PARENT SESSION
Posters P8C C4 and CAM. Abstracts (685-698)

Behavior of organelle in succulent plants under drought conditions. Ayumu Kondo^*,1, Keiko Shibata¹, Tatsuya Sakurai², Masahiro Tawata², Toru Funaguma¹, ¹ Faculty of Agriculture, Nagoya, Japan² Faculty of Science and Technology, Nagoya, Japan

ABSTRACT- In leaves of many succulent plants including Kalanchoë species, we found that clumping of chloroplasts is induced by light stress combined by water stress. In this case, the chloroplasts formed a spherical body within respective mesophyll cells (Kondo et al., Planta 2004). However, the positioning of other organelles except for the chloroplast was not investigated in detail. In this study we focused the behavior of cell nucleus and mitochondria in the phenomenon by fluorescence microscopy. In the leaves of well-watered plants, mitochondria were dispersed in wide area in the mesophyll cells, and 2 or 3 mitochondria located adjacent to each chloroplast. In the leaves of water-stressed plants, although many of mitochondria were observed in the clump of chloroplasts, they were also distributed in other area in the mesophyll cells. When the chloroplasts became densely clumped, the nucleus was observed in the clumped chloroplast. Structural analysis of the clump by use confocal laser microscope showed that the nucleus was localized within that just like concealing by many chloroplasts. It is suggested that the chloroplast movement in succulent plants have close connection with the nucleus. Cell function is consisted of the correlation between intracellular organelles, for instance that photorespiration operate from three organelles such as chloroplast, mitochondrion, and peroxisome. Considering effective cell function, the intracellular positioning and movement of organelles is very important. Further research is necessary to know how metabolic mechanism performs in the clumping phenomenon.ë

KEY WORDS: mitochondria, chloroplast clumping, nucleus, succulent plants