In this study, effects of different sowing dates and seeding rates on N uptake efficiency (NUE), N translocation efficiency (NTE), agronomic efficiency (AE), physiological efficiency (PE), water use efficiency for grain yield (WUEg) and water use efficiency for biomass (WUEb) of facultative wheat were investigated. As the average of cropping year, sowing dates and seeding rates, N uptake efficiency (NUE), N translocation efficiency (NTE), agronomic efficiency (AE), physiological efficiency (PE), water use efficiency for grain yield (WUEg) and water use efficiency for biomass (WUEb) values were respectively obtained as 1.17?kg Nuptake/kg Napplied, 68.5%, 36.9?kg grain/kg Napplied, 31.2?kg grain/kg Nuptake, 5.19?kg ha?1 mm?1 and 18.04?kg ha?1 mm?1.
Nitrogen and water use efficiencies decreased with delayed sowing dates and increased with increasing seeding rates. It is possible to maintain a high wheat yield, nitrogen and water use efficiency by increasing plant density through winter sowing. It was concluded based on present findings that sowing date and seeding rates had significant effects on nitrogen and water use efficiencies and winter sowing should be practiced as not to cause yield losses and high seeding rates (575 seeds m?2) yielded greater nitrogen-water use efficiencies.
We aimed to investigate whether sodium chloride seed priming and irrigation at seedling stage enhance response of 5-leaf stage tomato plants (Lycopersium esculentum Mill.) to high salt stress. Three experimental groups were as; non-primed seeds, seeds primed with 0.05M sodium chloride (NaCl), and seeds primed and irrigated with 0.05M NaCl starting from sowing to salt stress application. Sodium chloride solutions (0.1M, 0.2M, 0.4M, and 0.6M) were added to cups under pots in every 2 days for 10 days to treatment groups. Control groups were irrigated with distilled water at the same time intervals. At least two experimental setups contained at least four plants, and two samplings of leaf and root tissues were performed for analysis of each plant to evaluate changes in pigment and proline contents, lipid peroxidation and electrolyte leakage levels, and ascorbate peroxidase and catalase activity. Priming reduced mean germination time, and increased final germination percentage together with energy of germination. Increased root and hypocotyl lengths as well as increases in fresh weights supported enhanced seedling vigor. Considering growth and stress parameters such as chlorophyll content, chlorophyll to carotenoid ratios, and lipid peroxidation and electrolyte leakage were less affected in primed plants. Moreover, improvement of the accumulation of osmoregulating defense molecules, such as proline and anthocyanin, and of the inductions of the antioxidative enzyme system points out to higher adaptive response of these plants against deleterious effects of salt. 相似文献
Identification of trees with key microhabitats as well as knowledge of their ecological formation is important for the conservation of epiphytic bryophytes and lichens on beech. Based on the hypothesis that certain types of stem damage are crucial for the occurrence of epiphytes of conservation concern, we surveyed 145 beech trees (57-280 years) for different types of stem damage and analysed their relationship to other tree characteristics, epiphyte species and wood-inhabiting fungi in a forest landscape on acid soils.Three main types of stem damage were identified; canker, rot hole and surface rot. The incidence of rot holes was highest on trees with a low growth rate during the last 50 years, but was unrelated to tree size or age per se. Bark pH was significantly higher below than above rot holes, whereas no such relationship was found for cankers. Wood mould from rot holes had a very high pH, explaining the higher bark pH below this type of damage. The number of epiphyte species of conservation concern was strongly positively related to rot holes and high bark pH. Cankers had a weaker, yet significant positive effect. The fungus Psathyrella cernua was associated with the rot holes and is suggested to be a key species involved in creating this microhabitat.We conclude that slow-growing trees with rot holes are important for the conservation of epiphytes and should be selected as retention trees in managed forests. The study also highlights a potential for habitat restoration by inducing artificial damage and inoculation of decay fungi in beech trees. 相似文献
Conflict over marine fishery resources is a growing security concern. Experts expect that global changes in our climate, food systems and oceans may spark or exacerbate resource conflicts. An initial scan of 803 relevant papers and subsequent intensive review of 31 fisheries conflict studies, focused on subnational and international conflicts, suggests that four substantial scientific gaps need addressing to improve our understanding of the nature and drivers of fisheries conflict. First, fisheries conflict and levels of conflict intensity are not precisely defined. Second, complex adaptive systems thinking is underutilized but has the potential to produce more realistic causal models of fishery conflict. Third, comparative large‐scale data and suitably integrative methodologies are lacking, underscoring the need for a standardized and comparable database of fisheries conflict cases to aid extrapolation beyond single case‐studies. Fourth, there is room for a more widespread application of higher order concepts and associated terminology. Importantly, the four gaps highlight the homogenized nature of current methodological and theoretical approaches to understanding fishery conflict, which potentially presents us with an oversimplified understanding of these conflicts. A more nuanced understanding of the complex and dynamic nature of fishery conflict and its causes is not only scientifically critical, but increasingly relevant for policymakers and practitioners in this turbulent world. 相似文献
Commercial bath sponge population in the Mediterranean has been recently reduced due to diseases and the depletion of natural banks. The commercial supply is far below the demand on the last 10–15 years. In this study, we aimed to investigate the farming performance of Spongia officinalis in the Dardanelles. Sponges collected from the Dardanelles cut into pieces of different weight. They were divided into two groups depending on the wet weight ranging from 50 to 150 g (mean weight 102.6 ± 4.81 g) and from 160 to 360 g (mean weight 235.8 ± 8.56 g). Three rope systems located parallel to each other with 6–7 m inter‐distance were constructed for the cultivation of sponges. At the end of the study, while small‐sized sponges could reach mean wet weight of 120.7 ± 14.8 g, large‐sized sponges reached mean wet weight of 247.6 ± 22.4 g. Growth rates were estimated 5–17% at 21st month. The survival rates were found 82% and 88%. 相似文献
The present study investigated the effects of argan oil, obtained from Argania spinosa, on pre‐ and post‐challenge immuno‐haematological and biochemical responses of Nile tilapia, Oreochromis niloticus. For this purpose, the fish were fed diets containing 0, 0.5%, 1% or 2% argan oil for 45 days. Following 45 days of feeding, fish were challenged with Lactococcus garvieae and mortality was recorded for 15 days. During the pre‐challenge period, significantly higher respiratory burst activity, total white blood cell (WBC), serum lysozyme activity and myeloperoxidase activity were determined in the argan oil‐fed groups. The serum glucose and cholesterol levels decreased whilst total protein and albumin did not change in the groups fed with argan oil‐supplemented diets. After challenge with Lactococcus garvieae, the percentage survival (%) was found to be the highest in the 1% and 2% argan oil‐supplemented feeding groups. Also, there was a significant increase in weight gain, specific growth rate and feed conversion ratio in those fish fed argan oil. The results of this study indicated that after the supplementation of fish diets with argan oil, especially at 1% and 2% concentrations, the immunological, haematological and biochemical values remained similar in both the pre‐ and post‐challenge periods and the immune response against L. garvieae in Nile tilapia was modulated. 相似文献
Small‐scale fisheries often involve weak management regimes with limited top‐down enforcement of rules and minimal support from legal institutions, making them useful model systems for investigating the role of social influence in determining economic and environmental outcomes. In such regimes, interpersonal relationships are expected to have a strong effect on a fisher's catch portfolio, the set of fish species targeted by an individual fisher. Here, we test three competing hypotheses about social influence using belief propagation network models and show that a peer‐to‐peer information‐sharing social network is key to explaining catch portfolios at a small‐scale fishery in Jamaica. We find that experience dictates the direction of influence among fishers in the social network, with older fishers and information brokers having distinct roles in shaping catch patterns for large‐ and small‐sized fish species, respectively. These findings highlight concrete opportunities for harnessing social networks in natural resource management. Our new approach to modelling social influence is applicable to many social–ecological systems with minimal legal and institutional support or those that rely heavily on bottom‐up participatory processes. 相似文献
This study was designed to prevent fungal disease (Saprolegnia parasitica) that occurs on rainbow trout eggs (Oncorhynchus mykiss) by using wastes of onion (Allium cepa) and garlic (Allium sativum) plants. For this purpose, fertilized rainbow trout eggs were exposed to garlic skin, garlic stem and onion skin aqueous methanolic extracts by bathing in concentrations of 0.4, 0.8, 1.6 and 3.2 g/L, whereas the control group was left untreated. The larvae in all groups were monitored until they become free-swimming larvae, the number of eggs died due to fungus was recorded, and the data obtained from experimental groups and control group were compared. As a result, it was determined that onion skin had no effect on the number of eggs that died due to fungus (p > .05), while garlic skin and garlic stem extracts significantly reduced the number of fungal infestations without affecting the number of live larvae or the embryological development of the eggs (p < .05). In light of these data, we conclude that garlic skin (0.4, 0.8, and 1.6 g/L) and garlic stem (0.8 and 1.6 g/L) aqueous methanolic extracts are effective at preventing Saprolegnia parasitica infestation on rainbow trout eggs and may be used in aquaculture. 相似文献
Abstract The ecosystem of Lake Constance in central Europe has undergone profound modifications over the last six decades. Seasonal and inter‐annual changes in the vertical distribution patterns of whitefish were examined and related to changes in biotic and abiotic gradients. Between 1958 and 2007, the average fishing depth in late summer and autumn was related to two factors influencing food supply of whitefish – lake productivity and standing stock biomass. In years with low food supply, whitefish were harvested from greater depths, where temperatures were up to 4 °C lower. The whitefish’s distribution towards colder water might be a bioenergetic optimisation behaviour whereby fish reduce metabolic losses at lower temperatures, or it may result from a reassessment of habitat preference under conditions of limited food supply, according to the ideal free distribution theory. 相似文献