Jayawardena Dileepa M, Heckathorn Scott A, Boldt Jennifer K
Department of Environmental Sciences, University of Toledo, Toledo, OH 43606, USA.
Agricultural Research Service, United States Department of Agriculture, Toledo, OH 43606, USA.
Plants (Basel). 2020 Dec 1;9(12):1689. doi: 10.3390/plants9121689.
The concentration of nitrogen (N) in vegetative tissues is largely dependent on the balance among growth, root N uptake, and N assimilation. Elevated CO (eCO) plus warming is likely to affect the vegetative-tissue N and protein concentration of wheat by altering N metabolism, but this is poorly understood. To investigate this, spring wheat () was grown for three weeks at two levels of CO (400 or 700 ppm) and two temperature regimes (26/21 or 31/26 °C, day/night). Plant dry mass, plant %N, protein concentrations, NO and NH root uptake rates (using NO or NH), and whole-plant N- and NO-assimilation were measured. Plant growth, %N, protein concentration, and root N-uptake rate were each significantly affected only by CO, while N- and NO-assimilation were significantly affected only by temperature. However, plants grown at eCO plus warming had the lowest concentrations of N and protein. These results suggest that one strategy breeding programs can implement to minimize the negative effects of eCO and warming on wheat tissue N would be to target the maintenance of root N uptake rate at eCO and N assimilation at higher growth temperatures.
营养组织中氮（N）的浓度在很大程度上取决于生长、根系对氮的吸收和氮同化之间的平衡。高浓度二氧化碳（eCO）加升温可能会通过改变氮代谢来影响小麦营养组织中的氮和蛋白质浓度，但对此了解甚少。为了研究这一点，春小麦在两种二氧化碳水平（400或700 ppm）和两种温度条件（26/21或31/26 °C，昼/夜）下种植三周。测量了植株干质量、植株含氮量、蛋白质浓度、根系对硝酸根（NO）和铵根（NH）的吸收速率（使用NO或NH）以及全株氮和NO同化情况。植株生长、含氮量、蛋白质浓度和根系氮吸收速率仅受二氧化碳显著影响，而氮和NO同化仅受温度显著影响。然而，在eCO加升温条件下生长的植株氮和蛋白质浓度最低。这些结果表明，育种计划可以实施的一种策略是，在eCO条件下维持根系氮吸收速率，并在较高生长温度下维持氮同化，以尽量减少eCO和升温对小麦组织氮的负面影响。
