Sweet corn (Zea mays L.) growth and yield are influenced by establishment methods

Six experiments were performed in the term of three years in order to explore and compare the effects of transplanting and direct sowing (DS) on sweet corn (Zea mays L.) growth, earliness and yield. Different genotypes, tray cell sizes (volume) and seedling ages were assayed. In all experiments, direct sowing was performed with a final separation of 0.25 m between plants in each row. Growth parameters (height, leaf area and ear size) were reduced with the increase of age and/or decrease of the tray cell size, mainly in cultivars with early flowering i.e., low cumulative corn heat unit (CHU) requirements. Earlier harvests were obtained in transplanting compared to direct sowing, although with lower yields. When the thermal time accumulated by plants in the trays was higher than 100 CHU, the yield decreased by 3.91% (R2 = 0.79) for each unit of CHU. The results indicate that the transplanted sweet corn yield was generally lower than of direct seeded plants, and differences grew bigger as the tray cell volume was smaller and the seedlings age increased.Instituto de Fisiología y Recursos Genéticos VegetalesFil: Ceccoli, Gabriel. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ortega, Leandro Ismael. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Fisiología y Recursos Genéticos Vegetales; ArgentinaFil: Gariglio, Norberto Francisco. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias; ArgentinaFil: Favaro, Juan Carlos. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias; ArgentinaFil: Bouzo, Carlos Alberto. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias; Argentin

Salinity induced anatomical and morphological changes in Chloris gayana Kunth roots

Chloris gayana Kunth is a grass species valuable as forage which was introduced into Argentina to be used as pasture in saline soils of subtropical and warm-temperate zones, given its good adaptability to drought, salinity and mild freezing. However, its tolerance varies according to the cultivar. In tetraploid cultivars, important reductions in yield have been observed. Here, a study of the variations produced on the root and stem system by salinity at different NaCl concentrations (0, 150 y 250 mM) was performed in the Boma cultivar, with the aim of determining the anatomical and morphological alterations produced by the salt excess. Plants cultivated with the highest level of salinity showed, in the whole, significant differences in the measured variables. A diminution in absolute values of the variables and a major reduction in vascular tissue dimensions were observed, which suggests that the lack of tolerance to salt stress could be related to a deficient adaptation to absorb and transport water and nutrients from the roots.Instituto de Fisiología y Recursos Genéticos VegetalesFil: Ceccoli, Gabriel. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ramos, Julio C. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ortega, Leandro Ismael. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Fisiología y Recursos Genéticos Vegetales (ex IFFIVE); ArgentinaFil: Acosta, Juan M. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Perreta, Mariel Gladis. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Cociente fototermal en melón y su relación con la concentración de azúcares en los frutos

The aim of this work was to evaluate the effect of solar radiation and temperature on the sugar melon fruit using the photothermal quotient. Outdoor experiments were conducted in three successive years, using the hybrid cultivar 'HD Nº1'. The experiments were conducted at four sites in the central region of Argentina: Concordia, Esperanza, Media Agua and Colonia Fiscal. At the time of harvest were measured Total Soluble Solid (TSS) of fruits. The photothermal quotient (PQ) was calculated through the relationship between the average incident radiation (MJ m-2 d-1) and the average daily temperature (°C) at which base temperature was subtracted. The relationship obtained between TSS (%) and the PQ (MJ m-2 d-1 °C-1) was lineal positive. The slope of the line allowed deduce that for every unit increase in the PQ represented an increase of just over 4.0% of TSS. Moreover, this model explains 63% of the variability in the TSS due to the effect of PQ. Finally, to increase the TTS the importance of the results is discussed, for guiding the crop establishment so that fruits development coincides with the period of greatest value PQ.El objetivo de este trabajo fue evaluar el efecto de la radiación y la temperatura a través de un cociente fototermal sobre la acumulación de azúcar en melón. Se realizaron experimentos al aire libre en tres años consecutivos, utilizándose el híbrido ´HD Nº1´, una variedad de tipo ´Honey Dew´. Los experimentos se realizaron en cuatro localidades de la región central de Argentina: Concordia, Esperanza, Media Agua y Colonia Fiscal. Al momento de la cosecha fueron medidos los grados Brix (SST) de los frutos. Se calculó el cociente fototermal (CF) a través de la relación entre la radiación incidente media (MJ m-2 d-1) y la temperatura media diaria (ºC) a la que se sustrajo la temperatura base del cultivo. La relación obtenida entre la concentración de SST (%) y el CF (MJ m-2 d-1 ºC-1) fue lineal positiva. La pendiente de la recta permitió deducir que por cada unidad de incremento del CF representó un incremento de poco más de 4,0 % de SST. Por otra parte, este modelo lineal explica el 63 % de la variabilidad en la concentración de SST debida al efecto del CF. Finalmente, para lograr un incremento de los SST se discute la importancia de los resultados obtenidos para orientar la implantación del cultivo de manera que el desarrollo de los frutos coincida con el período de mayor valor de CF

Photothermal quotient in melon and its relationship with the fruits sugar concentration

The aim of this work was to evaluate the effect of solar radiation and temperature on the sugar melon fruit using the photothermal quotient. Outdoor experiments were conducted in three successive years, using the hybrid cultivar 'HD Nº1'. The experiments were conducted at four sites in the central region of Argentina: Concordia, Esperanza, Media Agua and Colonia Fiscal. At the time of harvest were measured Total Soluble Solid (TSS) of fruits. The photothermal quotient (PQ) was calculated through the relationship between the average incident radiation (MJ m-2 d-1) and the average daily temperature (°C) at which base temperature was subtracted. The relationship obtained between TSS (%) and the PQ (MJ m-2 d-1 °C-1) was lineal positive. The slope of the line allowed deduce that for every unit increase in the PQ represented an increase of just over 4.0% of TSS. Moreover, this model explains 63% of the variability in the TSS due to the effect of PQ. Finally, to increase the TTS the importance of the results is discussed, for guiding the crop establishment so that fruits development coincides with the period of greatest value PQ

Cociente fototermal en melón y su relación con la concentración de azúcares en los frutos

The aim of this work was to evaluate the effect of solar radiation and temperature on the sugar melon fruit using the photothermal quotient. Outdoor experiments were conducted in three successive years, using the hybrid cultivar 'HD Nº1'. The experiments were conducted at four sites in the central region of Argentina: Concordia, Esperanza, Media Agua and Colonia Fiscal. At the time of harvest were measured Total Soluble Solid (TSS) of fruits. The photothermal quotient (PQ) was calculated through the relationship between the average incident radiation (MJ m-2 d-1) and the average daily temperature (°C) at which base temperature was subtracted. The relationship obtained between TSS (%) and the PQ (MJ m-2 d-1 °C-1) was lineal positive. The slope of the line allowed deduce that for every unit increase in the PQ represented an increase of just over 4.0% of TSS. Moreover, this model explains 63% of the variability in the TSS due to the effect of PQ. Finally, to increase the TTS the importance of the results is discussed, for guiding the crop establishment so that fruits development coincides with the period of greatest value PQ.El objetivo de este trabajo fue evaluar el efecto de la radiación y la temperatura a través de un cociente fototermal sobre la acumulación de azúcar en melón. Se realizaron experimentos al aire libre en tres años consecutivos, utilizándose el híbrido ´HD Nº1´, una variedad de tipo ´Honey Dew´. Los experimentos se realizaron en cuatro localidades de la región central de Argentina: Concordia, Esperanza, Media Agua y Colonia Fiscal. Al momento de la cosecha fueron medidos los grados Brix (SST) de los frutos. Se calculó el cociente fototermal (CF) a través de la relación entre la radiación incidente media (MJ m-2 d-1) y la temperatura media diaria (ºC) a la que se sustrajo la temperatura base del cultivo. La relación obtenida entre la concentración de SST (%) y el CF (MJ m-2 d-1 ºC-1) fue lineal positiva. La pendiente de la recta permitió deducir que por cada unidad de incremento del CF representó un incremento de poco más de 4,0 % de SST. Por otra parte, este modelo lineal explica el 63 % de la variabilidad en la concentración de SST debida al efecto del CF. Finalmente, para lograr un incremento de los SST se discute la importancia de los resultados obtenidos para orientar la implantación del cultivo de manera que el desarrollo de los frutos coincida con el período de mayor valor de CF

Coeficiente fototermal del melón y su relación con la concentración de azucares en los frutos = Photothermal quotient in melon and its relationship with the fruits sugar concentration

El objetivo de este trabajo fue evaluar el efecto de la radiación y la temperatura a través de un cociente fototermal sobre la acumulación de azúcar en melón. Se realizaron experimentos al aire libre en tres años consecutivos, utilizándose el híbrido ´HD Nº1´, una variedad de tipo ´Honey Dew´. Los experimentos se realizaron en cuatro localidades de la región central de Argentina: Concordia, Esperanza, Media Agua y Colonia Fiscal. Al momento de la cosecha fueron medidos los grados Brix (SST) de los frutos. Se calculó el cociente fototermal (CF) a través de la relación entre la radiación incidente media (MJ m-2 d -1) y la temperatura media diaria (ºC) a la que se sustrajo la temperatura base del cultivo. La relación obtenida entre la concentración de SST (%) y el CF (MJ m-2 d-1 ºC-1) fue lineal positiva. La pendiente de la recta permitió deducir que por cada unidad de incremento del CF representó un incremento de poco más de 4,0 % de SST. Por otra parte, este modelo lineal explica el 63 % de la variabilidad en la concentración de SST debida al efecto del CF. Finalmente, para lograr un incremento de los SST se discute la importancia de los resultados obtenidos para orientar la implantación del cultivo de manera que el desarrollo de los frutos coincida con el período de mayor valor de CF.The aim of this work was to evaluate the effect of solar radiation and temperature on the sugar melon fruit using the photothermal quotient. Outdoor experiments were conducted in three successive years, using the hybrid cultivar 'HD Nº1'. The experiments were conducted at four sites in the central region of Argentina: Concordia, Esperanza, Media Agua and Colonia Fiscal. At the time of harvest were measured Total Soluble Solid (TSS) of fruits. The photothermal quotient (PQ) was calculated through the relationship between the average incident radiation (MJ m-2d-1) and the average daily temperature (°C) at which base temperature was subtracted. The relationship obtained between TSS (%) and the PQ (MJ m-2 d -1°C-1) was lineal positive. The slope of the line allowed deduce that for every unit increase in the PQ represented an increase of just over 4.0% of TSS. Moreover, this model explains 63% of the variability in the TSS due to the effect of PQ. Finally, to increase the TTS the importance of the results is discussed, for guiding the crop establishment so that fruits development coincides with the period of greatest value PQ.Fil: Bouzo, Carlos. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias; ArgentinaFil: Lavanderos Becerra, Débora María. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Juan; ArgentinaFil: Ceccoli, Gabriel. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias; ArgentinaFil: Gariglio, Norberto. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias; Argentin

Genetic variability for responses to short‐ and long‐term salt stress in vegetative sunflower plants

Sunflower (Helianthus annuus L.) has been rated as moderately salt‐resistant, and variability for salt resistance has been detected within this crop. However, variability in salt‐resistance mechanisms has not been assessed. Osmotic tolerance, the relation of salt resistance with whole‐plant Na+ and K+ distribution and tissue Na+ tolerance were investigated in several sunflower inbred lines. Plants were grown under controlled conditions, in pots with sand and perlite irrigated with salinized (NaCl, –0.65 MPa) nutrient solution. Osmotic tolerance was assessed from the initial effects of the salt treatment on plant elongation in eleven sunflower lines. Long‐term salinity responses were evaluated in four of those lines, by assessing whole‐plant growth. A principal components analysis (PCA) was run on relative‐to‐control growth data, and this information was used to establish a relative resistance ranking, which indicated lines HAR2 > HAR1 > HA64 > HAR5. Osmotic tolerance was observed in HA64 and HAR2. The lines showed different degrees of Na+ accumulation, it was very low in some of them, but relative salt resistance was not associated to this trait. Tissue Na+ tolerance was deduced by comparing the percentage of dead leaves as a function of leaf blade Na+ accumulation, and it was higher in HAR1 than in the rest. These results indicate that variability for salt‐resistance mechanisms exists in sunflower. Osmotic tolerance and tissue Na+ tolerance were detected in different lines, highlighting that such variability may be exploited for increasing salt resistance in this crop.Instituto de Fisiología y Recursos Genéticos VegetalesFil: Ceccoli, Gabriel. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Senn, María Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Fisiología y Recursos Genéticos Vegetales(ex IFFIVE); ArgentinaFil: Bustos, Dolores Angela. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Fisiología y Recursos Genéticos Vegetales; ArgentinaFil: Ortega, Leandro Ismael. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Fisiología y Recursos Genéticos Vegetales (ex IFFIVE); ArgentinaFil: Córdoba, Alicia R. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Fisiología y Recursos Genéticos Vegetales (ex IFFIVE); ArgentinaFil: Vegetti, Abelardo Carlos. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Taleisnik, Edith. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Fisiología y Recursos Genéticos Vegetales (ex IFFIVE); Argentin

Suppression of reactive oxygen species accumulation in chloroplasts prevents leaf damage but not growth arrest in salt-stressed tobacco plants

Crop yield reduction due to salinity is a growing agronomical concern in many regions. Increased production of reactive oxygen species (ROS) in plant cells accompanies many abiotic stresses including salinity, acting as toxic and signaling molecules during plant stress responses. While ROS are generated in various cellular compartments, chloroplasts represent a main source in the light, and plastid ROS synthesis and/or elimination have been manipulated to improve stress tolerance. Transgenic tobacco plants expressing a plastid-targeted cyanobacterial flavodoxin, a flavoprotein that prevents ROS accumulation specifically in chloroplasts, displayed increased tolerance to many environmental stresses, including drought, excess irradiation, extreme temperatures and iron starvation. Surprisingly, flavodoxin expression failed to protect transgenic plants against NaCl toxicity. However, when high salt was directly applied to leaf discs, flavodoxin did increase tolerance, as reflected by preservation of chlorophylls, carotenoids and photosynthetic activities. Flavodoxin decreased salt-dependent ROS accumulation in leaf tissue from discs and whole plants, but this decline did not improve tolerance at the whole plant level. NaCl accumulation in roots, as well as increased osmotic pressure and salt-induced root damage, were not prevented by flavodoxin expression. The results indicate that ROS formed in chloroplasts have a marginal effect on plant responses during salt stress, and that sensitive targets are present in roots which are not protected by flavodoxin.Para citar este articulo: Lodeyro AF, Giró M, Poli HO, Bettucci G, Cortadi A, Ferri AM, et al. (2016) Suppression of Reactive Oxygen Species Accumulation in Chloroplasts Prevents Leaf Damage but Not Growth Arrest in Salt-Stressed Tobacco Plants. PLoS ONE 11(7): e0159588. doi:10.1371/journal.pone.0159588Fil: Lodeyro, Anabella F. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario (IBR -CONICET); Argentina.Fil: Giró, Mariana. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario (IBR -CONICET); Argentina.Fil: Poli, Hugo O. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario (IBR -CONICET); Argentina.Fil: Bettucci, Gabriel. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Departamento de Ciencias Biológicas; Argentina.Fil: Cortadi, Adriana. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Departamento de Ciencias Biológicas; Argentina.Fil: Ferri, Alejandro M. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Departamento de Química Analítica; Argentina.Fil: Carrillo, Néstor. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario (IBR -CONICET); Argentina