Zinc Provisioned Enhancement of Manganese Use Efficiency Results in Differential Biomass and Grain Production in Two Rice Cultivars Grown in Clay Loam Soil

Zinc (Zn) and manganese (Mn) regulate multiple cellular processes in plants. However, the Zn and Mn interactive growth and development of rice remains largely unknown in clay loam soils. Previously, we reported the preference of rice cultivars for Zn and Mn nutrition to mitigate salinity stress. Here, we investigated biomass and yield enhancements of rice relevant to aboveground Zn and Mn interactive accumulations. Two rice cultivars (Basmati-515 and KSK-282) were subjected to four treatments, viz. control, Zn, Mn and Zn+Mn, in a pot experiment using clay-loam soil. The enhancements of plant height and root length caused increases in shoot dry weight (SDW) and root dry weight (RDW) of Basmati-515 and KSK-282 under Zn+Mn in comparison to Mn treatment. These regulations were enforced by the contrasting Zn and Mn concentrations as well as contents in root, shoot, husk and grains of both rice cultivars. Somehow, the augmentation of Zn concentration and contents manifested decreases in Mn concentration and contents in root, shoot, husk and grains of rice cultivars. Contrarily, the upsurges in manganese use efficiency (MnUE) of both Basmati-515 and KSK-282 highlighted the influential role of Zn in Zn+Mn treatment. This positive thrust in MnUE induced increments in length of panicle, number of panicles plant-1, number of branches panicle-1, number of filled grains panicle-1, number of filled grains pot-1 and grain weight pot-1 in KSK-282. The provision of Zn enhanced MnUE in both rice cultivars; however, this enhancement bettered the biomass and grain production of KSK-282.