Observations on the economic importance of tomato leaf miner (Liriomyza bryoniae) (agromyzidae)

Yield losses can occur as a result of leaf miner infestation, but are not dependent on severity of damage alone; proximity to fruit at an early stage of development is very important. If damage on leaves adjacent to a truss reached 30 mines/leaf at the time fruit was half-swollen, a 10% loss of yield resulted. At three levels of infestation investigated, losses amounted to 5, 13 and 20% of monetary returns. Although it was found that growing soft plants and keeping de-leafing to the minimum would maximise yields, it appeared that the direct effect of these cultural practices on yield was more important than their indirect effects on leaf miner damage.     

A novel cell division factor from tobacco 2B-13 cells that induced cell division in auxin-starved tobacco BY-2 cells

Effects of auxin as plant hormones are widespread; in fact in almost all aspects of plant growth and development auxin plays a pivotal role. Although auxin is required for propagating cell division in plant cells, its effect upon cell division is least understood. If auxin is depleted from the culture medium, cultured cells cease to divide. It has been demonstrated in this context that the addition of auxin to auxin-starved nondividing tobacco BY-2 cells induced semisynchronous cell division. On the other hand, there are some cell lines, named habituated cells, that can grow without auxin. The cause and reason for the habituated cells have not been clarified. A habituated cell line named 2B-13 is derived from the tobacco BY-2 cell line, which has been most intensively studied among plant cell lines. When we tried to find the difference between two cell lines of BY-2 and 2B-13 cells, we found that the addition of culture filtrated from the auxin-habituated 2B-13 cells induced semisynchronous cell division in auxin-starved BY-2 cells. The cell division factor (CDF) that is responsible for inducing cell division in auxin-starved BY-2 cells was purified to near-homogeneity by sequential passage through a hydroxyapatite column, a ConA Sepharose column and a Sephadex gel filtration column. The resulting purified fraction appeared as a single band of high molecular weight on sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels by silver staining and was able to induce cell division in auxin-starved BY-2 cells. Identification of the protein by MALD-TOF-MS/MS revealed that it is structurally related to P-glycoprotein from Gossypioides kirkii, which belongs to ATP-binding cassette (ABC)-transporters. The significance of CDF as a possible ABC-transporter is discussed in relationship to auxin–autotrophic growth and auxin-signaling pathway.     

聚苯乙烯纳米塑料对大蒜生长生理的影响

自然环境中的微/纳米塑料污染日趋严重,但纳米塑料对农作物生长的潜在影响尚不清楚.通过营养液培养方式,探讨了粒径为80 nm的聚苯乙烯纳米塑料（polystyrene nanoplastics,PS-NPs）对金乡大蒜（Allium sativum L.）叶绿素含量、抗氧化性能和营养品质的影响.结果显示,添加PS-NPs处理的大蒜,其叶片叶绿素含量均显著低于对照组,叶绿素的合成受到抑制.大蒜叶片SOD、APX活性和脯氨酸含量随着PS-NPs质量浓度的增加呈先升高后降低的趋势.10 d处理时大蒜叶片POD活性随PS-NPs质量浓度的增加而上升,但在20 d处理时,各处理组POD活性均受到抑制.大蒜叶片MDA质量摩尔浓度随PS-NPs质量浓度的增加而增加,在ρ（PS-NPs）为100 mg·L^-1处理下,10 d和20 d处理时其含量相比对照分别增加43.24%和89.70%.同时,经ρ（PS-NPs）为100 mg·L^-1胁迫处理10 d后,大蒜叶片可溶性蛋白质、可溶性糖和维生素C含量均高于对照组,但20 d后,维生素C含量较对照则降低了26.53%.以上结果表明PS-NPs能对大蒜产生较为显著的氧化胁迫效应,且较高质量浓度的PS-NPs胁迫会对大蒜叶片的营养品质产生一定的影响.     

丛枝菌根真菌对百菌清引起的旱稻(Oryza sativa L.)毒性的影响

采用盆栽实验的方法,研究了百菌清对旱稻(Oryza sativa L.)生长和氧化胁迫的影响,以及接种丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)对百菌清污染下旱稻生长的影响和对旱稻氧化胁迫的影响.结果表明,百菌清处理对旱稻的生长有明显的抑制作用,施加百菌清后可以使旱稻地上部的生物量由2.5 g·pot-1下降到1.0 g·pot-1以下;地下部分的生物量在施加百菌清处理后由0.9 g·pot-1下降到0.3 g·pot-1以下.百菌清处理下接种AMF能显著提高旱稻生物量,接种菌根真菌能使50mg·kg-1百菌清处理下旱稻的生物量增加1倍以上.百菌清处理能显著降低旱稻对磷(P)营养元素的吸收,在50 mg·kg-1百菌清处理下旱稻地上部分P的吸收量由3 200 μg·pot-1下降到860 μg·pot-1,接种AMF能使旱稻地上部P的吸收量增加到1 900 μg·pot-1.百菌清处理还可以引起旱稻体内的氧化胁迫,改变旱稻体内抗氧化酶系统的活性,而接种菌根真菌能降低百菌清对旱稻产生的氧化胁迫,从而减轻百菌清污染对旱稻的毒性作用.总之,百菌清土壤污染能够引起旱稻体内的氧化胁迫、降低旱稻P的吸收量而影响植物生长,接种菌根真菌能显著改善旱稻的生长和降低百菌清对旱稻的影响.     

Equilibrium and kinetics of copper(Ⅱ) biosorption by Myriophyllum spicatum L.

The potential use of Myriophyllum spicatum L. biomass as a biosorbent for the removal of copper（ Ⅱ ） from aqueous solution was investigated in laboratory condition. The sorption experiments were undertaken to obtain copper（ Ⅱ ） biosorption properties of M. spicatum L., i.e. equilibrium time, the maximum capacity, and rate constants. Copper（ Ⅱ ） biosorption was fast and equilibrium was attained within 35 min at initial copper（ Ⅱ ） concentration of 6 mg/L. Different isotherm models including the Langmuir, Freundlich, Temkin and Redlich-Peterson model, were used to investigate the sorption capacity and isotherm. These models showed an excellent match with the experimental data except for the Freundlich model. According to the Langmuir coefficients, the maximum sorption capacity of copper onto M. spicatum L. was 10.80 mg/g. The kinetics of copper（ Ⅱ ） sorption was also analysed and rate constants were derived. It was found that the overall sorption process was best described by the pseudo second-order equation, and that intraparticle diffusion was not the rate determining step. The results of this study showed that M. spicatum L. can be considered as useful vehicles for the removal and recovery of copper（ Ⅱ ） from aqueous solutions.     

Chemical profiles, division of labor and social status in Pachycondyla queens (Hymenoptera: formicidae)

Queens of the neotropical ponerine ant Pachycondyla cf. 'inversa' may co-operate during colony founding. One of several co-founding queens specializes in foraging, whereas the others remain in the nest and guard the brood. Division of labor is achieved by aggressive interactions, which result in the formation of dominance hierarchies. Gas chromatography and mass spectrometry of cuticular hydrocarbons obtained from live queens by SPME revealed consistent differences between the patterns of cuticular hydrocarbons of queens with high versus low rank: only high-ranking queens showed considerable amounts of cuticular pentadecane (n-C₁₅) and heptadecene (n-C₁₇:1). These two substances presumably originate from the queens' Dufour glands.     

Congenital sialoblastoma (embryoma) associated with premature centromere division and high level of alpha-fetoprotein

Sialoblastoma is a rare, locally aggressive, and potentially malignant perinatal salivary tumor that predominantly affects the parotid glands. To date, 29 cases of sialoblastoma have been reported. We report a further case of sialoblastoma diagnosed at 37 weeks of gestation presenting with novel findings that are the premature centromere division and a high level of alpha-fetoprotein. Copyright © 2005 John Wiley & Sons, Ltd.