J. M. BEAL 163 



A naturally parthenocarpic variety of cucumber similarly cut at the 

 base of the style and smeared with 2 per cent indoleacetic acid and 

 lanolin mixture behaved rather differently according to Young (39). 

 If treated at full bloom the tissues adjacent to the surface of appHcation 

 remained alive but showed shght proliferation. Ovules were intermediate 

 in size between those of controls and those given the prebloom treatment 

 with indoleacetic acid. If treated about 4 days before full bloom, tissues 

 of the nectary, floral tube, and neck proliferated to form a small apical 

 tumor in which no vascular bundles or root primordia appear. Ovules 

 developed to about half normal size, and seed coats became partially 

 hardened. 



AppHcation of a 3 per cent indoleacetic acid and lanoHn mixture to 

 the cut surfaces of partially mature bean pods which had had their tips 

 removed resulted in the production of large vascular apical tumors 

 and roots (20). The tissues composing these tumors were derived mainly 

 from the proliferated exocarp and mesocarp of the pod. The endocarp, 

 which in untreated pods is principally derived from proliferated epi- 

 dermal cells, became somewhat more active in treated pods, but formed 

 little or no part of the apical tumor. Vascular elements apparently were 

 not differentiated from this tissue. The large apical tumors are built up 

 from derivatives of cells near the treated surface, a far shorter distance 

 than was the case in stems. The seeds aborted in at least half the apically 

 treated pods; the larger the tumor the fewer the seeds. This appeared to 

 result from the mobihzed materials that entered the pod being diverted 

 to the tumor rather than to the seeds. 



Lateral Application to Stems 



Hamner and Kraus (20) made lateral applications of a 3 per cent 

 indoleacetic acid and lanolin mixture to bean stems by drawing the 

 mixture out as a thin thread which was then laid on the second internode 

 to encircle it completely. Care was taken to avoid injury to the stems. 



Marked yellowing and swelling occurred 2 or 3 mm. above, below, 

 and at the hne of application. The effects increased with time until by 

 the end of a week or ten days the tumors were often 2 cm. or more long, 

 spindle shaped, and markedly ridged over the vascular bundles. Roots 

 in longitudinal rows emerged mainly between the swellings over the 

 vascular bundles. 



The histological responses closely resembled those of stems decapitated 



