Effects of Mn-Cd antagonistic interaction on Cd accumulation and major agronomic traits in rice genotypes by different Mn forms
,?2017,82(2):317-331.
10.1007/s10725-017-0261-8
Abstract
The antagonistic interaction between Mn (Manganese) and Cd (Cadmium) was studied in Milyang 46 and Zhenshan 97B rice varieties in relation to Cd tolerance and accumulation in hydroponics. Additionally, a new method controlling Cd uptake and accumulation was established with Jinzao 47 and Zhongjiazao 32 rice varieties with similar growth periods in a soil culture system by application of different forms of Mn. (1) In hydroponics, the results showed that MnSO4 (9.1 and 91 μM) and EDTA·Na2Mn (9.1 μM) significantly alleviated Cd toxicity at high levels of Cd (1.0 and 5.0 μM), and Cd accumulation in roots and root plates were significantly reduced in contrast to shoots, but 91 μM EDTA·Na2Mn posed serious Mn toxicity in both rice genotypes, and increasing Cd levels could reduce Mn accumulation. (2) In a soil culture system, for rice shoots, roots and grains, soil application of MnSO4 significantly increased Cd accumulation, but EDTA·Na2Mn greatly decreased Cd accumulation and ameliorated Cd-induced pre-senescence. Furthermore, foliar application of MnSO4 or EDTA·Na2Mn reduced Cd accumulation in grains but increased Cd accumulation in shoots at the mature stage. Our data suggest there is significant interaction between Mn and Cd in relation to the forms of Mn. Alleviation of MnSO4 on Cd toxicity, and Cd accumulation in plants occurred only under Mn deficiency. Additionally, EDTA·Na2Mn is a chelated Mn complex, relatively more stable than MnSO4, and could maintain a high level of Mn2_add_ for a longer period in solution; therefore, EDTA·Na2Mn instead of MnSO4 could be a practical way to control Cd accumulation in rice.