Table 5.

Summary of research on modeling methods

Plant species	Heavy metal stress	Study area	Modeling methods	Reference
Rice	Cu, Pb	Leaf	PLSR	[97]
Brown rice	Cd	Leaf	PLSR	[70]
Miscanthus sacchariflorus	Cd	Leaf and root	PLSR, LS-SVM	[14]
Barley	Cd, Pb, As	Leaf	PLSR, MLR	[89]
Mustard spinach	Hg	Leaf	SMLR	[58]
Grapevine foliage	Cu, Zn, Pb, Cr, Cd	Leaf	MLR, SVM	[40]
Rice	Cd, Pb	Canopy	SVM	[94]
Rice	Cd, Pb	Canopy	SVM	[50]
Lettuce	Cd	Leaf	SVM	[98]
Lettuce	Cd, Pb	Leaf	SVR	[53]
Lettuce	Pb	Leaf	SVR	[71]
Lettuce	Cd	Leaf	SVR	[47]
Lettuce	Pb	Leaf	SVR	[99]
Oilseed rape	Pb	Leaf	SVR	[48]
Tobacco	Hg	Canopy	PLS-DA, LS-SVM	[7]
Lettuce	Pb	Leaf	PLS-DA, SVM, DBN	[61]
Lettuce	Cd	Leaf	PLSR, SVR, PSO-DBN	[37]
Rice	Cu, Cd	Leaf	BPNN	[54]