The Arabidopsis BLADE-ON-PETIOLE 1 (BOP1) and BOP2 genes encode redundant transcription factors that promote morphological asymmetry during leaf and floral development. Loss-of-function bop1 bop2 mutants display a range of developmental defects, including a loss of floral organ abscission. Abscission occurs along specialised cell files, called abscission zones (AZs) that develop at the junction...

1-Aminocyclopropane-1-carboxylic acid (ACC) supplied via the cut base of detached olive shoots caused a burst of ethylene from leaves, but other cyclopropanes tested did not exhibit this effect. Ethephon (ET) and another ethylene-releasing compound caused a prolonged increase in ethylene evolution. ACC had only a very limited effect on leaf abscission regardless of concentration, whereas shoots...

Ethrel, a mixture of 2-chloroethanephosphonic acid and its ethyl ester, hastens abscission of leaves, debladed petioles, and flower buds of cotton plants (Gossypium hirsutum, L.). Both young and old leaves abscissed while still green. Application of Ethrel stimulated evolution of ethylene, and this response preceded abscission. Air concentrations of ethylene around enclosed, treated-plants were...

Flower opening is a process that requires movement of petals from a closed position to a horizontal open position, while petal abscission requires cell-wall disassembly. Both processes are controlled by ethylene and require cell-wall modification at the junction (abscission zone) of the petal and thalamus to facilitate the movement or separation of petals. In the present study, a family of xylo...

The development of the leaf abscission zone in Ginkgo biloba trees and seedlings was studied. Leaves from Ginkgo seedlings were debladed to enhance anatomical changes in the abscission region. The development of an abscission layer was observed six days after deblading. The formation of the zone was not complete, but an abaxial to adaxial pattern of development was apparent. No evidence of sepa...

Plants utilize an innate immune system to protect themselves from disease. While many molecular components of plant innate immunity resemble the innate immunity of animals, plants also have evolved a number of truly unique defense mechanisms, particularly at the physiological level. Plant's flexible developmental program allows them the unique ability to simply produce new organs as needed, aff...

Abscission zone tissue of citrus was shown to have a higher rate of protein synthesis than tissue distal or proximal to it, based on the incorporation of leucine-1-(14)C. The proximal tissue had the slowest rate of protein synthesis. As the tissue approached abscission, the rate of synthesis in the abscission zone decreased and the differences in rate of protein synthesis between the 3 zones al...

Abscission occurs specifically in the abscission zone (AZ) tissue as a natural stage of plant development. Previously, we observed delay of tomato (Solanum lycopersicum) leaf abscission when the LX ribonuclease (LX) was inhibited. The known association between LX expression and programmed cell death (PCD) suggested involvement of PCD in abscission. In this study, hallmarks of PCD were identifie...

The main objective of this work was to identify and classify genes involved in the process of leaf abscission in Clementina de Nules (Citrus clementina Hort. Ex Tan.). A 7 K unigene citrus cDNA microarray containing 12 K spots was used to characterize the transcriptome of the ethylene-induced abscission process in laminar abscission zone-enriched tissues and the petiole of debladed leaf explant...

The genetics and expression of a lipid transfer protein (LTP) gene was examined during abscission of mature fruit of 'Valencia' orange. A cDNA encoding an LTP, CsLTP, was isolated from a cDNA subtraction library constructed from mature fruit abscission zones 48 h after application of a mature fruit-specific abscission agent, 5-chloro-3-methyl-4-nitro-pyrazole (CMN-pyrazole). A full-length cDNA ...