Cell Biology of Abscission

Abstract

INTRODUCTION ... ........ ...... 133 DEVELOPMENT OF EXPERIMENTAL METHODS TO STUDY ABSCISSION . 135 THE TIME COURSE OF ABSCISSION ....... 136 INFLUENCE OF HORMONES ON THE TIME COURSE 137 The Lag Phase 137 The Separation Phase 139 ANATOMY OF ABSCISSION ...... , , 140 Structural Features of Abscission Zones 140 Changes During the Lag Phase 143 Changes During the Separation Phase 145 BIOCHEMISTRY OF WALL BREAKDOWN 148 OTHER ENZYMIC CHANGES DURING CELL SEPARATION ,.... 152 ROLE OF LIGNIN, CALLOSE. AND TYLOSES , ,.... 153 MECHANICS OF SEPARATION . ........ ........ .. ..... ......... 153 ORGANIZATION OF ABSCISSION .... 155 SUMMARY AND CONCLUSIONS .... ........ 157