Poster: Cytoskeleton: Structure & Function

Abs # 1124: The effects of light on the morphology and motility of mitochondria in Arabidopsis thaliana

Presenter:	Königer, Martina , mkoniger@wellesley.edu
Authors	Königer, Martina  (A)   Jessen, Brita  (A)   Niwa, Yasuo  (B)   Harris, Gary C (A)
Affiliations:	(A): Wellesley College (B): University of Shizuoka

The mitochondria in many plant cells are capable of rapid movements and dynamic changes in shape. Using GPF-labeled mitochondria (Niwa et al. 1999, Plant Journal 18: 455-463) we investigated the effects of light on the morphology and motility of mitochondria in different tissues and cells of Arabidopsis thaliana leaves. In general, the mitochondria moved faster in epidermal cells than in guard cells. In the guard cells the mitochondria were either condensed or elongated and sometimes branched or long and circular. In guard cells most of the mitochondria were observed moving in the cortical area and in the vicinity of chloroplasts and the nucleus. Exposure of cells to a beam of blue light led to a rapid cessation of movement. Under all light conditions most mitochondria in the guard cells exhibited the condensed shape. Light intensity differentially influenced the prevalence of elongated mitochondria in adaxial and abaxial guard cells. Under high light (1500 µmol photons m ^-2 s ^-1 ) more elongated mitochondria were found in the abaxial guard cells, while in low light (4 µmol photons m ^-2 s ^-1 ) more elongated mitochondria were found in the adaxial guard cells.