The concept of habitat specificity revisited

Habitat specificity indices reflect richness (α) and/or distinctiveness (β) components of diversity. The latter may be defined by α and γ (landscape) diversity in two alternative ways: multiplicatively () and additively (). We demonstrate that the original habitat specificity concept of Wagner and Edwards (Landscape Ecol 16:121–131, 2001) consists of three independent components: core habitat specificity (uniqueness of the species composition), patch area and patch species richness. We describe habitat specificity as a family of indices that may include either area or richness components, or none or both, and open for use of different types of mean in calculation of core habitat specificity. Core habitat specificity is a beta diversity measure: the effective number of completely distinct communities in the landscape. Habitat specificity weighted by species number is a gamma diversity measure: the effective number of species that a patch contributes to landscape richness. We compared 12 habitat specificity indices by theoretical reasoning and by use of field data (vascular plant species in SE Norwegian agricultural landscapes). Habitat specificity indices are strongly influenced by weights for patch area and patch species richness, and the relative contribution of rare vs. common species (type of mean). The relevance of properties emphasized by each habitat specificity index for evaluation of patches in a biodiversity context is discussed. Core habitat specificity is emphasized as an ecologically interpretable measure that specifically addresses patch uniqueness while habitat specificity weighted by species number combines species richness and species composition in ways relevant for conservation biological assessment. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

广西唇柱苣苔属植物及其园林应用

介绍了广西唇柱苣苔属植物资源的基本特点、观花性状和园林应用,同时对广西唇柱苣苔属植物的保护和开发利用提出了建议.其中,广西唇柱苣苔属植物的6个基本特点是:①唇柱苣苔属观赏植物资源丰富;②观花性状显著;③特有现象突出;④抗逆性特点强;⑤同一种类不同居群其形态变化很大;⑥分布不均性.     

热带观赏水草日本荷根的组织培养

以日本荷根的根状茎为外植体,对日本荷根组织培养技术进行简要报道.     

长春南湖广场植物生态和生态经济效益的研究

城市广场作为城市绿地系统的一部分发挥着重要的生态作用。通过对长春市南湖广场的实地调查得出结论：园林植物折算为森林的面积为1．51hm^2;乔木的总叶面积为160442．8m^2,花灌木的总叶面积为15069．21m^2,草坪的面积为10000m^2。长春市南湖广场园林植物生态效益为：南湖广场园林植物每年可放出氧气72．43t,吸收CO2 99．59t,吸滞灰尘54．54t,吸收SO2 0．36t。运用环境效益评价法估算出南湖广场园林植物年吸收CO2经济效益值为12万元,年释放O2经济效益值为2．89万元,总经济价值达14．89万元。     

Growth rates and survival of western rock lobster (Panulirus cygnus) at two temperatures (ambient and 23 °C) and two feeding frequencies

Wild caught post-pueruli, year one and year two post settlement juvenile western rock lobster, Panulirus cygnus, were held at ambient temperatures (15.6 °C to 23.1 °C; mean 19.0 ± 0.07 °C) or at 23 °C, and fed the same ration of a formulated pellet diet either once per night, or 3 times per night, over 12 months, to determine whether elevated temperatures and multiple feeds per night would stimulate growth through increased metabolism and feed utilisation without significant negative impacts on survival. Survival of post-pueruli (mean 63%) did not differ between ambient and 23 °C. Survival of year 1 and 2 juveniles was higher at ambient temperatures (p < 0.01 ambient: year 1 juveniles, 68%; year 2 juveniles, 88%; 23 °C: 57% and 74%, respectively). Feeding frequency did not affect survival of post-pueruli and year 2 juveniles (mean 63%, 81% respectively), but survival was 9% higher for year 1 juveniles fed three times per night (58% versus 67%; p < 0.01). All lobsters grew faster at 23 °C than at ambient temperatures (p < 0.05), with the growth of post-pueruli almost doubled at 23 °C (weight gain at 23 °C versus ambient: post-pueruli, 18 438 % versus 9 915 %; year 1 juveniles 259% versus 165%; year 2 juveniles 23% versus 21%). Feed frequency did not influence the growth of year 1 and 2 juveniles. However, there was an interaction effect of temperature and feed frequency on post-pueruli where weight and carapace length were significantly higher at ambient temperatures when post-pueruli were fed three times a day, whereas at 23 °C weight and carapace length were significantly greater when fed once per day (p < 0.05). Feed intake (g pellet dry matter lobster^− 1 day^− 1) of pellet was higher at 23 °C for all lobsters (p < 0.05), but was the same between lobsters fed 3 times per night versus once per night. This study has shown that increasing temperatures to 23 °C significantly improved the growth of P. cygnus post-pueruli without any adverse effects on survival. The faster growth rates exhibited by year 1 and 2 juveniles at 23 °C may potentially offset their lower survival by significantly reducing culture period. There is no benefit of feeding P. cygnus multiple times at night in terms of growth and survival. The implications for P. cygnus culture are that temperatures should be maintained close to 23 °C during the entire growout period, with due care taken to minimise mortalities through adequate provision of food and shelter. Feeding P. cygnus once daily to excess just prior to dusk to co-incide with nocturnal feeding behaviour is recommended.     

大白菜种株碳同化分配及其对种荚发育的作用

用　14 C示踪方法研究大白菜种株不同生育时期同化产物分配及其对种荚形成的作用 ,结果表明 :叶片是主要同化器官 ;生育前期同化产物主要向茎枝和根系分配 ;后期主要向角果输送 ;种株开花前同化产物可通过再次分配进入角果 ,开花后同化产物对种子形成贡献更大。种株不同生育时期同化产物对角果皮和籽粒发育的作用存在差异     

柑桔体细胞融合再生9个组合的二倍体叶肉亲本类型植株

电场诱导９个柑桔种间及体内体细胞融合,各组合均再生叶肉原生质体亲本类型植株。这些植株经形态学和细胞学检查证明为二倍体（２ｎ＝２ｘ＝１８）。对其中５个组合进行ＲＡＰＤ分析表明,４个组合植株的谱带在所分析的引物上均表现为与叶肉细胞亲本谱带一致,另１个组合,即Ｐａｇｅ柑柚＋粗柠檬,个别植株除含有叶肉亲本的所有谱带外,还扩增出了悬浮系亲本的部分特征带,为杂种类型。探讨了这类植株的产生原因及潜在价值。     

寄主诱导的基因沉默提高植物真菌病害抗性研究进展

寄主诱导的基因沉默(host-induced gene silencing,HIGS)以病原菌生长发育、产孢繁殖、侵染或致病过程中的关键基因作为靶点,在寄主植物中表达针对靶基因的RNAi构建体,在病原菌侵染植物的过程中,摄入相应的ds RNA或si RNA分子,通过识别、结合特异核苷酸序列,干扰病菌靶基因表达,从而抑制病菌侵染和扩展,使植物表现抗病。这项技术为培育基于病原菌特异序列的植物抗病性奠定了基础,显示了巨大的应用潜力。本文综述了利用HIGS技术提高植物真菌病抗性的最新研究进展,总结了国内外利用这项技术改良植物真菌病害抗性的主要策略、技术路线,展望了发展应用前景。     

海南被子植物分布新资料(Ⅱ)

报道了海南岛被子植物5个新记录种。新记录种分别为三室黄麻(Corchorus trilocularis L.)、钻叶紫菀(Symphyotrichum subulatum(Michx.)G.L.Nesom)、光果姜(Zingiber nudicarpum D.Fang)、线纹香茶菜(Isodon lophanthoides(Buch.-Ham.ex D.Don)H.Hara)、狭序泡花树(Meliosma paupera Hand.-Mazz.)。凭证标本保存于中国热带农业科学院植物标本室(ATCH)。     

戴云山自然保护区种子植物传粉模式研究

以戴云山国家级自然保护区种子植物名录为研究对象,基于APWeb和文献资料统计种子植物科的传粉模式,研究了戴云山保护区种子植物的主要传粉模式及其传粉模式的祖先状态。结果表明:戴云山保护区种子植物中动物参与传粉有144科,占总科数87.27%;完全利用非生物模式传粉占总科数12.12%;单一传粉模式以动物传粉的科数最多(124科),其次为风媒传粉(14科),水媒传粉最少(4科)。混合传粉模式中,动物和风媒传粉的科数最多。动物传粉模式在戴云山保护区种子植物传粉中占据重要地位。戴云山保护区种子植物科中共有9个原始类群,单一动物传粉8科,动物和风媒混合传粉有1科,表明动物传粉在植物原始类群进化中占据主要地位,可能是现存戴云山被子植物传粉模式中的祖先状态。研究结果旨在为戴云山种子植物发育与演变提供理论依据。