Developmental and Structural Section
Sarkar, Purbasha , Gladish, Daniel, K. .
Identification and characterization of cell death mechanisms involved in hypoxia-induced vascular cavity formation in pea (Pisum sativum) primary roots.
In warm temperatures, hypoxic stress caused by high water content or low oxygen levels in the growth medium induce cell lysis in the central vascular cylinder of the primary roots, which results in formation of long vascular cavities in many cool-season legumes. Roots that form full-length cavities continue growth under the stressful conditions, whereas those that do not, stop growing. This suggests that the function of vascular cavities is to provide a passageway for oxygen to the roots. This function is similar to that of aerenchyma found in cortical tissue of roots of aquatic plants and some other plants such as maize and rice, when subjected to hypoxic conditions. The cell death mechanism involved in cortical aerenchyma formation has been reported to be programmed cell death (PCD). We have observed some characteristics of PCD in vascular cavity-forming roots of Pisum sativum. Ultra-structural studies using transmission electron microscopy showed thinning of cell walls, cytoplasmic shrinkage and nuclear distortion. Significant changes in the quantity and distribution pattern of cell wall pectins were observed by in situ immunolabeling. DNA fragmentation, which is a hallmark of PCD, has been detected by TUNEL in the vascular region of cavity-forming roots. The current study includes detection of DNA laddering by gel electrophoresis to determine the size of DNA fragments produced and to identify the stages of cell death where initiation and further fragmentation of DNA takes place. This study also determines if other hallmarks of PCD such as release of cytochrome c from mitochondria is involved in vascular cavity formation. These findings will provide further insights into the cell death mechanisms involved in vascular cavity formation and enrich our understanding of PCD in plants.
Log in to add this item to your schedule
1 - Miami University, Department of Botany, Oxford, Ohio, 45056, USA
2 - Miami University, Botany, 544, Mosler Hall, Hamilton, Ohio, 45011, USA
Programmed Cell Death.
Presentation Type: Oral Paper:Papers for Sections
Location: Boulevard C/Hilton
Date: Tuesday, July 10th, 2007
Time: 4:15 PM