Photosynthetic characteristics and nitrogen allocation in the black locust (Robinia pseudoacacia L.) grown in a FACE system

• Published in: Acta physiologiae plantarum 2017-03, Vol.39 (3), p.1-12, Article 71
• Main Authors: Choi, Dongsu, Watanabe, Yoko, Guy, Robert D., Sugai, Tetsuto, Toda, Hiroto, Koike, Takayoshi
• Format: Article
• Language: English
• Subjects: Acetylene; Acetylene reduction; Agriculture; Biomedical and Life Sciences; Carbon dioxide; Carboxylation; Chlorophyll; Electron transport; Environmental changes; Growth rate; Leaves; Life Sciences; Light-harvesting complex; Nitrogen; Original Article; Oxygenase; Photosynthesis; Photosystem I; Photosystem II; Physiological responses; Plant Anatomy/Development; Plant Biochemistry; Plant Genetics and Genomics; Plant Pathology; Plant Physiology; Proteins; Reduction; Regeneration; Ribulose-1,5-bisphosphate; Ribulose-bisphosphate carboxylase; Seasons; Symbiosis
• ISSN: 0137-5881; 1861-1664
• DOI: 10.1007/s11738-017-2366-0

Key message The black locust is adapted to elevated [CO 2 ] through changes in nitrogen allocation characteristics in leaves. The black locust ( Robinia pseudoacacia L.) is an invasive woody legume within Japan. This prolific species has a high photosynthetic rate and growth rate, and undergoes symbiosis with N 2 -fixing micro-organisms. To determine the effect of elevated CO 2 concentration [CO 2 ] on its photosynthetic characteristics, we studied the chlorophyll (Chl) and leaf nitrogen (N) content, and the leaf structure and N allocation patterns in the leaves and acetylene reduction activity after four growing seasons, in R. pseudoacacia . Our specimens were grown at ambient [CO 2 ] (370 μmol mol −1 ) and at elevated [CO 2 ] (500 μmol mol −1 ), using a free air CO 2 enrichment (FACE) system. Net photosynthetic rate at growth [CO 2 ] ( A growth ) and acetylene reduction activity were significantly higher, but maximum carboxylation rate of RuBisCo ( V cmax ), maximum rate of electron transport driving RUBP regeneration ( J max ), net photosynthetic rate under enhanced CO 2 concentration and light saturation ( A max ), the N concentration in leaf, and in leaf mass per unit area (LMA) and ribulose-1,5-bisphosphate carboxylase oxygenase (RuBisCo) content were significantly lower grown at elevated [CO 2 ] than at ambient [CO 2 ]. We also found that RuBisCo/N were less at elevated [CO 2 ], whereas Chl/N increased significantly. Allocation characteristics from N in leaves to photosynthetic proteins, N L (Light-harvesting complex: LHC, photosystem I and II: PSI and PSII) and other proteins also changed. When R. pseudoacacia was grown at elevated [CO 2 ], the N allocation to RuBisCo (N R ) decreased to a greater extent but N L and N remaining increased relative to specimens grown at ambient [CO 2 ]. We suggest that N remobilization from RuBisCo is more efficient than from proteins of electron transport (N E ), and from N L . These physiological responses of the black locust are significant as being an adaptation strategy to global environmental changes.