[Effects of soil moisture condition and phosphorus supply on the seedlings growth and phosphorus efficiency of Schima superba provenances].

Taking four representative Schima superba provenances from Longquan in Zhejiang, Jian'ou and Youxi in Fujian, and Ji'an in Jiangxi as test materials, and with the S. wallichii from Guangxi as the contrast, a pot experiment was conducted to study their seedlings growth and physiological responses under effects of different soil moisture condition and phosphorus supply. Significant differences were observed in the seedlings growth, root morphological parameters, and phosphorus absorption efficiency among the provenances under different soil moisture condition and phosphorus supply. The provenances from Jian'ou in Fujian and Longquan in Zhejiang exhibited larger growth increment, more developed root, and higher phosphorus absorption efficiency, compared with those from Youxi in Fujian and Ji'an in Jiangxi, while the S. wallichii from Guangxi Province remained its original characteristics of fast growing and drought and infertility resistance. Soil moisture condition and phosphorous supply had significant effects on the growth and development of S. superba. The seedlings growth, dry matter accumulation, root parameters, and phosphorus absorption efficiency were 18.5%-105.6% higher under appropriate soil moisture condition than under drought stress, and 37.5%-286.2% higher under high phosphorus than under low phosphorus supply. However, under drought stress and low phosphorus supply, S. superba seedlings allocated more photosynthetic products to their roots, and had higher phosphorus use efficiency, which could be an important physiological mechanism of the adaptation to drought stress and low phosphorus supply. Relative to the significant independent effects of provenance, watering level, and phosphorus supply, no significant interactive effects of the three factors were observed.