Intercropping of Gramineous Pasture Ryegrass (Lolium perenne L.) and Leguminous Forage Alfalfa (Medicago sativa L.) Increases the Resistance of Plants to Heavy Metals

Table 3

Concentration and total uptake of metals in ryegrass and alfalfa tissues.

Plant	Metal	Treatment	Concentration (mg·kg^−1)		Total uptake (μg·plant^−1)
			Shoot	Root	Shoot	Root
Ryegrass	Pb	Monoculture	75.2 ± 9.8^a	394 ± 5.2^a	39.0 ± 5.1^a	52.3 ± 0.7^a
		Intercropping	30.3 ± 0.5^b	198 ± 7.6^b	17.2 ± 0.3^b	35.5 ± 1.4^b
	Cd	Monoculture	1.14 ± 0.1^a	46.9 ± 0.3^a	0.59 ± 0.07^b	6.39 ± 0.1^a
		Intercropping	1.29 ± 0.1^a	36.5 ± 8.9^a	0.73 ± 0.06^a	6.57 ± 1.6^a
	Zn	Monoculture	87.2 ± 10.9^a	168 ± 7.5^a	45.4 ± 5.7^b	45.4 ± 5.7^b
		Intercropping	94.3 ± 4.6^a	193 ± 24.0^a	53.6 ± 2.6^a	53.6 ± 2.6^a
Alfalfa	Pb	Monoculture	69.7 ± 2.2^a	66.7 ± 1.0^a	23.5 ± 0.8^a	15.8 ± 0.2^a
		Intercropping	53.8 ± 2.4^b	26.6 ± 6.1^b	25.4 ± 1.1^a	9.91 ± 2.3^a
	Cd	Monoculture	2.71 ± 0.4^a	3.84 ± 1.3^a	0.91 ± 0.30^a	1.16 ± 0.01^a
		Intercropping	2.11 ± 0.1^b	2.55 ± 1.3^a	0.95 ± 0.04^a	0.55 ± 0.14^b
	Zn	Monoculture	62.3 ± 8.9^a	33.6 ± 5.4^a	21.0 ± 3.0^b	7.95 ± 1.3^b
		Intercropping	57.9 ± 6.2^a	30.0 ± 2.0^a	27.4 ± 3.0^a	11.2 ± 0.7^a

Note. Values are the means ± standard error (. Means followed by the same letter are not significantly different at .