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91.
Yuanchun Yu Jingyu Yang Shucai Zeng Daoming Wu Douglass F. Jacobs Joshua L. Sloan 《Journal of Soils and Sediments》2017,17(9):2230-2238
Purpose
Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) is an important native tree species in China. Consecutive cropping traditionally occurs in Chinese fir plantations (CFPs), but this practice has resulted in productivity declines in subsequent rotations. This study was designed to better understand the change of soil properties in the continuous cropping CFPs.Materials and methods
We investigated soil pH, soil organic matter (SOM), and nutrient contents in different soil layers and in rhizosphere soil (RS) and non-rhizosphere soil (NRS) under CFPs of different ages and in different rotations.Results and discussion
In the upper (0–20 cm) soil layer, soil pH decreased, while SOM increased, beneath mature CFPs with consecutive rotations. Total nitrogen (TN), available potassium, and available phosphorus contents in the upper soil layers did not differ significantly with consecutive rotations. Soil pH in RS was significantly lower than in NRS under mature plantations of the third rotation. Soil organic matter, TN, and available nitrogen did not differ between RS and NRS. Available phosphorus in RS was consistently lower than in NRS, and was highly deficient in the third rotation.Conclusions
We conclude that no severe soil nutrient degradation occurred in the continuous cropping CFPs examined in this study, with soil acidification and phosphorus deficiency being two primary problems observed.92.
93.
M. A. Taylor E. Rabe M. C. Dodd G. Jacobs 《The Journal of Horticultural Science and Biotechnology》2013,88(3):527-534
SummaryPlums (Prunus salicina cv. Songold) were cold stored according to a single-temperature regime comprising 28 d at ?0.5°C, and a dual-temperature regime comprising 10 d at ?0.5°C followed by 18 d at 7.2°C. After cold storage, the plums were ripened for 8 d at 10°C. Pectolytic enzyme activity, pectic composition, internal conductivity and gel breakdown were determined at seven stages during storage and ripening. Although not exposed to chilling temperatures prior to harvest, approximately 10% of the plums exhibited gel breakdown at harvest, indicating that the disorder cannot be classified solely as a cold-storage chilling disorder. The higher temperatures of the dual-temperature regime resulted in higher polygalacturonase activity than with the single-temperature fruit. Consequently, protopectin degradation and the concomitant production of water- soluble pectins were greater in the dual-temperature fruit. Single-temperature storage resulted in higher pectinmethylesterase activity during the latter stages of storage and during ripening. Increases in temperature after 10 d and 28 d in dual- and single- temperature fruit, respectively, were associated with significant increases in the viscosity of water-soluble pectins, internal conductivity and gel breakdown. The significant positive correlation between internal conductivity and gel breakdown suggested that membrane integrity is closely associated with development of gel breakdown. 相似文献
94.
S. Gu S. D. Jacobs B. S. Mccarthy H. L. Gohil 《The Journal of Horticultural Science and Biotechnology》2013,88(4):287-292
SummaryIn warmer regions, winegrapes ripen their fruit during the hottest portion of the growing season, producing wines of high pH, low acidity, less intense colour, and a less complex flavour. Experiments were conducted in a commercial vineyard of ‘Cabernet Sauvignon’ at Fresno, CA, USA in 2009, and in 2010, to determine if vines could be forced to enhance fruit quality. Forcing was conducted by hedging growing shoots to six nodes and removing summer laterals, leaves, and primary clusters between 14 – 70 d after anthesis in late-May, June, and July. Vines grown under conventional practices were used as controls. Forcing in June shifted fruit ripening from the hot (July and August) to the cool (October through early-November) portion of the growing season, a period with more hours at lower, more favourable temperatures. Fruit from the forced crop had smaller berries, a lower pH, higher acidity, and higher contents of anthocyanins, tannins, and total phenolics, compared with non-forced fruit. The yield and vigour of forced vines were comparable to, or slightly lower than, control vines. The best forcing treatment consisted of hedging growing shoots to six nodes and removing summer laterals, leaves, and primary clusters. Our study demonstrates the potential of forcing to address the detrimental effects of high temperatures on fruit quality in warmer regions of winegrape production. 相似文献
95.
Jacobs DM Fuhrmann JC van Dorsten FA Rein D Peters S van Velzen EJ Hollebrands B Draijer R van Duynhoven J Garczarek U 《Journal of agricultural and food chemistry》2012,60(12):3078-3085
Red wine and grape polyphenols are considered to promote cardiovascular health and are involved in multiple biological functions. Their overall impact on the human metabolome is not known. Therefore, exogenous and endogenous metabolic effects were determined in fasting plasma and 24 h urine from healthy male adults consuming a mix of red wine and grape juice extracts (WGM) for 4 days in a placebo-controlled, crossover study. Syringic acid, 3-hydroxyhippuric acid, pyrogallol, 3-hydroxyphenylacetic acid, and 3-hydroxyphenylpropionic acid were confirmed as the strongest urinary markers of WGM intake. Overall, WGM had a mild impact on the endogenous metabolism. Most noticeable were changes in several amino acids deriving from tyrosine and tryptophan. Reductions in the microbial metabolites p-cresol sulfate and 3-indoxylsulfuric acid and increases in indole-3-lactic acid and nicotinic acid were observed in urine. In plasma, tyrosine was reduced. The results suggest that short-term intake of WGM altered microbial protein fermentation and/or amino acid metabolism. 相似文献
96.
A Shirazi M Derakhshan‐Horeh AA Pilvarian E Ahmadi H Nazari B Heidari 《Reproduction in domestic animals》2011,46(1):87-94
The objective of this study was to determine the effects of various methods of sperm pre‐treatment on male pronuclear (MPN) formation and subsequent development of ovine embryos derived from in vitro‐matured oocytes and intracytoplasmic sperm injection (ICSI). The effect of treatment of injected oocytes with dithiothreitol (DTT) on embryo development was also assessed. In Exp. 1, the injected oocytes with non‐treated sperm were activated with three different procedures. The cleavage and blastocyst rates in those activated with DTT was lower (p < 0.05) than those activated with either ionomycin (Io) + 6‐dimethylaminopurine (6‐DMAP) or DTT + I + 6‐DMAP. In Exp. 2, the effects of sperm pre‐incubated with DTT, sodium dodecyl sulphate (SDS) or DTT + SDS as well as two‐time frozen/thawed sperm (without cryoprotectant) on MPN formation and oocyte activation were examined. The non‐treated sperm served as controls. The MPN formation in DTT + SDS group was higher (p < 0.05) than other groups except for freeze–thaw group. No difference in the rate of activated ICSI oocytes was observed among groups. In Exp. 3, the effect of pre‐treatment of sperm on subsequent development of ICSI embryos and blastocyst cell numbers were examined. The rates of cleavage and blastocyst formation as well as the blastocyst cell numbers were similar among the pre‐treated and control groups. In conclusion, pre‐treatment of sperm with DTT + SDS positively affected MPN formation, although the subsequent development capacity of the resulting embryos remained limited. Moreover, DTT was not effective on oocyte activation compared with Io + 6‐DMAP after ICSI. 相似文献
97.
98.
This article reviews contemporary concepts underlying the design of control strategies for the management of flea allergy dermatitis in dogs and cats. The limitations of palliative symptomatic approaches are noted, as is the fundamental requirement to differentiate simple pulicosis from true hypersensitivity. In the latter case, eradication of fleas from the affected animal and its surroundings has to be an essential aim. The different biological properties offered by modern chemotherapy are defined and the range of techniques for applying active compounds to the animal and its environment described. Factors for consideration when formulating control strategies and selecting chemotherapeutic agents are discussed in the context of the complexities of the flea life-cycle, the host-parasite relationship and client concerns. 相似文献
99.
F.R. McKenzie J.L. Jacobs P. Riffkin G. Kearney 《African Journal of Range and Forage Science》2013,30(1-2):1-6
Abstract Effects of nitrogen (N) (0, 15, 30, 45 and 60 kg N ha?1) applied at five different times during autumn and early winter on the N fixation of Trifolium repens L. (white clover) in Lolium perenne L. (perennial ryegrass) / white clover pastures were examined (Experiment 1). Effects of applying different N fertilisers (e.g. urea and ammonium nitrate) at 45 kg N ha?1 in autumn, with and without phosphorus (P), potassium (K) and sulphur (S) on N fixation were also tested (Experiment 2). In Experiment 1, percentage N derived from the atmosphere (percent Ndfa) by white clover varied between 87% and 91% in the period after (24 to 36 days) N application. Increasing rates of N and time of application did not influence percent Ndfa. The amount of N fixed by white clover ranged from 0.8 to 3.7 kg N ha?1 in the period after N application. Increasing rates of applied N produced a significant (P<0.05) linear increase in the amount of N fixed. In Experiment 2, percent Ndfa and amount of N fixed (1.9 to 4.1 kg N ha?1) were unaffected by different N fertilisers, with and without P, K and S, in the period after (37 days) fertiliser application. For both experiments, fertiliser N increased dry matter yield while having no effect on white clover composition. It is concluded that single applications of N during the autumn and early winter benefit pasture growth without adversely affecting white clover N fixation or clover composition. This finding, however, will require further investigation. 相似文献
100.
G Jacobs B Keene L M Cornelius P Rakich A Shug 《American journal of veterinary research》1990,51(9):1345-1348
Mean carnitine concentrations [( carnitine]) were higher (P less than 0.05) in adult cats than in kittens for skeletal muscle (total and free carnitine), myocardium (free carnitine), and urine (total and free carnitine). The free/total carnitine ratio was lower (P less than 0.05) in kittens than in adults for liver, myocardium, and urine. Carnitine concentrations were similar between genders in kittens, but in adult cats, [carnitine] in plasma (total, free, and esterified carnitine) and liver (total and free carnitine) were higher (P less than 0.05) in female than in male cats. Total and free plasma [carnitine] were correlated to total and free liver [carnitine], respectively. Skeletal muscle [carnitine] was not correlated to plasma [carnitine]. Correlations in [carnitine] between plasma and myocardium, kidney, or urine were inconsistent. 相似文献