Springer Online Journal Archives 1860-2000
Summary Cytoplasmic structure and rates of cyclosis in trichomes from chilling-sensitive watermelon (Citrullus vulgaris L.), tomato (Lycopersicon esculentum Mill.) andEpiscia reptans plants and from chilling-resistant foxglove (Digitalis purpurea) andVeronica persica were examined with differential interference contrast optics (DIC) as the temperature of the microscope stage was lowered. Below the chilling threshold, the rate of streaming in chilling-sensitive species fell markedly. At chilling temperatures the complex network of transvacuolar strands in the cytoplasm disappeared and the cytoplasm became vesiculated. During rewarming of the chilled cells, the vesicles fused into pleiomorphic blebs, which gradually stretched out into fully functional strands. These events were not seen during the chilling and rewarming of chilling-resistant plant cells. Similar inhibition of cyclosis and changes in cytoplasmic structure were observed in cells from all species studied when they were treated with the actin inhibitor, cytochalasin B, or with uncoupling agents. Phalloidin had no detectable effect. Cyclosis in colchicine-, nocodazole-, trifluralin- and IPC-treated cells was not affected for many hours and did not cause the structural changes seen with chilling. The possible role of actin in these low-temperature effects on cytoplasmic structure and function is discussed.
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