A pilot project testing the effectiveness of three weed control methods on the removal of Lantana camara in Forty Mile Scrub National Park,Queensland, Australia

Lantana (Lantana camara) poses a serious threat to the biodiversity of the dry rainforest vegetation at Forty Mile Scrub National Park, Queensland, Australia, by outcompeting native species and increasing vulnerability to fire. This pilot study tests the effectiveness of three weed control methods (hand pulling, a glyphosphate‐based foliar spray herbicide and a picloram‐ and triclopyr‐based basal bark herbicide) in removing lantana and their success in reducing lantana fuel loads. The foliar spray herbicide was the most effective in killing lantana, while manual pulling resulted in the largest decrease in fuel height. We suggest that foliar spraying will be most efficient for combating large infestations of lantana, while hand pulling techniques are recommended for creating firebreaks or when minimizing damage to native species is paramount.     

果园转型生态公益林防控薇甘菊的生态改造

【背景】深圳大面积果园已转型为生态公益林,但果树被入侵的薇甘菊攀爬覆盖,严重地段已导致群落退行性演替,问题亟待解决。【方法】选取有多种生境的转型果园,分片区开展以植树为核心的生态改造试验,树种以种植后不进行人工除草抚育的血桐、幌伞枫、阴香为主,辅以提高物种多样性为目标的演替中后期树种,均采用袋装大苗于2011年5月种植。【结果】在树冠连续、郁闭的果林片区,所植苗木死亡,林下草本稀少,始终无薇甘菊。在其他非郁闭片区,血桐与幌伞枫生长良好且从未被覆盖;阴香虽于秋冬季被全覆盖但不死亡,次年春新枝穿透覆盖层正常生长;其余种苗木对薇甘菊处于劣势。【结论与意义】郁闭度高的果林片区林下光照弱,能阻止薇甘菊定居,无需人工干预;血桐和幌伞枫分别具抗/耐受薇甘菊覆盖的特性,种后均无需抚育;其余树种则需抚育。因此,掌握各个树种的特性,适地种植、按需精准定株抚育是转型果园低成本、技术简单、一劳永逸地防控薇甘菊生态改造的精髓。在应对有害藤本危害时,勿忽略筛选出不惧该藤本的植物种的可能,在不使用农药、无有效动物或微生物天敌的情况下,它们有可能成为生态安全的防控改造树种。     

Identification of Vitis vinifera (-)-alpha-terpineol synthase by in silico screening of full-length cDNA ESTs and functional characterization of recombinant terpene synthase

The flavour and aroma of certain Vitis vinifera grape varieties is dominated by volatile terpenes and small volatile aldehydes. Monoterpenes contribute to the final grape and wine aroma and flavour in form of free volatiles and as glycoside conjugates of monoterpene alcohols. Typical monoterpenol components of the cultivar Gewürztraminer and other aroma-rich grape varieties are linalool, geraniol, nerol, citronellol, and alpha-terpineol. In a functional genomics effort to identify genes for the formation of monoterpene alcohols in V. vinifera, a database of full-length cDNA sequences was screened in silico and yielded two clones for putative monoterpene synthases. The gene products were functionally characterized by expression in Escherichia coli, in vitro enzyme assay and gas chromatography-mass spectrometry (GC-MS) product identification as multi-product (-)-alpha-terpineol synthases.     

Genetic variation in Pueraria lobata (Fabaceae), an introduced, clonal, invasive plant of the southeastern United States

Pueraria lobata (kudzu), a clonal, leguminous vine, is invading the southeastern United States at a rate of 50 000 ha per year. Genetic variability and clonal diversity were measured in 20 southeastern U.S. populations using 14 allozyme loci. Within its U.S. range, 92.9% of the loci were polymorphic and overall genetic diversity was 0.290. Such high levels of genetic diversity are consistent with its history of multiple introductions over an extended period of time. The average proportions of polymorphic loci and genetic diversity within populations were 55.7% (range = 28.6–85.7%) and 0.213 (range = 0.114–0.317), respectively. The proportion of total genetic diversity found among populations was similar to species with equivalent life history characters (G_ST = 0.199). No regional patterns of variation were seen. The number of putative genotypes in each population ranged from 2 to 26. Mean genotypic diversity was 0.694, ranging from 0.223 to 0.955. Such high levels of genotypic diversity indicate that local sites are often colonized by several propagules (most likely seeds) and/or that sexual reproduction occurs within populations after establishment. An excess of heterozygosity was observed in populations with few unique genets, implying that selection for highly heterozygous individuals may occur in populations of P. lobata.     

Impact of the black rhinoceros (Diceros bicornis minor) on a local population of Euphorbia bothae in the Great Fish River Reserve,South Africa

In the Great Fish River Reserve, South Africa, black rhinoceros (Diceros bicornis minor) feed extensively on a local population of Euphorbia bothae. Maintaining the endangered black rhinoceros and the protected E. bothae population are both conservation priorities of the reserve. Therefore, the sustainability of this plant–animal interaction was investigated by comparing population characteristics, browsing incidence and intensity within the reserve and in an adjacent exclosure without access to rhino. Fixed‐point photographs showed that over a 2‐month period 36.6% of 213 monitored plants were browsed, with an average biomass loss of 13%, and 1% were destroyed. Of 26 plants re‐photographed after approximately 3 years, 70% showed a decrease in biomass, averaging 37.8% over this period. In this time span, 19% of the monitored plants died. Small plants (<45 cm) were over‐represented in the rhino‐browsed area, whereas the fraction of reproductively active plants and overall plant density were found to be lower than in the adjacent exclosure. No evidence of short‐term compensatory growth in response to browsing was found for E. bothae. This study indicates that, with the current population size, rhinos are overexploiting the E. bothae population and special measures should be taken to prevent local extinction.     

The entomopathogenic nematode Steinernema kraussei and Metarhizium anisopliae work synergistically in controlling overwintering larvae of the black vine weevil,Otiorhynchus sulcatus,in strawberry growbags

Previously, the combination of reduced rate of entomopathogenic nematodes (EPN) and fungus caused additive or synergistic mortality to third-instar black vine weevil (BVW), Otiorhynchus sulcatus. In this study, we examined this interaction in unheated glasshouses during winter and compared a combination of commercial formulation of a cold-tolerant EPN, S. kraussei (Nemasys L?) and fungus Metarhizium anisopliae strain V275 against overwintering third-instar BVW. The combination of M. anisopliae with S. kraussei at a rate of 1×10¹⁰ conidia+250,000 nematodes/growbag resulted in additive or synergistic effects, providing 100% control of overwintering larvae.     

广西园林藤本植物的筛选研究

该文报道了广西藤本植物资源概况与园林藤本植物筛选研究成果,简要介绍了广西藤本植物的种质资源及资源藤本植物利用现状,经过引种和调查选择,收集观赏藤本植物62种,通过配置应用试验和决选评价,决选出适合于城市园林建设的10个花卉品种,21个垂直绿化品种,3个地被植物品种。     

Variation of life‐history parameters of Planococcus ficus (Hemiptera: Pseudococcidae) in response to grapevine nitrogen fertilization

The effects of different nitrogen fertilization regimes on body size and selected life‐history parameters (development time, survival, fecundity and fertility) of the vine mealybug, Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae), were investigated on potted grapevines under laboratory and screenhouse conditions. In both trials, five groups of four grapevines each were supplied with 0, 0.25, 0.5, 1.0 or 2.0 g/l of ammonium nitrate fertilizer for a month and then artificially infested with 200 first‐instar vine mealybugs (24 h of age). The concentration of nitrogen on grape leaves was measured during both experiments by a SPAD chlorophyll metre, showing statistical differences among treatments. The nitrogen fertilization significantly affected the investigated P. ficus parameters, providing consistent results in both laboratory and screenhouse trials. The vine mealybug females exhibited higher survival and fecundity, larger body size and lower development time on plants supplied with higher nitrogen fertilization rates. Survival, body size and fecundity of P. ficus were positively correlated with the leaf nitrogen concentration, whereas the development time was negatively correlated. Fertility did not vary significantly among treatments. Our results show that high nitrogen regimes increase the reproductive performance of P. ficus on grapevines and point out the importance of implementing balanced fertilization plans in grapevine IPM programs to reduce population densities and prevent insect outbreaks.     

Comparative Population Dynamics of an Invading Species in its Native and Novel Ranges

Although the ecology of many exotic invaders has been intensively examined in the novel range, few studies have comparatively explored how population dynamics differ in native and novel parts of an invading plants’ range. The population dynamics of mile-a-minute weed, Polygonum perfoliatum L., was explored in both the native (Japan) and novel (northeastern USA) portions of its range and evaluated using periodic matrix models. Projected per capita population growth rate (λ) varied within and between native and novel range populations. Surprisingly, five of the six populations in the novel range were projected to fail to replace themselves (λ<1) while only two of the four native range populations were projected to decline, although these projections had wider confidence intervals than in the novel habitat. While changes in germination, survivorship, fecundity and seed banking would have equivalent effects on population growth in the invasive habitat, small increases in plant survivorship would greatly increase λ in native populations. The differences between native and novel population growth rates were driven by lower adult survival in the native range caused by annual flooding and higher fecundity. Simulation analyses indicated that a 50% reduction in plant survival would be required to control growing populations in the novel range. Further comparative studies of other invading species in both their native and novel ranges are needed to examine whether the high per capita population growth and strong regulatory effects of adult survival in the native habitat are generally predictive of invasive behavior in novel habitats. Sachiko Araki: (Deceased)