Preharvest applications of growth regulators and their effect on postharvest quality of table grapes during cold storage

Over 54,600 ha of table grapes (Vitis vinifera), mainly cvs. ‘Thompson Seedless’, ‘Flame Seedless’ and ‘Redglobe’, are planted in Chile. Almost the entire production is exported to the USA, Europe, Asia, or one of several Latin American countries, which typically requires 15–40 d of maritime transportation. During this period, several physical, physiological, and pathological factors cause table grape deterioration. Because berry size is the main quality factor in international markets, farmers often overuse the growth regulators, gibberellic acid (GA₃) and forchlorfenuron (CPPU), in an effort to increase berry size. We examined the effect of preharvest growth regulators on seedless (‘Thompson Seedless’, and ‘Ruby Seedless’) and seeded (‘Redglobe’) table grape cultivars during cold (0 °C) storage plus a shelf life period of 3 d at 20 °C. The overuse of GA₃, eight instead of two GA₃ applications on Thompson Seedless, and the use of one GA₃ application on Redglobe and ‘Ruby Seedless’, increased berry pedicel thickness and lowered cuticle content but induced shatter and predisposed grapes to gray mold caused by Botrytis cinerea. In contrast, CPPU increased berry pedicel thickness and cuticle content but did not increase shatter or gray mold incidence. Clusters that were subjected to overuse of combined GA₃ and CPPU were highly sensitive to shatter, had the thickest pedicel, and developed a high gray mold incidence during cold storage. Hairline, a fine cracking developed during cold storage, was induced on ‘Thompson Seedless’ and ‘Ruby Seedless’ by growth regulators, but no hairline occurred on ‘Redglobe’ table grapes. Therefore, berry quality during cold storage is greatly influenced by growth regulator management in the vineyard.     

Sediment load variability in response to climate and land use changes in a Carpathian catchment (Raba River,Poland)

Journal of Soils and Sediments - This study analyzes the variability of sediment loads under variant climate change and land use scenarios in a Carpathian catchment with a dam reservoir. The areas...     

Fatty acid profile as affected by fat depot and the sex category of Polish Holstein-Friesian × Limousin fattening cattle fed silage ad libitum

This study was designed to compare the fatty acid profiles of four types of fat depots from bulls, steers, and heifers. All animals were Polish Holstein-Friesian and Limousin crossbreds fattened semi-intensively—silage at libitum and concentrate in the amount corresponding to 30% of their net energy requirements. The fatty acid profile in intramuscular, intermuscular, and external and internal fat was determined. The intramuscular fat of bulls was most abundant in total PUFAs and n-6 PUFAs, and functional fatty acids C 18:2, C 20:4, and C 22:5 in comparison with steers and heifers. Regardless of sex category, intramuscular and external fat were characterized by higher levels of UFAs and a more desirable MUFA/SFA ratio than the remaining fat types. It should also be noted that external fat was more abundant in CLA than other fat types, and that the highest CLA content was found in bull fat, compared with the remaining sex categories of cattle.     

Diel differences in blue whale (Balaenoptera musculus) dive behavior increase nighttime risk of ship strikes in northern Chilean Patagonia

The northern Chilean Patagonia region is a key feeding ground and a nursing habitat in the southern hemisphere for blue whales (Balaenoptera musculus). From 2014 to 2019, during 6 separate research cruises, the dive behavior of 28 individual blue whales was investigated using bio-logging tags (DTAGs), generating ≈190 h of data. Whales dove to significantly greater depths during the day compared to nighttime (day: 32.6 ± 18.7 m; night: 6.2 ± 2.7 m; P < 0.01). During the night, most time was spent close to the surface (86% ± 9.4%; P < 0.01) and at depths of less than 12 m. From 2016 to 2019, active acoustics (scientific echosounders) were used to record prey (euphausiids) density and distribution simultaneously with whale diving data. Tagged whales appeared to perform dives relative to the vertical migration of prey during the day. The association between diurnal prey migration and shallow nighttime dive behavior suggests that blue whales are at increased risk of ship collisions during periods of darkness since the estimated maximum ship draft of vessels operating in the region is also ≈12 m. In recent decades, northern Chilean Patagonia has seen a large increase in marine traffic due to a boom in salmon aquaculture and the passenger ship industry. Vessel strike risks for large whales are likely underestimated in this region. Results reported in this study may be valuable for policy and mitigation decisions regarding conservation of the endangered blue whale.     

Auswirkungen des Klimawandels auf die Verfügbarkeit von Kältewirkung (Chilling) für Obstgehölze in Deutschland

To quantify the effects of climate change on fruit production in Germany, this study aimed at determining long-term trends in winter chill, as calculated with the Chilling Hours and Dynamic Models (Chill Portions). An idealized daily temperature curve was used to convert daily temperature records from 43 weather stations, taken throughout the twentieth and late nineteenth centuries, into an hourly dataset, which was then converted to units of winter chill. Besides exposing temporal trends in winter chill, the data could be spatially interpolated, yielding contiguous maps of typical winter chill in Germany around 2010, as well as chilling losses since 1950. Throughout Germany, winter chill varied between 1700 and 3000 Chilling Hours or 125 and 150 Chill Portions. The areas of highest winter chill were located in the northern parts of the country. For the whole of Germany, there were no significant temporal trends. The extent of interregional variation in winter chill depended on the chilling model used. While the Chilling Hours Model showed strong declines in winter chill for the areas around Dresden and Leipzig, as well as for the Lake Constance region, the Dynamic Model did not detect such dramatic changes. More than a decline in winter chill, increased heat during the winter months might become a challenge to German fruit growers. As already experienced during the extraordinarily warm winter of 2006/07, warm temperatures during the winter can cause fruit trees that fulfill their chilling requirements relatively early to bloom prematurely. This can then lead to elevated risk of frost damage and hamper the homogeneity of flowering.     

Nitrogen uptake from 15N-enriched fertilizer by four tree crops in an Amazonian agroforest

Mixed tree cropping systems have been proposed for sustainable nutrient management in the humid tropics. Yet, the nutrient interactions between intercropped trees have not been addressed sufficiently. In the present study we compare the temporal and spatial patterns of the uptake of applied ¹⁵N by four different tree crops in a mixed tree cropping system on a Xanthic Ferralsol in central Amazônia, Brazil, during one year. Most of the N uptake occurred during the first two weeks. Very little N was recovered by peach palm (Bactris gasipaes), more by cupuassu (Theobroma grandiflorum) and annatto (Bixa orellana) and most by Brazil nut (Bertholletia excelsa). Due to tree pruning the total accumulation of applied ¹⁵N in the above-ground biomass of annatto decreased throughout the year. It remained constant in cupuassu and peach palm and increased in Brazil nut. Brazil nut showed an extensive root activity and took up more fertilizer N applied to neighboring trees than from the one applied under its own canopy in contrast to the other three tree crops. Therefore, trees with wide-spread root systems may not need to receive N fertilizer directly but can take up N applied to other trees in the mixed cropping system. This means that such trees may effectively decrease N leaching when intercropped with trees that have dormant periods or places with low N uptake, but also exert considerable resource competition.This revised version was published online in November 2005 with corrections to the Cover Date.     

Nitrogen recovery in a decoupled aquaponic system with lamellar settler and trickling biofilter: implications for system management

Careful nitrogen (N) management will be needed to nourish the growing human population while minimizing adverse environmental impacts. Aquaponic systems (AS) have a great potential to become a sustainable technology making further use of N-rich aquaculture wastewater. In the present study, we observed the N retention and losses in a running prototype of decoupled AS with Nile tilapia (Oreochromis niloticus) and tomatoes (Solanum lycopersicum) over 24 days. N losses amounted to 32.5% of feed N input and were observed in the recirculating aquaculture system (RAS) of the AS. Fish retained 21.1% of N input while 25.2% of N input accumulated in the RAS water. About 14.1% of the loss of N was caused probably by anaerobic denitrification processes in the lamellar settler (LS). In addition, 18.4% of N input was discharged during the three cleanings of LS. In the hydroponic unit of the AS that has been due to space limitations much smaller than an optimized AS could be (only about 20% of the optimal size relative to fish biomass), the tomato plants, including fruits, leaves, and stems, recovered 3.1% of N input with water uptake of 1700 L. The fish culture management, system design, and environmental management in the greenhouse affect the N recovery in the decoupled AS.

     

Temporal changes in seabird assemblage structure and trait diversity in the Rapa Nui (Easter Island) multiple-use marine protected area

1. For Rapa Nui (Easter Island) and its largest islet, Motu Nui, the change of the species assemblage over time was analysed, and a trait-based approach to evaluate the potential losses in seabird function across the past centuries was applied. At a finer scale, the seasonal changes in seabird species composition in the current seabird assemblage was assessed to better understand the dynamics of the long-term inferred patterns.
2. For Rapa Nui, the composition of the seabird assemblage between the prehistorical, historical, and current time has changed significantly. The most critical change, probably associated with human colonization, was observed between prehistoric and current times. The current diminished number of nesting seabird species was probably the result of local extirpation without evidence of colonization by new species.
3. For Motu Nui, changes in species composition were also followed by changes in trait structure, which were smaller than observed in Rapa Nui. This is probably due to the presence of a relatively high number of related species (i.e. Procellariids) with high similarities in their foraging behaviour.
4. The nesting seabird assemblages in Rapa Nui and Motu Nui differ in exposure to risk; thus, conservation strategies applied to the islands should be planned on a fine spatial scale. For Rapa Nui, which is an urban wildlife area with several invasive species and a low number of remaining native seabird species, management should focus on fencing and pets control. For Motu Nui, management should instead focus on the establishment of quarantine and other biosecurity tools to avoid both the entry and proliferation of new invasive species.