Abstract
Tolerance to Zn deficiency in wheat germplasm may be inversely related to uptake and transport of Fe to shoots. The present study examined eight bread (Triticum aestivum) and two durum (T. turgidum L. conv. durum) wheat genotypes for their capacity to take up and transport Fe when grown under either Fe or Zn deficiency. Bread wheat genotypes Aroona, Excalibur and Stilleto showed tolerance to Zn and Fe deficiency, while durum wheat genotypes are clearly less tolerant to either deficiency. Roots of bread wheats tolerant to Zn deficiency exuded more phytosiderophores than sensitive bread and durum genotypes. Greater amounts of phytosideophores were exuded by roots grown under Fe than Zn deficiency. A relatively poor relationship existed between phytosiderophore exudation or the Fe uptake rate and relative shoot growth under Fe deficiency. At advanced stages of Zn deficiency, genotypes tolerant to Zn deficiency (Aroona and Stilleto) had a greater rate of Fe uptake than other genotypes. Zinc deficiency depressed the rate of Fe transport to shoots in all genotypes in early stages, while advanced Zn deficiency had the opposite effect. Compared with Zn-sufficient plants, 17-day-old Zn-deficient plants of genotypes tolerant to Zn deficiency had a lower rate of Fe transport to shoots, while genotypes sensitive to Zn deficiency (Durati, Yallaroi) had the Fe transport rate increased by Zn deficiency. A proportion of total amount of Fe taken up that was transported to shoots increased with duration of either Fe or Zn deficiency. It is concluded that greater tolerance to Zn deficiency among wheat genotypes is associated with the increased exudation of phytosiderophores, an increased Fe uptake rate and decreased transport of Fe to shoots.
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References
Berg W A, Hodges M E and Krenzer E G 1993 Iron deficiency in wheat grown on the Southern Plains. J. Plant Nutr. 16, 1241–1248.
Bienfait H F, Van Der Briel W and Mesland-Mul N T 1985 Free space iron pools in roots. Generation and mobilization. Plant Physiol. 78, 596–600.
Cakmak I, Gülüt K Y, Marschner H and Graham R D 1994 Effect of zinc and iron deficiency on phytosiderophore release in wheat genotypes differing in zinc efficiency. J. Plant Nutr. 17, 1–17.
Cakmak I, Sari N, Marschner H, Kalayci M, Yilmaz A, Eker S and Gülüt K Y 1996a Dry matter production and distribution of zinc in bread and durum wheat genotypes differing in zinc efficiency. Plant Soil 180, 173–181.
Cakmak I, Sari N, Marschner H, Ekiz H, Kalayci M, Yilmaz A and Braun H J 1996b Phytosiderophore release in bread and durum wheat genotypes differing in zinc efficiency. Plant Soil 180, 183–189.
Erenoglu B, Cakmak I, Marschner H, Römheld V, Eker S, Daghan H, Kalayci M and Ekiz H 1996 Phytosiderophore release does not relate well with Zn efficiency in different bread wheat genotypes. J. Plant Nutr. 19, 1569–1580.
Graham R D, Ascher J S and Hynes S C 1992 Selecting zincefficient cereal genotypes for soils of low zinc status. Plant Soil 146, 241–250.
Hansen N C, Jolley V D and Brown J C 1995 Clipping foliage differentially affects phytosiderophore release by two wheat cultivars. Agron. J. 87, 1060–1063.
Hansen N C, Jolley V D, Berg W A, Hodges M E and Krenzer E G 1996 Phytosiderophore release related to susceptibility of wheat to iron deficiency. Crop Sci. 36, 1473–1476.
Hopkins B G, Whitney D A, Lamond R E and Jolley V D 1998 Phytosiderophore release by sorghum, wheat, and corn under zinc deficiency. J. Plant Nutr. 21, 2623–2637.
Rengel Z 1999a Zinc deficiency in wheat genotypes grown in conventional and chelator-buffered nutrient solutions. Plant Sci. 143, 221–230.
Rengel Z 1999b Physiological responses of wheat genotypes grown in chelator-buffered nutrient solutions with increasing concentrations of excess HEDTA. Plant Soil 215, 193–202.
Rengel Z and Graham R D 1995a Wheat genotypes differ in Zn efficiency when grown in chelate-buffered nutrient solution. I. Growth. Plant Soil 176, 307–316.
Rengel Z and Graham R D 1995b Wheat genotypes differ in Zn efficiency when grown in chelate-buffered nutrient solution. II. Nutrient uptake. Plant Soil 176, 317–324.
Rengel Z and Römheld V 2000 Genotypic differences in tolerance to Fe and Zn deficiencies in wheat. Euphytica. (In press).
Rengel Z, Römheld V and Marschner H 1998 Uptake of zinc and iron by wheat genotypes differing in zinc efficiency. J. Plant Physiol. 152, 433–438.
Römheld V and Marschner H 1990 Genotypical differences among gramineaceous species in release of phytosiderophores and uptake of iron phytosiderophores. Plant Soil 123, 147–153.
Sillanpää M and Vlek P L G 1985 Micronutrients and the agroecology of tropical and Mediterranean regions. Fert. Res. 7, 151–167.
VonWiren N, Marschner H and Römheld V 1995 Uptake kinetics of iron-phytosiderophores in two maize genotypes differing in iron efficiency. Physiol. Plant. 93, 611–616.
Walter A, Römheld V, Marschner H and Mori S 1994 Is the release of phytosiderophores in zinc-deficient wheat plants a response to impaired iron utilization? Physiol. Plant. 92, 493–500.
Welch R M, Allaway W H, House W A and Kubota J 1991 Geographic distribution of trace element problems. In Micronutrients in Agriculture, 2nd ed. Eds J J Mortvedt, F R Cox, L M Shuman and R M Welch. pp 31–57. Soil Sci. Soc. Am. Inc., Madison, WIS.
Zhang F, Römheld V and Marschner H 1989 Effect of zinc defi-ciency in wheat on the release of zinc and iron mobilizing root exudates. Z. Pflanzenernähr. Bodenk. 152, 205–210.
Zhang F-S, Römheld V and Marschner H 1991 Diurnal rhythm of release of phytosiderophores and uptake rate of zinc in iron-deficient wheat. Soil Sci. Plant Nutr. 37, 671–678.
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Rengel, Z., Römheld, V. Root exudation and Fe uptake and transport in wheat genotypes differing in tolerance to Zn deficiency. Plant and Soil 222, 25–34 (2000). https://doi.org/10.1023/A:1004799027861
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DOI: https://doi.org/10.1023/A:1004799027861