Biosolubilized zinc from ZnO in bacterial culture supernatant enhanced seed germination, early growth, and zinc accumulation in rice (Oryza sativa L.) under hydroponic system through seed priming method

Presently, zinc sulfate (ZnSO4) based fertilizers are reported inefficient in flooded paddy fields which necessitates to find a better alternative for sustainable rice cultivation. This study was conducted to find out the effectiveness of bacterially solubilized Zn (BSZn) on the early growth of rice plants and the concentration of Zn in the plant parts in comparison to conventional ZnSO4. BSZn preparations were obtained from culture supernatant following ZnO solubilization by bacterial isolates Burkholderia spp. and Achromobacter sp. The effectiveness of BSZn was assessed on rice seed germination on Petri plates and the growth of seedlings upon treatment in hydroponic culture under controlled conditions. In general, BSZn obtained from certain Burkholderia spp. increased seed germination percentage (SG%) (98-100%), mean germination rate (MGR), mean daily germination (MDG), decreased mean germination time (MGT) and impart stimulating effect on seed germination as indicated by increased vigor indices compared to ZnSO4 treatment regimes. The obtained data from the hydroponic culture of rice seedling growth indicated a positive influence of most of the BSZn preparation on dry and wet weight of roots and shoots, and seedling length compared to ZnSO4 at p < 0.05. Both chlorophyll and carotenoid content of the seedling increased in the presence of some BSZn preparations. In general, compared to shoot, the root of seedlings accumulated a higher amount of Zn (up to 888 mg Zn/g dry biomass). Zn concentration data indicated that BSZn16 obtained from Burkholderia sp. EIKU16 culture help to accumulate significantly higher amounts of Zn in rice seedlings under hydroponic culture than that while treated with ZnSO4.

Automated summary

This study investigated the effectiveness of bacterially solubilized zinc (BSZn) on the early growth of rice plants and the concentration of zinc in the plant parts. The results showed that BSZn can promote seed germination and seedling growth, increase chlorophyll and carotenoid content, and enhance zinc accumulation in the roots of rice seedlings.