| The present research focused on the zinc partitioning and accumulation in individual organ and the genetic variation in grain zinc mass fraction under field culture condition,greenhouse pot and isotope tracer, and some process of zinc partitioning in plant was quantified , the results were as follows:1. Significant variation existing among genotypes in grain zinc mass fraction in aerobic rice.It should be possible to develop high grain zinc mass fraction plants through either traditional plant breeding methods or molecular biological techniques to alleviate Zn deficiency in human populations. Under field condition, the range of grain zinc mass fraction was 8.96-18.32 mg/kg and 16.45-29.60mg/kg, and the average was 13.16mg/kg and 23.04mg/kg respectively, under no zinc supply condition and sufficient zinc supply condition. Combined with higher grain zinc mass fraction and partitioning ratio of zinc to the grain, among 14 varieties tested in the present experimentation, Hongkelaoshuya and 90B290 under no zinc supply condition and Liaohan109 and Qin'ai-3hun under sufficient zinc supplied level could be defined as high zinc-accumulation cultivars and optimal cultivars.2. Zinc mass fraction in grains was correlated with shoot zinc mass fraction. When the zinc supply level was below 50μmol/l, with the increasing of zinc supply, grain zinc mass fraction increased with higher shoot zinc mass fraction; however, when zinc supply level was above 50μmol/l, grain zinc mass fraction still increased but slowly, with most zinc detained in non-grain parts of the plants. The results indicated that when zinc supply level was lower, zinc in grains was mostly obtained by zinc reallocation in the other organs. Although sufficient zinc supply could advance zinc accumulation in grains, grain zinc mass fraction could only be increased 1.8 to 2.2 times to its most.3. The uptake of zinc was unrestricted, while the zinc accumulation in grains was controlled.Under water cultural condition, with the increasing of zinc supply, plant could keep taking up zinc although the zinc content might be above optimal demand, or even toxicity level, and the extra zinc was found to mainly store in stem and leaf sheath. zinc harvest index was sharply decreased with the increasing of zinc level, like Baxiludao (from above 0.2 to about 0.08). The observation demonstrated that the uptake of zinc of the plant was unrestricted, while the zinc accumulation in grains was controlled, that there might possibly exist an effective defending mechanism in the zinc transferring of zinc to grains.4. It was insufficient zinc source in the shoot that limited grain zinc mass fraction to increase under field condition.In the field condition, the shoot zinc mass fraction in the field was lower, although supplied with an excessive amount of zinc in the soil, which might be due to low zinc availability in the plant. Therefore it proved that many factors influenced the zinc absorption of the plant from the soil and extra zinc content in the plant could not meet the zinc demand by the grain.5. Zn deficiency or toxicity could affect plant growth especially after panicle initiation stage.At higher application rates in greenhouse pot experiment, there was a slightly negative correlation between dry matter production and plant zinc concentration, indicating toxicity effects. Especially at flowering stage, Zn deficiencies indeed led to drop in fertility and thousand-grain weight, which ultimately affected grain yield.6. 65Zn uptake and partitioning after flowering stage in aerobic rice. Plant could continue uptake 65Zn even under surplus conditions whether both at flowering stage and on 15th day after flowering stage, and plant took up more 65Zn applied under lower zinc mass fraction status in plant compared with high zinc mass fraction status. A certain 65Zn could be transported out from both flag leaf blade and dying leaf to other individual organs, and more 65Zn was found to moved to vegetative organs, instead of panicle parts.
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