Abstract:

The spatial distributions of the effective nitrogen and phosphorus possess great heterogeneity in forest soil, which results in unbalance supply of introgen and phosphorus for the rhizosphere of forest trees. In this resent paper,unbalance supply of nitrogen and phosphorus was applied to Fraxinus mandshurica seedlings, and we studied the uptake of nitrogen and phosphorus,growth response,and the ability to integrate nitrogen and phosphorus resources of these seedlings.Our results showed that total amount of nitrogen and phosphorus in an individual seedling supplied with balanced nitrogen and phosphorus was significantly higher than that in an individual seedling supplied with unbalanced nitrogen and phosphorus.Nitrogen concentration in leaves of nitrogen-deficient seedlings was significantly lower than that in leaves of nitrogen-enough seedlings.Nitrogen deficiency increased specific leaf area.Unbalance supply of nitrogen and phosphorus reduced biomass partitioning to leaves and increased biomass partitioning to roots.Total biomass of seedlings supplied with balanced nitrogen and phosphorus was significantly higher than that of seedlings supplied with unbalanced nitrogen and phosphorus,suggesting that F. mandshurica seedlings don’t have ability to integrate nitrogen and phosphorus resources.

Key words: Fraxinus mandshurica seedling, balance of nitrogen and phosphorus, uptake, growth, resources integration