Direct evidence of water-soluble organic matter leaching in brown earths and slightly podzolized soils

Summary Lysimetric observations in different deciduous forest sites show that the mobilization of water-soluble organic carbon in brown earths and weakly podzolized soils is in accordance with the evolutionary patterns of these soils.     

The effect of overfeeding the young in early postnatal ontogeny on brown fatty tissue

We studied the effects of overfeeding of neonatal Wistar rats on O2 consumption by the interscapular brown adipose tissue and DNA content in the tissue. The overfeeding was induced by reducing the litter size to two to three pups per dam compared with standard litters of five to ten pups. All animals were allowed free access to water and forage and were kept at 24 +/- 1 degrees C. Newborn and 16-day-old rat pups were used in the experiments. The body weight of overfed pups was significantly higher than that of standard fed pups (p < 0.001). There were no differences between groups of 16-day-old rats in the resting metabolic rate. The mass of dried brown adipose tissue relative to the body mass in overfed pups was lower than in the control pups (p < 0.01). O2 consumption in the rats from small litters was 35% higher (p < 0.001). DNA content (mg/g brown adipose tissue) in overfed rats was 35% lower as compared to the control pups (p < 0.001). These results indicate that overfeeding at the preweaning stage of life affects growth, cellularity, and thermogenic function of brown adipose tissue.     

A tale of two siblings: multiple paternity in big brown bats (Eptesicus fuscus) demonstrated using microsatellite markers

In many bat species, the opportunity for sperm competition or other mechanisms of post-copulatory paternity biasing is thought to be great, due to the long delay between copulation and fertilization, demonstrated sperm storage capabilities, and observed promiscuity. We present the results of the first study to assess whether litters of big brown bats (Eptesicus fuscus) containing dizygotic twins share the same father. We sampled 26 mother-offspring triads from three colonies in Indiana and Illinois, as well as 299 additional adults (237 females and 62 males) from these colonies and six other maternity colonies in the same area in 1997-1998. All individuals were genotyped at nine highly variable autosomal microsatellite loci and one X-linked locus. We assessed multiple paternity using autosomal and X-linked locus exclusions, and using maximum-likelihood methods. All methods confirmed multiple paternity within litters, and the maximum-likelihood analyses indicated that almost half of the sampled litters were composed of maternal half-siblings rather than full-siblings. Our results highlight the potential importance of post-copulatory mechanisms of paternity determination in the mating system of big brown bats, and have important implications for gene flow and population structuring in this species.     

Effects of litter size on sympathetic activity in young adult rats

Rearing animals in small litters induces a permanent increase in body weight and body fat. To determine whether changes in sympathoadrenal activity contribute to this effect, litter size was adjusted the day after birth and maintained until weaning at 21 days. Sympathetic nervous system (SNS) activity was measured in adult animals using [(3)H]norepinephrine ([(3)H]NE) turnover in peripheral tissues. Although litter size was without effect on [(3)H]NE turnover in chow-fed animals, acceleration of [(3)H]NE turnover by dietary sucrose was completely abolished in heart and attenuated in interscapular brown adipose tissue and kidney of rats reared in small litters. Body and epididymal fat-pad weights were heavier in rats reared in small litters; however, weight gain in response to dietary enrichment with sucrose did not differ as a function of litter size. Thus litter size alters dietary activation of the SNS, and this effect presumably reflects changes in central nervous system regulation.     

黑龙江省熊类年龄构成、性比及繁殖情况的初步研究

熊类是重要的狩猎动物,肉、皮、骨、脂均可利用,熊掌和熊胆尤为名贵,因而具有很高的经济价值。 目前,国际上对于熊类生态学的研究日益深入。近二十年来多次举行国际熊类研究专题讨论会并出版了论文集。研究方向集中于熊类的群体生态,行为生态及种群的管理方面并正朝着集约管理和合理利用的方向发展。     

Nutrient limitation to the decomposition of water hyacinth ( Eichhornia crassipes)

The responses of decomposition to N and P supply were investigated in three leaf types of water hyacinth (Eichhornia crassipes (Mart.) Solms): dead green leaves collected from Donghu Lake; green, and brown leaves collected from outdoor tanks. The ratios of C:N, C:P, lignin:N and lignin:P were lowest in the green leaves collected from Donghu Lake, and highest in the brown leaves collected from outdoor tanks. Decomposition constant (k) of water hyacinth varied greatly, ranged from 0.006 to 0.099 d^–1. Leaf litters decayed most quickly within the initial two weeks during the experimental period, but decomposition rate decreased significantly in the following days. Decomposition and nutrient (N and P) release were fastest in the green leaves collected from Donghu Lake, intermediate in the green leaves collected from outdoor tanks, slowest in the brown leaves collected from outdoor tanks. Statistical analyses revealed that the effects of P-availability on decomposition rate and N, P release rate of the three litter types were significant, whereas the impacts of N-availability was insignificant (p > 0.05) except for the brown leaves collected from outdoor tanks. These results suggest that decomposition rate and nutrient content dynamics of water hyacinth differ with their growth habitats, and could partly be regulated by nutrient availability, especially by P-availability, in the environments.     

稀土元素的生物安全性探讨

采用微核检测、单细胞凝胶电泳、同工酶等技术研究了稀土元素遗传毒理效应的有关结果。大量试验表明,稀土元素断裂DNA的能力,因而在一定浓度范围内,稀土元素确有致突变性。稀土元素在土壤中可专性吸附、不可降解,在动植物和人体皆有累积效应,因此稀土元素的生物安全性值得深入探讨。     

Reproductive performance of a laboratory colony of the deermouse, Peromyscus maniculatus gambelii.

During a 23-mo period approximately 600 litters and 2,500 offspring were produced in a laboratory colony established with wild-trapped deermice (Peromyscus maniculatus gambelii). The incidence of pregnancy and size of litters increased with domestication. Average litter size was 4.3 for all litters and 4.1 and 4.7 for litters born to wild-trapped and first generation females, respectively. Litter size increased up to the seventh sequential pregnancy for both wild-caught and first-generation females and then tapered off. In all litters more males were born than females. The departure from a 1:1 ratio was significant for the combined data and for litters of first-generation females, but not for litters of wild-caught females.     

退化红壤丘陵区森林凋落物初始化学组成与分解速率的关系

通过小盆+凋落袋控制试验,研究了我国南方退化红壤丘陵区8种森林凋落物和4种混合凋落物初始化学组成与分解速率的关系.结果表明:阔叶凋落物中的氮、磷、钾、镁含量显著高于针叶凋落物,木质素、碳含量显著低于针叶凋落物;凋落物分解速率与凋落物初始氮、磷、钾、镁含量呈显著正相关,与凋落物初始碳、木质素含量以及木质素/氮、木质素/磷和碳/磷值呈显著负相关;木质素含量解释了凋落物分解速率变异的54.3%,是影响分解速率的最关键因子,凋落物碳、氮、磷含量也与分解速率密切相关,它们与木质素含量一起可解释分解速率变异的81.4%.在退化红壤丘陵区植被恢复过程中,低木质素含量、高氮磷含量的阔叶物种的引入有利于加速凋落物的分解速率和土壤肥力的恢复进程.     

Epidemiological Studies of Piglet Diarrhoea in Intensively Managed Danish Sow Herds

The study comprised 70,796 litters in 104 sow herds, observed from 1976 through 1982. Weaning age decreased from approx. 42 days to approx. 30 days during the observation period. Diseases and symptoms were recorded together with production parameters (feeding, barn construction, economic returns etc.). The mean incidence rate of pre-weaning diarrhoea was 6.8 % of litters, with considerable inter-herd differences (incidence rates from 0 to approx. 50%). There was a slight increase in incidence during the autumn (August through October). Incidence rates increased with litter size, with a peak incidence in litters of 11–13 piglets, and decreased with increasing parity of the sow. There was a positive association between occurrence of arthritis and pre-weaning diarrhoea in the litters, and litters from sows with post parturient disease (MMA complex) had 1.8 times higher risk of getting diarrhoea than litters from healthy sows. No important differences among breeds were found. Small herds (< 200 farrowings per year) had higher incidence rates than large herds (400–499 farrowings per year). Herds with a gilt proportion above 30 % had an incidence rate of 12.3 %, i. e. nearly twice as high as the overall mean (6.8 %). There was a trend towards a higher incidence rate in litters kept in traditional pens (i. e. large pens with solid floor and loose sows) than in intensive pens (i. e. small pens with slatted flooring and tethered sows). The overall pre-weaning mortality rate was 16.2 % of pigs born, half of which was due to stillbirths (6.3 %) and overlaid piglets (2.2 %). In litters with pre-weaning diarrhoea, the mortality rate was 19 %, compared to 13 % in litters without occurrence of diarrhoea. This difference accounts for an excess loss of 0.6 piglets from birth to weaning in diarrhoeic vs. non-diarrhoeic litters. Piglets from litters with pre-weaning diarrhoea had reduced weight gain. Thus, on the average, they were 2.2 days older at 25 kg bodyweight and weighed 0.4 kg less at 30 days than piglets from non-diarrhoeic litters. Also, litters with pre-weaning diarrhoea had a significantly increased risk of post-weaning diarrhoea. The present information forms a basis for defining acceptable disease thresholds in suckling litters in intensively managed herds.     

三江平原小叶章湿地枯落物初期分解动态

通过4周淋洗分解试验,探讨了微生物活动和淋洗作用对三江平原沼泽湿地沼泽化草甸小叶章和湿草甸小叶章枯落物初期分解的影响.结果表明：两种小叶章植物初期分解的质量损失分别占当年分解物质损失量的59％和22％,28 d分解后枯落物残留量明显降低,并呈先快后慢的变化过程.两种枯落物中N、P含量均有明显下降,N含量分别下降了约3265%和2455%,P下降了36.71%和45.15％.抑制微生物处理的枯落物N、P含量较不抑制处理高,但差异不显著;抑制和不抑制微生物处理下枯落物释放到淋洗液N、P含量变化也不相同,但差异未达到显著水平.表明小叶章初期分解主要受淋洗作用的影响.两种小叶章植物的分解速率和养分损失速率差异均未达到显著水平.     

亚热带不同次生林地凋落物持水特性及季节变化

为了解亚热带不同演替阶段次生林地的凋落物持水特性规律,选取湖南大山冲森林公园保存完好的三种亚热带典型次生林地,按两月一次采集新近的凋落物并采用水浸泡法测定凋落物持水量、持水率和吸水速率,对比分析不同森林类型凋落物持水性差异及其与凋落物碳氮凋落量的关系。结果表明：（1）三种次生林地凋落物量及组成均表现出特有的变化规律。针叶林和常绿阔叶林凋落物量以夏季5-9月最大,落叶阔叶林凋落物则以春、秋两个季节最大;（2）三种次生林地凋落物的饱和持水量、半饱和时间以及与水亲和力均呈现显著季节性变化特征。针叶林凋落物饱和持水量在5-7月达到最高为（59.68±2.91） g/m²,常绿阔叶林凋落物饱和持水量则在9月达到最高,落叶阔叶林凋落物饱和持水量在11月份达到最高为（190.60±8.81） g/m²;三种次生林凋落物的半饱和时间均以11月份为最低,且落叶阔叶林凋落物半饱和时间比其他两种次生林地更低,全年平均（0.62±0.12） h;凋落物的水亲和力系数,全年均以落叶阔叶林最大为142.72±26.12;（3）落叶阔叶林凋落物饱和持水率全年显著高于其他两种次生林（P<0.01）,且针叶林和落叶阔叶林凋落物饱和持水率均在11月份达到最大值;（4）落叶阔叶林凋落物吸水速率A值显著低于其他两种次生林（P<0.01）,而针叶林凋落物吸水速率系数B值显著高于其他两种次生林（P<0.01）;（5）凋落物饱和持水量与凋落物水亲和力和饱和持水率存在显著正相关关系,与凋落物凋落碳氮总量同样存在显著正相关关系;凋落物饱和持水率与凋落物半饱和时间、吸水速率系数A和B值存在显著负相关,与凋落物碳含量和C/N比极显著负相关,与凋落物氮含量极显著正相关（P<0.01）。综上,不同次生林类型凋落物持水性存在显著差异,凋落物持水性与凋落物碳氮量存在显著联系,该研究为深入探讨森林生态环境效应提供了支撑,丰富了森林凋落物持水特性的研究理论。     

Glasshouse evaluation of the growth ofAlnus rubra andAlnus glutinosa on peat and acid brown earth soils when inoculated with four sources ofFrankia

The effects of soil type (an acid peat and 2 acid brown earths) andFrankia source (3 spore-positive crushed nodule inocula and spore-negative crushed nodules containing the singleFrankia ArI5) on nodulation, N content and growth ofAlnus glutinosa andA. rubra were determined in a glasshouse pot experiment of two years duration. Plants on all soils required additional P for growth. Growth of both species was very poor on peat withA. glutinosa superior toA. rubra. The former species was also superior toA. rubra on an acid brown earth with low pH and low P content. Some plant-inoculum combinations were of notable effectivity on particular soils but soil type was the major source of variation in plant weight. Inoculation with crushed nodules containingFrankia ArI5 only gave poor infection of the host plant, suggesting that inoculation with locally-collected crushed nodules can be a preferred alternative to inoculation withFrankia isolates of untested effectivity. Evidence of adaptation ofFrankia to particular soils was obtained. Thus, while the growth of all strains was stimulated by mineral soil extracts, inhibitory effects of peat extracts were more apparent with isolates from nodules from mineral soils than from peat, suggesting that survival ofFrankia on peat may be improved by strain selection.     

外源氮素调控C/N比对杉木林凋落叶细菌群落结构的影响

为探究不同C/N比对杉木凋落叶分解特性的影响,通过添加外源氮,采用分解袋法,分析林下植被保留和林下植被去除2种林分中不同C/N比值的杉木凋落叶分解300 d时细菌群落结构差异。研究显示：一定范围内,初始C/N比降低有利于杉木凋落叶分解和细菌群落多样性提升,过低的C/N比则具有抑制作用;相比于林下植被去除,林下植被保留管理措施更有利于杉木凋落叶的分解,且细菌群落多样性更高,但当初始C/N比值为20.3时,杉木凋落叶分解所受的抑制作用更为明显;在门水平上,变形菌门、放线菌门和浮霉菌门为杉木凋落叶中主要优势种群;在属水平上,慢生根瘤菌属、嗜酸栖热菌属和Singulisphaera属在杉木凋落叶中相对丰度较高;不同处理间的杉木凋落叶细菌群落结构具有显著差异,变形菌门、放线菌门和酸杆菌门等细菌门中的多类细菌相对丰度差异显著;在门分类水平上,杉木凋落叶C/N比值与主要细菌种群相对丰度的相关性最高,C/P比值与杉木凋落叶细菌群落结构变异的相关性最高;在属水平上,杉木凋落叶全碳含量、C/N比值和全钾含量与主要细菌种群相对丰度的相关性最高,全钾含量与杉木凋落叶细菌群落结构变异的相关性最高。结果表明初始C/N比的降低改变了杉木凋落叶细菌群落结构,进而作用于杉木凋落叶的分解。     

闽江河口湿地枯落物分解及主要影响因子

以闽江河口湿地挺水植物本地种芦苇和入侵种互花米草的花和叶枯落物为研究对象,采用分解袋法分析其分解过程及主要影响因素.结果表明: 立枯分解(0～90 d)是2种湿地盐沼植物重要的分解阶段,芦苇和互花米草的花和叶质量损失率分别为(15.0±3.5)%、(13.3±1.1)%和(31.9±1.1)%、(20.8±1.4)%.倒伏分解阶段(91～210 d),芦苇和互花米草的花和叶质量损失率分别为(69.5±0.6)%、(71.5±2.5)%和(76.8±1.9)%、(67.5±2.1)%.在立枯分解阶段,2种挺水植物枯落物的分解速率与C/N呈正相关,与N/P呈负相关,分解过程受到P的限制程度较大.倒伏分解阶段,枯落物C/N、C/P和N/P的影响降低,而大气温湿度、土壤水分、酸碱度、盐度和沉积物特性等的影响加大.不同分解阶段枯落物分解影响因子的差异主要与其所处的微域环境和潮汐因素有关.     

闽江河口湿地枯落物分解及主要影响因子

以闽江河口湿地挺水植物本地种芦苇和入侵种互花米草的花和叶枯落物为研究对象,采用分解袋法分析其分解过程及主要影响因素.结果表明:立枯分解(0～90 d)是2种湿地盐沼植物重要的分解阶段,芦苇和互花米草的花和叶质量损失率分别为(15.0±3.5)％、(13.3±1.1)％和(31.9±1.1)％、(20.8±1.4)％.倒伏分解阶段(91 ～210 d),芦苇和互花米草的花和叶质量损失率分别为(69.5±0.6)％、(71.5±2.5)％和(76.8±1.9)％、(67.5±2.1)％.在立枯分解阶段,2种挺水植物枯落物的分解速率与C/N呈正相关,与N/P呈负相关,分解过程受到P的限制程度较大.倒伏分解阶段,枯落物C/N、C/P和N/P的影响降低,而大气温湿度、土壤水分、酸碱度、盐度和沉积物特性等的影响加大.不同分解阶段枯落物分解影响因子的差异主要与其所处的微域环境和潮汐因素有关.     

降水量变化对蒙古栎落叶分解过程的间接影响

分析了在4种不同降水量条件下蒙古栎叶凋落物基质质量的变化,并应用分解袋法研究其凋落物在蒙古栎次生林内的分解过程.结果表明：与对照相比,降水量减少条件下,蒙古栎叶凋落物的初始N、P、K浓度显著升高,初始木质素浓度显著降低,凋落物分解速率大,N、P、K矿化率高,N和P固持时间缩短;降水量增加情况下,其凋落物初始N浓度显著降低、木质素浓度显著升高,N、P、K矿化率低,N和P固持时间延长.4种类型叶片凋落物的质量损失过程均符合指数降解模型,分解速率可以由凋落物木质素/N来预测.相关性分析显示,木质素浓度高、N浓度低的两种凋落物的分解速率与N浓度相关性最大;而木质素浓度低、N浓度高的两种凋落物的分解速率与木质素浓度相关性最大.说明降水量的变化显著地改变了蒙古栎叶凋落物的基质质量,进而间接地改变了凋落物的分解过程.     

Recent chinese research on analytical chemistry of the rare earths

The People's Republic of China has the world's largest reserves of rare earths. Recently, the rare earths have been found various applications in different fields of science and technology. The extensive research on analytical chemistry of rare earths has been made by Chinese analysts. The third Chinese Conference on the Analytical Chemistry of Rare Earths was held in 1982. A 2 volume treatise entitled “Analytical Chemistry of the Rare Earths” has been written by Cheng Jai-kai, Tseng Yung-ao, Luo Quing-yaoet al. [1]. The following is a short review of Chinese progress in analytical chemistry of the rare earths. Only developments of the past five years (1978–1983) will be described.     

The early development of white adipose tissue. Effects of litter size on the lipoprotein lipase activity of four adipose-tissue depots, serum immunoreactive insulin and tissue cellularity during the first four weeks of life in the rat

1. Newborn rats were reared in litters of either four or sixteen individuals. The animals from the small litters gained body weight more rapidly than those from large litters during the first 29 days of postnatal life studied. 2. The relative weights of the perigenital, perirenal, subcutaneous and intramuscular white-adipose-tissue sites in the animals from small litters indicated their relative obesity compared with controls. 3. The adipose depots from animals reared in small litters had a greater proportion of lipid present, by weight, and had a greater number of larger fat-cells present in them compared with the depots of animals reared in large litters. 4. Compared with both normal-sized litter controls and animals reared in sixteens, during the period of study the animals from small litters were hypertriacylglycerolaemic but normocholesterolaemic. 5. During suckling the blood glucose concentrations of animals reared in fours were increased, as were the concentrations of circulating immunoreactive insulin. 6. During the 29 days of life studied, in general, the lipoprotein lipase activity of adipose depots from animals reared in fours was greater than for animals in large litters when expressed as mumol of nonesterified fatty acid released from the substrate/h per g fresh weight of tissue, per depot, or per million fat-cells, but were similar per cm(2) of fat-cell surface area. 7. The previously noted [Cryer & Jones (1978) Biochem. J.172, 319-325] pattern of mid-suckling elevation, late-suckling decline and post-weaning increase in the lipoprotein lipase activity of the four white-adipose depots studied was not obliterated by the nutritional manipulations employed. 8. The relation of the enzyme-activity changes and their hormonal stimuli to triacylglycerol accumulation in fat-cells of animals from large and small litters is discussed in relation to the possible significance they may have to our understanding of neonatally induced obesity.     

土壤-植物系统中稀土元素与氮磷养分的交互作用

土壤－植物系统中稀土元素与N,P养分交互作用属农田稀土安全性评价研究的前沿,土壤中稀土元素与N,P交互作用直接关系到稀土对农田土壤生产力的影响以及稀土对农作物的增产机理和生态环境安全性的评价,就土壤－植物系统中有关稀土元素与N,P交互作用的研究作简要综述,提出今后应加强作物根际,农田土壤表层以及植物体内稀土与N,P养分之间交互作用的研究。