Dry matter production and distribution of zinc in bread and durum wheat genotypes differing in zinc efficiency
Six bread wheat (Triticum aestivum cvs. Kiraç-66, Gerek-79, Aroona, ES 91-12, ES-14 and Kirkpinar) and four durum wheat (Triticum durum cvs. BDMM-19, Kunduru-1149, Kiziltan-91 and Durati) genotypes were grown under controlled environmental conditions in nutrient solution for 20 days to study the effect of varied supply of Zn (0 to 1 µM) on Zn deficiency symptoms in shoots, root and shoot dry matter production, and distribution of Zn in roots and shoots.
Visual Zn deficiency symptoms, such as whitish-brown lesions on leaves, appeared rapidly and severly in durum wheats, particularly in Kiziltan-91 and Durati. Among the durum wheats, BDMM-19 was less affected by Zn deficiency, and among the bread wheats Kiraç-66, ES 91-12, Aroona and Gerek-79 were less affected than ES-14 and Kirkpinar.
Under Zn deficiency, shoot dry matter production was decreased in all genotypes, but more distinctly in durum wheat genotypes. Despite severe decreases in shoot growth, root growth of all genotypes was either not affected or even increased by Zn deficiency. Correspondingly, shoot/root dry weight ratios were lower in Zn-deficient than in Zn-sufficient plants, especially in durum wheat genotypes.
The distinct differences among the genotypes in sensitivity to Zn deficiency were closely related with the Zn content (Zn accumulation) per shoot but not with the Zn concentration in the shoot dry matter. On average, genotypes with lesser deficiency symptoms contained about 42% more Zn per shoot than genotypes with severe deficiency symptoms. In contrast to shoots, the Zn content in roots did not differ between genotypes. Shoot/root ratios of total Zn content were therefore greater for genotypes with lesser deficiency symptoms than for genotypes with severe deficiency symptoms (i.e. all durum wheat genotypes).
The results suggest that the enhanced capacity of genotypes for Zn uptake and translocation from roots to shoot meristems under deficient Zn supply might be the most important factor contributing to Zn efficiency in wheat genotypes. The results also demonstrate that under severe Zn deficiency, Zn concentration in the shoot dry matter is not a suitable parameter for distinguishing wheat genotypes in their sensitivity to Zn deficiency.
Key wordsbread wheat durum wheat genotypes zinc concentration zinc deficiency zinc efficiency
- Anghinoni I and Barber S A 1980 Phosphorus influx and growth characteristics of corn roots as influenced by phosphorus supply. Agron. J. 72, 685–688.Google Scholar
- Cakmak I, Gülüt K Y, Marschner H and Graham R D 1994 Effect of zinc and iron deficiency on phytosiderophure release in wheat genotypes differing in zinc efficiency. J. Plant Nutr. 17, 1–17.Google Scholar
- Cakmak I, Hengeler C and Marschner H 1994 Partitioning of shoot and root dry matter and carbohydrates in bean plants suffering from phosphorus, potassium and magnesium deficiency. J. Exp. Bot. 45, 1245–1250.Google Scholar
- Cakmak I, Yilmaz A, Kalayci M, Ekiz H, Torun B, Erenoglu B and Braun H J 1996a Zinc deficiency as a critical problem in wheat production in Central Anatolia. Plant and Soil 180, 165–172.Google Scholar
- 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 and Soil 180, 183–189.Google Scholar
- Dang Y P, Edwards D G, Dalal R C and Tiller K G 1993 Identification of an index tissue to predict zinc status of wheat. Plant and Soil 154, 161–167.Google Scholar
- Graham R D, Ascher J S and Hynes S C 1992 Selecting zinc-efficient cereal genotypes for soils of low zinc status. Plant and Soil 146, 241–250.Google Scholar
- Graham R D and Rengel Z 1993 Genotypic variation in zinc uptake and utilization by plants. In Zinc in Soils and Plants. Ed. A D Robson. pp 107–118. Kluwer Academic Publishers, Dordrecht, the Netherlands.Google Scholar
- Moraghan J T 1984 Differential responses of five species to phosphorus and zinc fertilizers. Commun. Soil Sci. Plant Anal. 15, 437–447.Google Scholar
- Mori S, Nishizawa N, Hayashi H, Chino M, Yoshimura E and Ishihara J 1991 Why are young rice plants highly susceptible to iron deficiency? Plant and Soil 130, 143–156.Google Scholar
- Rengel Z and Graham R D 1995a Wheat genotypes differ in zinc efficiency when grown in the chelate-buffered nutrient solution. I. Growth. Plant and Soil 176, 307–316.Google Scholar
- Rengel Z and Graham R D 1995b Wheat genotypes differ in zinc efficiency when grown in the chelate-buffered nutrient solution. II. Nutrient uptake. Plant and Soil 176, 317–324.Google Scholar
- Shukla U C and Raj H 1974 Influence of genetic variability on zinc response in wheat (Triticum spp.). Soil Sci. Soc. Am. Proc. 38, 477–479.Google Scholar
- Sugiura Y and Nomoto K 1984 Phytosiderophores structures and properties of mugineic acids and their metal complexes. Structure Bonding 58, 107–135.Google Scholar
- Takkar P N and Walker C D 1993 The distribution and correction of zinc deficiency. In Zinc in Soils and Plants. Ed. A D Robson. pp 151–166. Kluwer Academic Publishers, Dordrecht, the Netherlands.Google Scholar
- Treeby M, Marschner H and Römheld V 1989 Mobilization of iron and other micronutrient cations from a calcareous soil by plant-borne, microbial and synthetic metal chelators. Plant and Soil 114, 217–226.Google Scholar
- 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.Google Scholar
- Welch R M 1995 Micronutrient nutrition of plants. Crit. Rev. Plant Sci. 14, 49–82.Google Scholar
- Zhang F, Römheld V and Marschner H 1989 Effect of zinc deficiency in wheat on the release of zinc and iron mobilizing exudates. Z. Pflanzenernaehr. Bodenkd. 152, 205–210.Google Scholar
- Zhang F, Römheld V and Marschner H 1991 Role of the root apoplasm for iron acquisition by wheat plants. Plant Physiol. 97, 1302–1305.Google Scholar