239 



.A62. King, E. E. 1972. Pectinases from boll weevil larvae, Anthonomus grandis . 



J. Insect Physiol. 18: 1295-1301. 

 Assays were conducted throughout a wide pH range to measure the ability of 

 extracts from third instar boll weevil larvae to degrade pectic substances. 

 Pectin was deesterifJed and was depolymerized by both hydrolytic and trans- 

 eiiminative mechanisms. Sodium polypectate (deesterif led pection, or pectic 

 acid) was depolymerized solely by trans- elimination. Addition of Ca + failed 

 to stimulate the trans- eliminative cleavage of either pectin or polypectate. 

 It is possible that one or more of the pectinases from boll weevil larvae con- 

 tribute to the abscission of infested cotton flower buds. 



463. . 1973. Endo-polymethylgalacturonase of boll weevil larvae, Anthonomus 

 grand is : an initiator of cotton flower bud abscission. J. Insect Physiol. 

 19: 2433-2437. 



Pectinases of boll weevil larvae were fractionated by gel filtration, (NH,)2S0, 

 precipitation, and hydroxylapatite chromatography. A fraction rich in endo- 

 polymethylgalacturonase (endo-PMG) was able to macerate anther tissue and 

 initiate abscission when injected into cotton flower buds. By partially 

 destroying the cuticular permeability barrier, ethyl acetate and other sol- 

 vents enhanced the abscission- initiating ability of the enzyme fraction. Growth 

 regulator imbalances and degradation products resulting from endo-PMG action 

 are probably the ultimate causal agents of abscission in flower buds. 



464. , and Lane, H. C. 1969. Abscission of cotton flower buds and petioles 

 caused by protein from boll weevil larvae. Plant Physiol. 44: 903-906. 



Protein extracted from boll weevil larvae causes abscission of cotton flower 

 buds and debladed petioles. Abscission of buds is preceded by a rapid and 

 persistent flaring of bracts; cell proliferation is Induced in the abscission 

 >«one of debladed petioles. A possible mode <~f transmission of the agent from 



