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991.
Diallel analysis of fumonisin accumulation in maize 总被引:1,自引:0,他引:1
Contamination of maize (Zea mays L.) grain with aflatoxin, produced by the fungus Aspergillus flavus Link: Fries, or fumonisin, produced by the fungus Fusarium verticillioides (Saccardo) Nirenberg (Syn F. moniliforme Sheldon), greatly reduces its value and marketability. Host resistance to fungal infection and mycotoxin accumulation is considered a highly desirable way to reduce losses of both aflatoxin and fumonisin. Maize germplasm lines with resistance to aflatoxin accumulation have been developed in Mississippi. Three of the aflatoxin-resistant lines and five additional lines were used as parents to produce a diallel cross. The diallel cross was evaluated for fumonisin accumulation in field tests conducted in Mississippi in 2007 and 2008. General combining ability (GCA) was a highly significant source of variation in both 2007 and 2008, but specific combining ability (SCA) was not significant. GCA effects for reduced fumonisin levels were highly significant for Mp715, Mp717, and GA209. Mp715 and Mp717 were developed and released as sources of resistance to aflatoxin contamination and exhibit resistance as inbred lines and in hybrid combinations. These lines should be useful in developing maize lines and hybrids with resistance to both fumonisin and aflatoxin accumulation in grain. 相似文献
992.
J. Ehrenbergerová N. Březinová Belcredi J. Kopáček L. Melišová P. Hrstková S. Macuchová K. Vaculová I. Paulíčková 《Plant foods for human nutrition (Dordrecht, Netherlands)》2009,64(2):122-128
Green biomass of young barley plants exhibited statistically significant higher activity of superoxide dismutase (SOD) and
catalase (CAT) at sampling I (in the phase of plant development DC 29) compared to the later sampling II (DC 31). Significant
effects of varieties, years and interactions of the studied factors on the activity of the studied antioxidants were determined.
During the experiment period (2005–2007), the variety Sebastian provided statistically significant higher average SOD activity (486 U.g-1) versus the variety Malz (416 U.g-1 dry matter) and line KM1910 (418 U.g-1 dry matter). No statistically significant difference was recorded between the latter two varieties. Average catalase
activity of the varieties did not show any significant difference. Significantly higher CAT activity in the sampling I was
recorded on average of years and locations in the variety Sebastian and hull-less line KM1910 (935 and 907 U.g-1) compared to the variety Malz (675 U.g-1). We can state that green biomass of young spring barley plants
taken during the growth phase DC 29 was a significant source of enzymes catalase and superoxide dismutase in the course of
the experiment (2005–2007). 相似文献
993.
Investigation of an extract from the marine cyanobacterium Lyngbya semiplena, collected in Tumon Bay, Guam, led to the identification of three new cyclodepsipeptides, lyngbyastatins 8–10 (1–3). The structures of 1–3 were determined by NMR, MS, ESIMS fragmentation and chemical degradation. Compounds 1–3 are closely related to lyngbyastatins 4–7. Like the latter compounds, we found 1–3 to inhibit porcine pancreatic elastase, with IC50 values of 123 nM, 210 nM and 120 nM, respectively. 相似文献
994.
995.
David Pink Liz Bailey Sandy McClement Paul Hand Evy Mathas Vicky Buchanan-Wollaston Dave Astley Graham King Graham Teakle 《Euphytica》2008,164(2):509-514
Double haploid (DH) plants of Brassica spp. can be produced via anther culture or culture of microspores. This paper reviews the uses of double haploids in crop
improvement research in vegetable brassicas (B. oleracea). Applications of DH lines are described for breeding; construction of linkage maps; genetic analysis of quantitative traits
and capturing genetic variation. The advantages and disadvantages of DH lines are discussed 相似文献
996.
997.
998.
A preliminary study of an alternative controlled drainage strategy in surface drainage ditches: Low-grade weirs 总被引:3,自引:0,他引:3
This study examined hydrological characteristics of low-grade weirs, an alternative controlled drainage strategy in surface drainage ditches. Chemographs of vegetated and clear scraped (control) replicates of weir vs. non-weir treatments were compared to determine differences in time to peak (Tp) and time to base (Tb). Drainage ditches Tp and Tb were affected by both vegetation and weir presence. The order of treatment efficiency for Tp was observed to be: non-vegetated non-weir < vegetated non-weir < non-vegetated weir < vegetated weir. Furthermore, Tb for each ditch was the reverse relationship from Tp where vegetated weir > non-vegetated weir > vegetated non-weir > non-vegetated non-weir. Low-grade weirs increase chemical retention time (vegetated and clear scraped), the average time a molecule of contaminant remains in the system. Future research in water quality improvement and weir management will yield useful information for non-point source pollutant reduction. 相似文献
999.
Water use and carbon exchange of a red oak-dominated (Quercus rubra L.) forest and an eastern hemlock-dominated (Tsuga canadensis L.) forest, each located within the Harvard Forest in north-central Massachusetts, were measured for 2 years by the eddy flux method. Water use by the red oak forest reached 4 mm day(-1), compared to a maximum of 2 mm day(-1) by the eastern hemlock forest. Maximal carbon (C) uptake rate was also higher in the red oak forest than in the eastern hemlock forest (about 25 versus 15 micromol m(-2) s(-1)). Sap flux measurements indicated that transpiration of red oak, and also of black birch (Betula lenta L.), which frequently replaces eastern hemlock killed by hemlock woolly adelgid (Adelges tsugae Annand.), were almost twice that of eastern hemlock. Despite the difference between species in maximum summertime C assimilation rate, annual C storage of the eastern hemlock forest almost equaled that of the red oak forest because of net C uptake by eastern hemlock during unusually warm fall and spring weather, and a near-zero C balance during the winter. Thus, the effect on C storage of replacing eastern hemlock forest with a forest dominated by deciduous species is unclear. Carbon storage by eastern hemlock forests during fall, winter and spring is likely to increase in the event of climate warming, although this may be offset by C loss during hotter summers. Our results indicate that, although forest water use will decrease immediately following eastern hemlock mortality due to the hemlock woolly adelgid, the replacement of eastern hemlock by deciduous species such as red oak will likely increase summertime water use over current rates in areas where hemlock is a major forest species. 相似文献
1000.
In western North America, quaking aspen (Populus tremuloides) is the most common hardwood in montane landscapes. Fire suppression, grazing and wildlife management practices, and climate patterns of the past century are all potential threats to aspen coverage in this region. If aspen-dependent species are losing habitat, this raises concerns about their long-term viability. Though lichens have a rich history as air pollution indicators, we believe that they may also be useful as a metric of community diversity associated with habitat change. We established 47 plots in the Bear River Range of northern Utah and southern Idaho to evaluate the effects of forest succession on epiphytic macrolichen communities. Plots were located in a narrow elevational belt (2134–2438 m) to minimize the known covariant effects of elevation and moisture on lichen communities. Results show increasing total lichen diversity and a decrease in aspen-dependent species as aspen forests succeed to conifer cover types. The interactive roles of stand aspect, basal area and cover of dominant trees, stand age, aspen bark scars, and recent tree damage were examined as related to these trends. We developed an aspen index score based on lichens showing an affinity for aspen habitat (Phaeophyscia nigricans, Physcia tenella, Xanthomendoza fulva, Xanthomendoza galericulata) and found a significant negative relationship between the index and successional progression. Indicator species analysis showed the importance of all stages of aspen-conifer succession for lichen community diversity and highlighted the decline of aspen-dependent species with advancing succession. We present a landscape-level community analysis of lichens in the context of a conceptual model for aspen succession for the southern Rocky Mountains. We conclude that while total number of lichen species increases with succession, aspen-dependent species cover and richness will decline. In this way, epiphytic lichens communities may constitute an effective indicator of community-level diversity in for aspen-dependent species at-large. 相似文献