Growth Responses to Varying Zinc Activities in Rice Genotypes Differing in Zn Efficiency and Zn Density

ABSTRACT

The relationship between tolerance to Zn-deficiency and Zn-dense in grain was examined. The results showed that the plant height and leaf growth rate (number) decreased more in the Zn-dense genotype (Biyuzaonuo) than in the Zn-efficient genotype (IR8192) when grown at pZn2+ ≥ 11.0. Shoot dry matter yield decreased about 6 times for the dense CV whereas only around 3 times for the efficient CV at Zn activities pZn²⁺ 9.7–11.4. Zinc uptake by the whole plant was greater in the Zn-dense genotype than in the Zn-efficient genotype, and the lowest in the Zn-inefficient genotype grown at pZn2+ ≥ 11.0. However, both the efficient and the dense cultivars showed higher Zn translocation efficiency at low Zn activity. These results indicate that Zn uptake by rice seedling and translocation might be more suitable than growth parameters for identifying Zn-efficient and Zn-dense genotype at seedling stage.

Keywords:

• Zn²⁺ activity
• Zn uptake
• Zn efficiency
• Zn dense
• rice genotype

ACKNOWLEDGMENTS

This study is financially supported by the key International Cooperative Project from Science Ministry of China (#2006DFA31030), the HarvestPlus-China program (#2005HPC03), and a program for Changjiang Schlors and Innovative Research Team in University (# IRT0536).

Notes

∗, ∗∗ represent statistically significant and very significant, respectively; ND means no significant difference.

∗, ∗∗ represent statistically significant and very significant, respectively; ND means no significant difference.

∗, ∗∗ represent statistically significant and very significant, respectively; ND means no significant difference.