多效唑（MET）对啤酒花试管苗生长和移栽的影响

在培养基中加入0.1-0.2mg/L浓度的多效唑（MET）,啤酒花试管苗植株矮壮,单株生根数量增加、移栽成活率提高13％。0．5－2．0mg/L时,试管苗基部愈伤组织增多,枝叶失绿,生长受到抑制。初步发现多将唑对啤酒花试管苗的效力与葡萄糖用量呈正相关。     

Adaptive divergence for a fitness-related trait among invasive Ambrosia artemisiifolia populations in France

The impact of natural selection on the adaptive divergence of invasive populations can be assessed by testing the null hypothesis that the extent of quantitative genetic differentiation (Q(ST) ) would be similar to that of neutral molecular differentiation (F(ST) ). Using eight microsatellite loci and a common garden approach, we compared Q(ST) and F(ST) among ten populations of an invasive species Ambrosia artemisiifolia (common ragweed) in France. In a common garden study with varying water and nutrient levels, we measured Q(ST) for five traits (height, total biomass, reproductive allocation, above- to belowground biomass ratio, and days to flowering). Although low F(ST) indicated weak genetic structure and strong gene flow among populations, we found significant diversifying selection (Q(ST) > F(ST) ) for reproductive allocation that may be closely related to fitness. It suggests that abiotic conditions may have exerted selection pressure on A. artemisiifolia populations to differentiate adaptively, such that populations at higher altitude or latitude evolved greater reproductive allocation. As previous studies indicate multiple introductions from various source populations of A. artemisiifolia in North America, our results suggest that the admixture of introduced populations may have increased genetic diversity and additive genetic variance, and in turn, promoted the rapid evolution and adaptation of this invasive species.     

Biotic and abiotic controls on iron oxyhydroxide formation in the gill chamber of the hydrothermal vent shrimp Rimicaris exoculata

A unique feature of the shrimp, Rimicaris exoculata , from the Rainbow hydrothermal vent field is the abundance of iron oxyhydroxides in its branchial chamber. These minerals accumulate throughout the molting cycle and are intimately associated with the shrimps' epibiotic microflora. In this study, an enhancement of the iron oxidation rate through shrimp swarms in the vicinity of vents is highlighted. This process is sustained by the high molting frequency of the shrimp, and potentially has large biogeochemical and ecological consequences for the associated hydrothermal ecosystem. The calculated rate for abiotic (homogeneous and heterogeneous) iron oxidation suggests that autocatalytic oxidation is the predominant reaction pathway leading to the accumulation of iron oxyhydroxides throughout the molting cycle. The occurrence of iron-oxidizing bacteria is not excluded, but their growth is most probably restricted to the first molting stage when competition with the abiotic iron oxidation is low. The influence of epibiont activity on local oxygen conditions and on the surface properties of the formed mineral, combined with the position of the shrimp in the hydrothermal mixing gradient, is expected to drive the relative contribution of abiogenic and biogenic iron oxidation.     

双价抗病基因导入籽瓜的遗传转化研究

以籽瓜主栽品种新籽瓜2号、五原籽瓜等为研究材料,用苗龄1-3d的子叶切块作外植体,不定芽诱导培养基为MS 6-BA2mg/L IBA 0.1mg/L,芽伸长培养基为MS KT0．2mg／L,诱导生根的培养基是MS IAA0．5mg／L。籽瓜遗传转化研究结果表明农杆菌感染时间以10min,共培养时间以2d为合适。共获得抗卡那霉素100mg／L的试管苗41个,PCR检测呈阳性的有15株,转化率为34．9％。该研究初步建立了籽瓜的遗传转化体系和转化体的检测体系。     

马鹿茸血酶解肽体内免疫功能及抗氧化功能关系的研究

本文分别选用由木瓜蛋白酶水解天山马鹿茸血获得的肽Ⅰ、肽Ⅱ以及原血为受试样品,研究天山马鹿茸血及其酶解肽对小鼠免疫功能和抗氧化功能的影响,其中肽Ⅰ、肽ⅡDH分别为18．1％、12．2％时,清除OH·能力最强,清除率为50．8％。分别测定了脏器指数,脾细胞增殖实验,血清中溶血素和抗体生成细胞的含量以及小鼠血清总抗氧化能力、SOD活力和MDA含量。结果表明：与对照组相比较,肽Ⅱ组能极显著提高小鼠体液和细胞免疫功能,加强小鼠的抗氧化功能（P〈0．01或P〈0．05）。此外,具有较强抗氧化活性的肽显示出了很强的免疫活性（P〈0．05）。