Neolignans from Virola carinata fruit

The fruits of Virola carinata contain the lignans (?)-cubebin, (?)-hinokinin and (+)-asarinin, besides four neolignans of the β-aryloxy-arylpropane type and two neolignans of the benzodioxane (eusiderin) type.     

Detection and Partial Characterization of Milk vetch dwarf virus Isolates from Faba Bean (Vicia faba L.) in Yunnan Province, China

A virus disease of faba bean ( Vicia faba L.) in China, characterized by leaf yellowing and rolling and plant stunting, was shown to be caused by a virus of the genus Nanovirus based on serological reactions to nanovirus-specific monoclonal antibodies and the generation of polymerase chain reaction amplicons using nanovirus-specific primers. To identify the faba bean-infecting nanovirus, regions of the DNA components encoding the master replication initiator protein and capsid protein of two nanovirus isolates from China were cloned, sequenced and compared with those of other members of the genus Nanovirus . The two Chinese virus isolates shared nucleotide sequence identities ranging from 95 to 98% with the type isolate of Milk vetch dwarf virus (MDV) from Japan. They were thus identified as isolates of MDV, a virus so far known to cause important diseases of legumes in Japan. This is the first record of MDV-infecting faba bean in China.     

Enzyme activity of the phenylpropanoid pathway as a response to apple scab infection

The study was performed on apple trees, ‘Golden Delicious' cv., which is a scab-susceptible cultivar. The phenolic content of apple fruit was determined in different parts of the peel. The phenolic compounds were analysed in the scab spot, in the tissue around the spot and in the healthy tissue. We determined the concentration of various phenolic compounds and related enzyme activities. Infection with the Venturia inaequalis fungus enhanced the metabolism of phenolic compounds at the scab spot, around the spot and in healthy peel. Compared with the healthy tissue and the tissue around the spot, the scab spot showed higher enzyme activity for all tested enzymes, except for dihydrochalcone 2′-O-glucosyltransferase, which had lower activity in the scab spot. In comparison to the healthy peel, the scab spot showed up to 3.4 times more hydroxycinnamic acids, up to 1.1 times more dihydrochalcones and up to 1.4 times more flavan-3-ols. In contrast, the healthy peel showed up to 1.6 times more flavonols than the scab spot.     

Radical disinfestation protocol eliminates in vitro contamination in Guava (<Emphasis Type="Italic">Psidium guajava </Emphasis>L.) seeds

Controlling contamination in vitro is one of the basic requirements for successful tissue culture technology. In preliminary studies, in vitro contamination of guava seeds was almost 100%, even when disinfested with bleach. To overcome this problem, we developed a unique method to control contamination using bleach and strong acids. Submerging guava seeds in 10% HCl for 24–72 h followed by a 30 min treatment with 10% bleach (NaOCl) reduced contamination rates from 98 to 0%. Substituting 5% H₂SO₄ for 12 h for 10% HCL gave similar results. In addition to eliminating contamination, acid-treated seeds germinated faster in vitro than control seeds germinated in a greenhouse (15 vs. 40 days, respectively).     

荒漠植物角果藜的地上地下结果性

对分布于准噶尔荒漠中角果藜(Ceratocarpus arenarius)果实的形态特征、空间位置、发育特性及散布特性进行了比较研究,结果表明:角果藜具有地上地下结果性,地上果实和地下果实在颜色、形状、大小、质量、数量、空间位置、成熟期和散布特性上均有显著差异。角果藜地上地下结果性是植物适应荒漠多变环境所具有的一种特殊的繁殖方式。这种独特的繁殖方式增加了物种在荒漠极端环境中成功生存的机率,保证了物种的顺利繁衍。这是首次在藜科植物中发现的地上地下结果性现象。     

Distribution, diversity and environmental adaptation of highland papayas (Vasconcellea spp.) in tropical and subtropical America

Vasconcellea species, often referred to as highland papayas, consist of a group of fruit species that are closely related to the common papaya (Carica papaya). The genus deserves special attention as a number of species show potential as raw material in the tropical fruit industry, fresh or in processed products, or as genetic resources in papaya breeding programs. Some species show a very restricted distribution and are included in the IUCN Red List. This study on Vasconcellea distribution and diversity compiled collection data from five Vasconcellea projects and retrieved data from 62 herbaria, resulting in a total of 1,553 georeferenced collection sites, in 16 countries, including all 21 currently known Vasconcellea species. Spatial analysis of species richness clearly shows that Ecuador, Colombia and Peru are areas of high Vasconcellea diversity. Combination of species occurrence data with climatic data delimitates the potential distribution of each species and allows the modeling of potential richness at continent level. Based on these modeled richness maps, Ecuador appears to be the country with the highest potential Vasconcellea diversity. Despite differences in sampling densities, its neighboring countries, Peru and Colombia, possess high modeled species richness as well. A combination of observed richness maps and modeled potential richness maps makes it possible to identify important collection gaps. A Principal Component Analysis (PCA) of climate data at the collection sites allows us to define climatic preferences and adaptability of the different Vasconcellea species and to compare them with those of the common papaya.     

Consumer Risk Assessment Associated with Intake of Pesticide Residues in Food of Plant Origin from the Retail Market in Poland

The aim of this study was to characterize short- and long-term risk for consumers associated with dietary intake of pesticide residues in fruits, vegetables, and other foodstuffs available on the Polish market based on 2010–2013 official surveillance results. Among 779 samples collected from 2010 to 2013 no pesticide residue was found in 39.7% samples while 58.5% contained residues at or below the EU Maximum Residue Levels (MRLs). Non-compliances (residues above the respective MRLs) were found in 14 samples (1.8%). Most of the estimated daily intakes were well below 1% of respective acceptable daily intake (ADI) values. The highest intake for children and adults was about 7% and 1.5% of ADI, respectively. For non-compliant results acute risk was characterized. Predicted short-term intakes for children and adults ranged from 0.7% to 425%, and from 0.2% to 100% of respective acute reference dose, respectively. Results of chronic risk characterization show that consumers in Poland are adequately protected; however, incidental cases where residue levels may potentially pose a threat to consumers’ health due to acute exposure cannot be excluded.     

Climate change effects on walnut pests in California

Increasing temperatures are likely to impact ectothermic pests of fruits and nuts. This paper aims to assess changes to pest pressure in California's US$0.7 billion walnut industry due to recent historic and projected future temperature changes. For two past (1950 and 2000) and 18 future climate scenarios (2041–2060 and 2080–2099; each for three General Circulation Models and three greenhouse gas emissions scenarios), 100 years of hourly temperature were generated for 205 locations. Degree‐day models were used to project mean generation numbers for codling moth (Cydia pomonella L.), navel orangeworm (Amyelois transitella Walker), two‐spotted spider mite (Tetranychus urticae Koch), and European red mite (Panonychus ulmi Koch). In the Central Valley, the number of codling moth generations predicted for degree days accumulated between April 1 and October 1 rose from 2–4 in 1950 to 3–5 among all future scenarios. Generation numbers increased from 10–18 to 14–24 for two‐spotted spider mite, from 9–14 to 14–20 for European red mite, and from 2–4 to up to 5 for navel orangeworm. Overall pest pressure can thus be expected to increase substantially. Our study did not include the possibility of higher winter survival rates, leading to higher initial pest counts in spring, or of extended pest development times in the summer, factors that are likely to exacerbate future pest pressure. On the other hand, initiation of diapause may prevent an extension of the season length for arthropods, and higher incidence of heat death in summer may constrain pest population sizes. More information on the impact of climate change on complex agroecological food webs and on the response of pests to high temperatures is needed for improving the reliability of projections.     

Aryltetralone and arylindanone neolignans from Virola sebifera

The fruits of Virola sebifera contain several tetralone neolignans, including 2,4-dihydroxy-6,7-methylenedioxy-2,3-dimethyl-4-veratryltetralin-1-one. The 3-hydroxylated derivative of this compound may undergo a biosynthetic pinacol-pinacolone rearrangement to give 2-acetyl-3-hydroxy-2-methyl-5,6-methylenedioxy-3-veratrylindan-1-one which, together with other indanone neolignans, was also isolated.