|
| Heavy metal | Plant | Toxic effect on plant | Reference |
|
| As | Rice (Oryza sativa) | Reduction in seed germination; decrease in seedling height; reduced leaf area and dry matter production | [35, 36] |
| Tomato (Lycopersicon esculentum) | Reduced fruit yield; decrease in leaf fresh weight | [37] |
| Canola (Brassica napus) | Stunted growth; chlorosis; wilting | [38] |
|
| Cd | Wheat (Triticum sp.) | Reduction in seed germination; decrease in plant nutrient content; reduced shoot and root length | [33, 39] |
| Garlic (Allium sativum) | Reduced shoot growth; Cd accumulation | [40] |
| Maize (Zea mays) | Reduced shoot growth; inhibition of root growth | [41] |
|
| Co | Tomato (Lycopersicon esculentum) | Reduction in plant nutrient content | [42] |
| Mung bean (Vigna radiata) | Reduction in antioxidant enzyme activities; decrease in plant sugar, starch, amino acids, and protein content | [43] |
| Radish (Raphanus sativus) | Reduction in shoot length, root length, and total leaf area; decrease in chlorophyll content; reduction in plant nutrient content and antioxidant enzyme activity; decrease in plant sugar, amino acid, and protein content | [44] |
|
| Cr | Wheat (Triticum sp.) | Reduced shoot and root growth | [45, 46] |
| Tomato (Lycopersicon esculentum) | Decrease in plant nutrient acquisition | [47, 48] |
| Onion (Allium cepa) | Inhibition of germination process; reduction of plant biomass | [49] |
|
| Cu | Bean (Phaseolus vulgaris) | Accumulation of Cu in plant roots; root malformation and reduction | [50] |
| Black bindweed (Polygonum convolvulus) | Plant mortality; reduced biomass and seed production | [51] |
| Rhodes grass (Chloris gayana) | Root growth reduction | [52] |
|
| Hg | Rice (Oryza sativa) | Decrease in plant height; reduced tiller and panicle formation; yield reduction; bioaccumulation in shoot and root of seedlings | [32, 53] |
| Tomato (Lycopersicon esculentum) | Reduction in germination percentage; reduced plant height; reduction in flowering and fruit weight; chlorosis | [54] |
|
| Mn | Broad bean (Vicia faba) | Mn accumulation shoot and root; reduction in shoot and root length; chlorosis | [55] |
| Spearmint (Mentha spicata) | Decrease in chlorophyll a and carotenoid content; accumulation of Mn in plant roots | [56] |
| Pea (Pisum sativum) | Reduction in chlorophylls a and b content; reduction in relative growth rate; reduced photosynthetic O2 evolution activity and photosystem II activity | [57] |
| Tomato (Lycopersicon esculentum) | Slower plant growth; decrease in chlorophyll concentration | [58] |
|
| Ni | Pigeon pea (Cajanus cajan) | Decrease in chlorophyll content and stomatal conductance; decreased enzyme activity which affected Calvin cycle and CO2 fixation | [59] |
| Rye grass (Lolium perenne) | Reduction in plant nutrient acquisition; decrease in shoot yield; chlorosis | [60] |
| Wheat (Triticum sp.) | Reduction in plant nutrient acquisition | [61, 62] |
| Rice (Oryza sativa) | Inhibition of root growth | [63] |
|
| Pb | Maize (Zea mays) | Reduction in germination percentage; suppressed growth; reduced plant biomass; decrease in plant protein content | [64] |
| Portia tree (Thespesia populnea) | Reduction in number of leaves and leaf area; reduced plant height; decrease in plant biomass | [65] |
| Oat (Avena sativa) | Inhibition of enzyme activity which affected CO2 fixation | [66] |
|
| Zn | Cluster bean (Cyamopsis tetragonoloba) | Reduction in germination percentage; reduced plant height and biomass; decrease in chlorophyll, carotenoid, sugar, starch, and amino acid content | [67] |
| Pea (Pisum sativum) | Reduction in chlorophyll content; alteration in structure of chloroplast; reduction in photosystem II activity; reduced plant growth | [68] |
| Rye grass (Lolium perenne) | Accumulation of Zn in plant leaves; growth reduction; decrease in plant nutrient content; reduced efficiency of photosynthetic energy conversion | [69] |
|
