Papers by Esteban Alcantara
Springer eBooks, 1991
Iron chlorosis is an important problem in peach trees, but differences exist between peach rootst... more Iron chlorosis is an important problem in peach trees, but differences exist between peach rootstocks in their tolerance to Fe chlorosis in calcareous soils. The purpose of this investigation was to characterize the tolerance of different rootstocks to Fe chlorosis induced by bicarbonate in nutrient solution. The rootstocks studied included peach (Nemaguard), plums (Brompton, San Julian A and Puebla de Soto 101) and almond × peach hybrids (Adafuel and GF677). Young plants obtained from rooted cuttings or from in vitro culture techniques were grown individually, under controlled conditions, in flasks with 700 mL of aerated nutrient solution low in iron and with or without 10 mM bicarbonate or 10 mM phosphate. Susceptiblity to bicarbonate-induced chlorosis was inversely correlated with both the Fe content in young leaves and the reducing capacity of roots, but not with the phosphorus content in young leaves. The plum Puebla de Soto 101 and the hybrid GF677 showed the lowest degree of chlorosis and the highest reducing capacity. Phosphate did not induce chlorosis.
Genotypic differences in calcium and magnesium nutrition in sunflower
Springer eBooks, 1983
There is genetic variability between species or genotypes in their adaptation to soil with high c... more There is genetic variability between species or genotypes in their adaptation to soil with high calcium or magnesium content3,6 but little is known about the physiological basis of these adaptations. Clark1 found differential Ca and Mg efficiencies between corn inbreds, and Kawaski and Moritsugu5 have shown differences in the absorption of Ca by excised root of different corn and sorghum cultivars.
Journal of Fungi, Jan 29, 2022
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Frontiers in Plant Science, May 28, 2018
two MAOs (photosystem I and ALS inhibitors), but resistance to five MOAs could occur in the next ... more two MAOs (photosystem I and ALS inhibitors), but resistance to five MOAs could occur in the next cropping seasons, if alternatives to weed management, other than herbicides, are not included.
Interaction of bicarbonate and anaerobiosis with the responses to Fe-deficiency in dicotyledonous plants
El calcio como herramienta para el control de la antracnosis del olivo causada por Colletotrichum spp
Effects of bicarbonate and anaerobiosis on both ferric reducing capacity and ethylene production by roots of Fe-deficient cucumber plants
Ethylene has been involved in the induction of enhanced root ferric reducing capacity by Fe-defic... more Ethylene has been involved in the induction of enhanced root ferric reducing capacity by Fe-deficient Strategy I plants, since ethylene inhibitors block the induction of this response. Bicarbonate and anaerobiosis both inhibit the enhancement of ferric reducing capacity by Fe-deficient plants. The objective of this work was to study whether these factors act on the ferric reducing capacity through ethylene inhibition. The results suggest that anaerobiosis could inhibit ferric reducing capacity by blocking ethylene synthesis while bicarbonate could block ethylene action.
Differential response of sunflower genotypes to iron deficiency
Springer eBooks, 1987
In recent years chlorotic plants have appeared in the hybrid sunflower (Helianthus annuus L.) cro... more In recent years chlorotic plants have appeared in the hybrid sunflower (Helianthus annuus L.) crop in several Spanish growing areas. This prompted us to study the physiology and genetic variability of some of the hybrids and inbred parental lines in relation to their efficiency in iron nutrition.
Scientific Reports, Oct 28, 2019
Euphorbia heterophylla is a weed species that invades extensive crop areas in subtropical regions... more Euphorbia heterophylla is a weed species that invades extensive crop areas in subtropical regions of Brazil. this species was previously controlled by imazamox, but the continuous use of this herbicide has selected for resistant biotypes. two biotypes of E. heterophylla from southern Brazil, one resistant (R) and one susceptible (S) to imazamox, were compared. The resistance of the R biotype was confirmed by dose-response assays since it required 1250.2 g ai ha −1 to reduce the fresh weight by 50% versus 7.4 g ai ha −1 for the S biotype. the acetolactate synthase (ALS) enzyme activity was studied using ALS-inhibiting herbicides from five different chemical families. The R biotype required the highest concentrations to reduce this enzyme activity by 50%. A Ser653Asn mutation was found in the ALS gene of the R biotype. the experiments carried out showed that imazamox absorption and metabolism were not involved in resistance. However, greater 14 c-imazamox root exudation was found in the R biotype (~70% of the total absorbed imazamox). Target site mutation in the ALS gene is the principal mechanism that explains the imazamox resistance of the R biotype, but root exudation seems to also contribute to the resistance of this biotype. Euphorbia heterophylla L. is a dicotyledonous weed belonging to the Euphorbiaceae family. The species originated in the tropical and subtropical regions of America, where most of the affected crop areas are located 1-3. Until the 1990s, the presence of this species in cotton, soybean and corn fields was fairly well controlled with acetolactate synthase-inhibiting herbicides (ALS-inhibiting herbicides) (HRAC group B, WSSA group 2). However, due to poor control, the invasion range of E. heterophylla has increased to include more crop areas 4-6 , other countries such as Mexico and the USA 7,8 and even other continents such as Europe 9 , causing great economic losses. This lack of control is due to the evolution of new E. heterophylla biotypes resistant to these herbicides 6,10. The first known case of resistance to ALS-inhibiting herbicides in this species was reported in Brazil (1993) and some years later in Paraguay (1995) 6. Since then, other E. heterophylla cases with ALS-inhibiting herbicide resistance (including imazamox) have been found in large areas of Brazil (2004), also selecting for resistance to herbicides with other modes of action (MOA) 11-14. Imazamox [(5-(methoxymethyl)-2-(4-methyl-5-oxo-4-propan-2-yl-1H-imidazol-2-yl) pyridine-3-carboxylic acid)] belongs to the chemical family of imidazolinones within the ALS-inhibiting herbicides. It is a systemic herbicide that acts in early post-emergence stages, causing the inhibition of the ALS enzyme (EC 2.2.1.6), which is involved in the synthesis of the essential branched-chain amino acids isoleucine, leucine and valine 15. To study the basis of herbicide resistance, all the mechanisms should be considered. These mechanisms can be classified as target-site resistance (TSR) and non-target-site resistance (NTSR) mechanisms, depending on whether the target protein is involved or not, respectively 16,17. Currently, imazamox resistance is explained by the appearance of point mutations in the ALS gene (TSR mechanism) 18-20 , the lack of herbicide absorption and translocation 21,22 and the herbicide metabolism 22-24 (all these have NTSR mechanisms) in different grass and broadleaf weeds with resistance to ALS-inhibiting herbicides. Several point mutations are the most frequent mechanisms of resistance to imazamox found in the cases studied across weed species 24-27. Eight point mutations (Ala122,
Efficacy of Fe(<i>o</i>,<i>o</i>-EDDHA) and Fe(<i>o</i>,<i>p</i>-EDDHA) Isomers in Supplying Fe to Strategy I Plants Differs in Nutrient Solution and Calcareous Soil
Journal of Agricultural and Food Chemistry, Nov 1, 2008
The FeEDDHA [iron(3+) ethylenediamine di(o-hydroxyphenylacetic) acid] is one of the most efficien... more The FeEDDHA [iron(3+) ethylenediamine di(o-hydroxyphenylacetic) acid] is one of the most efficient iron chelates employed in the correction of iron clorosis in calcareous soils. FeEDDHA presents different positional isomers: the ortho-ortho (o,o), the ortho-para (o,p), and the para-para (p,p). Of these isomers, the p,p cannot chelate Fe in soil solution in a wide range of pH values, while both o,o and o,p can. The objective of this work was to compare the efficiency of both isomers (o,o and o,p) to provide Fe to two Strategy I plants (tomato and peach) in nutrient solution (pH approximately 6.0), as well as in calcareous soil (pH approximately 8.4; CALCIXEREPT). For this, chelates of both o,o-EDDHA and o,p-EDDHA with 57Fe (a nonradioactive isotope of Fe) were used, where the 57Fe acts as a tracer. The results obtained showed that the o,o isomer is capable of providing sufficient Fe to plants in both nutrient solution and calcareous soil. However, the o,p isomer is capable of providing sufficient Fe to plants in nutrient solution but not in calcareous soil.
Genotypic differences in bicarbonate‐induced iron chlorosis in sunflower
Journal of Plant Nutrition, 1988
Six sunflower (Helianthus annuus L.) lines were grown in nutrient solution to characterize their ... more Six sunflower (Helianthus annuus L.) lines were grown in nutrient solution to characterize their sensitivity to bicarbonate‐induced Fe chlorosis. Sensitivity was evaluated by chlorosis score and growth reduction relative to the control without added bicarbonate. Chlorosis score was inversely correlated to chlorophyll and Fe concentrations in the uppermost leaves. This technique seems valuable for determining genotypic differences in sensitivity to
Journal of Phytopathology, May 26, 2011
Verticillium wilt of olive, caused by Verticillium dahliae Kleb., is the most severe disease affe... more Verticillium wilt of olive, caused by Verticillium dahliae Kleb., is the most severe disease affecting this crop in most olive growing countries. In this study, the presence of viable structures of V. dahliae in dried inflorescences from wilted olive shoots was investigated. The pathogen was found inside peduncles and flowers, by assessing the number of typical star-shaped microsclerotial colonies formed onto the modified sodium polypectate agar medium. Microsclerotia of V. dahliae were observed inside the peduncles under the stereoscopic microscope. The presence of microsclerotia in these easily decomposable olive tissues shows that infected inflorescences can act as a source of inoculum for Verticillium wilt epidemics.
[Resistance of olive varieties to iron chlorosis: its importance for varieties selection]. [Spanish]
Advances on resistance of olive tree to Verticillium wilt caused by Verticillium dahliae
Differences in tolerance to iron deficiency among olive (Olea europaea L.) cultivars
Iron Nutrition in Soils and Plants, 1995
Iron deficiency chlorosis has been observed in olive trees grown on calcareous soils. In the pres... more Iron deficiency chlorosis has been observed in olive trees grown on calcareous soils. In the present work we have studied the tolerance to Fe deficiency of several olive cultivars grown in the Cordoba Olive World Collection. Iron deficiency was induced in plants grown in a hydroponic medium containing low levels of Fe (5 μM) and high levels of bicarbonate (10 mM) for a period of 2 months. Results showed differences among cultivars in the evolution of iron chlorosis, and in the leaf chlorophyll content at the end of the experiment. Shoot elongation also varied among cultivars, making it difficult to compare some of them. These results prompted us to use a control treatment (20 μM Fe and without bicarbonate) and two treatments with bicarbonate (10 mM) and two levels of Fe (5 and 10 μM). Accumulated dry matter in shoot of plants treated with bicarbonate, as compared to the control, was a parameter which allowed us to make a better comparison among cultivars. Growth of some cultivars was very affected by the bicarbonate treatment even when showing very little chlorosis.
Scientia Horticulturae, May 1, 2012
Thirteen quince clones, originated in previous studies, were evaluated for tolerance to iron chlo... more Thirteen quince clones, originated in previous studies, were evaluated for tolerance to iron chlorosis in a three years experiment carried out on a highly calcareous soil under field conditions. Chlorosis severity was determined by SPAD values and growth by shoot length increase. Two clones were identified as the most tolerant and the rest exhibited a susceptible or intermediate behavior. In general, chlorosis increased with the season and with the years, reaching the highest severity in summer and in the third year. The most tolerant clones maintained a lower chlorosis severity and a better growth than the rest of the clones during most of the experimental period. At the beginning of the third growing season, some very chlorotic plants received chelated-Fe in the soil and responded with a rapid and continuous recovery.
Plant Hormones and Nutrient Deficiency Responses
Plant in Challenging Environments, 2021
Planta, Feb 9, 2023
Main conclusion FO12 strain enhances Fe deficiency responses in cucumber plants, probably through... more Main conclusion FO12 strain enhances Fe deficiency responses in cucumber plants, probably through the production of ethylene and NO in the subapical regions of the roots.
Iron Reduction by Sunflower Roots under Iron Stress
Springer eBooks, 1988
Under iron deficiency stress several dicotyledonous species (sunflower, bean, cucumber, etc.) dev... more Under iron deficiency stress several dicotyledonous species (sunflower, bean, cucumber, etc.) develop in their roots morphological and physiological changes in order to increase iron uptake: root tips swelling, increase in the ferric reducing capacity (RC), proton efflux, and release of phenolic compounds. In this work we present the response to iron stress of a Fe-efficient inbred line (RHA 274) and the effect of an inhibitor of polar auxin transport 2,3,5-triiodobenzoic acid (TIBA) on the iron stress response.
Variability in the response of sunflower hybrids or parental lines to iron stress
Journal of Plant Nutrition, Mar 1, 1986
Abstract The degree of Fe efficiency of 3 inbred parental lines and 2 hybrids of sunflower was st... more Abstract The degree of Fe efficiency of 3 inbred parental lines and 2 hybrids of sunflower was studied using single 11 day old plants that had been growing under iron stress for the preceding 6 days. The pH of the root medium was recorded daily for each plant from the third to the sixth day of the treatment. The Fe3+ reducing capacity was then measured by placing the root in a small vessel with 20 ml of nutrient solution plus FeEDTA and Ferrozine and recording the absorbance at 562 run after 7.5 h. The inbred lines were classified as follows: line 89 was Fe inefficient, line 273 was Fe efficient, although some plants showed a low Fe3+ reducing capacity, and line 276 segregated for both Fe inefficient and Fe efficient plants. Two hybrids which had shown some chlorotic plants when grown in calcareous soils, developed Fe efficient and Fe inefficient plants in this assay. The progeny of 2 Fe efficient and 2 Fe inefficient plants was studied as previously described. The results point out that the capacity of t...
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Papers by Esteban Alcantara