Nitrogen preference across generations under changing ammonium nitrate ratios

Aims Nitrogen(N)in natural environments is typically supplied by a mix-ture of ammonia(NH_(4)^(+))and nitrate(NO_(3)^(-)).However,factors that underlie either NH_(4)^(+)or NO_(3)^(-)preference,and how such preference will change across generations remain unclear.We conducted a series of experiments to answer whether:(i)NH_(4)^(+):NO_(3)^(-)ratio is the driving factor for plant N preference,and(ii)this preference is con-sistent across generations.Methods We conducted both:(i)field observations(as a proxy for parent or P generation)and(ii)greenhouse experiments(the first generation or F1 and the second generation or F2)using corn and soybean grown under different NH_(4)^(+):NO_(3)^(-)ratios.Important Findings Both corn and soybean had the physiological plasticity to pre-fer either NH_(4)^(+)or NO_(3)^(-)depending on NH_(4)^(+):NO_(3)^(-)ratios,and this plasticity was consistent across generations.Corn,however,showed a stronger preference towards NO_(3)^(-)while soybean showed a stronger preference towards NH_(4)^(+).While both plants would try to make use of the most available form of N in their growing medium,plant species,physiological characteristics(e.g.maturity)and plant nutrient status also determined the extent of N uptake.From the evolutionary and productivity perspective,this plasticity is benefi-cial,allowing plants to effectively acquire available N particularly in a changing climate.