Characterization of 68Zn uptake, translocation, and accumulation into developing grains and young leaves of high Zn-density rice genotype

Abstract

Zinc (Zn) is an essential micronutrient for humans, but Zn deficiency has become serious as equally as iron (Fe) and vitamin A deficiencies nowadays. Selection and breeding of high Zn-density crops is a suitable, cost-effective, and sustainable way to improve human health. However, the mechanism of high Zn density in rice grain is not fully understood, especially how Zn transports from soil to grains. Hydroponics experiments were carried out to compare Zn uptake and distribution in two different Zn-density rice genotypes using stable isotope technique. At seedling stage, IR68144 showed higher 68 Zn uptake and transport rate to the shoot for the short-term, but no significant difference was observed in both genotypes for the long-term. Zn in xylem sap of IR68144 was consistently higher, and IR68144 exhibited higher Zn absorption ratio than IR64 at sufficient (2.0 µmol/L) or surplus (8.0 µmol/L) Zn supply level. IR64 and IR68144 showed similar patterns of 68 Zn accumulation in new leaves at seedling stage and in developing grains at ripening stage, whereas 68 Zn in new leaves and grains of IR68144 was consistently higher. These results suggested that a rapid root-to-shoot translocation and enhanced xylem loading capacity may be the crucial processes for high Zn density in rice grains.

Improved yield and Zn accumulation for rice grain by Zn fertilization and optimized water management

“…However, zinc (Zn) deficiency in rice has been widely reported in many rice-growing regions of the world (Lonergan et al, 2009;Tiong et al, 2014). Zn deficiency in crop plants results in not only yield reduction but also Zn malnutrition in humans, where a high proportion of rice is consumed as a staple food (Wu et al, 2011;Chasapis et al, 2012). Zn biofortification of rice grains, which aims at increasing Zn concentration and bioavailability of food crop, appears to be the most feasible, sustainable, and economical approach among the different interventions to address human Zn deficiency (Zhao and Mcgrath, 2009;Salunke et al, 2011).…”

Impact of wheat straw biochar on yield of rice and some properties of Psammaquent and Plinthudult

“…Seeds were obtained from the Zhejiang Seed Co. They were surface sterilized in 70 percent ethanol for 1 min and then soaked in 0.01 g mL -1 sodium hypochlorite for 5 min, rinsed thoroughly in deionized water, and then maintained in deionized water for 48 h at 30 °C (Wu et al, 2011 Microbial PLFAs were extracted from soil samples collected from the pots at harvest. The PLFAs were extracted from 3.0 g of freeze-dried soil, fractionated and methylated (Wu et al, 2009b).…”

Effects of single and combined pollution of Pb, Cd and Cu on growth, metal uptake and translocation in rice

“…0.416c 0.046c 0.006b -- The translocation of heavy metals in a rice plant is an important process, which affects metal accumulation in rice grains. Reportedly, root-to-shoot translocation and xylem loading capacity may be the crucial processes for Zn density in rice grains [15]. Most of Cd accumulated in rice grains is transported via phloem [16].…”