Responses of secondary chemicals in sugar maple (Acer saccharum) seedlings to UV-B, springtime warming and nitrogen additions     

Sager EP  Hutchinson TC 《Tree physiology》2006,26(10):1351-1361

Anticipated effects of climate change involve complex interactions in the field. To assess the effects of springtime warming, ambient ultraviolet-B radiation (UV-B) and nitrogen fertilization on the foliar chemistry and herbivore activity of native sugar maple (Acer saccharum Marsh.) seedlings, we carried out a field experiment for 2 years at two sugar maple forests growing on soils of contrasting acidity. At the Oliver site, soils are derived from a strongly calcareous till, whereas the naturally acidic soils and base-poor soils of the Haliburton site are derived from the largely granitic Precambrian Shield. At both sites, removal of ambient UV-B led to increases in chlorogenic acid and some flavonoids and reduced herbivore activity. At Haliburton, ammonium nitrate fertilization led to further increases in foliar manganese (Mn), whereas at Oliver there were no such changes. Nitrogen additions led to decreases in the concentrations of some flavonoids at both sites, but seedlings at Oliver had significantly higher concentrations of flavonoids and chlorogenic acid than seedlings at Haliburton. We suggest that this could be associated with increased mobilization of Mn due to increased soil acidity, which interferes with the role of calcium (Ca) in the phenolic biosynthetic pathway. It appears that the composition of the forest soil governs the response of seedlings when they are exposed to abiotic stressors.  相似文献   

Food consumption and selectivity by larval yellowtail kingfish Seriola lalandi cultured at different live feed densities     

Zhenhua Ma  Jian G. Qin  Wayne Hutchinson  Ben N. Chen 《Aquaculture Nutrition》2013,19(4):523-534

Live food supply is a key factor contributing to the success of larval fish rearing. However, live food densities vary greatly between fish species and management protocols across fish hatcheries. The growth, survival, food selection and consumption of yellowtail kingfish larvae were examined at different regimes of live food supply in an attempt to identify a suitable live food feeding protocol for larval rearing in marine fish. This study was divided into two feeding phases: rotifer phase from 3 to 14 DPH (phase I) and Artemia nauplii phase from 15 to 22 DPH (phase II). In phase I, four rotifer densities (1, 10, 20 and 40 mL⁻¹) were used. In phase II, Artemia started at 0.8 nauplii mL⁻¹ on 15 DPH, and then the density of Artemia was daily incremented by 50%, 70%, 90% and 110%, respectively, in four treatments from 15 to 22 DPH. In phase I, rotifer density significantly affected larval growth, but not survival. By 7 DPH, the number of rotifers consumed by fish larvae reached 170–260 individuals, but did not significantly differ between rotifer densities. During cofeeding, fish larvae selected against Artemia nauplii by 10 DPH, but by 14 DPH Artemia nauplii became the preferred prey item by fish larvae exposed to the 10, 20 and 40 rotifers mL⁻¹. In phase II, both fish growth and survival were affected by Artemia densities. Fish daily consumption on Artemia by 20 DPH reached 500–600 individuals but did not significantly differ between prey densities. The result suggests that rotifer densities be offered at 20–40 mL⁻¹ before 6 DPH and 10–20 mL⁻¹ afterwards to support larval fish growth and survival. Likewise, Artemia is recommended at a daily increment of 90–110% of 0.8 mL⁻¹ from 15 to 22 DPH. This study proposes a management protocol to use appropriate type and quantity of live food to feed yellowtail kingfish larvae, which could be applicable to larval culture of other similar marine fish species.  相似文献   

Response of Potatoes to Soil-Applied Insecticides, Fungicides, and Herbicides     

Michael Thornton  Jeff Miller  Pamela Hutchinson  Juan Alvarez 《Potato Research》2010,53(4):351-358

Non-target impacts of pesticides are well documented in crops such as soybeans and corn. However, little effort has been made to evaluate these impacts in potatoes. Field trials were conducted at the Parma and Aberdeen Research and Extension Centers during 2005 and 2006 to evaluate the potential for systemic insecticides, fungicides, and herbicides to affect disease development, crop injury, and tuber yield. The first set of trials evaluated six insecticide treatments (aldicarb, oxamyl, phorate, imidacloprid, thiamethoxam, and non-treated) in a factorial combination with in-furrow application of the fungicide azoxystrobin. Azoxystrobin significantly decreased Rhizoctonia stem canker, while aldicarb and phorate tended to increase it compared to the non-treated control. There was a significant insecticide by fungicide interaction due to a bigger reduction in disease index by the fungicide when certain insecticides were used. Despite the association of these insecticides with increased disease incidence, there was no significant impact on yield. In the second set of trials, sulfentrazone herbicide was applied just prior to plant emergence to potatoes treated with the same six insecticides to evaluate the potential for the in-furrow treatments to increase plant injury. Sulfentrazone caused stunting and visible plant injury, but the level of plant injury was influenced by insecticide treatment in only one out of four trials.  相似文献   

Topical anaesthesia alleviates short-term pain of castration and tail docking in lambs     

S Lomax  H Dickson  M Sheil  PA Windsor 《Australian veterinary journal》2010,88(3):67-74

Objective To investigate the effect of a topical anaesthetic formulation on pain alleviation, wound healing and systemic levels of local anaesthetic actives in lambs undergoing castration and tail docking. Design Three placebo-controlled and/or randomised experiments were conducted using three groups of Merino lambs (n = 62, 68 and 19) undergoing routine castration and tail docking. Procedure Surgical castration, with either surgical or hot-iron tail docking, was performed with and without the application of topical anaesthetic (Tri-Solfen®) or placebo. The effects of this procedure were compared with those of rubber ring castration and tail docking, and of the handled but unmarked controls. Wound pain was assessed using calibrated Von-Frey monofilaments over a 4-h period, pain-related behaviour was assessed over 5 h, wound healing was assessed at 14 and 28 days, and the plasma levels of lignocaine and bupivacaine were determined. Results Rapid and up to 4 h primary hyperalgesia developed following surgical castration and tail docking in the untreated and placebo-treated lambs. It was absent in the castration wounds, and significantly reduced in the tail-docking wounds, of the treated lambs. Hot-iron docking was associated with mild and transient secondary hyperalgesia, which was abolished by the topical anaesthesia. There was a significant reduction in pain-related behaviours in treated lambs, which were not significantly different in their behaviour to the sham-operation handled controls. Plasma lignocaine and bupivacaine levels were below the toxic thresholds in all tested lambs. Conclusion Topical anaesthesia alleviates wound pain and significantly reduces pain-related behaviours in lambs undergoing surgical castration plus surgical or hot-iron tail docking, without a negative effect on wound healing or a risk of systemic toxicity.  相似文献   

Rangelands West/Global Rangelands,eXtension Rangelands,and the Range Science Information System: A Suite of New Web Resources     

Barbara Hutchinson  Jeanne Pfander  John Tanaka  Jason Clark 《Herpetological Monographs》2011,33(4):55-63

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Evaluation of Controlled-Release Fertilizers for Northeast Florida Chip Potato Production     

Jeff E. Pack  Chad M. Hutchinson  Eric H. Simonne 《Journal of plant nutrition》2013,36(7):1301-1313

ABSTRACT

Controlled-release fertilizers (CRF) were compared with ammonium nitrate (AN) in a potato (Solanum tuberosum L.) production study at the University of Florida farm in Hastings, FL, in 2002. Treatments were no nitrogen (No-N), AN, and nine CRFs at 146 kg ha^?1 N and 225 kg ha^?1 N. CRF7 (146 kg ha^?1 N) resulted in highest total and marketable yields at 33.7 MT ha^?1 and 29.4 MT ha^?1, respectively. Tubers from the AN (225 kg ha^?1 N) and CRF9 (225 kg ha^?1 N) treatments had the highest specific gravity at 1.073. Nitrogen removal efficiency was highest in plants in CRF1 (43.0%) and CRF7 (47.3%) plots. Both were significantly higher than AN-treated plants. At 39 days after planting, NO₃-N and NH₄-N concentrations in lysimeter water samples were significantly higher in AN treatments. Leaf tissue N concentrations were sufficient throughout the growing season in all treatments except No-N.  相似文献   

THE VISUAL ESTIMATION OF PASTURE AVAILABILITY USING STANDARD PASTURE CORES     

K. J. Hutchinson  R. W. McLean  B. A. Hamilton 《Grass and Forage Science》1972,27(1):29-34

A coring technique (6), that may be used for estimating the mean amount of herbage on closely grazed pastures, has been adapted to include visual scoring. Two methods are described, both of which use sets of pasture cores from the sward as reference standards. The observers score the herbage on view at random sites against the standards. In the first method the scores are converted to herbage yields directly by reference to the yields of the standards. In the second method a double sampling regression technique is used and the set of standards is used as a visual guide only.  相似文献   

施用竹炭对卷心菜叶绿素含量和荧光参数的影响          下载免费PDF全文

舒海燕  江洪  马锦丽  潘晓娇  孙文文 《西南大学学报(自然科学版)》2015,37(9):49-57

为探究人工施用竹炭对卷心菜叶绿素含量和荧光参数的影响,进而明确卷心菜的最适竹炭有机肥施用量,在田间试验条件下设置了无碳(CK)、中碳(MC)和高碳(SC)3个处理,对卷心菜莲座期和结球期的叶绿素含量及荧光参数进行测量研究.结果表明:(1)结球期的卷心菜叶绿素含量极显著高于莲座期(p0.01),且随着竹炭量的增加,两个时期的叶绿素含量变化趋势一致,从高到低依次为:MC,CK,SC.(2)结球期的卷心菜初始最小荧光Fo、初始最大荧光Fm、PSⅡ的最大光化学效率Fv/Fm,PSⅡ的潜在活性Fv/Fo、非光化学猝灭系数qN均低于莲座期,而PSⅡ实际光化学效率ΦPSⅡ、光化学猝灭系数qP高于莲座期,且随着竹炭量的增加,两个时期的这些参数均表现出一致的变化趋势,Fo和qN均呈"V"型变化,而Fm,Fv/Fm,Fv/Fo,ΦPSⅡ和qP均呈现倒"V"趋势,但对ΦPSⅡ和qP没有显著影响(p0.05).说明结球期的卷心菜光合作用高于莲座期;当竹炭量由CK增加到MC,有利于提高叶片叶绿素含量,增强光能利用率,减少植株热耗散,提高植株光合作用;但随着竹炭量进一步增加到SC,卷心菜叶片叶绿素含量降低,光能利用率减弱,热耗散增加,光合作用受到抑制,即中炭(MC)处理条件下,此卷心菜长势最优,表明中炭是该卷心菜生长的最适竹炭有机肥施用量.  相似文献   

PG99S智能型喷灌机的调试及维护     

肖林刚  王晓冬  帕尔哈丁  马彩雯  张丽  吴乐天  王彦 《农机具之友》2010,(7):23-25

在蔬菜、花卉的工厂化育苗生产中,准确控制肥水的浓度和喷洒的均匀性显得尤为重要,而喷灌设备作为智能型连栋育苗温室的主要浇灌设备,被广泛应用于现代化育苗温室中。该设备自动作业,水量控制精准。本文就PG99S型智能喷灌机介绍其调试方法和故障维修。  相似文献   

Comparison of dot immunobinding assay, enzyme-linked immunosorbent assay and immunodiffusion for serodiagnosis of paratuberculosis.   总被引：2，自引：0，他引：2       下载免费PDF全文

S J Tsai  L J Hutchinson    A Zarkower 《Canadian journal of veterinary research》1989,53(4):405-410

A rapid, simple and inexpensive dot immunobinding assay (DIA) was evaluated for the serodiagnosis of paratuberculosis in cattle. The assay was performed on nitrocellulose strips which were dotted with purified protoplasmic antigen of Mycobacterium paratuberculosis. After incubation with test serum samples, the bound antibodies were detected using an enzyme-amplified immunostaining procedure. The efficacy of DIA as a screening test for paratuberculosis was compared to that of an enzyme-linked immunosorbent assay (ELISA), a modified agar gel immunodiffusion (mAGID) test, and an AGID test using 329 serum samples from cattle which were examined for M. paratuberculosis infection by a sensitive fecal culture technique. The DIA and ELISA had comparable results and both of the enzyme immunoassays had higher sensitivity than tests based on AGID. The sensitivity of all four tests was influenced by the intensity of fecal bacterial shedding. Preabsorption of sera with Mycobacterium phlei increased the sensitivity of both enzyme immunoassays. the specificity but reduced the sensitivity of both enzyme immunoassays.  相似文献