Population dynamics of Dremomys pernyi and Callosciurus erythraeus in protective and non-protective pine forests at different ages

Four pine forests (6-10,11-15,16-20,and 31-40 year-old)located in the Cangshan Mountain and Erhai Lake National Reserve and 7 pine forests (1-5,6-10,11-15,16-20,21-30,31-40,and more than 50 year-old)located in the non-protective area near the national reserve were selected.Three replications of each forest was set and a total of 33 sites were investigated.At each site,we quantified 6 habitat variables (species richness,abundance,and percentage of grasses and shrubs coverage respectively at the bottom layer of forests)within randomly determined 5 m×5 m areas.One hundred cages were set in five lines at each site to trap small mammals,whose species and numbers were recorded.Dominance of Dremomys pernyi and Callosciurus erythraeus in small mammal communities,time niche breadth,and time niche overlap between the two small mammals were calculated,respectively.Step-wise regression was used to analyze the relationship between small mammals and habitat factors.Our results indicated that D.pernyi occurred earlier than C.erythraeus in protective pine forests.D.pernyi was captured in 6-10 year-old forest initially,and C.erythraeus was captured in 16-20 year-old forest initially.D.pernyi and C.erythraeus were captured in the 31-40 and 21-30 year-oldforests initially in the non-protective area,respectively.Populations of D.pernyi and C.erythraeus in the 31-40 year-old protective forests were 3 and 3.75 times of those in the sameaged non-protective forests,respectively.Shrubs significantly influenced the populations of the two small mammals.The population of D.pernyi was positively correlated with the density of shrubs;the population of C.allosciurus erythraeus was positively correlated with the coverage of shrubs,and negatively correlated with the coverage of grasses.D.remomys pernyi and C.allosciurus erythraeus were important for pine forests to scatter pine seeds.Human activities in the nonprotective pine forests decreased the vegetation heterogeneity at the bottom layer of pine forests,postponed the occurrence of D.pernyi and C.erythraeus,and decreased the populations of the two small mammals.     

珀氏长吻松鼠和赤腹松鼠在保护区与非保护区各年龄松林内的种群动态

2004年6~7月,在云南省大理白族自治州苍山和洱海国家自然保护区选取4种年龄段(6~10、11~15、16~20、31~40年)的松林和保护区周围的非保护区选取7种年龄段(1~5、6~10、11~15、16~20、21~30、31~40、50年以上)的松林,每种松林设3个重复,共33个样地,在样地内随机选取3个5m×5m的样方,调查并记录样方内草本植物和灌木的种类、数量、覆盖度。在每个样地按5条样线布笼100个捕捉小兽,每天检查捕获的种类和数量。计算珀氏长吻松鼠和赤腹松鼠在小兽群落中物种优势度、时间生态位宽度、两种小兽的时间生态位重叠度;用逐步回归分析两种松鼠与松林栖境因子的关系。上述结果表明,在保护区珀氏长吻松鼠出现的时间早于(6~10年的松林开始捕获到)赤腹松鼠(16~20年的松林内开始捕获到);在非保护区,分别在31~40年和21~30年的松林内才捕到珀氏长吻松鼠和赤腹松鼠。保护区31~40年的松林内珀氏长吻松鼠和赤腹松鼠种群数量分别是同年龄段非保护区松林的3倍和3·75倍。松林底层的灌木对两种小兽的种群数量有重要影响。珀氏长吻松鼠种群数量与灌木密度呈正相关;赤腹松鼠种群数量与灌木覆盖度呈正相关,而与草本植物覆盖度呈负相关。非保护区树底植被的异质性降低,延迟了两种松鼠在松林里建立种群的时间。     

Indications of Hydraulic Lift by Pinus halepensis and Its Effects on the Water Relations of Neighbour Shrubs

We measured the stable deuterium isotopic composition of xylem sap, the shoot predawn and midday water potentials, and the leaf δ¹³C of Mediterranean shrubs Pistacia lentiscus, Globularia alypum and Rosmarinus officinalis in a south-oriented transect from a large (12 m tall) Aleppo pine tree, Pinus halepensis. We aimed to study the possibility of hydraulic lift from the deep roots of this pine tree to the shallow soil layers and its influence on these neighbour shrubs. These same traits were also studied in several individuals of the shrub Pistacia lentiscus growing with different types of neighbours: just shrubs, a small (3 – 4 m) pine tree, and the above mentioned large pine tree. The greater the distance from P. halepensis the plants grew, the higher xylem water δD, the lower the soil water content, and, the lower the predawn and midday water potentials were found. These results suggest the existence of an hydraulic lift from deep roots to shallow soil in this big tree. Further indication of this existence is provided by the improved water status of P. lentiscus (higher water potentials and δD, and lower δ¹³C and, therefore, lower water use efficiencies) when growing close to the big pine in comparison with the same shrub species growing close to small pines or just surrounded by other shrubs. Moreover, all these trends occurred in the dry summer season, but disappeared in the wet spring season. This revised version was published online in July 2006 with corrections to the Cover Date.     

不同林龄樟子松人工林径向生长对气候及地下水位变化的响应

全球气候变化导致森林生态系统的结构与功能发生改变,甚至出现树木死亡与林分衰退的现象,研究林分生长对气候变化尤其是干旱事件的响应有助于预测未来气候变化下生态系统的稳定性。以辽宁章古台5个林龄的樟子松人工林为研究对象,分析了树木径向生长对气候因子与地下水位的响应,结果表明：秋季气温,尤其是最低气温显著影响樟子松林的生长（44年生林分除外）;低林龄樟子松林（36、39年）生长与当年夏季及生长季内的降水显著正相关,而高林龄樟子松林（52年）生长则与当年春季尤其是当年2月与5月降水显著正相关;36、39、52年生樟子松人工林年表与当年夏季的Palmer干旱指数（PDSI）显著正相关,44、58年生樟子松人工林年表则与地下水位显著正相关。应对早期干旱（即1997年）时,樟子松人工林表现为随林龄增加,其抵抗力增加而恢复力降低;在随后的两个干旱事件中,高林龄樟子松林的抵抗力不再明显高于低林龄,可能是由于地下水位显著降低影响根系吸水;受累积干旱的影响,所有林龄樟子松人工林对2007-2008干旱事件的弹性力均小于1,径向生长量明显降低。地下水位是影响不同林龄樟子松人工林生长及对干旱抵抗力的重要因子,考虑地下水位有助于进一步提升森林生态系统对气候变化响应研究的准确性。     

滇西北鼠疫自然疫源地齐氏姬鼠和大绒鼠对不同生境的选择

对仓山和洱海国家自然保护区4种年龄的森林以及周边的农田、果园、荒山灌丛和非保护区6种年龄的森林中齐氏姬鼠（Apodemus chevrieri）和大绒鼠（Eothenomys miletus）的种群数量进行了调查,研究了森林中2种小兽与栖境因子的关系以及人类活动对其种群数量的影响。结果表明,齐氏姬鼠和大绒鼠的生态位宽度分别为0．706和0．641,生态位重叠度为0．831。聚类分析显示：农田中2种小兽的种群数量最高;在非保护区森林、灌丛和果园,齐氏姬鼠和大绒鼠的数量显著低于农田,而高于保护区森林。人类干扰活动对森林底层植物有显著影响,能显著降低灌木的覆盖度、物种多度（除了6～10年生的森林）和密度,而增加草本植物的覆盖度和密度。回归结果表明,2种小兽的数量与森林草本植物的覆盖度呈正相关,而与灌木的密度呈负相关。     

Rearing of two predators,Thanasimus dubius andTemnochila virescens, for the biological control ofIps grandicollis in Australia

Rearing methods for two coleopterous predators,Thanasimus dubius andTemnochila virescens, imported into Australia for the biological control ofIps grandicollis, were developed. Bionomic data obtained from laboratory rearings between 1982–1987 showed thatT. dubius eggs took about 7 days to hatch and that duration of the larval stage was about 42 days. Observations showed thatT. dubius had a prolonged prepupal stage (x=56.4 days, range 14–274 days), which was probably non-diapausal in nature. Mean adult longevity was 50 days (range 1–358 days).Temnochila virescens eggs took almost 9 days to hatch, and a lengthy larval stage (x=155.4 days, range 73–333 days) was observed. Mean duration of the pupal stage was 14 days (range 7–28 days). A long preoviposition period (x=141 days, range 47–206 days) was observed, and adults were very long-lived (x=232.7 days, range 14–667 days). Capacity for increase (r_c) calculated from rearing data suggested that numbers ofT. dubius could be increased faster thanT. virescens. Mortality between 1982–1987 averaged about 70% for both species. However, mortality ofT. dubius in 1987 increased significantly, suggesting that inbreeding or other methodological factors could be responsible. A mass-rearing method usingIps-infested pine billets was developed as a cheaper alternative to laboratory rearing, and was shown to be effective in producing large numbers of insects for release.     

The allelopathic potential ofCoridothymus capitatus L. (Labiatae). Preliminary studies on the roles of the shrub in the inhibition of annuals germination and/or to promote allelopathically active actinomycetes

Summary Suppression of annuals at various intensities was observed around some shrubs ofCoridothymus capitatus growing on kurkar formation in the coastal hills of Israel. The phenomenon was clearly observed as annuals-free belts of 15–20 cm around ‘aggressive’ shrubs. Quantitatively, density of annuals decreased by 16 fold in the annual-free belts as compared to a distance of 60–80 cm from the canopies of the shrubs. Their dry matter was decreased by 5.4 fold around the shrubs. Suppression rate of emergence of planted seeds of annuals (Plantago psyllium andErucaria hispanica) early in the season was 45% higher around ‘aggressive’C. capitatus than that around ‘non-aggressive’ ones. In the laboratory, seed germination of the annuals was strongly suppressed by diffusates and volatiles from shoots, as well as from their water extracts and their essential oils. Incubation of fresh shoots ofC. capitatus in soil collected from around ‘non-aggressive’ shrubs, for 7 days, increased population levels of actinomycetes by 9.6 fold and by 36.7 fold when soil was collected from around ‘aggressive’ shrubs. Isolates of some soil-borne actinomycetes inhibited germination of the test plantsLactuca sativa andAnastatica hierochuntica on agar plates (4–98%). The preliminary results indicate a possible synergistic inhibitory effect induced by essential oils of the aromatic shrub and the phytototic activity of actinomycetes.     

Aboveground net production and dry matter allocation ofPinus pumila forests in the Kiso mountain range,central Japan

Aboveground net production rates of the subalpine stone pine (Pinus pumila) forests in central Japan were estimated by the summation method; net production was defined as the sum of annual biomass increment and annual loss due to death. In the two pine stands of different scrub heights, P1 (200 cm) and P2 (140 cm), aboveground biomass reached 177 and 126 ton ha⁻¹, respectively. Leaf biomass was about 14 ton ha⁻¹ in each stand. The estimates of aboveground net production during the 2 year period (1987–1989) averaged 4.1 and 3.7 ton ha⁻¹ y⁻¹ in P1 and P2, respectively, which were at the lowest among the pine forests in the world. Two indices of efficiency of energy fixation, that is, the ratio of net production to the total radiation during a growing season and the ratio of net production to total radiation per unit of leaf weight, were evaluated. Both efficiency indices for the twoP. pumila stands fell in the range obtained for other Japanese evergreen conifer forests. This suggested that the low annual net production of the stone pine stands were mainly due to a limitation in the length of the growing season. The pine forests were also characterized by a small allocation (about 17%) of aboveground net production into biomass increment, in comparison with other evergreen conifer forest types. Annual net carbon gain in theP. pumila forests was suggested to be largely invested in leaf production at the expense of the growth of woody parts.     

Heterologous expression and characterization of man gene from Bacillus Subtilis in Pichia Pastoris

β-Mannanase catalyzes endo-wise hydrolysis of the backbone of mannan and heteromannan, which are abundant in the cell wall structure of ungerminated leguminous seeds. The mature β-mannanase originated from Bacillus subtilis was expressed in Pichia pastoris, a methylotrophic yeast, using the leader peptide sequence of Saccharomyces cerevisiae α-factor. The cultivation of β-mannanase expressing Pichia pastoris yields up to 1.8 g/L protein. In the supernatant the activity of the 40 kDa—total mannanase attained a level of 1102.0 IU/mL. The properties of the β-mannanase were characterized. Optimum pH and temperature for the recombinant enzyme were 5.5 and 50°C respectively. The enzyme was stable at pH 5.0–10.0 and maintained over 30% original activity after incubating at 70°C for 30 min. __________ Translated from China Biotechnology, 2005, 26(7): 52–56 [译自: 中国生物工程杂志]     

Fruits foraging patterns and seed dispersal effect of frugivorous birds on Hippophae rhamnoides sinensis

Behaviors of 18 species of birds eating fruits of Hippophae rhamnoides spp. sinensis were observed from September 2003 to March 2004. Their foraging patterns were found to be very different and can be divided into five classes: (1) direct swallowing the fruits on crown of the shrubs and sometimes regurgitating seeds soon after; (2) carrying the fruits to their perching sites and swallowing; (3) pecking the fruits from the shrubs to the ground, eating pulp and seeds but leaving pericarp; (4) pecking through the pericarp, eating pulp and leaving pericarp and seeds; (5) pecking through the pericarp on the top of fruits, and only eating seeds. These foraging patterns have different effects on seed dispersal of H. rhamnoides spp. sinensis. The germination experiment of three groups of seeds (seeds from feces, dry fruits and extracted seeds from dry fruits) was carried out. Although ingestion processes of birds had some adverse effects on the seed germination of H. rhamnoides spp. sinensis, the seeds from feces still have a relatively higher germination ratio. H. rhamnoides spp. sinensis provides food to a variety of frugivorous birds, and the birds disperse its seeds. Thus, a mutually beneficial relationship between the bird and the seed is formed. __________ Translated from Chinese Journal of Ecology, 2005, 24(6): 635–638 [译自: 生态学杂志, 2005, 24(6): 635–638]     

A comparison of the genetic diversity in Dipteronia sinensis Oliv. and Dipteronia dyeriana Henry

Dipteronia is an endemic genus to China and includes only two species, Dipteronia sinensis and D. dyeriana. Based on random amplified polymorphic DNA (RAPD) markers, a comparative study of the genetic diversity and genetic structure of Dipteronia was performed. In total, 128 and 103 loci were detected in 17 D. sinensis populations and 4 D. dyeriana populations, respectively, using 18 random primers. These results showed that the proportions of polymorphic loci for the two species were 92.97% and 81.55%, respectively, indicating that the genetic diversity of D. sinensis was higher than that of D. dyeriana. Analysis, based on similarity coefficients, Shannon diversity index and Nei gene diversity index, also confirmed this result. AMOVA analysis demonstrated that the genetic variation of D. sinensis within and among populations accounted for 56.89% and 43.11% of the total variation, respectively, and that of D. dyeriana was 57.86% and 42.14%, respectively. The Shannon diversity index and Nei gene diversity index showed similar results. The abovementioned characteristics indicated that the genetic diversity levels of these two species were extremely similar and that the interpopulational genetic differentiation within both species was relatively high. Analysis of the genetic distance among populations also supported this conclusion. Low levels of interpopulational gene flow within both species were believed to be among the leading causes for the above-mentioned phenomenon. The correlation analysis between genetic and geographical distances showed the existence of a remarkably significant correlation between the genetic distance and the longitudinal difference among populations of D. sinensis (p < 0.01), while no significant correlation was found between genetic and geographical distances among populations of D. dyeriana. This indicated that genetic distance was correlated with geographical distances on a large scale rather than on a small scale. This result may be related to differences in the selection pressure on species by their habitats with different distribution ranges. We suggest that in situ conservation efforts should focus on establishing more sites to protect the natural populations and their habitats. Ex situ conservation efforts should focus on enhancing the exchange of seeds and seedlings among populations to facilitate gene exchange and recombination, and to help conserve genetic diversity. __________ Translated from Acta Phytoecologica Sinica, 2005, 29(5): 785–792 [译自: 植物生态学报, 2005, 29(5): 785–792]     

Induction of a non-specific permeability transition in mitochondria from Yarrowia lipolytica and Dipodascus (Endomyces) magnusii yeasts

In this study we used tightly-coupled mitochondria from Yarrowia lipolytica and Dipodascus (Endomyces) magnusii yeasts, possessing a respiratory chain with the usual three points of energy conservation. High-amplitude swelling and collapse of the membrane potential were used as parameters for demonstrating induction of the mitochondrial permeability transition due to opening of a pore (mPTP). Mitochondria from Y. lipolytica, lacking a natural mitochondrial Ca²⁺ uptake pathway, and from D. magnusii, harboring a high-capacitive, regulated mitochondrial Ca²⁺ transport system (Bazhenova et al. J Biol Chem 273:4372–4377, 1998a; Bazhenova et al. Biochim Biophys Acta 1371:96–100, 1998b; Deryabina and Zvyagilskaya Biochemistry (Moscow) 65:1352–1356, 2000; Deryabina et al. J Biol Chem 276:47801–47806, 2001) were very resistant to Ca²⁺ overload. However, exposure of yeast mitochondria to 50–100 μM Ca²⁺ in the presence of the Ca²⁺ ionophore ETH129 induced collapse of the membrane potential, possibly due to activation of the fatty acid-dependent Ca²⁺/nH⁺-antiporter, with no classical mPTP induction. The absence of response in yeast mitochondria was not simply due to structural limitations, since large-amplitude swelling occurred in the presence of alamethicin, a hydrophobic, helical peptide, forming voltage-sensitive ion channels in lipid membranes. Ca²⁺- ETH129-induced activation of the Ca²⁺/H⁺-antiport system was inhibited and prevented by bovine serum albumin, and partially by inorganic phosphate and ATP. We subjected yeast mitochondria to other conditions known to induce the permeability transition in animal mitochondria, i.e., Ca²⁺ overload (in the presence of ETH129) combined with palmitic acid (Mironova et al. J Bioenerg Biomembr 33:319–331, 2001; Sultan and Sokolove Arch Biochem Biophys 386:37–51, 2001), SH-reagents, carboxyatractyloside (an inhibitor of the ADP/ATP translocator), depletion of intramitochondrial adenine nucleotide pools, deenergization of mitochondria, and shifting to acidic pH values in the presence of high phosphate concentrations. None of the above-mentioned substances or conditions induced a mPTP-like pore. It is thus evident that the permeability transition in yeast mitochondria is not coupled with Ca²⁺ uptake and is differently regulated compared to the mPTP of animal mitochondria.     

Early subcellular responses of susceptible and resistant Vitis taxa to feeding by grape phylloxera Daktulosphaira vitifoliae

Species, varieties, and hybrids of Vitis are differently susceptible to feeding by the aphid Daktulosphaira vitifoliae (Fitch) (Hemiptera: Phylloxeridae). The differing levels of susceptibility were examined in Vitis riparia × V. rupestris cv. C-3309, V. vinifera × V. labrusca cv. Weiβe Amerikaner, and V. vinifera cv. Portugieser Weiβherbst by characterizing early subcellular changes to aphid feeding. We examined the fifth and sixth layers of mesophyll parenchyma between 3 and 48 h after introducing neonate nymphs of D. vitifoliae on to those leaves. In the susceptible variety C-3309, activated and metaplasied cells appeared in 3–6 h of feeding by D. vitifoliae and developed into nutritive tissue in the next 24–48 h. On the contrary, cells of the resistant variety Portugieser Weiβherbst accumulated phenolic materials indicating a hypersensitive response; those of Weiβe Amerikaner showed a mixed response of developing a nutritive tissue and a concurrent accumulation of phenolic materials especially in cells away from the nutritive tissue, indicating that this hybrid could tolerate D. vitifoliae. Galls developed on the leaves of C-3309 in 21 days, whereas no gall development occurred on the leaves of Portugieser Weiβherbst and Weiβe Amerikaner. D. vitifoliae nymphs introduced on the leaves of Portugieser Weiβherbst died in 3–4 days, whereas on the leaves of Weiβe Amerikaner, nymphs lived up to 21 days. Thus early subcellular changes in leaf tissues determined the feeding activity of nymphs on leaves and the susceptibility of plants to insect feeding.

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Zusammenfassung  Bl?tter verschiedener Rebsorten reagieren unterschiedlich auf den Befall mit der Reblaus Daktulosphaira vitifoliae (Fitch). Hier wurde die Reaktion der Sorten Vitis riparia × V. rupestris cv. C-3309, V. vinifera × V. labrusca cv. Weiβe Amerikaner und V. vinifera cv. Portugieser Weiβherbst (kurz: C-3309, Weiβe Amerikaner und Portugieser Weiβherbst) verglichen, um die unterschiedliche Empfindlichkeit zu verstehen. Dazu wurden frühe subzellul?re Ver?nderungen der Blattgewebe in aseptischen Dualkulturen aus Vitis und D. vitifoliae charakterisiert. Da die Stechborsten der jungen Nymphen von D. vitifoliae bis in die fünfte oder sechste Mesophyllschicht von C-3309 eindringen, wurden Zellen dieser Schichten bei allen drei Rebsorten 3–48 Stunden nach Zugabe der Nymphen beobachtet. Bei der Sorte C-3309 erfolgte eine Differenzierung von aktivierten und metaplasierten Zellen 3–6 Stunden nach dem Befall. In den folgenden 24–48 Stunden entwickelten sich diese Zellen zu einem N?hrgewebe; somit erfolgte eine kompatible Reaktion. Im Gegensatz dazu zeigten die Zellen der Sorte Portugieser Weiβherbst eine hypersensitive Reaktion mit Akkumulation phenolischer Verbindungen. Zellen der Sorte Weiβe Amerikaner reagierten sowohl mit der Bildung von N?hrzellen als auch mit der Akkumulation phenolischer Verbindungen ausserhalb der N?hrzellen; dies ist ein Zeichen für Toleranz. Die Entwicklung typischer Gallen erfolgte in 21 Tagen ausschliesslich an den Bl?ttern der Sorte C-3309. An Portugieser Weiβherbst starben die Nymphen innerhalb von 3–4 Tagen ab, an Bl?ttern von Weiβe Amerikaner überlebten sie bis zum 21 Tag, ohne dass eine Gallbildung erfolgte. Die frühen subzellul?re Ver?nderungen der Blattgewebe bestimmten somit die Frasst?tigkeit der Nymphen und die Empfindlichkeit der drei Rebsorten auf den Insektenbefall.

     

Cocoon predation on diprionid sawflies: the effect of forest fertility

Predation by small mammals is thought to be one of the main regulators of outbreaking sawfly species. It has been suggested that predation may be lower in poor and dryish forests, and this is the reason why outbreaks often begin from this type of environment. We studied experimentally how fertility of the forest site affects cocoon predation experienced by two sawfly species, the common pine sawfly Diprion pini (Linnaeus) and the European pine sawfly Neodiprion sertifer (Geoffroy). We applied a fertilization treatment to selected pine-dominated barren forest sites in Finland, and 2–4 years later monitored predation on the sawfly cocoons in fertilized and control areas. The results did not support the idea that forest fertility was related to cocoon predation. We also could not verify that small mammal abundance was related to fertility of the forest. The most obvious pattern we observed was that the two sawfly species differed dramatically in predation experienced. N. sertifer has its cocoon phase in mid-summer and experienced only moderate predation (37%) whereas D. pini, with its cocoon phase in autumn, suffered from very heavy predation (96%). Our observations suggest that if predation is important in controlling the population dynamics of the species, its impact depends more on the sawfly species and season than on the fertility of the forest site. Received: 1 March 1998 / Accepted: 25 May 1998     

Genetic diversity of six populations of Atractomorpha sinensis and Atractomorpha peregrina in Shanxi Province, China

Ten enzymes (AAT, CK, G3PDH, HEX, IDH, LDH, MDH, ME, PGI, PGM) were examined using horizontal starch gel electrophoresis to estimate the levels of genetic variation within and among six natural populations of two grasshopper species Atractomorpha sinensis and A. peregrina from Shanxi, China. The collecting sites were geographically distant from each other from south to north: Quwo district, Linfen city; Xiangyuan county, Changzhi; Jinyuan district, Taiyuan city; Yuanping county, Xinzhou city and Fanshi county of Xinzhou.A. sinensis showed 43 alleles at 16 loci but A. peregrine showed 39 alleles at 15 loci (Idh-1 was deficient). The zymograms showed that some common alleles were shared at several loci in these two species (Aat-1-b, Aat-2-b, G3pdh-a, Ck-1-b and Ldh-b). However, Hex-1-a, Hex-2-a, Hex-3-a, Idh-2-b, Mdh-2-b, Mdh-1-f, Pgi-b, Pgm-b had common alles in A. sinensis and Hex-1-b, Hex-2-b, Hex-3-b, Idh-2-a, Mdh-2-a, Mdh-1-d, Pgi-a, Pgm-c were of high frequency in A. peregrine instead. Most of the observed genotype frequencies were found to significantly deviate from the Hardy-Weinberg expectations in both species. A tendency of clinal distribution of allele frequency was observed at three loci. The frequency of the moderately migrating allele Me-c (0.318–0.740) in A. peregrina, Hex-1-a (0.800–1.000) and Ldh-b (0.487–0.750) in A. sinensis demonstrated increased frequency from north to south. Such tendency suggests that the allele frequency in these three loci may be correlated with the species’ geographic distributions. A. sinensis showed higher genetic diversity than A. peregrina as indicated by higher mean number of alleles per locus (A = 1.9–2.3 in A. sinensis and 1.7–2.2 in A. peregrina), percentage of polymorphic loci (56.3%–68.8% in A. sinensis and 43.8%–56.3% in A. peregrina), and the observed heterozygosities (H _o = 0.072–0.096 in A. sinensis and 0.70–0.107 in A. peregrina). The observed heterozygosities of the six populations were all noticeably lower than the Hardy-Weinberg expectations, mostly due to heterozygote deficiency in the populations of both species. The overall mean F _ST were small (F _ST = 0.045, P > 0.05 in A. sinensis populations and 0.087, P > 0.05 in A. peregrina populations). Nei’s genetic identity (I) estimates indicate low intraspecific (>0.95) but higher interspecific (0.377–0.447) genetic diversity. The cluster analysis based on modified Roger’s genetic distance (D) showed that the two species were divided into two branches. Both species are of limited dispersal capacity and a moderate geographical barrier might significantly restrict the gene exchange among populations, resulting in accumulation of local genetic differentiations. The A. sinensis populations used in this study were separated from each other by 155.2 to 271.4 km and the A. peregrina populations were separated from each other by 78.8 to 174.9 km with observable physical barriers. The allozyme data showed only minimal genetic differentiation at population level, most likely as a result of gene exchange. It is reasoned that natural factors and human agricultural activities might have facilitated migration and dispersal for the two species. __________ Translated from Acta Ecologica Sinica, 2005, 25(10): 2574–2481 [译自: 生态学报]     

油樟幼苗对马尾松林窗面积的光合响应特征

为了解马尾松人工林窗对伴生树种的影响,为马尾松人工纯林的团块状混交提供科学依据,研究了10 m×10 m(T1)、15 m×15 m(T2)、20 m×20 m(T3)、25 m×25 m(T4)、30 m×30 m(T5)、35 m×35 m(T6)和40 m×40 m(T7)马尾松人工林窗中油樟(Cinnamomum longepaniculatum)幼苗叶片形态和光合生理特征的变化,探讨马尾松林窗斑块对混生树种生长的影响。结果表明:1)林窗面积低于20 m×20 m时,油樟幼苗叶片最大净光合速率显著低于旷地对照;2)叶片比叶重随着林窗面积的增大显著升高;林窗内油樟幼苗叶氮含量在小林窗中(10 m×10 m)显著低于旷地对照,但在大林窗中(如20 m×20 m)显著高于对照;林窗内幼苗叶磷含量则与旷地无显著性差异;3)叶氮在光合组分中的总分配系数随着林窗面积的增加而增大,其中叶氮在羧化组分中的分配系数升高尤为明显,而捕光组分的分配系数在林窗面积10 m×10 m—20 m×20 m范围内随林窗面积的增加而显著降低。可见,当马尾松林窗面积低于20 m×20 m时,林窗环境会显著影响油樟幼苗的光合能力,油樟幼苗可以通过调节比叶面积、叶氮含量以及叶氮在光合组分中的分配等形态、生理适应特征来适应林窗环境的变化。     

Cortinarius badiolaevis, a new conifer-associated, darkening species in the subgenus Telamonia (Basidiomycota, Agaricales)

A new species, Cortinarius badiolaevis Niskanen, Liimat., Mahiques, Ballarà, Kyt?v. in subgenus Telamonia, is described based on morphological and molecular data. Typical for the species is a dark brown cap, pale flesh, indistinct universal veil, small amygdaloid to ellipsoid spores [7.0–8.5 × 4.5–5.0(−5.5) μm], and dark exsiccata. It occurs in mesic to dryish coniferous forests, and grows in calcareous soil presumably with Pinus and Picea. So far, it is only known from Spain and Sweden, and considered rare. Based on the phylogenetic analyses of the ITS regions, it does not belong to any of the known sections, nor does it have any very closely related sister species.     

Age-Dependent Changes in Ecosystem Carbon Fluxes in Managed Forests in Northern Wisconsin,USA

The age-dependent variability of ecosystem carbon (C) fluxes was assessed by measuring the net ecosystem exchange of C (NEE) in five managed forest stands in northern Wisconsin, USA. The study sites ranged in age from 3-year-old clearcut to mature stands (65 years). All stands, except the clearcut, accumulated C over the study period from May to October 2002. Seasonal NEE estimates were −655 ± 17.5 g C m^–2 in the mature hardwood (MHW), −648 ± 16.8 in the mature red pine (MRP), −195 ± 15.6 in the pine barrens (PB), +128 ± 17.1 in the young hardwood clearcut (YHW), and −313 ± 14.6 in the young red pine (YRP). The age-dependent differences were similar in the hardwood and conifer forests. Even though PB was not part of either the hardwood or conifer chronosequence, and had a different disturbance agent, it still fits the same general age relationship. Higher ecosystem respiration (ER) in the young than in the mature stands was the combined result of earlier soil warming in spring, and higher temperature and greater biological activity in summer, as indicated by temperature-normalized respiration rates. The fire-generated PB had lower ER than the harvest-generated YHW and YRP, where high ER was sustained partly on account of logging residue. During the main growing season, the equivalent of 31 (MHW), 48 (MRP), 68 (PB), 114 (YHW) and 71% (YRP) of daily gross ecosystem production (GEP) was released in ER during the same day. The lower ER:GEP ratio in the mature stands was driven by greater age-dependent changes in ER than GEP. The magnitude of the increase in ER:GEP ratio in spring and fall was interpreted as the extent of the decoupling of ER and GEP. Decoupling (sustained high ER despite decreasing GEP) was observed in YHW, PB and MHW, whereas in coniferous stands (MRP and YRP) the stable ER:GEP ratio suggested preferential use of new photosynthates in ER. The results indicate that a great part of the variation in landscape-level C fluxes can be accounted for by mean stand age and associated parameters, which highlights the need to consider this source of heterogeneity in regional C balance estimates.     

Distribution of Boros schneideri (Panzer, 1796) (Coleoptera, Boridae) in Lithuania

The distribution of the endangered species Boros schneideri was studied by checking the presence of larvae and adults under the bark of dead Pinus sylvestris trees in 13 pine forests in Lithuania. B. schneideri was found in 10 biggest pine forests, the area of which exceeded 20,000 ha. However, it was not detected in smaller isolated forests. In Kazlų Rūda, Šimonys, Pabradė and Rūdiškės forests this species was recorded for the first time. The part of localities in which B. schneideri was found and the percentage of trees with B. schneideri were significantly higher in the main parts of the biggest forests than in satellite or smaller forests. Both these parameters were significantly lower in forests located in the close vicinity of urban territories than in forests further from them. Consequently, the forest size and the distance of the forest from urban territories were found to be of critical importance for the survival and density of the B. schneideri population. These distribution regularities are important for the establishment of protected areas for this species conservation.     

Karyotype analysis and physical mapping of 45S rDNA in eight species of Sophora, Robinia , and Amorpha

The karyotype analysis and physical locations of 45S rDNA were carried out by means of fluorescence in situ hybridization in three species, and two forms of Sophora, two species of Robina, and one species of Amorpha. S. japonica L., S. japonica L. f. oligophylla Franch., S. japonica L. f. pendula Loud., and S. xanthantha C. Y. Ma. are all tetraploids with 2n = 28. There were four 45S rDNA sites in pericentromeric regions of two pairs of chromosomes in each of them. S. rubriflora Tsoong. is a triploid with 2n = 21, and three sites were located in each satellite of group 5 chromosomes. In R. pseudoacacia L. (2n = 2x = 22), we examined four intensive signals in telomeric regions of two pairs of satellite chromosomes. In R. hispida L. (2n = 2x = 30), there were four other signals in centromeric regions besides those like in R. pseudoacacia. Amorpha fruticosa L. has most chromosomes (2n = 40) among the eight materials, however, there were only six 45S rDNA loci and they laid in centromeric regions, and satellites of three pairs of chromosomes. 45S rDNA is a valuable chromosomal landmark in karyotype analysis. The distribution and genomic organization of rDNA in the three genera were also discussed. __________ Translated from Acta Botanica Yunnanica, 2005, 27(3): 261–268 [译自: 云南植物研究, 2005, 27(3): 261–268]