Response mechanism of grapevine rootstocks to severe iron deficiency

In many important viticultural areas of the Mediterranean basin, plants often face prolonged periods of scarce iron (Fe) availability in the soil. The main objective of the present work was to compare physiological and biochemical response mechanisms to severe Fe-deficiency in Vitis genotypes. A hydroponic experiment was conducted, in which three rootstocks characterized by a different susceptibility degree to Fe chlorosis have been submitted to two Fe levels. The Fe chlorosis susceptible rootstock 101-14 (Vitis riparia x Vitis rupestris) reacted to a prolonged Fe-deficiency reducing the root activity of phosphoenolpyruvate carboxylase (PEPC) and malate dehydrogenase (MDH). Noteworthy, it accumulated high levels of citric acid in roots. In contrast, the Fe chlorosis tolerant rootstock 110 Richter (Vitis berlandieri x Vitis rupestris) was capable of maintaining an active metabolism of organic acids in roots, accumulating them to a lesser extent than 101-14. Similarly to 101-14, SO4 genotype (Vitis berlandieri x Vitis riparia) displayed a strong decrease of PEPC and MDH enzyme activities. Nevertheless it was able to avoid excessive accumulation of citric acid in roots, similarly to 110 Richter. In conclusion, root PEPC and MDH activities represent an important tool for screening Fe chlorosis tolerance. After a prolonged exposure to Fe-deficiency, the accumulation of organic acids in the roots may not represent a reliable indicator of Fe chlorosis tolerance

Changes on the Iron Deficiency Response Mechanisms of Grapevine with Sustainable Strategies for Iron Chlorosis Prevention

The prevention/cure of iron (Fe) chlorosis with Fe chelates is a very widespread agronomical practice in vineyards and orchards, although it implies high costs and potential environmental and health risks. Such factors strongly suggest the need of adopting alternative strategies for managing grapevine Fe nutrition according to more sustainable practices. The aim of this work was to study the changes on the Fe deficiency physiological and biochemical response mechanisms of grapevine when using sustainable strategies for Fe chlorosis prevention, based on the management of nitrogen (N) forms and the use of intercropping with graminaceous species. A pot experiment was conducted in the 2010-2011 seasons with vines of ‘Cabernet Sauvignon’ grafted on the Fe-chlorosis susceptible genotype Vitis riparia, using 33-L pots filled with calcareous soil. Results indicate a potential for efficiently preventing grapevine Fe-chlorosis by adding ammonium to the rhizosphere or intercropping with Fe-efficient grasses. The intercropping with Festuca rubra reduced markedly vine growth. In the second vegetative season, Fe-deficient control vines showed the lowest leaf chlorophyll levels, as well as the highest root citrate concentrations (along that found in the with Fe-EDTA foliar-treated plants) and PEPC activity in root extracts. Vines fertilized with ammonium (with and without a nitrification inhibitor) or cocultivated with Festuca rubra displayed levels of root organic acids and activities of the Fe-deficiency induced enzyme PEPC that were similar to values recorded in the plants fertilized with Fe-EDDHA

Anomalie della maturazione delle uve in Emilia Romagna

Sono molti i fattori di stress che possono causare alterazioni nella fisiologia delle piante e nella qualità del frutto. La valutazione delle strategie agronomiche

Clorosi ferrica della vite: un problema, diverse soluzioni

In questo articolo si illustrano alcune novità relative all’adozione di sostanze anticlorosi e alle strategie per controllare la clorosi ferrica

Root exudates of grasses improve Fe uptake in a citrus rootstock sensitive to Fe-deficiency

Aim of the present work was to assess the capability of two perennial grasses (Poa pratensis L. and Festuca rubra L.) to improve Fe uptake by the highly-susceptible citrus rootstock citrumelo "Swingle". Citrus plants were unable to induce the physiological responses to Fe-deficiency; however, in these plants uptake of 59Fe from 59Fe-hydroxide could be increased by the presence of Fe-deficient grasses. No beneficial effect was observed with the use Fe-sufficient grasses. A progressive increase in 59Fe uptake by citrus plants was also evident after supplying increasing amounts of DMA, the major phytosiderofore (PS) released by grasses. Re-greening of Fe-deficient citrus plants was obtained by intercropping with grasses in rhizoboxes filled with a chlorosis-inducing calcareous soil; a concomitant increase in the amount of Fe in the leachates was also observed. Data indicate that Fe nutrition of a Fe-inefficient citrus rootstock can benefit from Fe mobilized by PS released by perennial graminaceous species

Improvement of Grapevine Iron Nutrition by a Bovine Blood-Derived Compound

Iron (Fe) is essential for chlorophyll formation and plant growth. Iron-deficiency chlorosis is a major nutritional disorder in several fruit trees cultivated in calcareous and alkaline soils, reducing fruit yield and quality and causing heavy economic losses. Since chelated Fe, the most widespread fertilizers used for preventing or curing Fe deficiency, pose risks of environmental pollution, the development of sustainable agronomic alternatives represents a priority for the fruit industry. In this work, we investigated the effectiveness of a bovine blood-derived product (BB; 0,125% Fe) for preventing Fe-deficiency in grapevine plants. During the vegetative season 2011 potted plants of five graft combinations: Sangiovese/SO4, Cabernet Sauvignon/SO4 and Cabernet Sauvignon/140 Ruggeri, 140 Ruggeri/Cabernet Sauvignon, Vitis riparia/Cabernet Sauvignon were grown on calcareous soil. Soil treatments included: 1) Control; 2) Fe-EDDHA (Fe 6%); 3) Bovine-Blood (5 g/l); 4) Bovine-Blood (20 g/l). With the exception of Cabernet Sauvignon/SO4 plants, Fe-EDDHA increased SPAD units (leaf chlorophyll content). Bovine-blood at low concentrations had similar or higher SPAD units than Fe-EDDHA. Increasing concentration resulted in further increases in SPAD units only in some graft combinations. Data highlight the efficiency of Fe blood-compound in the prevention of grapevine Fe-deficiency over one growing season

SPECTROSCOPIC INVESTIGATION OF ALUMINUM COMPLEXES IN PLANTS GROWTH MEDIA

Cytotoxicity of aluminum is a serious problem that can severely limit productivity in crops, particularly in acid soils. When the soil pH is lower than 4.5–5.0, Al3+ is solubilized in soil water and is absorbed by plant roots, inhibiting root elongation severely. Furthermore, the involvement of aluminum in biological systems has been emphasized in recent years, suggesting its potential interaction with cells. For example, the biotoxic effect of aluminum was correlated with the onset of Alzheimer's and other diseases. It has been observed that certain vegetal species that grow easily in acid soils using, for detoxify from aluminum, the production of organic acids capable of complexing it. To this purpose, plants make use of two strategies: the first is the exclusion of aluminum from roots (the complex formed in the soil cannot cross the cell membrane), the other provides a greater resistance to the effects of the aluminum through its complexation within the cell. In the present study, a tree species (olive tree, Olea Europea) and an herbaceous species (barley, Hordeum vulgare), were investigated through the analysis of the effects of increasing concentration of Al3+ ions in hydroponics growth conditions, analyzing the plants’ exudates. As expected, an increased concentration of Al3+ inhibited root elongation and proliferation. Moreover, a SEM observation of root tips evidenced an increasing number of cracks and fractures with increasing Al3+ concentration. The characterization of theses complexes is quite limited: the use of vibrational spectroscopic techniques (in particular Raman spectroscopy) offers the great advantage of operating satisfactorily also in an aqueous environment, allowing studies in systems similar to those occurring in nature and exploring the ppm concentration range through SERS analysis. We studied the Raman and IR spectra of three organic acids of agricultural interest (oxalic, tartaric and citric acids) together with their Na and Al salts, both in the solid state as well as in H2O and/or D2O solution. The results arising from the study of the differences between symmetric and asymmetric COO– stretching vibrations give interesting information on the type (monodentate, bidentate or bridging) and the strength of the bound involved in the complexing process. The structural data derived by spectroscopic methods are supported by computational methods, allowing the determination of complexing constants and stability