Improved Cold Tolerance is Associated with Altered Cell Wall Composition in Pre-Planted Tobacco

摘要

Tobacco seedlings produced by floating system are susceptible to cold injury. This problem can be solved by pre-planting technique. However, little is known about the mechanism underlying the improved cold tolerance in pre-planting tobacco. To investigate it, the cytological features of the leaf and root cells from floating and pre-planting tobacco were studied. Obvious cold injury and rupture of cell membrane system were observed in the cells from floating tobacco under cold stress conditions but very little in the cells from pre-planting tobacco. The cell wall in cells from pre-planting tobacco was thicker than in floating tobacco before cold stress. The cell wall was higher in cellulose and pectin contents in pre-planting tobacco than in floating tobacco before and after cold stress. These results suggest that pre-planting technique facilitates the accumulation of cell wall compositions-cellulose and pectin in pre-planting plants to prevent the cold injury, and possibly attenuates the negative effect of flooding stress on cell wall composition.