Abstract Detail

Frontiers in fern gametophyte research

Wada, Masamitsu [1].

The fern gametophyte as a model system for chloroplast movement analysis.

Fern gametophytes are a good model system for cell biological and photobiological studies on phenomena common to both ferns and seed plants, while not possible using higher plant tissues. Because of their high sensitivity to light, and simple structure being not covered with any other tissue, manipulation and observation of cells are quite easy. I will show in my talk some experimental results on chloroplast movement analyzed using either protonemata or prothalli of Adiantum capillus-veneris. A protonema cultured under red light gave rise to a long cell with one nucleus. These long protonemal cells are quite useful in facilitating studies of chloroplast movement as it allows one to make a cell fragment without nucleus and/or to measure the speed of signal transfer in chloroplast movement. Chloroplast movement could be observed in an enucleated cell, meaning that gene expression is not involved in the signal transduction pathways of chloroplast movement. When a part of dark-adapted long cell was irradiated with a red or blue microbeam 20 µm in width to induce chloroplast movement, chloroplasts moved from a non-irradiated area towards the light irradiated area. Chloroplasts located at different distances from the light irradiated area, started to move when the signal emitted from photoreceptors in the light irradiated area reached the chloroplasts. The speed of the signal transfer can be calculated from the relationship between the distance of chloroplast location from the light irradiated area and the time that the chloroplast movement starts. The speeds are dependent on cell polarity but not on wavelength. One-layer thick two-dimensional prothalli are also useful material for chloroplast movement analyses. Opposite to one directional movement in protonemal cells, chloroplasts can move two dimensionally showing accumulation towards small beam spot or escape from strong light spot. Moving behavior of chloroplasts and the route of movement could easily be analyzed. I will show how chloroplasts move and how they use actin filaments raising motive force of the movement.

Broader Impacts:

1 - Kyushu University, Biology Department, Hakozaki 6-10-1, Higashi-ku, Fukuoka, 812-8581, Japan

Keywords:
Adiantum capillus-veneris
chloroplast movement
light
phototropin
neochrome
actin filament.

Presentation Type: Symposium or Colloquium Presentation
Session: C4
Location: Prince of Wales/Riverside Hilton
Date: Tuesday, July 30th, 2013
Time: 11:30 AM
Number: C4012
Abstract ID:289
Candidate for Awards:None