可口革囊星虫对Cd2+和Hg2+的富集及其影响

采用原子吸收、原子荧光等分析检测技术,探讨了Cd²⁺、Hg²⁺在可口革囊星虫中的富集规律及其对生长与主要营养成分的影响.结果表明: 在试验设定的胁迫浓度内,可口革囊星虫体壁肌肉对Cd²⁺、Hg²⁺的富集均随胁迫时间的延长而增加,最终达到饱和浓度;环境中Cd²⁺、Hg²⁺浓度越高,富集速度越快,达到饱和的时间越短,饱和浓度也越高.可口革囊星虫体质量增长随着重金属胁迫浓度的升高而减慢,且联合胁迫的影响程度大于单一胁迫.体壁肌肉蛋白质含量随重金属胁迫浓度的增加而升高,Cd²⁺、Hg²⁺分别在0.05和0.02 mg·L^-1胁迫浓度下达到最高,然后开始降低.联合胁迫也呈同样的规律,且影响程度更大.体壁肌肉脂肪含量随重金属胁迫浓度的增加而降低,联合胁迫下降低程度更大.     

栽培模式对沙棘人工林土壤微生物群落结构和参与氮循环功能基因的影响

以沙棘×油松混交林、沙棘×侧柏混交林、沙棘×刺槐混交林、沙棘纯林的土壤为研究对象,对其土壤微生物种群结构、参与氮循环功能基因丰度进行了检测.结果表明: 沙棘与油松或侧柏混交能显著增加林地土壤总磷脂脂肪酸(总PLFA)、细菌脂肪酸(BPLFA)和革兰氏阳性菌脂肪酸(G⁺PLFA)含量,而真菌脂肪酸 (FPLFA)含量无明显变化.两种混交林地土壤的nifH、amoA、nirK和narG基因丰度明显高于沙棘纯林土壤.土壤总PLFA、G⁺PLFA、革兰氏阴性菌生物量(G^-PLFA)和4种功能基因的丰度均与土壤pH、土壤有机碳、总氮、NH₄⁺-N、速效钾呈显著正相关.不同栽培模式人工林土壤微生物群落和基因丰度的差异主要与土壤理化特性有关.沙棘与油松或侧柏混交为当地2种较好的栽培模式,能有效地改善土壤质量.     

Seasonal differences in foliar content of chlorogenic acid, a phenylpropanoid antioxidant, in Mahonia repens

To assess the possible physiological function of chlorogenic acid (CGA, 3-O-caffeoylquinic acid) in vivo , we characterized the free radical scavenging properties of pure phenylpropanoids and leaf extracts against two free radicals, superoxide and the 2,2'-azinobis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical cation. CGA was found to be a highly efficient scavenger of these free radicals, surpassing the activity of all other phenylpropanoids tested, as well as the 'classical' antioxidant ascorbate. Seasonal differences in the leaf content of CGA were examined in field populations of the broadleaf evergreen Mahonia repens growing in different light environments. Leaves of fully sun-exposed plants contained significantly more (74 ± 10 mmol m^–2) CGA in winter than leaves from plants growing under deeply shaded conditions (17 ± 2 mmol m^–2). Sun-acclimated, but not shade-acclimated, leaves also produced high levels of anthocyanins in winter, suggesting a simultaneous increase in carbon flow through the phenylpropanoid and flavonoid pathways in response to high light and seasonal low temperature stress. In summer, high light-acclimated leaves contained ≈ 2-fold less CGA than in winter, whereas CGA levels were similar between seasons in shaded leaves. Consistent with the strong scavenging capacity of CGA measured in vitro , a linear correlation was observed between CGA content and the antioxidant activity of leaf extracts in both scavenging assays. On the basis of these results, we propose that CGA is a powerful hydrogen-donating antioxidant that may play an important role in mitigating the effects of oxidative stress in plants.     

箬叶多糖及其化学修饰物、亚硒酸钠和GSH对Cu~(2+)诱导的LDL氧化修饰的保护作用

研究了箬叶多糖ＦⅢ－ａ及其化学修饰物、亚硒酸钠和ＧＳＨ对Ｃｕ２＋诱导的低密度脂蛋白氧化修饰的保护作用．其结果表明箬叶多糖、硫酸酯多糖、硒酸酯多糖可显著抑制脂质过氧化产物（ＴＢＡＲＳ）及荧光物质的生成,彼此之间无明显差异．但对ＶＥ的消耗有着不同的保护作用,其顺序是ＦⅢ－ａ＞Ｓ－ＦⅢ－ａ＞Ｓｅ－ＦⅢ－ａ,并且具有明显的量效关系．硒或ＧＳＨ对Ｃｕ２＋诱导的ＬＤＬ氧化修饰无明显的抑制,但联合使用在０．１２５ｍｍｏｌ／ＬＮａ２ＳｅＯ３和０．２ｍｍｏｌ／ＬＧＳＨ及１２．５μｍｏｌ／ＬＮａ２ＳｅＯ３和０．０２ｍｍｏｌ／ＬＧＳＨ的浓度下能强烈地抑制ＴＢＡＲＳ的生成,甚至比正常的ＬＤＬ还要低．但是对ＶＥ的消耗只有较弱的保护作用,硒酸酯多糖与此相似．Ｎａ２ＳｅＯ３在０．１２５ｍｍｏｌ／Ｌ时可以明显抑制荧光物质的生成．     

贵阳十大功劳染色体核型分析

<正> 十大功劳是一种药用植物,根、茎可作黄连代用品。广西植物所标本园栽培的十大功劳原认为是阔叶十大功劳(Mahonia bealei Carr.)。韦发南先生根据Ahrendt,L.W.A. 1961:Berberis and Mahonia,a taxonomic revision,Journ.Linn.Soc.Bot.57(369):1—410.经过详细考证,认为是贵阳十大功劳(Mahonia leveilleana Schneid.)。我们对贵阳十大功劳进行了染色体核型分析,结果如下:14对染色体全部为中部着丝点,不     

四川十大功劳属一新变种

<正> 菱叶刺黄柏 新变种 图 Mahonia graciupes(Oliv.)Feddo var. rhombicus Z. F. Pan et Z. P. Song,var. nov.     

接种刺状无梗囊霉对番茄生长及psy1与psy2基因表达的影响

本研究利用前期筛选获得的丛枝菌根真菌(AMF)刺状无梗囊霉XJ27侵染矮化观赏型番茄品种“小汤姆”,分析番茄植株生物量、叶绿素含量以及果实番茄红素含量等相关指标,并采用半定量RT-PCR与实时PCR检测对番茄红素合成相关基因psy1与psy2的表达情况.结果表明：与对照组相比,刺状无梗囊霉处理组番茄的生物量显著增加,增产效果明显;番茄红素合成相关基因psy1与psy2表达增强,果实中的番茄红素含量显著提高.表明刺状无梗囊霉XJ27是一株很有应用潜力的AM真菌.     

采用RAPD和ISSR标记探讨中国疣粒野生稻的遗传多样性

Random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) methods were applied to detect genetic variation of 20 bulking samples and two individually sampled populations of Oryza granulata (Nees et Arn. ex Watt.) from China (M5 from Hainan Province and M27 from Yunnan Province). For the bulking sampled populations, 20 RAPD and 12 ISSR primers generated 209 and 122 bands, of which 134 (64.11%) and 89 (72.95%) were polymorphic respectively. For population M5, 146 and 95 bands were generated with 21.48% and 34.78% being polymorphic (PPB). For population M27, 151 (PPB = 17.22%) and 94 (PPB = 19.15%) bands of RAPD and ISSR were obtained. The results indicated that the level of genetic variation of O． granulata was lower than other species detected in the genus Oryza. UPGMA cluster based on genetic similarity and principle component analyses (PCA) based on band patterns divided the populations into two groups corresponding to their sources, which revealed that the majority of genetic variation of O. granulata occurred between Hainan and Yunnan. Consequently, more populations of the species should be considered for a reasonable conservation management. Comparison between the two marker systems showed that ISSR was better than RAPD in terms of reproducibility and ability of detecting genetic polymorphism. Mantel test revealed that the goodness of fit between them was significant (r=0.917, t=12.718) when detecting genetic diversity at species level, but was poor at population level (r<0.200). The discrepancy was considered as the facts that different fragments were targeted by RAPD and ISSR, and that evolutionary process of O. granulata varied at different hierarchical levels.     

Revealing the F_actin Networks in Interphase Nuclei of Garlic Clove Cells by Confocal Fluorescence Microscopy

The interphase nuclei of parenchyma cells and epidermal cells of garlic (Allium sativum L.) clove were labelled with rabbit anti-actin antibody and FITC-conjugated goat anti-rabbit IgG antibody. The authors observed results with fluorescence microscopy and confocal laser scanning microscopy. The nuclei showed prominent green-yellow fluorescence, indicating the presence of actin in the nuclei. Fluorescence examination with TRITC-phalloidin showed distinctive red fluorescence in the nuclei, indicating that F-actin is present in the nuclei. Confocal laser scanning microscopy indicated the presence of F-actin containing network structures in the nuclei, but the network structures were absent and the nuclei still showed red fluorescence when the cells were treated with cytochalasin D before fixation; the red fluorescence in the nuclei was hard to be observed when the cells were treated with unlabelled phalloidin before the cells were stained with TRITC-phalloidin. These results indicate that F-actin is in the nuclei and forms network structures in the nuclei of garlic cells.     

增强UV-B辐射对暖温带落叶阔叶林土庄绣线菊水分利用效率、气孔导度、叶氮素含量及形态特性的影响

在北京东灵山暖温带森林生态系统中,选择常见灌丛土庄绣线菊(Spiraea pubescens),建立UV-B控制实验。连续3个生长季每天增补9.4 kJ·m^-2的辐射剂量,模拟臭氧衰减17%时近地表面UV-B辐射的增强。该实验的目的是在野外环境下观测,长时间人工增强UV-B辐射对土庄绣线菊叶片的气孔导度、碳同位素比率(δ¹³C)、叶含水量、叶面积、特别是水分利用效率(WUE)和叶片全氮含量等指标的影响。实验结果表明,增强UV-B辐射显著减少了土庄绣线菊的叶面积(50.1%),提高了叶片全氮含量(102%)。同时,UV-B辐射还在一定程度上(尽管统计显示不显著)降低了气孔导度(16.1%)、胞间CO₂浓度与大气CO₂浓度之比(C_i/C_a) (4.0%)、提高了碳同位素比率(δ¹³C)(20.5‰)、叶含水量(3.1%)及比叶重(SLW)(5.2%),从而导致WUE的增加(4.1%)和植物的抗旱能力增强。值得注意的是,深层土壤(30~40 cm)含水量变化会影响气孔导度、δ¹³C和WUE对紫外辐射的响应程度:在土壤干旱的季节(6月和9月),气孔导度、δ¹³C、WUE这些指标处理和对照的差异很小,但是当土壤水分充足时(7月和8月),处理和对照的差异就较为显著。另外,随着实验处理时间的延长,UV-B的效应变得不显著。相关分析表明,UV-B辐射降低了土壤含水量(30~40 cm)与土庄绣线菊叶含水量、δ¹³C、C_i/C_a和气孔导度的相关系数,增强了WUE与土壤含水量的相关性,这也许是由于UV-B辐射增强了WUE对土壤水分变化的敏感性。该研究的结果表明UV-B辐射对土庄绣线菊的形态和生长有显著的影响,但对主要水分生理指标影响不显著。