Inhibitory effect of colchicine on growth and gravitropic responses in Arabidopsis root was explored to find whether there was an involvement of ethylene production. It has been known that cytoskeleton components are implicated in sedimentation of statoliths to respond to gravitropism and growth. The root growth was inhibited by 25% and 40% over control for 8 hr treatment of colchicine at a concentration of 10-5 M and 10-7 M, respectively. The roots treated with colchicine at the concentration of 10-7 M showed the same pattern as control in 3 hr, however, gravitropic response was decreased in the next 5 hr. The colchicine treatment at the concentration of 10-5 M inhibited the gravitropic response resulting in 60° of curvature. In order to better understand the role of colchicine, the production of ethylene was measured with and without the treatment of colchicine. Colchicine increased the ethylene production by 20% when compared to control via the activation of ACC oxidase and ACC synthase activity. These results suggest that the inhibition of the growth and gravitropic responses of Arabidopsis roots by the treatment of colchicine could be attributed to the rearrangement of microtubule, and increase of ethylene production.

Ultrastructural studies on oocyte differentiation and vitellogenesis in the oocytes of female Kareius bicoloratus were investigated by transmission electron microscopy. The Golgi complex in the cytoplasm is involved in the formation of yolk vesicles that contain yolk carbohydrates in the yolk vesicle of oocytes in the early vitellogenic phase. In this phase, many pinocytotic vesicles (PVs), which are formed by pinocytosis, contain yolk precursors (exogenous substances). These substances are associated with exogenous heterosynthetic vitellogenesis. In yolked oocytes in the late vitellogenic phase, two morphologically different bodies, which formed by modified mitochondria, appear in oocytes. One is a multivesicular body (synthesized by autosynthetic vitellogenesis), and the other is a yolk precursor (an exogenous substance formed by heterosynthetic vitellogenesis). The multivesicular bodies (MVB) are taken into the yolk precursors (YP) and are transformed into primary yolk globules. However, after the YP mix with exogenous PVs near the zona pellucida, they are transformed into primary yolk globules. Vitellogenesis of this species occurs via endogenous autosynthesis and exogenous heterogenesis. Vitellogenesis occurs through endogenous autosynthesis, which involves the combined activity of the Golgi complex, mitochondria and MVB formed by modified mitochondria. However, heterosynthesis involves pinocytotic incorporation of extraovarian precursors (such as vitellogenin in the liver) into the zona pellucida (via granulosa cells and thecal cells) of the yolked oocyte.