Nitrogen fixing activity in warty lenticellate tree barks

Detached lenticellate warty bark of Inga laurina was first shown to develop acetylene reducing activity (ARA) (18 nmol C₂H₂red·g^-1 (F.W.)·hr^-1) after a few days' incubation with ambient air containing 0.10 atm C₂H₂. Similar N₂ase development was found to occur with warty barks of many other plant species including 12 leguminous and 9 non-leguminous trees growing in wet tropical and temperate forests. Among them higher activities (>7 nmol C₂H₂ red·g^-1 (F.W.)·hr^-1) were recorded in Inga laurina, Cynometra ramiflora, Cassia siamea, Robinia pseudo-acacia, Albizia julibrissin in the leguminous plants, and Ilex crenata, Ilex pedunculosa, Rhizophora mucronata, Bruguiera gymnorrhiza and Mallotus japonicus in the non-leguminous plants. The development of ARA was often accelerated under lower pO₂ (0.05 atm) and pC₂H₂ (0.05 atm). Complete replacement of O₂ with N₂ or Ar in the incubation atmosphere resulted in full suppression of the development of N₂ase activity.

When ARA measurement was made with intact barks of natural stands (Robinia pseudo-acacia, Ilex pedunculosa and Mallotus japonicus), it was found that all of these intact barks were reducing C₂H₂ linearly without any time lag. The activities recorded were 4.6–11.5 nmol C₂H₂ red·g^-1 (F.W.)·hr^-1 corresponding to 1.19–1.27 nmol C₂H₂ red·cm^-2hr^-1. These values roughly coincided with ARA of detached warty barks of the same plant species. The present results suggest that in situ N₂-fixation in tree barks of the forests would amount to several 10 kg·ha^-1·year^-1 in temperate and tropical wet forests     

长沙地区樟树林土壤水稳定同位素的变化及影响因素

为揭示季风区土壤水稳定同位素的变化规律,基于长沙地区樟树林0~130 cm土壤水、降水和地下水稳定同位素以及环境因子连续2年的监测数据,分析了土壤水稳定同位素的变化特征。结果表明：0~60 cm土壤水稳定同位素的季节变化明显,与降水稳定同位素存在不同程度的时滞,60 cm以下土壤水和地下水稳定同位素的季节变化均不明显。不同深度土壤水中氢稳定同位素比率（δ²H）与区域大气水线（Local meteoric water line, LMWL）的差值（Line-conditioned excess, lc）均与δ²H呈显著正相关,即土壤水中δ²H越大时,δ²H偏离 LMWL的程度越小,土壤水经历的蒸发作用越弱;土壤水中δ²H越小时,δ²H偏离LMWL的程度越大,土壤水经历的蒸发作用越强。相关分析表明,前期大气的累积蒸发（∑E）和累积温度（∑TA）对0~60 cm土壤水中 lc的影响显著。研究显示,各土壤层中相对较低的水稳定同位素比率多散布于∑E和∑TA较大的暖季,由于期间经历的蒸发富集作用更强,土壤水中lc更小,土壤水稳定同位素散点更偏离LMWL;反之亦然,从而表现出不同深度土壤水线（Soil water line, SWL）的斜率较LMWL的斜率明显偏高。综上,大气降水稳定同位素是影响土壤水稳定同位素变化的直接因素;土壤水中稳定同位素的丰度与前期大气的湿热程度有关;SWL斜率较LMWL斜率偏高的原因与降水稳定同位素及土壤水稳定同位素蒸发富集作用强度的反向季节性变化有关。     

厚朴扦插繁殖技术的初步研究

影响厚朴扦插成活率的主导因子是插穗本身，插床基质也有影响，本试验所使用的促进剂、覆盖物对扦插成活率无明显作用。     

Geographical variation in spawning histories of age-1 Pacific saury Cololabis saira in the North Pacific Ocean during June and July

Fisheries Science - We examine geographical differences in percentages of age-1 Pacific saury Cololabis saira with previous spawning experience collected from 143°E to 165°W during June...     

Correction to: Geographical variation in spawning histories of age-1 Pacific saury Cololabis saira in the North Pacific Ocean during June and July

Fisheries Science - The article "Geographical variation in spawning histories of age 1 Pacific saury Cololabis saira in the North Pacific Ocean during June and July", written by Satoshi...     

Freshwater migration and feeding habits of juvenile temperate seabass <Emphasis Type="Italic">Lateolabrax japonicus</Emphasis> in the stratified Yura River estuary,the Sea of Japan

Juvenile temperate seabass Lateolabrax japonicus were sampled along the Yura River estuary from April to July 2008 to determine their distribution and feeding habits during migration within a microtidal estuary. Throughout the sampling period, juvenile seabass were distributed not only in the surf zone, but also in the freshwater zone, and they were particularly abundant in areas with aquatic vegetation in the freshwater zone. This distribution pattern suggests that the early life history of the temperate seabass depends more intensively on the river (freshwater) than previously considered. Small juveniles in the freshwater zone fed on copepods and chironomid larvae and upon reaching a standard length (SL) of approximately 20 mm did they fed on mysids. In contrast, juveniles (approx. 17–80 mm SL) in the surf zone fed mainly on mysids.     

杉木不同优树材性的比较研究

通过对浙江省临安县和龙泉市各１５株杉木子代优树材性测试和综合评定，认为临７５，临５，龙７，龙２５和龙２６号是优良的工程用材优树，龙２３，龙２５，龙２８和临７８号是优良的制浆造纸有材优树。其中龙２５号是两者兼优的优树，临７８和龙２６号是两者较好的优树。     

Partial migration of juvenile temperate seabass <Emphasis Type="Italic">Lateolabrax japonicus</Emphasis>: a versatile survival strategy

Partial migration describes intrapopulation variation in the migratory behavior, i.e. some individuals from a population migrate to low-salinity river areas, while others remain in coastal areas. This paper reviews the partial migration pattern of juvenile temperate seabass Lateolabrax japonicus, which is a migration pattern not commonly seen in Japan. Seabass spawn offshore, and eggs and larvae are transported to coastal areas. Some of these juveniles then ascend rivers, while others remain in coastal areas. Juveniles efficiently use physical structures in their habitat; they use tidal currents to ascend rivers in macrotidal estuaries, while they use the salt wedge in microtidal estuaries. Once juveniles ascend the river, they can feed on the abundant prey and attain more rapid growth than those remaining in coastal areas. As estuaries are highly productive areas, they play significant roles as nurseries for juveniles of various fishes. However, compared with coastal areas, the relative area of estuaries is considerably smaller and its environmental conditions are more variable. For example, nearly 40% of adult seabass in Tango Bay were estimated to use estuarine areas as a nursery, while the other 60% use coastal areas during their juvenile stage. Using both estuaries and coastal areas through partial migration during the juvenile stage is concluded to contribute to the stabilization and yield of seabass populations.     

离子液体提取山楂绿原酸的工艺优化

绿原酸是许多植物中的活性成分,因其有显著的药理活性和生物活性而被广泛关注,选择合适的提取溶剂、提取方法和工艺参数是绿原酸得以进一步应用的重要环节。该文以离子液体为溶剂,采用超声辅助方法提取山楂中的绿原酸,首先选择离子液体种类,再通过单因素试验确定离子液体浓度、提取时间和固液比3个主要因素的参数,并用响应面法分析法优化提取工艺参数。结果表明,优化工艺为以离子液体1-乙基咪唑盐酸盐[EIm]Cl的水溶液为提取溶剂,当其浓度为1.19 mol/L,固液比为1∶19.67 g/mL,每次提取时间为42.83 min时,理论的绿原酸提取率为4 179.48μg/g,获得工艺参数的回归模型。验证试验绿原酸提取率为4 128.28μg/g,与模型符合很好。另外,因离子液体的价格昂贵、难降解和不可预知的毒性,进行了离子液体和目标物质的分离操作,在酸性条件下,以乙酸乙酯为反萃取剂萃取出绿原酸,其得率为提取液中质量分数的96.3%;离子液体通过减压蒸馏、在65℃烘干后循环使用,提取率达到第1次的92.96%。此外,试验考察了离子液体与普通溶剂比较,在提取率上和循环使用上具有明显优势,是一种高效、绿色萃取溶剂。