The relationships between Apocrita wasp populations and flowering plants in Maine's wild lowbush blueberry agroecosystems

This was the first study to have surveyed the spatial and temporal structure of Apocrita wasps in lowbush blueberry fields, a unique native agricultural landscape in Maine and eastern Canada. The relative abundances of wasps associated with lowbush blueberry (Vaccinium angustifolium Ait.) were investigated in 33 blueberry fields throughout Washington County, Maine, USA. Native wasps were captured during the springs and summers of 1997 and 1998 in Malaise traps erected along a transect in each field. Vegetation sampling was also conducted along these transects to quantify available floral resources. Data indicate the abundance of the total wasp community was positively associated with the abundance of sheep laurel (Kalmia angustifolia L.). Relationships between trap capture of 13 wasp morphospecies and other flowering weeds were also investigated. Most taxa in 1998 were positively associated with one or more of the following flowering plants: bunchberry (Cornus canadensis L.), bush honeysuckle (Diervilla lonicera P. Mill.), dogbane (Apocynum androsaemifolium L.), sheep laurel, and witherod (Viburnum nudum var. cassinoides L.). Similar results were not evident in 1997 because the method used to sample vegetation was not as extensive as that used in 1998. However, sheep laurel was positively associated with the wasp genera Microplitis spp. and Phanerotoma spp. during both years.     

红豆越桔VviDREB1基因转化烟草的研究

通过构建pVB4215植物双元表达载体,采用农杆菌介导法转化烟草,研究VviDREB1在植物体中的异源表达特性.结果显示,实验获得了25个Hyg抗性株系,经过PCR、RT-PCR和GUS组织化学染色检测及Hyg基因的PCR复检等多点验证,证实表达载体边界内序列完整地整合到2个烟草株系的基因组中.转基因烟草株系在4℃低温处理20 h后,恢复生长5 h,叶片光系统PSⅡ抗寒性分析结果表明,转基因植株的叶片快速叶绿素荧光曲线OJIP各点数值高于对照植株,VviDREB1基因能够显著提高烟草的荧光产量,最大光化学效率Fv/Fm和以吸收光能为基础的性能指数PIABS较对照高,说明VviDREB1对保护植物组织细胞内光合系统PSⅡ有明显的作用,转VviDREB1基因烟草对低温有一定的忍耐能力.     

Inoculation of cranberry (Vaccinium macrocarpon) with the ericoid mycorrhizal fungus Rhizoscyphus ericae increases nitrate influx

Despite the ubiquitous presence of ericoid mycorrhizal (ERM) fungi in cranberry (Vaccinium macrocarpon), no prior studies have examined the effect of ERM colonization on NO(3)(-) influx kinetics. Here, (15)NO(3)(-) influx was measured in nonmycorrhizal and mycorrhizal cranberry in hydroponics. Mycorrhizal cranberry were inoculated with the ERM fungus Rhizoscyphus (syn. Hymenoscyphus) ericae. (15)NO(3)(-) influx by R. ericae in solution culture was also measured. Rhizoscyphus ericae NO(3)(-) influx kinetics were linear when mycelium was exposed for 24 h to 3.8 mm NH(4)(+), and saturable when pretreated with 3.8 mm NO(3)(-), 50 microm NO(3)(-), or 50 microm NH(4)(+). Both low-N pretreatments induced greater NO(3)(-) influx than either of the high-N pretreatments. Nonmycorrhizal cranberry exhibited linear NO(3)(-) influx kinetics. By contrast, mycorrhizal cranberry had saturable NO(3)(-) influx kinetics, with c. eightfold greater NO(3)(-) influx than nonmycorrhizal cranberry at NO(3)(-) concentrations from 20 microm to 2 mm. There was no influence of pretreatments on cranberry NO(3)(-) influx kinetics, regardless of mycorrhizal status. Inoculation with R. ericae increased the capacity of cranberry to utilize NO(3)(-)-N. This finding is significant both for understanding the potential nutrient niche breadth of cranberry and for management of cultivated cranberry when irrigation water sources contain nitrate.     

铵态氮与硝态氮比例对南方高丛蓝浆果丛生枝增殖及生长的影响

以MWPM为基本培养基,在总氮浓度不变的前提下比较了铵态氮(NH4+-N)与硝态氮(NO3--N)比例对南方高丛蓝浆果(Vaccinium corymbosum hybrids)品种‘南月’(‘Southmoon’)优选系A47、A119和A167丛生枝增殖和生长的影响.结果表明:与对照[n(NH4+-N)∶n( NO3--N)=4∶10]相比,当培养基中的n(NH4+ -N)∶n(NO3--N)调整为5∶10、6∶10、7∶10、8∶10、9∶10和10∶10时,总体上对优选系A47、A119和A167丛生枝的总增殖倍数、有效增殖倍数、鲜质量、干质量、含水量、总长度以及叶片叶绿素含量有一定的提高作用,具体表现则因优选系的基因型而异.调整培养基中n(NH4 +-N)∶n( NO3- -N)为7∶10,优选系A47丛生枝的总增殖倍数、有效增殖倍数、鲜质量、干质量和总长度均显著提高,叶片叶绿素含量也有所提高.调整培养基中n(NH4 +-N)∶n(NO3--N)为7∶10和9∶10,对优选系A119和A167丛生枝的生长有一定的促进作用,但总体增殖效果与对照无显著差异.研究结果显示:培养基中的铵态氮与硝态氮比例对南方高丛蓝浆果丛生枝的增殖及生长有一定的影响;在离体增殖时应针对不同品种或优选系采用适宜的NH4 +-N与NO3 - -N比例.     

高质量浓度IBA和插条木质化程度对兔眼蓝浆果扦插生根的影响

采用速蘸法研究了高质量浓度(3 000、5 000、7 000和9 000 mg.L-1)IBA对兔眼蓝浆果(Vaccinium asheiReade)品种‘粉蓝’(‘Powderblue’)、‘梯芙蓝’(‘Tifblue’)和‘芭尔德温’(‘Baldwin’)插条生根率和开始生根时间的影响,并对木质化程度不同的‘顶峰’(‘Climax’)和‘雾达德’(‘Woodard’)插条的生根率和开始生根时间进行了比较。结果表明:经3 000~9 000 mg.L-1IBA溶液速蘸3 s,3个品种插条的生根率均高于或显著高于对照(P<0.05),开始生根时间则较对照明显提前,但不同品种有明显差异;随IBA质量浓度的提高,‘粉蓝’和‘芭尔德温’的生根率逐渐增加,开始生根时间逐渐提早,以9 000 mg.L-1IBA处理组的生根率最高(分别为93.98%和86.46%),开始生根时间最早(分别为15和21 d);品种‘梯芙蓝’插条的生根率则以5 000 mg.L-1IBA处理组最高(88.02%),开始生根时间最早(18 d)。木质化程度不同的插条生根率有显著差异(P<0.05),木质化程度越低,插条的生根率越高且开始生根时间越早;采用木质化程度低的插条,品种‘顶峰’和‘雾达德’插条的生根率分别达到88.54%和77.60%,开始生根时间分别为25和29 d。研究结果显示:高浓度IBA速蘸法是兔眼蓝浆果扦插生根的有效方法,在实际生产中应根据不同品种的特性选择适宜的IBA浓度;从木质化程度及插条可取数量两方面考虑宜选用半木质化枝条作为插条。     

Is the degree of clonality of forest herbs dependent on gap age? Using fingerprinting approaches to assess optimum successional stages for montane forest herbs

Using molecular fingerprinting (amplified fragment length polymorphism [AFLP] method), we explored the potential of small-scale population analysis for understanding colonization patterns of herb layer species in forests after canopy disturbance. We investigated three common forest understorey species with different life forms (Trientalis europaea, Calamagrostis villosa, and Vaccinium myrtillus) in the Harz Mountains in Germany in three different gap age classes and undisturbed forest. For two of them (T. europaea and C. villosa), we analyzed clone sizes and clonal structure. We hypothesized that clone sizes depend on age since gap formation and are affected by light availability. Mean patch sizes of V. myrtillus, T. europaea, and C. villosa formed were 3.7 m(2), 27.9 m(2), and 40.6 m(2), respectively. Trientalis europaea and C. villosa patches consisted mostly of more than one genet. Largest clone sizes of T. europaea were encountered in gaps of intermediate successional age (15-60 years, averaged minimum estimation of clone sizes: 6.56 m(2)) whereas clone size of C. villosa was found to be independent from gap age and had a mean minimum clone size of 0.49 m(2). In both species, clone size was positively related to light availability. Additionally, there was a positive relationship between clone size and ramet density for T. europaea and C. villosa. Genetic variation was higher within populations of T. europaea and C. villosa than among populations. Trientalis europaea was the only species with a clear genetic isolation by distance, pointing at an equilibrium between gene flow and genetic drift. In conclusion, we showed that forest canopy gap dynamics clearly affect the small-scale structure of populations of understorey plants. Species with high lateral growth rates, such as T. europaea offer the possibility to serve as "ecological clock" for dating ecological processes.     

Settling behavior of the glassy‐winged sharpshooter,Homalodisca vitripennis,vector of Xylella fastidiosa,on southern highbush blueberry cultivars

The xylem‐limited bacterium Xylella fastidiosa Wells, Raju, Hung, Wiseberg, Mandelico‐Paul & Brenner causes bacterial leaf scorch, a new disease of southern highbush blueberry [Vaccinium corymbosum L. (Ericaceae) interspecific hybrids] in the southeastern USA. The bacterium is transmitted by sharpshooter leafhoppers (Hemiptera: Cicadellidae), with the glassy‐winged sharpshooter (GWSS), Homalodisca vitripennis (Germar), being the most common potential vector in blueberry plantings. Considerable differences are observed in disease intensity among blueberry cultivars in the field, but it remains unknown whether these differences are due to variations in cultivar susceptibility to the bacterium, differences in attractiveness to its vector(s), or both. The settling and feeding behavior of GWSS was evaluated on three southern highbush blueberry cultivars (FL 86‐19, Star, and Emerald) in the greenhouse; in previous field studies, these cultivars were found to be affected by bacterial leaf scorch at high, moderate, and low levels, respectively. Potted plants were caged together with field‐collected GWSS adults for a period of 5 days, with either all three cultivars caged simultaneously (choice test) or individually (no‐choice test). In the choice tests, no differences in cultivar attractiveness were observed during the first 2 days of study. However, from the 3rd day, significantly more adults settled on Emerald (52.7%) than on Star (25.5%) and FL 86‐19 (17.7%). In contrast, in no‐choice tests, the overall host plant acceptance for the three cultivars was similar, and 89.3–92.1% of adults settled on these plants. A significantly greater number of adults settled on the stems (79.3%) vs. the leaves (11.2%). Moreover, they preferred the middle portion of the shoot (56.9%) compared with the upper (7.8%) and the lower (14.7%) portions. In a separate study on FL 86‐19, greater numbers of GWSS nymphs settled on the upper (actively growing) portion of the shoot (82.3%), whereas only 15.8 and 1.5% settled on the middle and lower portions, respectively.     

“Berry Patch” As a Kind of Place—the Ethnoecology of Black Huckleberry in Northwestern Canada

The Gitksan and Wet’suwet’en of Northwestern British Columbia formerly used landscape burning to manage patches of black huckleberry (Vaccinium membranaceum), the most important plant resource of their seasonal round. In view of its significance one might postulate that managed sites would conform to a biophysical or ecological type to maximize return for effort. However, a survey of a number of traditionally managed sites indicated that managed sites are characterized by wide variation in biophysical attributes including elevation, aspect and moisture regime, while proximity to fishing sites, village sites, or sites for harvest of alpine resources proved to be a common factor in known historic berry patch sites. We conclude that characterization of the ideal site type for aboriginal V. membranaceum management must include the economy and social institutions of the local First Nations and requires an enhanced appreciation for the sophistication of the strategies and techniques employed in their management and utilization of the species.

樱桃李与蓝莓果的营养价值

本文论述了野樱桃李、蓝莓果的营养成分,比较它们的共同点和某些差异,对其营养价值作了简要评述,为开发利用野樱桃李植物资源提供参考资料.     

Effectiveness of honey bees in delivering the biocontrol agent Bacillus subtilis to blueberry flowers to suppress mummy berry disease

Honey bees are important pollinators of commercial blueberries in the southeastern United States, and blueberry producers often use supplemental bees to achieve adequate fruit set. However, honey bees also vector the plant pathogenic fungus Monilinia vaccinii-corymbosi which infects open blueberry flowers through the gynoecial pathway causing mummy berry disease. Here, we report the results of a 3-year field study to test the hypothesis that using bee hives equipped with dispensers containing the biocontrol product Serenade, a commercial formulation of the bacterium Bacillus subtilis which has shown activity against flower infection by M. vaccinii-corymbosi in laboratory experiments, can reduce mummy berry disease incidence when honey bees are used as pollinators in blueberries. Individual honey bees carried 5.1–6.4 × 10⁵ colony-forming units (CFU) of B. subtilis when exiting hive-mounted dispensers with Serenade. On caged rabbiteye blueberry bushes in the field, population densities of B. subtilis vectored by honey bees reached a carrying capacity of <10³ CFU per flower stigma within 2 days of exposure, and there was a highly significant non-linear relationship between B. subtilis populations per stigma and bee activity, expressed as number of legitimate flower visits per time interval per cage (R = 0.6928, P < 0.0001, n = 32). Honey bee density (1600 or 6400 individuals per 5.8-m³ cage) and Serenade treatment (presence or absence of the product in hive-mounted dispensers) significantly (P < 0.05) affected the incidence of fruit mummification on caged bushes, whereby increasing bee density increased disease incidence and application of Serenade reduced disease levels. Taken together, results of this study suggest that use of a hive-dispersed biocontrol product such as Serenade as a supplement during pollination can reduce the risk of mummy berry disease. This may be a prudent practice that optimizes the benefits to pollination of high bee densities while reducing the associated disease-vectoring risk.