Table 1.

Related differential metabolites and the relative content identified in roots between the nitrogen deficiency treatments and CK.

Differential metabolites	metabolic pathway	RN-z	RN-h	RN-n
Adenosine	Purine metabolism	3.1275	6.8881	0.9724
Deoxyadenosine	Purine metabolism	7.2720	4.9004	11.9217
Hypoxanthine	Purine metabolism	0.5072	0.4723	1.9469
L-Citrulline	Agrine metabolism	1.4217	0.7875	5.2285
Ribitol	Riboflavin metabolism	0.3824	0.3191	0.2893
Riboflavin	Riboflavin metabolism	0.0712	0.0854	0.1066
Maltotriose	Carbohydrate digestion and absorption	2.6778	4.0549	4.4395
5-Hydroxyindoleacetate	Tryptophan metabolism	1.0192	1.1472	0.4855
Matairesinol	Biosynthesis of phenylpropanoids	0.3302	0.2307	0.1659
Dictamnine	Biosynthesis of alkaloids derived from shikimate pathway	0.0733	0.0641	0.0354
Glycerophosphocholine	Glycerophosphlipid metabolism	0.0332	0.0333	0.0658
Prunasin	Cyanoamino acid metabolism	0.0800	0.0853	0.0345
ADP-glucose	Amino sugar and nucleotide sugar metabolism	0.0486	0.0753	0.0208
	Starch and sucrose metabolism
L-Arabinose	Amino sugar and nucleotide sugar metabolism	0.0960	0.0710	0.1489
Glycogen	Starch and sucrose metabolism	0.0357	0.0532	0.0420
	Carbohydrate digestion and absorption
4-Guanidinobutyric acid；	Agrine and proline metabolism	3.4244	2.8916	4.8994
L-Proline	Agrine and proline metabolism	0.8593	0.5766	1.4069
	Carbapenem biosynthesis
Traumatic acid	alpha-linolenic acid metabolism	0.0392	0.0405	0.6521
Eicosapentaenoic acid	Unsaturated fatty acids metabolism	0.0686	0.0763	0.1419
S-Adenosyl-L-homocysteine	Cysteine and methionine metabolism	0.3255	0.2422	0.4603