Anatomical and histological changes in the fruit abscission zone of water dropwort (Oenanthe stolonifera DC.)

Abstract

Our goal was to investigate fruit abscission in Oenanthe stolonifera DC. by studying the morphological and cytological changes in the abscission zone. One abscission zone existed at the junction between the fruit and the pedicel. The region was clearly distinguishable 10 days after anthesis onwards and consisted of 3 to 5 layers of cells that formed a small, closely packed shape. Cells in the abscission layer began to flatten as the fruit developed. At the beginning of cell separation, cells in the middle area returned to a round shape and adjacent pedicel parenchyma cells enlarged. As abscission began, the cell wall dissolved from the middle lamella. Cell separation gradually extended toward the periphery from the middle area and, eventually, a distinct separation layer was formed. As the process proceeded, abscission zone cells developed large vacuoles and the organelles lost their shape. However, in explants treated with cycloheximide, the cell wall separated from the membrane and a whorled membrane was observed. This finding suggests that structural changes in the cell membrane may help explain the control of fruit abscission in O. stolonifera.

Spatio-temporal localization of LlBOP following early events of floral abscission in yellow lupine

“…The protein products of these molecules are probably essential for cell wall hydrolysis and modifications, e.g., cellulases, polygalacturonases, and may directly influence the middle lamella dissolution followed by cell wall rapture, as was confirmed in other plant species (Bonghi et al 1992; Kalaitzis et al 1997; Belfield et al 2005; Ogawa et al 2009). The evidence supporting the thesis concerning de novo protein synthesis during separation event initiation was provided on the basis of studies conducted in Oenanthe stolonifera (Eo and Lee 2011). Similar cytosol localization pattern of LlBOP and poly(A) mRNA (Figs.…”

Disruption of the Auxin Gradient in the Abscission Zone Area Evokes Asymmetrical Changes Leading to Flower Separation in Yellow Lupine

“…We showed that cells of the AZ isolated from naturally abscised flowers divided intensively and were linked by numerous plasmodesmata, which suggest the possibility of intercellular communication [29]. The cytoplasm of active AZ cells was dense, heterogeneous, and enriched in proteins, suggesting the de novo synthesis of enzymes crucial for organ separation [30]. Analyses performed using transmission electron microscopy also revealed that these cells were progressively degraded.…”

EPIP-Evoked Modifications of Redox, Lipid, and Pectin Homeostasis in the Abscission Zone of Lupine Flowers

“…This, in turn, triggers in the cytoplasm of AZ cells a signal transduction pathway involving MAP kinases that activates transcriptional factors, e.g., KNAT2 and KNAT6 (knotted-like from Arabidopsis thaliana 2 and 6), which induce organ abscission [ 23 , 24 ]. AZ activation requires intensive de novo synthesis of proteins [ 25 ] that are involved in the degradation of cell walls, but also in some cases the formation of newly-formed cell walls of daughter cells. Moreover, observations of cell organelles, including chloroplasts and nuclei, indicated DNA fragmentation and possible induction of programmed cell death (PCD), probably caused by intensive reactive oxygen species (ROS) generation [ 2 , 20 , 23 , 24 , 26 ].…”