Effects of sodium chloride on Cornus stolonifera: Responses of actively growing seedlings and of seedlings during bud break.

摘要

Cornus stolonifera has been identified as a relatively salt tolerant species compared to other species of the boreal forest. Understanding the effects of NaCl on C. stolonifera is necessary as this species has been recommended for the reclamation of saline oil sands tailings. Both actively growing and dormant seedlings may be planted on sites to be reclaimed. The effect of salt stress on both actively growing and dormant seedlings was examined. Seedlings were treated hydroponically with NaCl. Shoot dry weight, stomatal conductance, transpiration and photosynthetic rates were reduced by NaCl in actively growing seedlings. The amount of hemicellulose in the cell wall of actively growing seedlings increased during salt stress. Plant water relations, cell wall elasticity and the carbohydrate composition of the pectin and hemicellulose fractions were not affected by the salt stress. Dormant seedlings treated with NaCl during bud break had lower shoot dry weights and shoot heights than untreated seedlings. The cell walls of seedlings treated with NaCl during bud break were more rigid, but the plant water relations suggest that this change did not contribute to salt tolerance. Salt stress did not alter the cell wall composition of seedlings treated with NaCl during bud break. The results of this study suggest that actively growing C. stolonifera seedlings may be more salt tolerant than seedlings during bud break; however, more work will need to be done to gain a more complete understanding of salt tolerance in C. stolonifera.