بررسي تغييرات حجم واكويل در سلول هاي مريستم نوك ريشه برنج (Oryza sativa L)تحت تاثير تنش شوري

Study of changes in volume of vacuole in meristem cells at root tip of rice {Oryza sative L.) under saline conditions

To study changes of volume of vacuole meristemic cells at the root tip of rice under saline conditions, suspension-cultured cells and protoplasts from three rice genotypes including IR29 (susceptible), and IR651, Ahlami-Tarom (tolerant rice cultivars) were treated with 0.1 M NaCl, 0.2 M mannitol, 20 nM bafilomycin Al, 0.1M NaCl complemented with 20 nM bafilomycin Al and distilled water (as control). Sampling carried out at 3, 8 and 24 hours after application of treatments. Results showed that vacuolar volumes increased only in tolerant cultivars when treated with NaCl. However, after exposure of cells to the mannitol with osmolarity similar to 0.1 M NaCl, such drastic changes were not observed in the vacuole volumes, indicating that salt-specific effect responses in vacuoles. Furthermore, bafilomycin Al completely inhibited the increase of vacuolar volume due to NaCl effects. This findings suggest that the V-ATPase may play an essential role in energizing a Na+/H+ antiporter activity as well as vacuolar Na+ compartmentation in meristimeic cells at the root tip of rice.