不同浓度铅处理对两种木本植物种子萌发的影响     

王国娟  陆秀君 《辽宁林业科技》2006,(6):11-13,32

文章以山皂角、刺槐为试材,研究不同浓度铅处理对种子萌发、胚生长的影响。结果表明,不同浓度铅处理对刺槐种子的萌发表现出不同程度的抑制作用,当铅浓度为200mg.L-1、400mg.L-1时,刺槐种子能正常发芽;当浓度大于800mg.L-1时,发芽率与对照差异极显著。不同浓度铅处理对山皂角种子萌发几乎无影响。随着浓度的升高,铅对山皂角、刺槐胚根、胚轴的伸长抑制作用增强,对胚根伸长的抑制大于对胚轴;山皂角在铅浓度为200mg.L-1以内可以正常生长。刺槐对铅的反应极为敏感,在最低浓度200mg.L-1时,鲜重就与对照形成显著差异。山皂角、刺槐胚根POD活性随铅浓度的增加有逐渐增加的趋势。山皂角胚轴POD活性随铅浓度的增加而降低。刺槐胚轴POD活性在200mg.L-14、00mg.L-1时较对照升高,在800mg.L-1时酶的活性达到峰值,之后降低。  相似文献   

Effect of pre-sowing treatments on germination and initial seedling development of Albizia saman in the nursery     

Mohammed Alamgir M．K．Hossain 《林业研究》2005,16(3):200-204

Albizia saman （Jacq.） F. Muell. commonly known as rain tree seeds were treated with five pre-sowing treatments to study the effect of pre-sowing treatments on germination and initial seedling development in the nursery.The experiment was established in the nursery of the Institute of Forestry and Environmental Sciences.University of Chittagong, Chittagong, Bangladesh. Results revealed that Nail clipping in one side of the seed （at the distal end of the seed） （T4） provides the highest （50%） seed germination. The second highest germination （42%） was obtained for the seeds treated with immersion in cold water for 24 h （T1）. Germination was completely inhibited when the seeds immersed in boiled water for 30 s followed in cold water soaking for 24 h. Other germination parameter and initial morphological growth and biomass production of the seedlings was also higher for the treatments T4and Ti in comparison to the control （Ta）treatment. Pre-sowing treatments of T4 e.g. Nail clipping in one side of the seed （at the distal end of the seed） and T1 （Seeds immersed in cold water for 24 h） may be recommended for maximum germination and initial vigorous seedlings growth of Albizia sarnan in the nursery.  相似文献   

Preventing establishment of exotic shrubs (Cytisus scoparius (L.) Link. and Cytisus striatus (Hill)) with soil active herbicides (hexazinone,sulfometuron, and metsulfuron)     

Ketchum  J. Scott  Rose  Robin 《New Forests》2003,25(2):83-92

A greenhouse study was conducted evaluating the potential for commonlyused forestry herbicides to control germination success of Scotch broom(Cytisus scoparius (L.) Link.) and Portuguese broom(Cytisus striatus (Hill). Three herbicides, hexazinone,sulfometuron and metsulfuron, were evaluated at six rates encompassing normalrates used for herbaceous weed control. The data suggest that these herbicidesapplied prior to establishment can strongly affect seedling establishment ofthese species even though they are ineffective on mature individuals.Hexazinonestrongly affected both the final weight of surviving seedlings and theprobability of seedlings from broom species to survive to week nine.Sulfometuron had no effect on survival probability of either species butreducedfinal dry weight and delayed true leaf development at increased rates.Metsulfuron reduced the survivorship potential of Scotch broom but notPortugesebroom. Final dry weight decreased and development of true leaves was delayedforboth species treated with metsulfuron. These results suggest that preemergencetreatments with hexazinone may provide an effective method of preventing broomestablishment. Sulfometuron and metsulfuron were not as effective at preventingsuccessful establishment as hexazinone.  相似文献   

Vitamin E and Selenium Supplementation Reduces Plasma Cortisol and Oxidative Stress in Dystocia-Affected Buffaloes     

Sathya A  Prabhakar S  Sangha SP  Ghuman SP 《Veterinary research communications》2007,31(7):809-818

The aim of the study was to evaluate oxidative stress around parturition in normally calved and dystocia-affected buffaloes and the clinical efficacy of vitamin E and selenium (Se) in reducing the effects in buffaloes suffering from dystocia. Plasma cortisol concentration, erythrocytic malondialdehyde (MDA) level and superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities were evaluated in dystocia-affected (supplemented (n = 8) and unsupplemented (n = 5) with vitamin E and Se) and normally calved (unsupplemented; n = 6) buffaloes. The decline in plasma cortisol concentration, MDA level and SOD activity was greater in the group of dystocia-affected buffaloes supplemented with vitamin E and Se (78.62 ± 2.7%, 13.38 ± 9.75% and 28.83 ± 7.72%, respectively) than in the unsupplemented group (54.33 ± 12.62%, 3.48 ± 4.16% and 17.69 ± 12.93%, respectively). These results suggests that supplementation with antioxidants like vitamin E and Se may be beneficial in reducing oxidative stress in dystocia-affected buffaloes in the immediate postpartum period.  相似文献   

Complete AV block in a neonatal foal suffering from nutritional myodegeneration     

T. M. Conze  A. Falkenau  L. S. Goehring  A. May 《Equine Veterinary Education》2022,34(7):e282-e288

This case report concerns a 1-day-old, full-term Quarter Horse colt presented due to a progressive inability to rise and nurse. Besides the general weakness, a marked bradycardia was evident, which was caused by a third-degree atrioventricular (AV) block. Subsequently, the diagnosis of acute nutritional myodegeneration (NMD) was made based on clinical signs, elevated muscle enzymes, ECG findings, as well as low serum selenium and vitamin E values. Despite intensive care and supportive therapy, the foal´s condition deteriorated, and euthanasia was elected. Necropsy confirmed the diagnosis of NMD and revealed diffuse necrosis and inflammatory infiltration of the skeletal and myocardial musculature, as well as the cardiac conduction system which might have resulted in complete AV block.  相似文献   

Selenium nutrition of hybrid striped bass (Morone chrysops × M. saxatilis) bioavailability, toxicity and interaction with vitamin E     

F. JARAMILLO JR  LI PENG  & D.M. GATLIN III 《Aquaculture Nutrition》2009,15(2):160-165

Two concurrent 12-week feeding trials were conducted to evaluate the bioavailability of inorganic sodium selenite and organic seleno-DL-methionine and to investigate the potential interaction between selenium and vitamin E in juvenile hybrid striped bass. In experiment 1, purified diets utilizing casein, gelatin and an amino acid premix as protein sources with a basal selenium concentration of 0.11 mg Se   kg⁻¹ were supplemented with either Na₂SeO₃ to provide selenium concentrations of 1.19, 2.00, 5.17 and 21.23 mg Se kg⁻¹ or with seleno-DL-methionine to provide 0.90, 1.26 and 2.55 mg Se kg⁻¹ and fed to juvenile hybrid striped bass in aquaria. A second experiment evaluated potential interactions by feeding these purified diets with or without supplemental vitamin E or sodium selenite, singularly or in combination. No overt selenium deficiency signs were exhibited by fish in either of the experiments; however, signs of selenium toxicity including retarded weight gain (WG), reduced feed intake and feed efficiency ratio (FER) as well as increased mortality, were observed in fish fed the diet containing more than 20 mg Se kg⁻¹. Whole-body selenium and whole-body selenium retention were linearly influenced by sodium selenite and selenomethionine. However, there was no significant effect of dietary selenium, vitamin E or their interaction on WG, FER and survival. Slope-ratio analysis showed that bioavailability of seleno-DL-methionine as a selenium source for juvenile hybrid striped bass was significantly ( P  < 0.01) higher (3.3-fold) than sodium selenite.  相似文献   

江苏典型富硒区表层土壤硒空间分布及影响因素分析     

崔晓丹  华明  黄顺生  廖启林  许伟伟  任静华  黄标 《农业环境科学学报》2023,42(11):2472-2482

为探究江苏省宜兴市这一典型天然富硒区土壤硒的空间分布及影响因素,采集表层土壤(0～20 cm)4 461件,利用统计学和相关分析方法研究土壤硒的空间分布特征和影响因素。结果表明：研究区表层土壤硒含量范围为0.06～1.74 mg·kg^-1,均值为0.42 mg·kg^-1,是全国土壤硒元素背景值(0.29 mg·kg^-1)的1.45倍,是江苏表层土壤硒含量均值(0.20 mg·kg^-1)的2.1倍。土壤硒含量的变异系数为43.47%,表明土壤硒元素呈中等程度变异。半方差函数分析显示,土壤硒空间分布的最优模型为球状模型,块金效应值为0.568,具有较强空间相关性,变程为30 250 m,空间自相关范围较大。研究区土壤硒总体空间分布特征为南部低山丘陵显著高于北部太湖堆积平原,碎屑岩类成土母质风化形成的土壤硒含量高,同时土地利用方式为园林地、海拔较高、地形起伏大的丘陵山区的土壤硒含量也相对较高。土壤理化性质、人类活动对土壤硒的分布也有影响,pH低、有机质含量高的土壤硒含量高,距离金属矿点近、距离湖泊河流越远...  相似文献   

不同硒源对虹鳟生长性能及抗氧化能力的影响   总被引：6，自引：0，他引：6  

赵吉伟  张颖  卢彤岩  刘红柏  徐连伟  范兆廷 《水产学杂志》2005,18(2):28-34

在以鱼粉为主要蛋白源的基础饲料中分别添加亚硒酸钠和硒酵母,使饲料中硒的含量达到1．5％、2．0％、2．5％、3．0％。基础饲料设为对照组,不添加外源硒,对照组的硒含量为1．0％。在水温10℃～15℃、溶解氧5．6mg／L的条件下,对初始体重150g的虹鳟进行为期50d的生长对比试验。实验结束后取鱼的肝脏及血清,分别测定其超氧化物岐化酶（SoD）、谷胱甘肽过氧化物酶（GSH—Px）活力及总抗氧化能力（T—AOC）、丙二醛（MDA）的值。结果表明：虹鳟鱼的增重率、饲料利用率各组之间差异不显著。各组之间的SOD、GSH—Px、T—AOC、MDA没有显著差异。因此在以鱼粉为主要蛋白源的虹鳟鱼饲料中添加外源硒,对虹鳟的生长及抗氧化能力没有显著影响。  相似文献   

The effect of a mixture of seed-borne Microdochium nivale var. majus and Microdochium nivale var. nivale infection on Fusarium seedling blight severity and subsequent stem colonisation and growth of winter wheat in pot experiments     

I. M. Haigh  P. Jenkinson  M. C. Hare 《European journal of plant pathology / European Foundation for Plant Pathology》2009,124(1):65-73

Greenhouse experiments were conducted in order to determine the impact of seed-borne Microdochium nivale var. nivale and var. majus inoculum, and seed treatment with a carboxin+thiram mixture, on the development of seedling blight, and on subsequent stem colonisation and growth of winter wheat (cv. Cadenza). Experiments were conducted at temperatures favourable (3°C) and unfavourable (22°C) to M. nivale. Seed-borne inoculum resulted in seedling blight symptom development when plants were grown at 3°C, but not when plants were grown at 22°C. For seedlings grown at 3°C, plants arising from heavily blighted seedlings developed more severe symptoms of stem colonisation, when compared with those arising from seedlings from carboxin+thiram treated seeds. In addition, the vigour of such plants (assessed by determining the number of tillers and ears per plant, stem length, green leaf area, dry weight and yield) was also significantly lower than for plants arising from carboxin+thiram treated seeds. Microdochium nivale var. majus and var. nivale appeared to have little effect on plant vigour from seedlings grown at 22°C. This is the first recorded incidence of seedling blight affecting subsequent plant growth. Microdochium nivale var. majus and var. nivale stem colonisation increased from growth stage (GS) 40–49 to harvest in plants raised from seedlings grown at both temperatures. Microdochium nivale var. majus and var. nivale were isolated from the second node at GS 40–49 and the third node at harvest of plants from seedlings grown at 3°C. For plants from seedlings raised at 22°C, M. nivale var. majus and var. nivale were isolated from the first node at GS 40–49 and the second node at harvest. Carboxin+thiram seed treatment decreased the extent and severity of stem colonisation on plants from seedlings grown at 22°C.  相似文献   

Can the impact of deer browsing on tree regeneration be mitigated by shelterwood cutting and strip clearcutting?     

Julien Beguin  David Pothier  Marcel Prévost 《Forest Ecology and Management》2009

Silvicultural treatments creating large canopy openings failed to restore regeneration of balsam fir (Abies balsamea (L.) Mill.) due to browsing pressure from white-tailed deer (Odocoileus virginianus Zimmermann). Consequently, we tested two alternative silvicultural treatments aimed at improving balsam fir establishment on Anticosti Island (Québec, Canada). In 1998 and 1999, we set up shelterwood seed cutting using three harvest intensities (0, 25 and 40% of basal area) and strip clearcutting with scarification using three different strip widths (15, 30 and 45 m), both with fenced and unfenced regeneration plots, in balsam fir stands. After 8 years, shelterwood seed cutting did not allow the establishment of new balsam fir seedlings, nor the development of unbrowsed balsam fir seedlings. In the strip clearcutting, deer browsing suppressed growth of palatable species in all strip widths. This favoured the development of unpalatable species, especially white spruce (Picea glauca (Moench) Voss). Our study demonstrates that the use of silvicultural treatments alone is unlikely to restore balsam fir regeneration on Anticosti Island, as long as the deer population remains higher than 20 deer/km².  相似文献