Fig. 4. Effect of CO2 (ambient CO2, a p p r o x i m a t e l y 4 0 0 M , m o l m o l " ' a n d elevated
CO2. 7 0 0 p . m o l m o l - ' ) a n d i n c r e a s i n g d o s e s o f NH4NO3 ( 0 . 1 0 a n d 1 5 m M ) o n i S "C
i n n o d u l a t e d a l f a l fa at the age of 4 4 {A, c o r r e s p o n d i n g to 2 weeks of treatment)
a n d 60 d a y s (B, c o r r e s p o n d i n g t o 4 w e e k s o f t r e a t m e n t ) . M e a s u r e s w e r e made using
samples o f w h o l e plant. T h e SE w a s less t h a n 1 %. Bars r e p r e s e n t the m e a n ± SE; n = 8.
Bars w i t h t h e same l e t t e r are n o t s i g n i f i c a n t l y d i f f e r e n t (P > 0.05) a c c o r d i n g LSD test.