Table 1.

Major classes of secondary metabolites in poplars and Populus species applied in these studies.

Secondary Metabolite Product	Populus Species	Reference
Shikimate–Phenylpropanoid	Populus trichocarpa Populus tremula × Populus alba	[5,6]
Flavonoids	Populus tomentosa Populus deltoides Populus trichocarpa	[7,8,9,10]
Anthocyanins	Populus deltoides (sp. Linn) Populus deltoids	[11,12]
Phenolic Glycosides	Populus davidiana	[13]
Hydroxycinnamates	Populus tomentosa Populus tremuloides	[14,15]
Fatty acids	Populus trichocarpa Populus nigra Populus × euramericana Populus deltoides	[16,17,18,19]
Terpenoid	Populus euphratica Populus × canescens Populus trichocarpa Populus × euramericana (sp. Nanlin)	[20,21,22,23,24,25]