扎龙湿地芦苇恢复与生态补水分析

芦苇是珍稀水禽的栖息地，具有调节气候、涵养水源、降低风速等生态效应。文章介绍了扎龙湿地植被的类型、影响芦苇生长的主要因子。资料表明，严重缺水使芦苇退化，生物量显著降低，而水量过多又造成芦苇生长受限，只有适量的生态补水才能促进芦苇的生长。     

香叶树和杉木人工林生态功能的比较

通过对28年生香叶树和杉木人工林生物量和土壤肥力的测定,进行香叶树和杉木人工林培肥土壤和涵养水源功能的比较研究,结果表明:与杉木人工林相比,营造香叶树人工林后林地土壤水稳性团聚体含量增加,团聚体稳定性增强,土壤密度降低,总孔隙度增加,林地土壤结构状况、孔隙和水分状况得到不同程度的改善,表层土壤养分得到富集,香叶树具有比杉木林更好的培肥土壤功能;香叶树叶的最大持水率高于杉木叶,其林分地上部分持水量是杉木纯林的1.21倍,同时由于香叶树人工林土壤结构及孔隙状况的改善,林地的蓄水能力增强,使得香叶树人工林表现出比杉木林更好的涵养水源功能.     

蓖麻挥发物与创伤诱导挥发物组成成分分析

植物在正常的生理状态下,会产生并释放具有种属特征的挥发性物质,这些物质形成了植物气味特征的主体,调控着昆虫的多种行为,诸如寄主定向、产卵、逃避、取食、聚集等(杜家纬,2001).植物一旦受到植食性昆虫侵袭,会释放一些特殊的化合物,这些气味往往具有信号功能,可以招引天敌昆虫(董文霞等,2000;Souissi etal.,1998)或是作为植食性昆虫的趋避物(Faeth,1986;Leather et al.1987).试验表明:人为造成的机械损伤能全部或部分地模拟昆虫取食(Baldwin et al.,1983;Lyytik,1999).因此,研究植物挥发物及创伤诱导挥发物可为利用天然活性化合物防治害虫提供理论依据.     

Transesterified Chinese Spicehush (Lindera communis) seed oil as a biodiesel fuel

Studies were carried out on the transesterification of the Chinese Spicehush (Lindera communis) seed (LCS) oil with methanol for the production of biodiesel. The methyl esters of LCS oil were compared with soybean esters to determine biodiesel fuel performance and properties. The fatty acids content in the seed kernel oil (LKO) and coat oil (LCO) were quantified by gas chromatography and mass spectrometry method (GC-MS). LKO contains 95.1% saturated acids (capric, lauric, myristic and palmitic) and 2.3% unsaturated acids (oleic). LCO contains 24.6% saturated acids (palmitic and stearic) and 73.6% unsaturated acids (oleic, linoleic and palmitoleic). The kinematic viscosity, cold filter plugging point, cloud point, flash point and cetane index were determined. The methyl esters of LKO had a higher kinematic viscosity and a lower cold filter plugging point value, so it has better per- formance in cold weather. The biodiesel of LCS oil has fuel properties within the limits prescribed by American (ASTM D 6751-02) standards, except for a slightly lower flash point of LKO biodiesel than that prescribed by these standards (130°C). Thus, LKO and LCO biodiesel have great potential to be used on a large scale as fuel for diesel engines.     

Nematicidal activity of the leaf powder and extracts of Myrtus communis against the root‐knot nematode Meloidogyne javanica

Nematicidal activity of the leaf powder, leaf extracts and formulated leaf extracts of Myrtus communis, an evergreen shrub that is widely distributed in Israel and other Mediterranean countries, was evaluated using the root‐knot nematode Meloidogyne javanica in in vitro and pot experiments. Leaf powder added to sand at 0·1% (w/w) reduced the number of juveniles recovered from the sand by more than 50%. Reduction in galling index and number of nematode eggs on tomato roots was also observed by incorporating the leaf powder at 0·1–0·4% (w/w) in the soil in pot experiments. Leaf powder extracts with methanol or ethanol showed the highest nematicidal activity among all extracts tested. Emulsifiable concentrates of leaf‐paste extract at a concentration as low as 0·005% (a.i., w/w) reduced the number of juveniles recovered from treated sand and the gall index of cucumber seedlings. The extract paste at 26 g m^?2 was also effective in reducing the gall index of tomato plants in field‐plot experiments. The leaf powder at 0·2% and the formulated leaf‐paste extract at 0·02% were also nematicidal to Tylenchulus semipenetrans and Ditylenchus dipsaci, but not to Pratylenchus penetrans or Steinernema feltiae. At least three nematicidal compounds were found in the leaf extract upon fractionation by thin‐layer chromatography. The results suggest that the leaf powder and paste extract of M. communis are potential nematicides against root‐knot nematodes.     

蓖麻LPAAT基因序列的SNPs及与油脂的相关性

LPAAT对蓖麻储存油脂（triacylglycerols,TAG）的合成调控具有重要作用。为了研究蓖麻LPAAT的多态性,参考GenBank中编码蓖麻LPAAT的基因组序列设计引物,对来自32个不同地区蓖麻种质的LPAAT进行测序,获得长约804bp的基因组序列。多态分析表明：在804bp的区间内共发现2个SNP和3个InDel,SNP频率为1／161bp,多样性指数Pi为0．00067。在外显予区域,有1个SNP和2个InDel,其中2个为同义突变,1个为错意突变。结果表明,基因删丁的exon10与种子油脂含量有明显相关性。     

Activity of Ricinus communis (Euphorbiaceae) and ricinine against the leaf-cutting ant Atta sexdens rubropilosa (Hymenoptera: Formicidae) and the symbiotic fungus Leucoagaricus gongylophorus

The focus of this study was the identification of compounds from plant extracts for use in crop protection. This paper reports on the toxic activity of fractions of leaf extracts of Ricinus communis L (Euphorbiaceae) and isolated active compounds in the leaf-cutting ant Atta sexdens rubropilosa Forel and its symbiotic fungus Leucoagaricus gongylophorus (Singer) M?ller. The main compounds responsible for activity against the fungus and ant in leaf extracts of R communis were found to be fatty acids for the former and ricinine for the ants.     

Partial characterization and insecticidal properties of Ricinus communis L foliage flavonoids

Aqueous leaf extract of Ricinus communis L (Euphorbiaceae), a cultivated plant in tropical countries, showed excellent insecticidal activity against Callosobruchus chinensis L (Coleoptera: Bruchidae). We have isolated and tested flavonoids as insecticidal and antimicrobial agents. The isolated flavonoids showed potential insecticidal, ovicidal and oviposition deterrent activities against C chinensis L. However, antimicrobial activity against the common microbial infestants of stored pulses, of which C chinensis is a major pest, was found to be insignificant. Two bands having Rf 0.63 and 0.69 were seen on HPTLC plates using mobile phase benzene + ethyl acetate + methanol + formic acid (12 + 4.5 + 2 + 1.5 by volume) as eluant. The Rf values and scanning of the spectrum in the ultraviolet region, showed identity with the flavonoids quercetin and kaempferol. This was further confirmed using HPLC and IR and UV spectrometry. HPLC and HPTLC chromatograms also suggested quercetin to be the major flavonoid present in the hydrolyzed aqueous leaf extract of R communis.     

薄壳优质扁桃新品种‘浓美’

 ‘浓美’系由美国引入的扁桃品种中经品比试验和多点区试后选育出来的新品种。该品种种子整齐一致，壳薄，出仁率高，商品性状优良，早期丰产，成熟早，适合在我国西北、华北的干旱少雨和年平均温度1 I~C以上地区栽植发展。     

不同生态条件下芦苇无性系种群调节分析

芦苇是典型的无性系植物,天然种群主要依靠营养繁殖补充更新。在松嫩平原,芦苇的主蘖仅在去顶干扰时才能产生侧生蘖,芦苇根茎存活时间最多为６年,根茎从第５年开始大量死亡,至最高６龄级仅占甚小比重,根茎干物质贮存的可塑性对变境的反应比根茎的生长更为有敏感,不同生态条件下,１龄级根茎均为休眠芽,２龄级根茎的活动芽均最多,并且随着龄级的增加呈依次减少趋势,６龄级根茎的休眠芽一般均丧失了萌发力,芦苇种群的１龄级