Effect of aluminum stress on the absorption and transportation of aluminum and macronutrients in roots and leaves of Aleurites montana

Abstract

Aluminum toxicity is common in subtropical acidic soils, and the effect of Al stress on Aleurites montana is unknown. This study determined the growth and Al and macronutrient contents (C, N, P, K, Ca, and Mg) in leaves and roots of 1-year-old A. montana seedings to reveal the effects of Al stress on growth and elements of A. montana seedings and the difference of growth and content of elements in potted seedlings and hydroponic seedlings under Al addition. The content of Al in the leaves of potted A. montana seedlings was greater than 1000 mg kg−1 under Al stress, so it can be judged that A. montana is likely an Al accumulator and has a high Al tolerance in potted soil. The changes of macronutrient contents in the seedlings varied with Al concentration. For potted seedlings, Al stress had a significant effect on Mg and K contents in roots and Mg and C contents in leaves, but it had no effect on other macronutrients, such as N, P and Ca. For hydroponic seedlings, Al content in roots and N, P, and K contents in roots and leaves increased significantly, and C and Ca contents in roots decreased significantly when the Al concentration exceeded 0.290 mmol L−1. The Al stress affected the distribution and transportation of macronutrients between roots and leaves. The Al and K contents in the roots were higher than those in leaves in both cultivation methods, while the C, N, and Ca contents were smaller than those in leaves. The transportation of N, P and Ca from root to leaf in potted seedlings changed with the increase of Al concentration. There were major differences in the growth and the absorption and transportation of elements between potted and hydroponic seedlings under Al stress. In this study, Al promoted or had no significant effect on the growth of potted seedlings, while the growth of hydroponic seedlings was significantly inhibited when the Al concentration was relatively high. Moreover, the effect of Al concentration on Al and macronutrients of potted seedlings was less than that of hydroponic seedlings. Therefore, the effects of the primary environment should be considered in future stress experiments. This study revealed the effect of Al concentration on A. montana seedlings from the perspective of growth and nutrition, which are crucial in ecological restoration function of mixed tree species in acid rain area. Comparison of the effects of Al concentration on A. montana seedlings under two cultivation methods provides new perspectives for future stress test research.