Phosphorus assimilation of Chinese fir from two provenances during acclimation to changing phosphorus availability

• DOI: 10.1016/j.envexpbot.2018.04.013
• Publication Date: 2018-05-05T16:05:54Z
• Authors: Yinghao Chen; Thi Hong Nhung Ng...; Jingjing Qin; Yu Jiao; Ziliang Li; Shen Ding; Yan Lu; Qifeng Liu; Zhi-Bin Luo
• Keywords: Assimilation (phonology); Phosphorus deficiency

Abstract To identify the differences in phosphorus (P) assimilation of Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) from provenances Y and G displaying slow and fast growth, respectively, and to elucidate the physiological acclimation mechanisms of these conifers to changes in P availability, Chinese fir seedlings were treated with 0 (P starvation), 2 (normal P) or 4 (high P) mM P. The conifer from provenance Y had a greater specific root surface area, and higher activities of APs and PEPC in the roots, resulting in higher P concentrations and lower PUEs in the roots than those from provenance G. Notably, higher activities of APs, PEPC and MDH, and a greater PUE were observed in the needles from provenance G compared to those from provenance Y supplied with high P level. The transcriptional regulation responsiveness of several genes involved in P acquisition and transport was stronger in conifers from provenance Y than those from provenance G treated with P starvation, but the opposite was true under high P condition. These results suggest that Chinese fir from provenance Y possesses a greater capacity for P acquisition and transport compared to that from provenance G under low P availability, whereas conifers from provenance G can more efficiently utilize available P to produce biomass than those from provenance Y under high P conditions. P starvation resulted in increased specific root surface area, higher activities of APs, PEPC and MDH, lower P concentrations, and higher PUEs in Chinese fir, while high P supply caused the opposite changes. Consistently, P starvation led to transcriptional overexpression of genes involved in P acquisition and transport including PHT1.4 and PHO1, AP, and MDH in Chinese fir, and high P availability suppressed PHT1.4 transcript levels and increased PHT2.1 mRNA levels. These results suggest that Chinese fir can activate P-solubilizing enzymes, and upregulate transcript levels of key genes involved in P acquisition and transport under P deficiency conditions, whereas the conifers can enhance P translocation from the roots to the shoots to promote the growth of aerial parts under high P conditions.