Effect of bicarbonate on uptake and translocation of 59Fe in two grapevine rootstocks differing in their resistance to Fe deficiency chlorosis

In order to study the effect of high bicarbonate concentration in the root medium on root FeIII reduction, Fe uptake and its translocation to the leaves, two rootstocks (Vitis riparia Michx., susceptible, and 41 B (Vitis vinifera L. cv. Chasselas x Vitis berlandieri Planch.), resistant to Fe deficiency chlorosis) were pre-cultivated in nutrient solutions with high and low Fe supply. After three weeks of preculture at low Fe, chlorosis symptoms occurred in both, Fe-resistant and Fe-susceptible genotypes. The FeIII reducing capacity by roots was enhanced at Fe deficiency in both genotypes, which was consistent with the increase of subsequent root uptake and translocation rates of 59Fe. In the presence of bicarbonate in the solutions the FeIII reducing capacity, 59Fe uptake and translocation rate decreased in both genotypes precultured with low re supply. The 59Fe uptake and translocation rate, however, were significantly higher in the Fe chlorosis-resistant rootstock 41 B. These results clearly indicate that bicarbonate-induced Fe chlorosis in grapevine rootstocks is obviously caused by an inhibition of Fe uptake and translocation due to an inhibition of FeIII reduction by root cells. The fact that these processes were less inhibited in the chlorosis-resistant rootstock hints to genotypical differences in Fe acquisition by roots at high bicarbonate levels. These differences might be used in breeding programs to identify Fe chlorosis-resistant rootstocks

Physical Mapping of Micronutritional Genes in Wheat-rye Translocations

In rye (Secale cereale L.), there are loci on chromosome arm 5RL which give rise to increased copper (Cu)- and iron (Fe)-efficiency, respectively. Four different wheat-rye translocations each harboring a terminal segment of different size of the rye chromosome arm 5RL were identified by test crosses and Giemsa-banding: \u27T29\u27 (5AS.5RL), \u27T63\u27 (5BS.5BL-5RL), \u27Vhn\u27 (4BS.4BL-5RL) and \u27Cor\u27 (4BS.4BL-5RL). The translocation break points were detected by chromosome painting technique GISH and the sizes of the rye chromosome segments involved were determined by computer image analysis. The Cu-efficiency gene Ce was physically mapped to the terminal region of 5RL, and the genes for mugineic acid and for hydroxymugineic acid synthetases involved in the strategy II of Fe-efficiency control to two intercalary regions of 5RL. In all wheat-rye translocation lines the Ce gene is linked to the dominant hairy neck character (HaI) from rye. This morphological trait and the RFLP probe \u27WG 199\u27 as well can serve as proper markers for a marker-based large-scale selection in wheat breeding

Beziehungen zwischen Chlorosegrad, Eisengehalten und Blattwachstum von Weinreben auf verschiedenen Standorten

Relationship between chlorosis, iron and leaf growth in grapevines growing at different locationsAt different locations, samples from chlorotic and green leaves were taken periodically during the growing season. Leaf area, contents of chlorophyll, total iron and acid-soluble iron were determined in leaf samples from various positions within the shoots. At locations where chlorosis became evident during the growth period, analysis showed that these leaves had lower levels of both total iron and acid-soluble iron compared with leaves of locations without chlorosis. At all locations, a close linear correlation was found between the contents of acid-soluble iron and chlorophyll. For total iron this positive correlation was confined to the lower concentration range (50-90 μg Feig dry weight). The highest and lowest contents of total iron and of acid-soluble iron were found in the youngest leaves and in the leaves with the largest growth rate, respectively. This demonstrates 'dilution' and 'concentration' effects of iron in the leaf dry matter. Therefore, particular care is necessary in leaf sampling as a basis for causal interpretations of iron chlorosis.The results of the present study indicate that the lower uptake and translocation rates of iron rather than the 'inactivation' of iron within the shoots are responsible for chloros is at the various locations

Einfluss unterschiedlicher Inokulationstiefen mit dem arbuskulären Mykorrhizapilz Glomus mosseae auf die Mykorrhizierung bei Reben (Vitis sp.) in Wurzelbeobachtungskästen

In einem Gefäßversuch mit Grünstecklingen der Unterlagssorte SO 4 (Vitis berlandieri x Vitis riparia) wurde der Einfluss einer unterschiedlichen Bandinokulation mit dem AM-Pilz Glomus mosseae (Nicol. et Gerd.) Gerdemann et Trappe auf die Entwicklung des Pilzes innerhalb des Wurzelsystems untersucht. Hierbei wurde in 70 cm tiefe Wurzelbeobachtungskästen mit einem P-armen, sterilisierten Rebschulboden in eine Tiefe von 9-18 cm bzw. 36-45 cm eine 9 cm dicke Inokulationsschicht eingebracht. Im unmittelbaren Inokulationsbereich war bei beiden Inokulationsvarianten mit 45 bzw. 35% der AM-Infektionsgrad am höchsten. Mit zunehmendem Abstand vom Inokulationsband waren die Rebwurzeln geringer mykorrhiziert bzw. es konnte keine AM-Infektion festgestellt werden. Durch die Inokulation im oberen Bodenbereich wurden Trockengewicht und P-Gehalt der SO 4-Stecklinge erhöht. Die Zn-Gehalte in den Blattspreiten waren bei beiden Inokulationsmethoden erhöht, der Cu-Gehalt bei Inokulation des unteren Bodenbereichs. Bereits eine Teilbesiedlung des Wurzelsystems mit AM führte zu ausreichenden Inokulationserfolgen in Form von erhöhten Nährstoffgehalten in den Blättern und erhöhter Trockensubstanzbildung. Die Inokulation in der größeren Bodentiefe (36-45 cm) führte zu einer verzögerten Mykorrhizierung der Wurzeln, so dass möglicherweise die positiven Effekte des AM-Pilzes bei dieser Inokulationsmethode nicht zum Tragen kamen.Influence of different inoculum places of the mycorrhizal fungus Glomus mosseae on mycorrhizal colonization in grapevine rootstocks (Vitis sp.)Grapevine rootstocks (Vitis berlandieri x Vitis riparia, cv. SO 4) were grown in pots with sterilised soil with low P level from a nursery to test the effect of a local supply of inoculum of an arbuscular mycorrhizal fungus (Glomus mosseae [Nicol. et Gerd.] Gerdemann et Trappe) on mycorrhizal colonization of the root system. The inoculum was placed in a 9-cm deep band either in 9-18 cm or in 36-45 cm soil depths. After 6 weeks of growth, mycorrhizal colonisation of roots was highest in the inoculated soil zone. With increasing distance from the inoculum band, mycorrhizal colonization decreased or was absent. When the inoculum was placed in the top soil, the shoot dry weight and the leaf blade Zn and P concentrations significantly increased in mycorrhizal as compared to nonmycorrhizal plants. When the inoculum was placed in 36-45 cm soil depth, leaf blade Zn and Cu concentrations increased in mycorrhizal plants, but shoot dry weight was not affected. In conclusion, a locally restricted mycorrhizal colonization of the root system was sufficient to increase growth and nutrient uptake of grape rootstocks

Absorption and mobility of foliar-applied boron in soybean as affected by plant boron status and application as a polyol complex

In the present study (i) the impact of plant Boron (B) status on foliar B absorption and (ii) the effect of B complexation with polyols (sorbitol or mannitol) on B absorption and translocation was investigated. Soybean (Glycine max (L.) Meer.) plants grown in nutrient solution containing 0 μM, 10 μM, 30 μM or 100 μM 11B labelled boric acid (BA) were treated with 50 mM 10B labelled BA applied to the basal parts of two leaflets of one leaf, either pure or in combination with 500 mM sorbitol or mannitol. After one week, 10B concentrations in different plant parts were determined. In B deficient leaves (0 μM 11B), 10B absorption was significantly lower than in all other treatments (9.7% of the applied dose vs. 26%–32%). The application of BA in combination with polyols increased absorption by 18–25% as compared to pure BA. The absolute amount of applied 10B moving out of the application zone was lowest in plants with 0 μM 11B supply (1.1% of the applied dose) and highest in those grown in 100 μM 11B (2.8%). The presence of sorbitol significantly decreased the share of mobile 10B in relation to the amount absorbed. The results suggest that 11B deficiency reduces the permeability of the leaf surface for BA. The addition of polyols may increase 10B absorption, but did not improve 10B distribution within the plant, which was even hindered when applied a sorbitol complex

Clorose férrica induzida pelo calcário

Iron chlorosis is one of the most common and difficult to control problems in crops grown on calcareous soils. In alkaline soils, which represent one third of the Earth surface, the bicarbonate ion prevails and is a major induction factor of iron chlorosis. As a result, alkalinity limits Fe bioavailability in the soil solution, Fe reduction and assimilation, as well as transport and uptake within the plant. Due to this nutritional imbalance, plants develop different response strategies which are not entirely successful on calcareous soils. In consequence, yield, fruit quality and harvesting season are negatively affected. Preventing and treating iron chlorosis is highly costly, but is inevitable, in order to ensure crop sustainability in regions where soil calcium carbonate and aridity are limiting factors. In this work, we present a short overview of Fe dynamics in calcareous soils and its influence on crop productivit