Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: Autophagic response of higher plant cells to a prolonged period of sucrose deprivation. | 797s Ann. Sci. For. 1989 46 suppl. 797s-806s Forest Tree Physiology E. Dreyer et al. eds. Elsevier INRA Autophagic response of higher plant cells to a prolonged period of sucrose deprivation R. Bligny1 c. Roby2 A. Dome1 and R. Douce1 CEN-G and Université Joseph-Fourier DRF Pcvl and DRF RMBM2 85X F-38041 Grenoble Cedex France Introduction One of the most original properties of higher plant metabolism lies in the great flexibility of their adaptation processes when faced with variable environmental conditions. Thus sudden temperature drop water stress or the decrease of the circadian light period diminishes the rates of intracellular carbohydrate biosynthesis. Consequently the supply of organic carbon necessary for sustaining cell respiration may be decreased. However plant cells owing to the presence of intracellular pools of carbohydrate and to their ability to control an autophagic process can survive for a period of several days without synthesizing or receiving any additional organic carbon. Some morphological observations have shown that in higher plant cells portions of the cytoplasm including cell organelles such as mitochondria may be engulfed by the tonoplast membrane for a review see Matile and Wiemken 1976 . In this study we try to biochemically characterize the changes occurring in higher plant cells after a prolonged period of sucrose deprivation followed by a period of recovery. Materials and Methods Sycamore Acer pseudoplatanus L. cells were grown in a nutrient medium as described previously Bligny 1977 except Mn2 was excluded to prevent excessive broadening of the vacuolar 31 p orthophosphate resonance in 31 p nuclear magnetic resonance NMR experiments. Cells harvested from the culture medium were rinsed 3 times by successive resuspensions in fresh culture medium devoid of sucrose and incubated in flasks containing sucrose-free culture medium. Every 5 or 10 h cells were harvested for perchloric acid PCA extraction Roby et al. 1987 sucrose and starch
