The final cleavage event that terminates cell division, abscission of the small, dense intercellular bridge, has been particularly challenging to resolve. Here, we describe imaging innovations that helped answer long-standing questions about the mechanism of abscission. We further explain how computational modeling of high-resolution data was employed to test hypotheses and generate additional ...

Whole plant defoliation studies were performed using dark red kidney bean (Phaseolus vulgarisL.) to compare the effect of cyclanilide [1(2,4-dichlorophenylaminocarbonyl)-cyclopropane carboxylic acid], ethephon (2-chloroethylphosphonic acid), auxin transport inhibitors, and temperature on leaf abscission. Ethephon induced bean leaf defoliation, but ethephon combinedwith cyclanilide induced great...

Plasma membranes from abscission zones of kidney bean seedlings were isolated on sucrose density gradients using cellulase and KCl-stimulated ATPase as marker enzymes. Following treatment of the seedling explants with 50 microliters per liter ethylene, an increase in the buoyant density of the plasma membrane fraction from 1.165 to 1.175 grams per cubic centimeter was observed. Such a change is...

In the course of biological screening for herbicidal activity in synthetic compounds, various organic iodide complexes had marked defoliating properties when applied to leguminous test plants. Simple iodides such as the salts of alkali metals also caused defoliation. Although this effect has been reported in the patent literature (4, 8), our present investigation was undertaken principally to l...

Pistachio produces an abundant number of inflorescent buds every year (during spring and early summer) which abscise mainly on fruiting branches during seed development. Competition of the developing ovaries/seeds with inflorescent buds for nutrients was suggested as being primarily responsible for bud abscission. Although leaf N correlated with bud retention, foliar application of N did not re...

A major event in domestication of crops was the elimination of seed shattering, so that instead of falling to the ground, seeds stayed on the stalk until farmers could harvest them (Doebley, 2006). The SH4 (for grain shattering quantitative trait locus on chromosome4) and qSH1 (for quantitative trait locus of seed shattering on chromosome1) transcription factor genes are known to play key roles...

Plants constantly renew during their life cycle and thus require to shed senescent and damaged organs. Floral abscission is controlled by the leucine-rich repeat receptor kinase (LRR-RK) HAESA and the peptide hormone IDA. It is unknown how expression of IDA in the abscission zone leads to HAESA activation. Here we show that IDA is sensed directly by the HAESA ectodomain. Crystal structures of H...

Although present in different organisms and conserved in their protein sequence, the biological functions of T2 ribonucleases (RNase) are generally unknown. Tomato (Lycopersicon esculentum) LX is a T2/S-like RNase and its expression is known to be associated with phosphate starvation, ethylene responses, and senescence and programmed cell death. In this study, LX function was investigated using...

The endosomal sorting complexes required for transport (ESCRT) proteins have a critical function in abscission, the final separation of the daughter cells during cytokinesis. Here, we describe the structure and function of a previously uncharacterized ESCRT-III interacting protein, MIT-domain containing protein 1 (MITD1). Crystal structures of MITD1 reveal a dimer, with a microtubule-interactin...