Environmental influences on post-harvest natural regeneration of <Emphasis Type="Italic">Pinus pinaster</Emphasis> Ait. in Mediterranean forest stands submitted to the seed-tree selection method

Research on natural regeneration is crucial for the development of sustainable forestry practices, in light of the global climate changes taking place. In this study, 151 plots were sampled in six Pinus pinaster stands that were naturally regenerated by the seed-tree method in Mediterranean forests in central Spain. The objectives of the survey were to study the suitability of different forest stands designated for natural regeneration as well as to analyse seedling establishment and the relationship between regeneration and different site factors. Analysis of variance and multivariate analysis with canonical ordination techniques were employed. Full and partial redundancy analyses on a correlation matrix were used to carry out a direct gradient analysis of regeneration density as a function of site factors. Nearly all stands presented seedling densities over 2,000 seedlings ha⁻¹ and were thus found to be suitable for natural regeneration of Pinus pinaster by the seed-tree selection method. Significant variables that best explained total seedling and viable seedling density were spring and autumn precipitation of the year prior to establishment, spring and summer precipitation of the year of establishment and percentage cover of litter. There were no signs of competition between shrubs and seedlings, but a negative significant correlation with grass cover was observed. Pinus pinaster natural regeneration was successful with the seed-tree method, although it appeared to be highly dependent on climate and stand conditions.     

Yield map generation of perennial crops for fresh consumption

Yield mapping technologies can help to increase the quantity and quality of agricultural production. Current systems only focus on the quantification of the harvest, but the quality has equal or greater importance in some perennial crops and impacts directly on the financial profitability. Therefore, a system was developed to quantify and relate the quality obtained in the classification line with the plants of the orchard and for decision-making. The system is comprised of hardware, which obtains the location of the harvester bag during harvesting and unloading at the unloading site, and software that processes the collected data. The cloud of real-time data contributed from the different collectors (bins) allows the construction of yield maps, considering the multi-stage harvesting system. Further, the system enables the creation of a detailed map of the plants and fruits harvested. As the harvest focuses on quality, it takes place in stages, depending on the ripening of the fruits. In addition to the yield maps, the system allows identification of the efficiency of each worker undertaking the harvest by the number of performed discharges and by the time spent. The system was developed in partnership with the Federal Technological University of Paraná and Embrapa Uva & Vinho and was tested in apple orchards in southern Brazil. Although the system was evaluated with only data from apple cultivation, monitoring the quality and quantifying other orchard fruits can positively impact the fruit sector.

     

Guava decline: effect of root exudates from Meloidogyne enterolobii-parasitized plants on Fusarium solani in vitro and on growth and development of guava seedlings under controlled conditions

In guava decline, Fusarium solani-immune guava trees become susceptible to extensive root rot caused by this fungus after parasitism by Meloidogyne enterolobii. To understand the mechanisms involved in this disease, root exudates were collected from nematode-inoculated (NI) or uninoculated (UN) guava plants cultivated in sand. After filtration through a Millipore® membrane, NI and UN exudates were used: i) to prepare media to assess their effect on mycelial growth and production of propagules of F. solani isolate UENF/CF 163, and ii) to incubate macro- and microconidia to assess their effect on germination. NI exudates promoted (P?<?0.05) more mycelial growth and production of propagules than UN exudates or water. NI and UN exudates were used to water guava seedlings laid over seed germination paper inside plastic boxes. Half of the seedlings had an agar plug colonized by the fungus positioned in the collar region. Upon watering with NI exudates the fungus caused (P?<?0.05) extensive rotting of the seedlings’ rootlets. NI and UN exudates, either unlyophilized or lyophilized and re-suspended to the original concentration, were used to water guava seedlings grown in sterile sand before being inoculated (or left uninoculated) as described before. Solely upon watering with NI exudates, in its unlyophilized form or after lyophilization, the fungus caused a reduction (P?<?0.05) of shoot and root biomass associated with rotting of roots. These results suggest that M. enterolobii induces chemical changes in the root exudates of guava trees, which are necessary for root invasion causing root rotting by F. solani.     

Structural Characterization of New Peptide Variants Produced by Cyanobacteria from the Brazilian Atlantic Coastal Forest Using Liquid Chromatography Coupled to Quadrupole Time-of-Flight Tandem Mass Spectrometry

Cyanobacteria from underexplored and extreme habitats are attracting increasing attention in the search for new bioactive substances. However, cyanobacterial communities from tropical and subtropical regions are still largely unknown, especially with respect to metabolite production. Among the structurally diverse secondary metabolites produced by these organisms, peptides are by far the most frequently described structures. In this work, liquid chromatography/electrospray ionization coupled to high resolution quadrupole time-of-flight tandem mass spectrometry with positive ion detection was applied to study the peptide profile of a group of cyanobacteria isolated from the Southeastern Brazilian coastal forest. A total of 38 peptides belonging to three different families (anabaenopeptins, aeruginosins, and cyanopeptolins) were detected in the extracts. Of the 38 peptides, 37 were detected here for the first time. New structural features were proposed based on mass accuracy data and isotopic patterns derived from full scan and MS/MS spectra. Interestingly, of the 40 surveyed strains only nine were confirmed to be peptide producers; all of these strains belonged to the order Nostocales (three Nostoc sp., two Desmonostoc sp. and four Brasilonema sp.).     

Comparative analysis of Andiodrilus pachoensis casts in forests and pastures of South-Eastern Amazon (Brazil)

Soil ecosystem engineers produce biogenic structures (casts, mounds, galleries) that strongly affect soil processes. A comparative analysis of the physical characteristics of the casts produced by the earthworm Andiodrilus pachoensis was carried out in four pastures sowed with Brachiaria brizantha and four primary forests on the deforestation front of the Amazonian forest. In both systems, we recorded surface cast density and spatial patterns as well as surface cast physical properties. Cast and vegetation distributions were mapped within plots of sizes ranging from 25 to 50 m², and cast production was monitored during 2 months. Cast spatial distribution varied greatly among plots and across spatial scales ranging from regular at small spatial scales (0–20 cm) to clumped for larger distance ranges (>80 cm). Cast density was not significantly correlated with grass tuft density and their production was independent from the presence of grass tufts in pastures or litter quantity in forests. Although bulk soil properties (pH, C content, structural stability, etc) differed between pastures and forests, cast physical properties did not differ significantly among the studied ecosystem.     

Effect of root temperature on carob growth: Nitrate versus ammonium nutrition

The response of carob (Ceratonia siliqua L.) seedlings grown at different root zone temperatures affected by nitrate and ammonium nutrition was studied. When root temperatures ranged from 10 to 35°C, ammonium‐fed plants were significantly larger than nitrate‐fed plants. Ammonium‐fed plants displayed toxicity symptoms and were much smaller at 40°C root temperature in comparison with the nitrate‐fed plants grown at the same root temperature. Root/shoot ratio slightly increase with root temperature in ammonium‐ and nitrate‐fed plants in a similar way, and shoot demand per root unit decreased with root temperature between 15 and 25°C. There was a general increase in net photosynthesis with root temperature, though nitrate‐fed plants were more sensitive to low and ammonium‐fed plants to high temperatures. Increasing the root temperature of ammonium fed plants from 10 to 40°C leads to a 30% increase in the amount of photosynthates sent to the roots. The presence of ammonium resulted in the distribution of newly fixed carbon away from carbohydrates and into nitrogen compounds. Potassium, calcium, and nitrogen content of the plants also increased with increasing root temperature.     

Sperm subpopulations influence the pregnancy rates in cattle

This study aimed to study the characteristics and subpopulations of spermatozoa from bulls with low and high reproductive performance based on pregnancy rates. Based on historical records of pregnancy rate from four farms, 24 bulls were selected. Two groups were established, with low pregnancy rates (n = 12; LOW), including bulls that presented pregnancy rates <52.27% (33.33% to 51.81%); and a group with high pregnancy rates (n = 12; HIGH), with pregnancy rates >52.27% (52.27% to 69.64%), after fixed-time artificial insemination (FTAI). The thawed sperm straws were analysed to sperm kinetics, morphology, plasma membrane integrity and sperm subpopulations. The LOW group exhibited a higher proportion of static cells (p < .05). In contrast, the HIGH group showed greater percentages for membrane integrity and total and progressive motility, and cells with fast and medium velocity (p < .05). In the cluster procedures, four sperm subpopulations were established. The low-fertility bulls presented the highest percentage of subpopulation 2 (41.46%), characterized by slow and progressive spermatozoa. The high-fertility bulls exhibited the highest percentage of subpopulation 3 (37.17%), characterized by fast and nonlinear spermatozoa. Results from this study indicated that bulls with greater percentages of fast and nonlinear spermatozoa seem to have greater fertilization capacity and the subpopulations analysis can be considered a tool to identify ejaculates with high fertility.