Abstract: Nutrient internal cycling plays an important role in reducing the nutrient loss while enhancing its use efficiency by trees. The fine root of trees is short in life but fast in turnover, and thus, the research of nutrient internal cycling in tree fine root has being recognized in recent two decades. This paper discussed the significance of nutrient internal cycling in tree fine root, introduced the current situations of its research at home and abroad, and prospected its research trend in the future.

Key words: Paralytic shellfish toxins, Red tides, HPLC, Mouse bioassay