3Sehat H, SharmaS S, Vooijs R. Heavy metal-induced accumulation of free praline in a metal-tolerant and a nontolerant ecotype of Silene vulgaris[J]. Physiol Plant, 1997, 101: 477-482.
4Bassi R Sharma SS. Proline accumulation in wheat seeding exposed to zinc and copper[J]. Phytochemistry, 1993, 33: 1339-1342.