UNIVERSITY OF CALIFORNIA PUBLICATIONS 



IN 



BOTANY 



Vol. 5, No. 12, pp. 347-428, 10 text figs., plates 49-53 March 6, 1918 



ABSCISSION OF FLOWERS AND FRUITS IN 



THE SOLANACEAE, WITH SPECIAL 



REFERENCE TO NICOTIAN A 



BY 



JOHN N. KENDALL 



CONTENTS 



PAGE 



L Introduction 348 



IL Summary of the literature 350 



III. Technique ^ 361 



IV. Histology and cytology of the pedicel 363 



1. Histological and cytological condition of the mature pedicel 363 



2. Development of the separation zone in Nicotiana and Lycoper- 

 sicum 367 



3. Increase in size and development of mechanical tissue in the 



pedicel of Nicotiana and Lycopersicum 369 



V. The process of abscission 371 



1. General description of the process in several genera 371 



2. Method of cell separation 376 



VI. Abscission of the style and corolla 383 



VII. Time of abscission 385 



1. Eeaction time 385 



2. Abscission time 396 



VIII. Experimental induction of abscission 397 



1. Induction by illuminating gas 397 



2. Action of acids on the separation layer of Nicotiana 404 



3. Induction by mechanical injury 406 



4. The ability of certain species to throw off pedicels from which 

 all the floral organs have been removed, as related to the induc- 

 tion of abscission by mechanical injury 410 



IX. Summary 411 



X. Conclusion 415 



XI. Literature cited 418 



XII. Plates 420 



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