~（60）Co－γ射线对柞蚕（Antheraea pernyi G）蛹某些生理生化特性的影响

本实验对（６０）Ｃｏ－γ射线１～１００×０．２５８Ｃ／ｋｇ照射量辐射柞蚕蛹所引起的一系列变化进行了研究．柞蚕蛹解除滞育后，进行旺盛的代谢活动．经照射后，发现６０Ｃｏ－γ射线对柞蚕蛹呼吸代谢、血淋巴中蛋白质代谢和糖代谢都有一定影响，其中对雌性个体影响比较大，对血淋巴蛋白质代谢和糖代谢的影响趋势基本一致．当照射量增加到一定值时，对各种代谢均有抑制趋势，高照射量还有致死作用．     

白玫瑰挥发油化学成分的研究

本研究采用GC/MS/DS联用技术,分析了白玫瑰花挥发油的化学成分。从分离的的44化合物中,鉴定了41个组分,占挥发油总含量的97.64%。白玫瑰挥发油的主要成分是β—笨乙醇,含量高达86.53%,其次是丁香酚(4.75%)和香叶醇(2.45%)。     

Food irradiation in the news: The cultural clash of a postharvest technology

Food irradiation has been acommercially viable postharvest technology fornearly 50 years (the actual idea of usingionizing radiation to extend the shelf-life offoods is over a century old), yet it has beenused only occasionally and sporadically.Interviews with reporters and the sources theyused at a Louisiana newspaper and a Floridanewspaper uncovered three cultural spherespresent in the debate over this post harvesttechnology – food, science/technology, andjournalism. Each of these spheres were pointsof contention for reporters and sources, andthis has had an affect on the adoption of thetechnology among those involved in the foodindustry. Interviews with both reporters andthe individuals they relied on as sourceselucidate how different issues encompassedwithin different cultural spheres have beenlinked to this post harvest technology, andhave been used to help shape this debate. Thesecultural spheres offer various groups power tocontrol relations with reporters, though thatpower can be usurped by others, including thereporters themselves. Interviews with reportersand their sourses may help us understand howthe values attached to cultural spheres aremobilized by various groups to make sense of acontroversial topic, and how those groups gainentrance to public arenas and are then able tomaintain their presence.     

Addition of Ammonium Acetate to Protein-Borax Baited Traps Does Not Improve Attraction of Anastrepha obliqua or Anastrepha serpentina (Diptera: Tephritidae)

Ammonia is considered a key component in the attraction of tephritid flies to protein-based lures. The addition of ammonium acetate to improve hydrolyzed protein-borax mixtures used to monitor tephritids has not been evaluated, although it has improved attraction to toxic baits. The presence of ammonium acetate crystals in a ventilated tube inside a trap containing hydrolyzed protein + borax, did not improve the capture of Anastrepha obliqua or Anastrepha serpentina flies in field experiments when compared with hydrolyzed protein + borax alone. In contrast, the addition of 1% ammonium acetate into the drowning solution of a hydrolyzed protein + borax mixture resulted in significantly reduced captures of both pests. Laboratory tests indicated that the emission of ammonia gas was increased 1.6–4.5-fold from traps that included ammonium acetate. These results confirm the hypothesis that a higher release of ammonia does not improve the attraction of tephritids when protein-derived odors are also present.     

Growth,photosynthetic performance and shade adaptation of rubber (Hevea brasiliensis) grown in natural shade

We compared growth, photosynthetic performance and shade adaptation of rubber (Hevea brasiliensis Muell. Arg.) plants growing in natural shade (33, 55 and 77% reduction in incoming radiation) to control plants growing in full sunlight. Stem diameter and plant height, measured over a 15-month period, were greatest in plants grown in full sunlight, and both parameters decreased with increasing shade. At 7 and 14 months after planting (MAP), total plant dry mass was highest in control plants and lowest in plants in 77% shade. Expansion of the fourth leaf whorl, monitored at 5-6 MAP, was slowest in plants in 77% shade and fastest in unshaded plants, which had more leaves and higher leaf areas and inter-whorl shoot lengths. In response to increasing shade, specific leaf area increased, whereas leaf weight ratio and relative growth rate decreased. Chlorophyll a/b ratio decreased with increasing shade, indicating shade-induced partitioning of chlorophyll into light-harvesting complexes. Compared to the response in unshaded plants, CO2 assimilation saturated at lower photosynthetic photon flux densities in plants in 77% shade, with a lower upper-asymptote to the light response curve. Chlorophyll fluorescence revealed no evidence of sustained photoinhibitory damage in unshaded plants. Dynamic photoinhibition decreased with increasing shade, with the greatest depression in the ratio of variable to maximal fluorescence around midday. We conclude that shade adaptation and shade-induced reductions in dynamic photoinhibition account for the enhanced early growth of rubber in light shade.     

Isolation and selection of Hemileia Vastatrix antagonists

Organic coffee growing is rapidly increasing in Brazil, and many diseases, especially coffee leaf rust (Hemileia vastatrix), are threatening its production. This study is a first step towards a biocontrol program for coffee rust on organically grown plants. In three organic coffee farms in the state of Minas Gerais, 393 microbial strains including 154 bacterial and 239 fungal strains were isolated from leaves, leaf debris, and soil samples, and in 6 month-old coffee plants, 17 of these isolates reduced both the infection frequency (IF) and the number of H. vastatrix urediniospores produced per leaf (UPL) by more than 70 %. The isolates were identified as eight bacteria isolates, seven Bacillus spp. and one Pseudomonas sp., and nine fungal isolates, four Fusarium spp., two Penicillium spp., one Aspergillus sp., one Acremonium sp. and one Cladosporium sp. Each fungal and bacterial isolate was applied 0, 4, 8, 12 or 16 days before and 0, 4, 8, 12 or 16 days after H. vastatrix inoculation, and the efficiency in reducing both IF and UPL was evaluated. The efficiency was higher and lasted longer when the bacterial isolates were applied before H. vastatrix inoculation. Six Bacillus (B10, B25, B143, B157, B171, B175), two Fusarium (F205, F281), and one Pseudomonas (B286) isolates are potentially efficient as biocontrol agents of H. vastatrix and will be tested using field experiments.     

Strain-specific alfalfa water stress induced by <Emphasis Type="Italic">Xylella fastidiosa</Emphasis>

Differences in the virulence of a pathogen among host species can occur because hosts differ in their resistance or tolerance to infection or because of underlying genetic variation in the pathogen. The xylem-limited bacterium Xylella fastidiosa is pathogenic to dozens of plant species throughout the Americas, and is structured into genetically and biologically distinct strains. In some plants X. fastidiosa causes striking leaf scorch symptoms and in others, such as alfalfa, stunting is the primary symptom. The mechanism by which these symptoms occur has been debated. We tested the hypothesis that symptoms result from X. fastidiosa-induced water stress, and that the magnitude of water stress is strain-dependent. We mechanically inoculated alfalfa plants with one of 14 isolates (5 identified genetically as “almond” and 9 as “grape” isolates), and compared stable carbon isotope ratios among isolates. Infected plants showed significant isotopic shifts (up to 2% on average) relative to healthy plants that were consistent with water stress. Moreover, there were significant differences in water stress among isolates, with a tendency for grape isolates to cause more severe water stress than almond isolates. There was also a positive relationship between plant infection level and isotopic shift (slope ± SE = 0.273 ± 0.068), which supports the hypothesis that X. fastidiosa symptoms result from bacterial multiplication and vessel occlusion. Unexpectedly, however, water stress was not correlated with measures of alfalfa stunting. These results suggest X. fastidiosa induces strain-specific levels of water stress, but factors other than water stress alone are responsible for stunting.