Table 7.
Mass balance comparisons of net Zn movement in various plant tissues between 50% flowering and maturity.
| Treatment | Genotype | Changes in total plant Zn content | Differences in Zn content of individual plant parts: maturity–50% flowering (μg plant–1) | Predominant sources of grain Zn loading | |||
|---|---|---|---|---|---|---|---|
| Root | Leaf blade | Stem and sheath | Panicle | Continued root uptake versus remobilization | |||
| Zn-sufficient | IR64 | 228±23 | 98±7 | 10±6 | 25±16 | 98±9 | Continued root uptake |
| IR82247 | 255±38 | 153±17 | 11±6 | 52±35 | 67±6 | Continued root uptake | |
| IR69428 (Exp 2) | 151±29 | 78±17 | 6±3 | 38±12 | 34±6 | Continued root uptake | |
| IR69428 (Exp 3) | 329±33 | 242±32 | 29±6 | 79±11 | 21±2 | Continued root uptake | |
| RIL-46 | 264±50 | 143±25 | 13±5 | 54±26 | 84±17 | Continued root uptake | |
| A69-1 | 368±22 | 312±7 | 10±5 | 56±14 | 26±4 | Continued root uptake | |
| IR55179 | 267±35 | 180±30 | 32±13 | 23±6 | 37±7 | Continued root uptake | |
| KP | 57±2 | –6±2 | 24±4 | 13±6 | 11±0.04 | Continued root uptake | |
| IR74 | 280±40 | 95±30 | –15±5 | –20±11 | 170±30 | Both | |
| SWHOO | 167±50 | 122±15 | –17±5 | –49±7 | 49±6 | Remobilization from shoot | |
| IR68144 | 71±34 | 53±4 | –7±5 | –11±10 | 50±14 | Both | |
| Joryoongbyeo | 139±29 | 105±30 | 0.6±1.7 | –14±4 | 36±12 | Both | |
| IR75862 | No dataa | 45±20 | –6±2 | –6±6 | No dataa | ND | |
| Zn-deficient | IR64 | 90±31 | 44±14 | –8±3 | –38±9 | 50±11 | Both |
| IR82247 | –115±37 | –114±11 | 9±4 | –16±6 | 46±16 | Remobilization from roots | |
| IR69428 (Exp 2) | 165±49 | 70±28 | 14±3 | 35±23 | 47±12 | Continued root uptake | |
| IR69428 (Exp 3) | 141±22 | 22±3 | 42±18 | 35±12 | 50±15 | Continued root uptake | |
| RIL-46 | –25±14 | –49±21 | –6±3 | –36±14 | 49±11 | Remobilization from root and shoot | |
| A69-1 | 42±15 | 7±4 | 3.4±2.6 | 25±12 | 9±3 | Continued root uptake | |
| IR55179 | 31±8 | 6±3 | 4±3 | 8±3 | 16±5 | Continued root uptake | |
| IR74 | 97±24 | –5±2 | –6±4 | –40±16 | 110±35 | Both | |
| SWHOO | 6±3 | –9±8 | –7±2 | –39±9 | 38±18 | Remobilization from root and shoot | |
| IR68144 | 13±5 | 7±3 | –9±2 | –13±3 | 18±5 | Remobilization from shoot | |
| Joryoongbyeo | 70±30 | 52±12 | –4±2 | –20±7 | 23±4 | Remobilization from shoot | |
| IR75862 | No dataa | –36±28 | –2±1 | –35±4 | No dataa | ND | |
Panicle includes rachis, hull, and brown rice. Values given are means ±SE (n=5).
a IR75862 had insufficient amount of ground hull samples for Zn measurement through ICP-MS at maturity. KP did not produce grains under Zn-deficient conditions, ND = not determined.