Showing papers by "Ismail Cakmak published in 1997"

Boron deficiency-induced impairments of cellular functions in plants

Abstract: The essentiality of B for growth and development of plants is well-known, but the primary functions of B still remain unknown Evidence in the literature supports the idea that the major functions of B in growth and development of plants are based on its ability to form complexes with the compounds having cis-diol configurations In this regard, the formation of B complexes with the constituents of cell walls and plasma membranes as well as with the phenolic compounds seems to be a decisive step affecting the physiological functions of B Boron seems to be of crucial importance for the maintenance of structural integrity of plasma membranes This function of B is mainly related to stabilisation of cell membranes by B association with membrane constituents Possibly, B may also protect plasma membranes against peroxidative damage by toxic O2 species In B-deficient plants, plasma membranes are highly leaky and lose their functional integrity Under B-deficient conditions, substantial changes in ion fluxes and proton pumping activity of the plasma membranes were noted Impairments in phenol metabolism and increases in levels of phenolics and polyphenoloxidase activity are typical indications of B deficiency, particularly in B deficiency-sensitive plant species, such as Helianthus annuus (sunflower) Enhanced oxidation of phenols is responsible for generation of reactive quinones which subsequently produce extremely toxic O2 species, thus resulting in the increased risk of a peroxidative damage to vital cell components such as membrane lipids and proteins In B-deficient tissues, enhancement in levels of toxic O2 species may also occur as a result of impairments in photosynthesis and antioxidative defence systems Recent evidence shows that the levels of ascorbic acid, non-protein SH-compounds (mainly glutathione) and glutathione reductase, the major defence systems of cells against toxic O2 species, are reduced in response to B deficiency There is also increasing evidence that, in the heterocyst cells of cyanobacteria, B is involved in protection of nitrogenase activity against O2 damage

Effect of different zinc application methods on grain yield and zinc concentration in wheat cultivars grown on zinc‐deficient calcareous soils

Abstract: The effect of six different zinc (Zn) application methods on grain yield and concentrations of Zn in whole shoots and grain was studied in wheat cultivars (Triticum aestivum, L. cvs. Gerek‐79, Dagdas‐94 and Bezostaja‐1 and Triticum durum, Desf. cv. Kunduru‐1149) grown on severely Zn‐deficient calcareous soils (DTPA‐extractable Zn: 0.12 mg‐kg‐1 soil) of Central Anatolia which is the major wheat growing area of Turkey. Zinc application methods tested were: a) control (no Zn application), b) soil, c) seed, d) leaf, e) soil+leaf, and f) seed+leaf applications. Irrespective of the method, application of Zn significantly increased grain yield in all cultivars. Compared to the control, increases in grain yield were about 260% with soil, soil+leaf, and seed+leaf, 204% with seed and 124% with leaf application of Zn. In a similar manner, biomass production (dry weight of above‐ground parts) was increased by Zn treatments. The highest increase (109%) was obtained with the soil application and the lowest inc...

Differential response of rye, triticale, bread and durum wheats to zinc deficiency in calcareous soils

Abstract: Field and greenhouse experiments were carried out to study the response of rye (Secale cereale L. cv. Aslim), triticale ( Triticosecale Wittmark. cv. Presto), two bread wheats (Triticum aestivum L, cvs. Bezostaja-1 and Atay-85) and two durum wheats (Triticum durumL. cvs. Kunduru-1149 and C-1252) to zinc (Zn) deficiency and Zn fertilization in severely Zn-deficient calcareus soils (DTPA-Zn=0.09 mg kg 1 soil). The first visible symptom of Zn deficiency was a reduction in shoot elongation followed by the appearance of whitish-brown necrotic patches on the leaf blades. These symptoms were either absent or only slight in rye and triticale, but occurred more rapidly and severely in wheats, particularly in durum wheats. The same was true for the decrease in shoot dry matter production and grain yield. For example, in field experiments at the milk stage, decreases in shoot dry matter production due to Zn deficiency were absent in rye, and were on average 5% in triticale, 34% in bread wheats and 70%, in durum wheats. Zinc fertilization had no effect on grain yield in rye but enhanced grain yield of the other cereals. Zinc efficiency of cereals, expressed as the ratio of yield (shoot dry matter or grain) produced under Zn deficiency compared to Zn fertilization were, on average, 99% for rye, 74% for triticale, 59% for bread wheats and 25% for durum wheats. These distinct differences among and within the cereal species in susceptibility to Zn deficiency were closely related to the total amount (content) of Zn per shoot, but not with the Zn concentrations in shoot dry matter. For example, the most Zn-efficient rye and the Zn-inefficient durum wheat cultivar C-1252 did not differ in shoot Zn concentration under Zn deficiency, but the total amount of Zn per whole shoot was approximately 6-fold higher in rye than the durum wheat. When Zn was applied, rye and triticale accumulated markedly more Zn both per whole shoot and per unit shoot dry matter in comparison to wheats. The results demonstrate an exceptionally high Zn efficiency of rye and show that among the cereals studied Zn efficiency declines in the order rye>triticale>bread wheat>durum wheat. The differences in expression of Zn efficiency are possibly related to a greater capacity of efficient genotypes to acquire Zn from the soil compared to inefficient genotypes.

Studies on differential response of wheat cultivars to boron toxicity

Abstract: Experiments were carried out to study the differential responses of different wheat cultivars to boron toxicity in field, greenhouse and growth chamber conditions. In field trials carried out at two locations, both of which are known to contain toxic amounts of water-extractable B, significant correlations were obtained between toxicity symptoms and grain yields. The only durum cultivar included in this group of experiments (Kunduru 1149) was the most sensitive of the 21 cultivars trialed. The most tolerant cultivars were of local origin. Genotype-environment interaction was considerably large. Twenty-nine bread wheat and three durum wheat cultivars were compared in a greenhouse experiment with and without the application of 40 mg L-1 B. Again, the durums were the most sensitive cultivars. The most tolerant cultivars were either selections from local populations or had at least one parent of local origin. The detrimental effect of B on root dry matter production was much higher than on shoot dry matter (45 and 26%, respectively), but genotypical variation was greater in shoot growth retardation. While this implies the possible role of reduced translocation, high concentrations of B in the shoots of tolerant cultivars (though lower than in the sensitive cultivars) indicated the existence of other contributing mechanisms, such as tissue tolerance. Also, greater genotypical variation in older leaves showed that reduced uptake might be more important than reduced translocation in some cases. Due to the lack of correlation between results from the field and the controlled-environment studies, it was concluded that screenings should be undertaken in both situations as a means of verification. Another conclusion drawn was that symptom scoring for B tolerance was more reliable than measuring plant B concentrations.

Role of rye chromosomes in improvement of zinc efficiency in wheat and triticale

Abstract: Using the disomic wheat-rye addition lines (Triticum aestivum L., cv. Holdfast-Secale cereale L., cv. King-II) and an octoploid triticale line (xTriticosecale Wittmark L. “PlutoxFakon”) as well as the respective wheat and rye parents, greenhouse experiments were carried out to study the role of rye chromosomes on the severity of Zn deficiency symptoms, shoot dry matter production, Zn efficiency, shoot Zn concentration and Zn content. Plants were grown in a Zn-deficient calcareous soil with (10 mg Zn kg−1 soil) and without Zn supply. Zinc efficiency was calculated as the ratio of dry weight produced under Zn deficiency to the dry weight produced under Zn fertilization. In the experiments with addition lines, visual Zn deficiency symptoms were slight in the rye cultivar King-II, but were severe in the wheat cultivar Holdfast. The addition of rye chromosomes, particularly 1R, 2R and 7R, into Holdfast reduced the severity of deficiency symptoms. Holdfast showed higher decreases in shoot dry matter production by Zn deficiency and thus had a low Zn efficiency (53%), while King-II was less affected by Zn deficiency and had a higher Zn efficiency (89%). With the exception of the 3R line, all addition lines had higher Zn efficiency than their wheat parent: the 1R line had the highest Zn efficiency (80%). In the experiment with the triticale cultivar and its parents, rye cv. Pluto and wheat cv. Fakon, Zn deficiency symptoms were absent in Pluto, slight in triticale and very severe in Fakon. Zinc efficiency was 88% for Pluto, 73% for triticale and 64% for Fakon. Such differences in Zn efficiency were better related to the total amount of Zn per shoot than to the amount of Zn per unit dry weight of shoot. Only in the rye cultivars, Zn efficiency was closely related with Zn concentration. Triticale was more similar to rye than wheat regarding Zn concentration and Zn accumulation per shoot under both Zn-deficient and Zn-sufficient conditions.

Screening for zinc efficiency among wheat relatives and their utilisation for alien gene transfer

Abstract: Genetic diversity for micronutrient efficiency among the most highly adapted and advanced hexaploid and tetraploid wheat cultivars in the world is limited compared with alien species of wheat or rye. Therefore, screening for zinc efficiency was conducted in greenhouse experiments under controlled conditions, and in field trials. Different varieties of hexaploid wheat, hexaploid oats and diploid rye, together with hexaploid and octoploid triticales, wheat-Agropyron, wheat-Aegilops and several wheat-alien chromosome addition series were studied. Considerable differences in zinc efficiency were found between wheat and its relatives. Individual chromosomes of Secale, Agropyron and Haynaldia were found to carry major genes for this character. The transfer of alien chromosome segments was effective, demonstrated using several wheat-rye translocation lines. Alien genetic information was clearly expressed in the wheat genetic background. Further experimental introgressions by chromosome manipulation and marker-aided selection may efficiently contribute to wheat improvement in marginal soils.

The effect of rye genetic information on zinc, copper, manganese and iron concentration of wheat shoots in zinc deficient soil

Abstract: Experiments were conducted to study the genetic variability of Zn, Fe, Mn and Cu concentration in the shoot of wheat and other cereals. Cultivars of rye showed higher Zn efficiency than the wheats. There was a considerable variability for the four elements between rye and wheat varieties. By utilisation of disomic wheat-rye addition lines it could be demonstrated that the rye chromosomes 2R and 7R may improve the Mn and Fe concentrations of wheat, chromosome 1R the Zn and 5R the Cu, respectively. Even in a particular 4B/5R wheat-rye translocation line the Zn, Fe and Mn concentrations were significantly modified from 5.8 to 6.7, 92 to 171 and 123 to 236 ug/g DW, respectively. Both wheat and rye positively respond to Zn supply in Zn concentration of shoots, although the effect in rye is less pronounced. The average increases in Zn concentration in wheat and rye reached 851 % and 689 %, respectively, and correlated with a subsequent decrease of Cu>Fe>Mn. Among the wheats there were remarkable differences in the uptake of Zn additionally applied. The English variety ‘Avalon’ showed the best Zn utilisation.

Physical mapping of rye genes determining micronutritional efficiency in wheat

Abstract: By utilisation of Triticum-Secale, Triticum-Agropyron, Triticum-Aegilops or Triticum-Hordeum amphidiploids, wheat-alien addition, substitution and translocation lines it was revealed that genes from the rye chromosome region 5RL2.3 may contribute to a high copper (Cu) and iron (Fe) efficiency. Other genes of the chromosomes/arms 1RS and 7R of rye increased the zinc efficiency of wheat. Dosage and cytoplasmic effects were less pronounced. Genetic and cytological data point to homoeoloci among cereal genomes for genes encoding phytosiderophores and/or micronutritional efficiency.