4l8 PLANT GROWTH SUBSTANCES 



gall formation in Solidago stems with extracts of gall tissues, maggot 

 cultures, or maggots, although he induced some gall formation by 

 injections of trypsin, mixtures of amino acids, and protein digests. Martin 

 (io,ii), working with sugar cane, reported success in producing stem 

 galls following inoculation of extracts of leaf hoppers and mealy-bugs 

 producing galls on this plant normally. He also obtained galls with 

 autoclaved extracts. 



Parr (i8) investigated gall formation on chestnut oak by the coccid, 

 Asterolecanium variolosum, and found that 90 pef cent of the injections 

 of salivary gland extracts into young stems resulted in gall formation. 

 The galls had the same shape as those produced by the living insects, 

 though they were slightly smaller. Since no gall formation was obtained 

 by injection of salivary gland extracts heated to 6o°C., Parr concluded 

 that enzymes or enzyme-like substances were the causative agents. 

 Ptyalin and indole-3-acetic acid failed to produce galls. 



The successes of Martin and Parr were achieved with insects producing 

 relatively simple galls which belong among Kiister's "kataplasmas." 

 Kiister (7) defined kataplasmas as those galls which are less highly 

 differentiated than the normal structures on which they are borne, and 

 are inconstant and indefinite in size and form. Prosoplasmas, on the other 

 hand, were defined as the more specialized galls characterized by definite 

 size and form, which in tissue differentiation are different from but 

 not below normal. The kataplasmas include such galls as the familiar 

 enlargements on goldenrod stems, while the prosoplasmas include most 

 of the galls produced by gall midges and gall wasps. 



Gall insects are known to secrete various enzymes, and some workers 

 have attributed gall-forming properties to these. Kiistenmacher (6), 

 Magnus (9), and others showed that the larvae of gall insects produce 

 diastase and invertase. Cosens (4) identified diastase in the secretions or 

 excretions of gall insects, and believed it played an important role in 

 gall formation. Beck (2) identified amylase, invertase, and a protease 

 in the excrement oiEurosta maggots, and concluded that the proteolytic 

 enzymes were important factors in the production of galls. In the salivary 

 glands of the coccid, Asterolecanium, Parr, in 1940, found amylase, in- 

 vertase, a protease, and an oxidase, but he was not able to detect perox- 

 idase or ccllulase (18). Nierenstein (15) found that tannase is produced 

 by the larvae of the sawfly, Pontania proxima, which produces galls on 

 Salix caprea. 



