below the normal rate. 



Wounding markedly increases the rate of respiration. 6 In one experiment 



1 Zaliesskii, V., Influence dc l'cxcitation sur la respiration ' : 

 Mem. Inst. Agron. et Forest. Novo-Alexandria 15- : r-41. 1902. [Parts of vol. an iged.] 



■ Puriewitsch, K., Physiologische Untersuchungen über Pflanzenatmung. Jahrb. wiss. Bot. 35: S73- 

 610. 1900. 



3 Palladin, W., Uebcr die Wirkung von Giften auf die Atmung lebender und Pflanzen, 



sowie auf Atmungsenzyme. Jahrb. wiss. Bot. 47: 431-461. 1910. 



* Morkowin, N., Recherches sur l'influence des anesthetiques sur la 1 plantes. Rev. 



gen. bot. 11: 289-303, 341-352. 1899. Idem, Recherches sur l'influence des alcaloides sur la ti 

 des plantes. iit'rf. 13 : 109-126, 177-192, 21 2-226, 265-275- 1901. 



6 Zaliesskii, 1902. [See nute 1, thi 



e Stich, Conrad, Die Athmung der Pflanzen bei verminderter Sauerstoffspannung und bei Verletzungen. 

 Flora 74: 1-57. 1891. P. 15. Pfeffer, W. t Г. ; rang der Athmung und der 



production nach Verlel Ber. ü. d. Verh. d. K. Sachs. >. 



(Math.-phys. Cl.) 48: 384-389. 1896. Smirnoff, Influence des blessures sur La 

 intratnoleculaire (fermentation) des bulbes. Rev. ym. bot. 115: 26-38. 1903. 



