Teleconnection between the early immigration of brown planthopper (Nilaparvata lugens Stål) and ENSO indices: implication for its medium- and long-term forecast

Teleconnection between the early immigration of brown planthopper (BPH) and El Nino/Southern Oscillation (ENSO) indices from January of two years previously to the current June was investigated to make long-term forecast. The teleconnection results were as follows: ENSO indices which were significantly correlated with the early immigration of BPH were primarily sea surface temperature anomalies (SSTA) in N3, N4 and N3.4 regions, accounting for 71.8% of the total. Significant ENSO indices from two years and one year before the immigration events had a proportion of about 84%, while those in the current year only accounted for 16.7%. There was significantly negative correlation between the early immigration of BPH and SSTA in each Nino region from two years before to the previous spring, whereas there was significantly positive correlation between these two factors during the period from the previous winter to the current spring. The significant correlation between the early immigration of BPH and SSTA in each Nino region in the last summer and autumn did not show any obvious tendencies. The relationship between the southern oscillation index (SOI) and the early immigration of BPH was opposite to that between the immigration and SSTA in each Nino region. The above mentioned significant ENSO indices were used as key factors to build forecasting models for the early immigration of BPH by step-wise multiple linear regression analysis. Finally, 12 integrated forecasting models were obtained, which could make predictions 3–27 months ahead and had a predictive accuracy of 88.9%.     

Age, growth and reproduction of Sarcocheilichthys nigripinnis from the Qingyi Stream in the Huangshan Mountains

Identifying the life-history strategies of fish and their associations with the surrounding environment is the basic foundation in the conservation and sustainable utilization of fish species.We examined the age,growth,and reproduction of Sarcocheilichthys nigripinnis using 352 specimens collected monthly from May 2009 to April 2010 in the Qingyi Stream.We found the sex ratio of this study population was 0.58:1(female:male),significantly different from expected 1:1.Females and males both comprised four age groups.The annuli on the scales were formed during February and March.No obvious between-sex difference was observed in length-weight and length-scale-radius relationships.The total length in back-calculation significantly increased with age for both sexes,but did not differ significantly at each age between the two sexes.An inflection point was observed in the growth curves given by the von Bertalanffy growth function for total weight.At this inflection point,fish were 3.95 years.Both sexes reach their 50% sex maturity at age 2,when females and males were 94.7 mm and 103.0 mm total length.The temporal pattern of the gonado-somatic index corresponded to a spawning period that occurred from April through July.The non-synchronicity of egg diameter in each mature ovary during the breeding period suggested these fish may be batch spawners.The absolute fecundity increased significantly with total length and weight,whereas no significant correlation was observed between the relative fecundity and body size.     

内蒙古草原沙地白扦年轮生长指数的变异

The variation in ring growth indices of Picea meyeri was assessed by dendrochronological techniques including response functions, correlation functions and single-year analysis on sandy dunes in the Xilin River basin steppe. The results show that growth of Picea meyeri was sensitive to climate change. Furthermore, it was determined that mean monthly temperature and total monthly precipitation from September of the current year to August of the preceding year can account for about 70% of the variance in the tree-ring width. The rainfalls in February and May of the current year together with that of the previous September were significantly correlated with the current year’s growth pattern. Additionally ,radial growth was negatively correlated with mean monthly temperature in current May. In this region the sandy substrate is characterized by high water infiltration and low soil moisture evaporation rates. As a result, relatively high precipitation from prior August to prior October can be reserved in the sandy soil and the Picea meyeri trees show strong adaptation to the sandy substrate in these se- mi-arid grasslands. Therefore, the establishment of Picea meyeri forest plantations in the sandy belt along the middle reaches of Xilin River are deemed feasible.     

Morphological characteristics of the hair of Japanese monkeys (Macaca fuscata fuscata): Length,diameter and shape in cross-section,and arrangement of the medulla

A morphological study was carried out on hairs of the Japanese monkey. The shapes in cross-section were circles or ellipses. The diameters of the hairs ranged from 13.5 to 92 μ, and the mean value in each monkey was between about 30 and 40 μ. The average value of the fibre index was approximately 90 in each monkey. The arrangement of the medulla was considered to be of the narrow medulla lattice type. Medullae were developed poorly or disappeared in hairs with a diameter of less than 30 μ. A correlation was noted between the hair thickness and presence of medulla: medullated hairs were thicker than non-medullated hairs. A tendency was found for thicker hairs to be of greater length. The hairs of the Japanese monkey could be divided broadly into two types: medullated hair and non-medullated hair. The medullated hairs could be regarded as guard hair-like hairs since they were thick and long, and the non-medullated hairs as underhair-like hairs since they were thin and short.     

Population dynamics of the oriental fruit fly, Bactrocera dorsalis （Diptera： Tephritidae） in the Kunming area,southwestern China

Population dynamics of Bactrocera dorsalis Hendel （Diptera： Tephritidae） were studied through pheromone trapping over 4 years （1997, 1999, 2000, 2003） in the Kunming region, a high plateau area in southwestern China. B. dorsalis immigrates from southern Yunnan to Kunming each year, and occurs during early May through November. Annual trap captures recorded an increase in the B. dorsalis populations from May to July, when they peaked in abundance, and a decline until November. No flies were detected from November to April. The fruit flies had two generations. There was considerable overlapping due to the continuous arrival of immigrating flies during the summer months. Annual capture rates were significantly related to numbers of flies caught in July when peak captures were recorded; whereas the peak captures, in turn, positively depended on numbers of flies recorded in May, the first month of fly appearance in the current year. It suggested that the annual population abundance was mainly dependent on the size of the initial emigrating population. A daily average temperature of 18℃ was probably the threshold temperature required for the flies to undertake long-range dispersal, which partially explained the start of the fly in May each year on this high plateau. Under field conditions, the fruit flies can withstand 13℃ as a daily average temperature. No flies were recorded in any of the study years at a daily temperature colder than 10 ℃.     

Monitoring of brown stink bug (Hemiptera: Pentatomidae) population dynamics in corn to predict its abundance using weather data

The brown stink bug (BSB), Euschistus servus (Say)(Hemiptera: Pentatomidae), is a serious economic pest of corn production in the southeastern United States. The BSB population dynamics was mon itored for 17 weeks from tasseling to preharvest of corn plants (i.e., late May to mid-September) using pheromone traps in three corn fields from 2005 to 2009. The trap data showed two peaks in early June and mid-August, respectively. The relationship between trap catch and pregrowing season weather data was examined using correlation and stepwise multiple factor regression analyses. Weather indices used for the analyses were accumulated growing degree day (AGDD), number of days with minimum temperature below 0℃(Subz), accumulated daily maximum (AMaxT) and minimum temperatures (AMinT) and rainfall (ARain). The weather indices were calculated with lower (10℃) and upper (35℃) as biological thresholds. The parameters used in regression analysis were seasonal abundance (or overall mean of BSB adult catch)(BSBm), number of BSB adults caught at a peak (PeakBSB), and peak week (Peakwk). The BSBm was negatively related to high temperature (AmaxT or AGDD) consistently, whereas IstPeakBSB was positively correlated to both ARain and Subz, irrespective of weather data durations (the first 4, 4.5, and 5 months). In contrast, the 7-month weather data (AGDD7) were negatively correlated to the BSBm only, but not correlated to the second PeakBSB. The 5-year monitoring study demonstrated that weather data can be used to predict the BSB abundance at its first peak in tasseling corn fields in the southeastern U.S. states.     

Conventional digital cameras as a tool for assessing leaf area index and biomass for cereal breeding

Affordable and easy-to-use methods for assessing biomass and leaf area index （LAI） would be of interest in most breeding programs. Here, we describe the evaluation of a protocol for photographic sampling and image analysis aimed at providing low-labor yet robust indicators of biomass and LAI. In this trial, two genotypes of triticale, two of bread wheat, and four of tritordeum were studied. At six dates during the growing cycle, biomass and LAI were measured destructively, and digital photography was taken on the same dates. Several vegetation indices were calculated from each image. The results showed that repeatable and consistent values of the indices were obtained in consecutive photographic samplings on the same plots. The photographic indices were highly correlated with the destructive measure-ments, though the magnitude of the correlation was lower after anthesis. This work shows that photographic assess-ment of biomass and LAI can be fast, affordable, have good repeatability, and can be used under bright and overcast skies. A practical vegetation index derived from pictures is the fraction of green pixels over the total pixels of the image, and as it shows good correlations with all biomass variables, is the most robust to lighting conditions and has easy interpretation.     

Evaluation of spatial and temporal patterns of insect damage and aflatoxin level in the pre-harvest corn fields to improve management tactics

Spatial and temporal patterns of insect damage in relation to aflatoxin contamination in a corn field with plants of uniform genetic background are not well understood. After previous examination of spatial patterns of insect damage and aflatoxin in pre-harvest corn fields, we further examined both spatial and temporal patterns of cob- and kernel- feeding insect damage, and aflatoxin level with two samplings at pre-harvest in 2008 and 2009. The feeding damage by each of the ear/kernel-feeding insects （i.e., corn earworm/fall armyworm damage on the silk/cob, and discoloration of corn kernels by stink bugs） and maize weevil population were assessed at each grid point with five ears. Sampling data showed a field edge effect in both insect damage and aflatoxin contamination in both years. Maize weevils tended toward an aggregated distribution more frequently than either corn earworm or stink bug damage in both years. The frequency of detecting aggregated distribution for aflatoxin level was less than any of the insect damage assessments. Stink bug damage and maize weevil number were more closely associated with aflatoxin level than was corn earworm damage. In addition, the indices of spatial-temporal association （χ） demonstrated that the number of maize weevils was associated between the first （4 weeks pre-harvest） and second （1 week pre-harvest） samplings in both years on all fields. In contrast, corn earworm damage between the first and second samplings from the field on the Belflower Farm, and aflatoxin level and corn earworm damage from the field on the Lang Farm were dissociated in 2009.     

Developmental competence and ultrastructural changes of heat-stressed mouse early blastocysts produced in vitro

Mouse early blastocysts were exposed to temporatures of 39℃ and 41℃ for 2 h,respectively,to determine their developmental competence and uhrastructural changes. The results showed that heat stress at 41 ℃ for 2 h,significantly reduced the percentages of expanded and hatched blastocysts,but not at 39℃ for 2 h. The average cell numbers in expanded blastocysts,which developed from early blastocysts heat-stressed at temperatures of 39℃ and 41 ℃,were significantly reduced. The average cell numbers in hatched blastocysts subjected to heat stress were no different from those in the control group cultured at 37℃ . The mitochondria of the early blastocysts heat-stressed at 39T℃ for 2 h,were slightly swollen,but they had recovered after culturing at 37℃ for 2 h. However,the mitochondria in the blastocysts heat stressed at 41 ℃ for 2 h were severely swollen,and their number increased. The ribosomes shed from the rough endoplasmic reticulum,and the number of secondary lysosomes in the plasma increased. The integrity of desmosomes was disrupted. The space between the nuclear envelope and the perivitelline membrane enlarged. The fibre fraction and the particulate fraction of nucleoli were separated. The heterochromatin in nucleoli was also increased in its quantity. There were some lamellar-shape structures and heterogeneous dense materials exhibiting in the cytoplasm. The ultrastructural changes induced by heat shock at 41 ℃ for 2 h were not reversible. In conclusion,the damage of heat stress to mitochondria,lysosomes,ribosomes and cell nucleus,may be one of the most important factors that inhibit the normal development of mouse early blastocysts.     

Developmental competence and ultrastructural changes of heat- stressed mouse early blastocysts produced in vitro

Mouse early blastocysts were exposed to temperatures of 39℃ and 41℃ for 2 h, respectively, to determine their developmental competence and ultrastructural changes. The results showed that heat stress at 41 ℃ for 2 h, significantly reduced the percentages of expanded and hatched blastocysts, but not at 39℃ for 2 h. The average cell numbers in expanded blastocysts, which developed from early blastoeysts heat-stressed at temperatures of 39℃ and 41 ℃, were significantly reduced. The average cell numbers in hatched blastocysts subjected to heat stress were no different from those in the control group cultured at 37 ℃ . The mitochondria of the early blastocysts heat-stressed at 39℃ for 2 h, were slightly swollen, but they had recovered after culturing at 37 ℃ for 2 h. However, the mitochondria in the blastocysts heat stressed at 41 ℃ for 2 h were severely swollen, and their number increased. The ribosomes shed from the rough endoplasmic reticulum, and the number of secondary lysosomes in the plasma increased. The integrity of desmosomes was disrupted. The space between the nuclear envelope and the perivitelline membrane enlarged. The fibre fraction and the particulate fraction of nueleoli were separated. The heterochromatin in nueleoli was also increased in its quantity. There were some lamellar-shape structures and heterogeneous dense materials exhibiting in the cytoplasm. The ultrastructural changes induced by heat shock at 41 ℃ for 2 h were not reversible. In conclusion, the damage of heat stress to mitoehondria, lysosomes, ribosomes and cell nucleus, may be one of the most important factors that inhibit the normal development of mouse early blastoeysts .     

Plant species, atmospheric CO2 and soil N interactively or additively control C allocation within plant-soil systems

Two plant species,Medicago truncatula (legume) and Avena sativa (non-legume),were grown in low-or high-N soils under two CO2 concentrations to test the hypothesis whether C allocation within plant-soil system is interactively or additively controlled by soil N and atmospheric CO2 is dependent upon plant species. The results showed the interaction between plant species and soil N had a significant impact on microbial activity and plant growth. The interaction between CO2 and soil N had a significant impact on soil soluble C and soil microbial biomass C under Madicago but not under Avena. Although both CO2 and soil N affected plant growth significantly,there was no interaction between CO2 and soil N on plant growth. In other words,the effects of CO2 and soil N on plant growth were additive. We considered that the interaction between N2 fixation trait of legume plant and elevated CO2 might have obscured the interaction between soil N and elevated CO2 on the growth of legume plant. In low-N soil,the shoot-to-root ratio of Avena dropped from 2.63±0.20 in the early growth stage to 1.47±0.03 in the late growth stage,indicating that Avena plant allocated more energy to roots to optimize nutrient uptake (i.e. N) when soil N was limiting. In high-N soil,the shoot-to-root ratio of Medicago increased significantly over time (from 2.45±0.30 to 5.43±0.10),suggesting that Medicago plants allocated more energy to shoots to optimize photosynthesis when N was not limiting. The shoot-to-root ratios were not significantly different between two CO2 levels.     

A large impact of tropical biomass burning on CO and CO2 in the upper troposphere

A large interannual variation of biomass burning emissions from Southeast Asia is asso-ciated with the ENSO events. During 1997/98 and 1994 El Nino years, uncontrolled wildfires of tropical rainforests and peat lands in Indonesia were enlarged due to a long drought. EnhancedCO injection into the upper troposphere from the intense Indonesian fires was clearly observed in the 8-year measurements from a regular flask sampling over the western Pacific using a JAL air-liner between Australia and Japan. This airliner observation also revealed that upper tropospheric CO_2 cycle largely changed during the 1997 El Nino year due partly to the biomass burning emis-sions. Widespread pollution from the biomass burnings in Southeast Asia was simulated using aCO tracer driven by a 3D global chemical transport model. This simulation indicates that tropical deep convections connected to rapid advection by the subtropical jet play a significant role in dis-persing biomass-burning emissions from Southeast Asia on a global scale.     

Spatio-temporal dynamics of two alpine treeline ecotones and ecological characteristics of their dominate species at the eastern margin of Qinghai-Xizang Plateau北大核心CSCD

Aims Temperature limit is the main cause of alpine treeline formation. Therefore, it is important to understand the response mechanisms of alpine treeline as well as their tree species under the global climate change. The present study focused on the spatio-temporal dynamics of treeline and ecological characteristics of the tree species in two treeline ecotones. Methods Two vertical belt-transect plots were established in each treeline ecotone of the Zheduo Mountain and Jianziwan Mountain of the eastern Qinghai-Xizang Plateau. Top and bottom of each transects were lain between species line and forest line, respectively. Detailed information of each tree species treeline, including species name, latitude, longitude, height, age, base diameter, and coordinates, was recorded accordingly. Important findings The temperatures of the two research areas have increased during the past 58 years. The precipitation has decreased slightly in both the Zheduo Mountain and Jianziwan Mountain. The age structure of Abies fabri from the Zheduo Mountain and A. squamata from the Jianziwan Mountain showed a reversed “J” shape curve and a bimodal shape, respectively. Within the two transects, due to the limitation of seed diffusion, the dominate species showed aggregated distributions at the small scale. At the large scale, A. fabri was aggregated at the Zheduo Mountain, while A. squanmata of the Jianziwan Mountain was randomly distributed due to the impact of surrounding environmental factors. Both tree height and base diameter decreased with the increase of elevation. The fir trees (Abies spp.) at the upper part of the treeline ecotone presented an allometric growth, whose height growth rate was higher than that of base growth, while the relationships between height growth and base growth were isometric at almost mid and lower part of the treeline ecotone. Compared with 10 years ago, there was no significant change at the position of treeline and tree species line of the Zheduo Mountain and the Jianziwan Mountain, neither of the tree density in the Jianziwan Mountain. However, the number of trees in the Zheduo Mountain increased by about 25%. Compared with 20 years ago, tree species lines of the Zheduo Mountain and Jianziwan Mountain were shifted upwards by 50 and 30 m, respectively. Besides, their treeline positions were increased by 75 and 40 m, respectively. Furthermore, the number of trees also increased significantly by 220% and 100%, respectively. Therefore, the treeline and its constructive species are mainly affected by temperature at the large spatio-temporal scale, while influenced by temperature and ambient environment at the small spatio-temporal scale. © Chinese Journal of Plant Ecology.     

Distribution and interspecific correlation of root biomass density in an arid Elaeagnus angustifolia–Achnatherum splendens community

Main objective of this study was to determine the interspecific relationships between two dominant species in terms of root distribution in a typical arid tree-herbage (Elaeagnus angustifolia–Achnatherum splendens) community at Xidatan, Pingluo County, Ningxia Autonomous Region, Northwest China. Eight concentric zones (namely, Z1–Z8) were set from the bases of E. angustifolia individuals to the open lands and five soil profiles were excavated in each zone. Each soil profile was divided into five layers at the depths of 0–10 cm, 10–30 cm, 30–60 cm, 60–100 cm and 100–150 cm. Roots were collected for each species, and soil water content (SWC) and soil bulk density (SBD) were measured for each layer. We found noteworthy roots layer separation in the sub-canopy zones (Z1–Z4). The soil layers with highest fine root biomass density (FRBD) of A. splendens was primarily in the 0–10 cm, which were significantly shallower than those of E. angustifolia; whereas in the inter-canopy zones (Z5–Z8), inconsistent separation, or even overlapping of highest-FRBD-layers emerged between the two dominant species. Correlation analyses showed that negative correlations of FRBD between the two species mainly occurred in those soil layers with relatively higher FRBD and lower SWC. In contrast, positive correlations corresponded with relatively lower FRBD and higher SWC.     

Distribution and interspecific correlation of root biomass density in an arid Elaeagnus angustifolia–Achnatherum splendens community

Main objective of this study was to determine the interspecific relationships between two dominant species in terms of root distribution in a typical arid tree-herbage (Elaeagnus angustifolia–Achnatherum splendens) community at Xidatan, Pingluo County, Ningxia Autonomous Region, Northwest China. Eight concentric zones (namely, Z1–Z8) were set from the bases of E. angustifolia individuals to the open lands and five soil profiles were excavated in each zone. Each soil profile was divided into five layers at the depths of 0–10 cm, 10–30 cm, 30–60 cm, 60–100 cm and 100–150 cm. Roots were collected for each species, and soil water content (SWC) and soil bulk density (SBD) were measured for each layer. We found noteworthy roots layer separation in the sub-canopy zones (Z1–Z4). The soil layers with highest fine root biomass density (FRBD) of A. splendens was primarily in the 0–10 cm, which were significantly shallower than those of E. angustifolia; whereas in the inter-canopy zones (Z5–Z8), inconsistent separation, or even overlapping of highest-FRBD-layers emerged between the two dominant species. Correlation analyses showed that negative correlations of FRBD between the two species mainly occurred in those soil layers with relatively higher FRBD and lower SWC. In contrast, positive correlations corresponded with relatively lower FRBD and higher SWC.     

Stratigraphic record of U37K in Sanmen Bay: the effect of SST and EI Niño on life activity in macrobenthos communities

Sea surface temperature (SST) from 1916–2003 was estimated by using the index of U₃₇^K of organic compounds in Sanmen Bay (SMB) sediment. It fluctuated between 15.97°C and 18.00°C with an average of 17.03°C. The estimated SST was 3.52°C lower than the annual average temperature measured in the same year but was close to the temperature measured in fall. The research suggested that the climate events (EI Ni?o) on large scale in Sanmen Bay were affected by the climate, similar to that in the East Pacific Ocean (EPC). The change scale was also affected by geographical location and local climate such as monsoon. According to the chronological basis, the events in SMB corresponded to those in EPC, but the scale of variation is not so strong as that in EPC. By comparing the community, biomass, individual density and biodiversity of macrobenthos during EI Ni?o (between 2002 and 2003) and non-EI Ni?o (between 2005 and 2006) periods, it was indicated that certain macrobenthos communities in SMB responded to EI Ni?o events. During the EI Ni?o period, Taiwan warm current (TWC) is much stronger than that in normal years. The diversity of macrobenthos during 2002 and 2003 was relatively low owing to invasion of the warm current that caused salinity change. The macrobenthos and zooplankton in Sanmen Bay responded to EI Ni?o events significantly. The diversity of macrobenthos decreased significantly because TWC invaded into the shallow bay from the floor and thus changed the temperature and salinity in the bay. On the other hand, zooplankton species, biomass and abundance increased in the period of EI Ni?o since the invaded warm current brought abundant species of zooplankton.     

A study on the diversity of the moth community in the North Dagang Wetland Nature Reserve, Tianjin, China

North Dagang Wetland Nature Reserve is situated in the southeast of Tianjin, China. It is the biggest wetland nature reserve in Tianjin. An investigation into the diversity of the moth community was carried out from June 12 to October 14, 2001, and then from April 12 to October 30, 2002. The investigation was conducted in order to identify the moth species in wetlands, study their dynamic laws, select indicator insects to indicate wetland quality, and assist in the study and protection of wetlands. A total of 132 moth species were collected, which belonged to 105 genera in 17 families. The data about insects which was collected during the survey was listed and constructed in terms of species-abundance, indices of diversity (H′), evenness (J′), specific richness (S) and individual number (N) using the Microsoft Excel Program. The status of the wetlands was also analyzed using the moth community species-abundance curve, indices of diversity, the connection between evenness and richness indices, etc. The results show that moth species in the wetlands were not rich, and the moth community was unstable. In other words, the living environment of the moths and the environmental quality of the wetlands were unstable due to the serious degeneration of the wetland environment and human activities.     

Endothelial nitric oxide synthase gene intron 4, 27 bp repeat polymorphism and essential hypertension in the Kazakh Chinese population

To investigate the relationship between 27 bp repeat polymorphism in intron 4 in the endothelial nitric oxide synthase (eNOS4) gene and essential hypertension in the Kazakh Chinese population, 151 patients with essential hypertension and 138 healthy people were selected from the Boertonggu countryside of Shawan region in the Xinjiang Uygur Autonomous Region of China in 2006. The polymorphism of eNOS in the two groups was detected with polymerase chain reaction assays and the genotype frequencies in each group were calculated following the Hardy-Weinberg law. Four and five tandem 27 bp repeats were designated as "a" and "b", respectively. It was found that the frequencies of b/b, b/a and a/a genotypes of the eNOS4 gene were 84.06%, 15.22% and 0.72% in the control group, and 81.46%, 15.89% and 2.65% in the hypertension group, respectively. The frequencies of gene "b" and "a" were 91.67% and 8.33% in the control group and 89.40% and 10.60% in the hypertension group, respectively. It was found that plasma eNOS activity was not associated with genotypes and alleles of eNOS gene. Plasma eNOS activity in the hypertension group was significantly decreased compared with the control group (P<0.01). The results suggest that eNOS4 gene polymorphisms are unlikely to be the major genetic susceptibility factors for essential hypertension in the Xinjiang Kazakh population. However, a positive association between plasma eNOS activity and essential hypertension has been revealed.