The role of abscisic acid and water relations in drought responses of subterranean clover

The role of water relations and abscisic acid (ABA) in the responses to drought were studied in a mediterranean forage crop, Trifolium subterraneum L. under field conditions. soil and plant water status, leaf gas exchange parameters, and xylem sap ABA content were determined at different times during a long-term soil drying episode in irrigated and droughted plants. The diurnal time-courses of these parameters were also measured at the end of a drought period. In response to soil drying stomatal conductance (g) was reduced early to 50% that of irrigated plants before any substantial change in water potential was detected. A close logarithmic regression between photosynthesis rate (A) and g was present. For the first weeks of drought the decline in A was less pronounced than in g, thus increasing water use efficiency. Stomatal conductance during diurnal time-courses showed no consistent relationships with respect to either ABA or leaf water potential. throughout the experimental period dependence of g on leaf water status was evident from the tight correlation (r(2) = 0.88, P < 0.01) achieved between stomatal conductance and midday water potential, but the correlation was also high when comparing g with respect to ABA content in xylem sap (r(2) = 0.83, P < 0.001). However, the stomata from drought acclimated plants were apparently more sensitive to xylem ABA content. For similar xylem ABA concentrations stomatal conductance was significantly higher in irrigated than in water-stressed plants.info:eu-repo/semantics/publishedVersio

Catalyzing Transitions to Sociality: Ecology Builds on Parental Care

In the context of social evolution research, great emphasis on kin-selected benefits has led to an understanding of parental care as one of the activities that helpers can perform in extended cooperative families. Nevertheless, this perspective might have precluded a deeper understanding of the implications of parental care for social evolution. We argue that parental care is a broader set of processes playing a key role both before and during the emergence of sociality. The care system of a species may be understood as the result of long coevolutionary processes with environmental pressures during pre-social stages that impact transitions to sociality. We evaluate the present framework against evidence on the evolution of parental care and transitions toward sociality in subsocial and parasocial vertebrate and invertebrate species. Moreover, following previous evidence for the importance of modes of foraging and resting, we structure our inquiry by classifying societies into three types. Our results suggest that in “central place foragers” and “fortress defenders”, ecological factors promoting the evolution of parental care foster a set of coevolutionary feedback loops resulting in increases in parental effort and offspring needs. Offspring needs alone or in combination with limited breeding options enhance the relative benefits of positive social interactions, catalyzing transitions to sociality. In “itinerant foragers”, sociality is associated with colonizing new niches. Changes in predation pressure entail changes in the modes of care or selection for certain types of care already present in solitary ancestors. Further changes in the form of collective defense may be needed for permanent sociality to evolve. We conclude that there is evidence that social transitions to different types of societies are the result of long coevolutionary processes between environmental pressures and the care systems in a wide variety of taxa. Therefore, advances in the study of the origins of sociality may require further investigation of parental care evolution in solitary ancestors of today's social species

Changes in the Ixodes ricinus microbiome associated with artificial tick feeding

Artificial tick feeding systems (ATFS) can be used to study tick biology and tick-pathogen interactions. Due to the long feeding duration of hard ticks, antibiotics are commonly added to the in vitro blood meal to prevent the blood from decaying. This may affect the ticks’ microbiome, including mutualistic bacteria that play an important role in tick biology. This effect was examined by the consecutive feeding of Ixodes ricinus larvae, nymphs, and adults in vitro with and without the supplementation of gentamicin and in parallel on calves. DNA extracted from unfed females was analyzed by 16S rRNA sequencing. The abundance of Candidatus Midichloria mitochondrii, Rickettsia helvetica and Spiroplasma spp. was measured by qPCR in unfed larvae, nymphs, and adults. Larvae and nymphs fed on calves performed significantly better compared to both in vitro groups. Adults fed on blood supplemented with gentamicin and B vitamins had a higher detachment proportion and weight compared to the group fed with B vitamins but without gentamicin. The detachment proportion and weights of females did not differ significantly between ticks fed on calves and in vitro with gentamicin, but the fecundity was significantly higher in ticks fed on calves. 16S rRNA sequencing showed a higher microbiome species richness in ticks fed on calves compared to ticks fed in vitro. A shift in microbiome composition, with Ca. Midichloria mitochondrii as dominant species in females fed as juveniles on calves and R. helvetica as the most abundant species in females previously fed in vitro was observed. Females fed in vitro without gentamicin showed significant lower loads of Ca. M. mitochondrii compared to females fed in vitro with gentamicin and ticks fed on calves. Spiroplasma spp. were exclusively detected in female ticks fed on cattle by qPCR, but 16S rRNA sequencing results also showed a low abundance in in vitro females exposed to gentamicin. In conclusion, the employed feeding method and gentamicin supplementation affected the ticks’ microbiome composition and fecundity. Since these changes may have an impact on tick biology and vector competence, they should be taken into account in studies employing ATFS

Commercial and industrial implication of the variability of oil and protein content and of the nut and kernel physical traits of almond in Mediterranean climates

Se determinaron los caracteres físicos y la composición química de los frutos de 11 cultivares de almendro cultivados en dos zonas distintas, Zaragoza (España) y Meknès (Marruecos). Independientemente de la variabilidad entre cultivares para todos los parámetros medidos, el efecto del año fue significativo para todos los parámetros físicos, excepto para el espesor de la pepita. Igualmente fue significativo el efecto de la localidad para todos los parámetros físicos, excepto para la longitud y el índice de esfericidad del fruto, la longitud y la anchura de la pepita, y el rendimiento en pepita. La calidad física de las pepitas producidas en Zaragoza fue mayor que las producidas en Meknès, probablemente por el diferente sistema de cultivo y las condiciones ambientales que fueron más extremas en Meknès. Estos resultados muestran que las condiciones de cultivo adecuadas favorecen el aumento de los caracteres conducentes a una mayor calidad física del fruto y de la pepita. En cuanto al contenido en aceite y en proteína, se encontraron diferencias significativas entre los genotipos y las localidades. Las condiciones ambientales y de cultivo de Zaragoza favorecieron la acumulación de aceite en la pepita, mientras que las de Meknès favorecieron la acumulación de proteína. Ello apunta a que la utilización industrial de los distintos cultivares estudiados no sólo depende del propio cultivar, sino también de las condiciones ambientales y de cultivo, lo que debe tenerse muy en cuenta para la valorización de la producción en las distintas zonas de cultivo del almendroThe fruit physical traits and the chemical composition were determined for 11 almond cultivars grown in two different regions: Zaragoza (Spain) and Meknès (Morocco). Independently of the variability among cultivars for all traits measured, the year effect was significant for all physical traits except for kernel thickness. The location effect was significant for all physical traits except for fruit length and sphericity, kernel length and width, and kernel percentage. The physical quality of the kernels produced in Zaragoza was higher than that of the kernels produced in Meknès, probably because of the different growing system and the environmental conditions, more extreme in Meknès. These results show that adequate growing conditions favour the increase of traits leading to increased physical quality of nuts and kernels. The cultivar and the location effects were significant for the contents of oil and protein. The environmental and growing conditions of Zaragoza led to a higher oil accumulation, whereas those of Meknès to a higher protein accumulation. These results indicate that the industrial utilization of the different almond cultivars does not only depend on the cultivar, but also on the environmental and growing conditions, a fact to be considered when marketing the production of the different growing region

Comunicación corta. Exportación de los macroelementos mayoritarios por los frutos de diferentes cultivares de almendro

The amount of the major macroelements required to produce a given crop has been determined for a set of 11 almond (Prunus amygdalus Batsch) cultivars growing in the Middle Ebro Valley (NE Spain). A wide diversity of nutrient exports was found among the different cultivars. Although the production of kernels is the main objective when growing almonds, all the different fruit components: the mesocarp (hull), the endocarp (shell) and the seed (kernel), were taken into account. The different fruit components showed a great variation among cultivars, and the amount of fruit dry matter required for producing 1 kg of kernel ranged from 4.32 kg in ‘Guara’ to 10.56 kg in ‘Desmayo Largueta’. Similarly, the macroelement requirements to produce a given amount of kernels varied among the different cultivars. ‘Guara’ has proved to be the most effective cultivar in taking advantage of the mineral elements for producing a crop, showing that this efficiency is independent of the shell type. Se determin&oacute; la cantidad de macroelementos mayoritarios necesarios para producir una determinada cantidad de cosecha en un grupo de 11 cultivares de almendro (Prunus amygdalus Batsch) cultivados en el Valle Medio del Ebro (NE de Espa&ntilde;a). Se encontr&oacute; una gran diversidad de requerimientos entre los diferentes cultivares. Aunque la producci&oacute;n de pepitas es el objetivo principal en el cultivo del almendro, todos los componentes del fruto se han de tener en cuenta en este c&aacute;lculo: el mesocarpo (la piel), el endocarpo (la c&aacute;scara) y la semilla (la pepita). Estos tres componentes del fruto mostraron una gran variabilidad entre los cultivares y la cantidad de materia seca necesaria para producir 1 kg de pepita oscil&oacute; entre 4,32 kg en &lsquo;Guara&rsquo; y 10,56 kg en &lsquo;Desmayo Largueta&rsquo;. Igualmente, los requisitos en macroelementos para producir una cantidad determinada de pepita vari&oacute; entre los diferentes cultivares. &lsquo;Guara&rsquo; mostr&oacute; ser el cultivar m&aacute;s eficiente en la utilizaci&oacute;n de los elementos minerales para la producci&oacute;n de una cosecha, mostrando que esta eficiencia es independiente del tipo de c&aacute;scara

Flowering and pollination time affect fruit set of foreign almond cultivars in Morocco

The associations ‘Marcona’-‘Fournat de Brézenaud’ and ‘Ferragnès’-‘Ferraduel’ are the cultivar combinations mostly planted in commercial almond orchards in Morocco. The blooming times and effective pollination period (EPP) were determined for these associations to determine the effect of blooming and pollination times on the irregular yields observed in Morocco with these cultivars. ‘Marcona’ bloom was earlier than that of ‘Fournat de Brézenaud’, but ‘Ferragnès and ‘Ferraduel’ coincided. Fruit set and percentage of pistils with pollen grains was maximized when pollination occurred at day 2 after emasculation. Fruit set and stigmatic receptivity decreased drastically by day 4 after emasculation. Fruit set in the open pollination treatment was lower than that obtained after hand pollination at days 0 and 2 after emasculation, especially in ‘Marcona’. These results emphasize the importance of early pollination and the selection of new cultivars with the same flowering period as ‘Marcona’ to improve almond yields in Morocco.Peer ReviewedPrunus amygdalusbloomeffective pollination periodstigmatic receptivityfruit setPublishe