X38 



The simplest process by which w© can arrest the normal 

 growth." in plants consists in destroying one or all parts of 

 the vegetative tips of their shoots* If correlat ion-he tero- 

 plasmas are then produced, their formation results after the 

 injury to be sure, but not because of it, No doubt exists that 

 the same heteroplasraas are also produced when the normal vege- 

 tative points continue to live, If these are kept from further 

 development, perhaps by being put into plaster oasts. They may 

 not be associated therefore with the callus formations named 

 later. 



(15£) Voohting has published valuable data on oorrelation- 

 heteroplasmas* , 



If the inflorescences and all axillary buds vrere removed 

 from vigorous kohl-rabi plants { Brass ioa oleraoea t, goRgylodes ) 

 the leaf cushions swelled gradually to extensive bodies, possi- 

 bjy to 8om» wide, which "had been formed from the pc.renoh3TaG of 

 the bark of the cushion and from the vascular bundles running 

 through it« These were formed in an unusual vmy and had devel- 

 oped partly to round, vigorous bodies covered all over with 

 cambium. In the vascular parts, the tissue produced fribm the 

 cambium consisted of thin walled elements, through VJhlch passed 

 rows of small ducts. The abnormal tissue was distinguished from 

 normal tissue by the absence of mechanical elements and the 

 narrovmess of the lumina of the ducts. 



In outback Helienthus plants analogous conditions may be 

 found, "here too a significant development of the parenchyEXX 

 and a retrogression of the mechanical elements is found in the 

 stalk," especially in the upper part of the stem. In the lower 

 part hollow cells are als o produced after the operation but 

 these are shorter than normal on^^s.. On all sides a bending and 

 twisting is frequently found. Vochting found tnber-like swell- 

 ings produced on the roots of decapitated HelianthuS plants. 



In the aerial runners of Oxalis crassicauljg . which are 

 filled with reserve stuffs, are robbed of their apical cejls and 

 all axillary embryonic sprout cells, heteroplastic swellings are 

 produced by the swelling of the leaves snd internodes. Accord- 

 ing to Vochting the cells of the fundamental tissue participate 

 in the new formation chiefly by enlargement; the vascular bun- 

 dles have fewer ducts than normal ones, but the sieve tubes are 

 richly developed and at times extensive parenohjTna outgrowths 

 lie between xylem and phloem. vSchting at times observed bi-col- 

 lateral bundles in the abnormal tubers^. The development of col- 

 lenohyma was absent in the stasr , which had become inflated to a 

 tuber, the mechanical elements usually accompanying vascular bun- 

 dles were few or entirely lacking. I will return later to the 

 noticeably large qnd irregularly formed starch grains, which 

 fill *he"Seaf tubers" in especially striking foims. (Chapter VI, I). 



It seems possible that cells of a permanent tissue may also 

 be "correlatively" incited to growth and division. 



^ Zur Physio^j. d. Knollengewachse. Jahrb. f. wlss. Bot. 

 1900, Bd. XXXIV, p. 1, - Zur experiemtellen Anatomic. Haohr. 

 K. Ges. Wiss. Gottingen, 1902. Math.-naturw. Kl,, Heft 5. 



2 Abnormal Vascular bundles of the same kind may be found 

 in many galls (prosoplasmas) , see below chapter V, B, 5, 



