Table 1.

Summary of read numbers based on the RNA-SEQ data from poplar roots under different N forms.

	S1 [${\text{NH}}_4^{+}$]	S2 [NH4NO3]	S3 [${\text{NO}}_3^{-}$]
Total reads	5,981,660	6,075,136	6,175,206
Mapped reads	3,829,967	4,503,472	4,694,482
	(64.04%)	(74.10%)	(76.03%)
Unique match	3,226,026	3,996,757	4,186,976
	(53.94%)	(65.76%)	(67.81%)
Multi-position match	603,940	506,714	507,506
	(10.08%)	(8.34%)	(8.22%)
Unmapped reads	2,151,693	1,571,664	1,480,724
	(35.96%)	(25.90%)	(23.97%)