Biochemical and physiological impacts of zinc sulphate,potassium phosphite and hydrogen sulphide in mitigating stress conditions in soybean

Soybean is the most widely grown oilseed in the world. It is an important source of protein and oil which are derived from its seeds. Drought stress is a major constraint to soybean yields. Finding alternative methods to mitigate the water stress for soybean is useful to maintain adequate crop yields. The aim of this study was to evaluate the morpho-physiological, biochemical and metabolic changes in soybean plants in two ontogenetic stages, under exposure to water deficit and treatment with zinc sulphate (ZS), potassium phosphite (PP) or hydrogen sulphide (HS). We carried out two independent experiments in the V4 and R1 development stages consisting of the following treatments: well-watered control (WW, 100% maximum water holding capacity, MWHC), water deficit (WD, 50% MWHC), PP + WW, PP + WD, HS + WW, HS + WD, ZS + WW and ZS + WD. The experimental design consisted of randomized blocks with eight treatments with five replicates. Morphological, physiological and metabolic analyses were performed 8 days after the start of the treatments for both experiments. We identified two tolerance mechanisms acting in response to compound application during water stress: the first involved the upregulation of antioxidant enzyme activity and the second involved the accumulation of soluble sugars, free amino acids and proline to facilitate osmotic adjustment. Both mechanisms are related to the maintenance of the photosynthetic parameters and cell membrane integrity. This report suggests the potential agricultural use of these compounds to mitigate drought effects in soybean plants.     

Characterization of epididymal sperm from Spix's yellow‐toothed cavies (Galea spixii Wagler, 1831) recovered by different methods

The aim of the present study was to characterize the epididymal sperm of Spix's yellow‐toothed cavy (Galea spixii) through two different recovery methods. Nine sexually mature males were euthanized and the complexes, testes–epididymis, were dissected. For each animal, one epididymis was processed by flotation method and the other was processed by retrograde flushing method, both using a TES‐based buffered media. After recovery, we evaluated the sperm for motility, vigour, viability, functional membrane integrity and morphology. Morphometric data from the different sperm regions were evaluated by using an appropriate software. After recovery, both methods provide similar values for all the sperm parameters, aiming the recovery of more than 300 × 10⁶ sperm, presenting >50% motile sperm, with normal morphology and functional membrane. The total sperm length in this sperm was 48.87 ± 0.1, and the sperm head presented 9.4%, on average. A notable characteristic was the prominent acrosome found in the G. spixii sperm. In conclusion, we demonstrate that either flotation or retrograde flushing methods are suitable for the recovery of sperm from cauda epididymis of Spix's yellow‐toothed cavies.     

A new species of <Emphasis Type="Italic">Orthophytum</Emphasis> (Bromeliaceae,Bromelioideae) from Minas Gerais,Brazil

Orthophytum vidaliorum, a new species from Minas Gerais, Brazil, is described and illustrated, and its relationship to Orthophytum itambense is discussed.     

Chromosomal localization of microsatellite loci in Drosophila mediopunctata

Drosophila mediopunctata has been used as a model organism for genetics and evolutionary studies in the last three decades. A linkage map with 48 microsatellite loci recently published for this species showed five syntenic groups, which had their homology determined to Drosophila melanogaster chromosomes. Then, by inference, each of the groups was associated with one of the five major chromosomes of D. mediopunctata. Our objective was to carry out a genetic (chromosomal) analysis to increase the number of available loci with known chromosomal location. We made a simultaneous analysis of visible mutant phenotypes and microsatellite genotypes in a backcross of a standard strain and a mutant strain, which had each major autosome marked. Hence, we could establish the chromosomal location of seventeen loci; including one from each of the five major linkage groups previously published, and twelve new loci. Our results were congruent with the previous location and they open new possibilities to future work integrating microsatellites, chromosomal inversions, and genetic determinants of physiological and morphological variation.     

Effect of progesterone on the expression of GABAA receptor subunits in the prefrontal cortex of rats: implications of sex differences and brain hemisphere

Progesterone is a neuroactive hormone with non‐genomic effects on GABA_A receptors (GABA_AR). Changes in the expression of GABA_AR subunits are related to depressive‐like behaviors in rats. Moreover, sex differences and depressive behaviors have been associated with prefrontal brain asymmetry in rodents and humans. Thus, our objective was to investigate the effect of progesterone on the GABA_AR α1 and γ2 subunits mRNA expression in the right and left prefrontal cortex of diestrus female and male rats exposed to the forced swimming test (FST). Male and female rats (n = 8/group) were randomly selected to receive a daily dose of progesterone (0·4 mg·kg^–1) or vehicle, during two complete female estrous cycles (8–10 days). On the experiment day, male rats or diestrus female rats were euthanized 30 min after the FST. Our results showed that progesterone significantly increased the α1 subunit mRNA in both hemispheres of male and female rats. Moreover, there was an inverse correlation between depressive‐like behaviors and GABA_AR α1 subunit mRNA expression in the right hemisphere in female rats. Progesterone decreased the GABA_AR γ2 mRNA expression only in the left hemisphere of male rats. Therefore, we conclude that the GABA_A system displays an asymmetric distribution according to sex and that progesterone, at lower doses, presents an antidepressant effect after increasing the GABA_AR α1 subunit expression in the right prefrontal cortex of female rats. Copyright © 2012 John Wiley & Sons, Ltd.     

Richness and composition of terrestrial mammals vary in eucalyptus plantations due to stand age

Plantation forests substitute natural habitats and have rotation cycles of 7 years due to their high growth rates. This variation reflects on local and landscape changes, influencing habitat availability and affecting mammal communities. In this study, our general hypothesis was that the richness and composition of mammals varied in eucalyptus plantations in relation to native forest patches and in relation to the age of eucalyptus plantations. We predicted that (1) there would be lower mammalian richness and compositional differences in eucalyptus plantations compared to native vegetation due to monocultures having simplified environmental characteristics and (2) predicted that the richness and composition would vary according to eucalyptus age and that the highest values of richness would be found in plantations of up to middle age, considering that in these phases there are environmental characteristics that positively qualify these structures for a greater presence of fauna, such as the shrubby aspect of the plantations and the presence of undergrowth. We performed model selection to observe the effect of environmental variables on mammalian richness. We also performed a multivariate permutational analysis of variance, a non-metric multidimensional scaling and partitioned the beta diversity to observe how the composition was influenced by environmental variables. We found greater richness in the native vegetation compared to eucalyptus plantations. The richness of the plantations varied according to the age, with higher values up to middle age. The composition varied according to the land user/cover, with the eucalyptus age and with the management unit due to the nestedness of species. We suggest that eucalyptus plantations at early ages are more used by mammals due to the shrubby aspect of the stand, generating a positive visual effect for the search of resources and shelter, in addition to the possibility of the occurrence of grasses, some understory and lower anthropogenic disturbance.     

Micropropagation of Piper crassinervium: an improved protocol for faster growth and augmented production of phenolic compounds

Plant Cell, Tissue and Organ Culture (PCTOC) - The medicinal plant Piper crassinervium is a source of bioactive compounds with potential use in agrochemical and pharmaceutical industries. However,...