植物油脂积累机理和品质改良—利用RNAi改良大豆油脂品质—四合木茎积累三脂酰甘油特征

利用RNAi改良大豆油脂品质 大豆[Glycine max (L.) Merr.]起源于中国，栽培历史悠久，是重要的粮食作物， 同时也是植物油和蛋白的重要来源。随着经济的发展和生活水平的提高，人们不但对大豆的需求量大大增加，同时对大豆的品质也提出了更高的要求。近年来，我国大豆进口量逐年攀升，已远远超过本国生产量。国外转抗除草剂转基因大豆大面积种植大大降低了生产成本，直接影响了我国大豆生产。因此，提高产量和改良品质是当前中国大豆生产所面临的重要课题。基因工程是大豆品种改良更为有效和快速的方法，但是由于历史原因我国的大豆转基因育种与发达国家尚存在一定差距，对我国的大豆生产贡献十分有限。因此，建立高效的大豆转化体系，加强大豆基因工程研究和育种是解决大豆面临困境的关键。 本研究的目的是以我国主要栽培大豆品种（黑农、合丰和东农等）为材料，利用GUS（β-glucuronidase）报告基因和RNAi技术，建立高效的大豆基因转化体系和基因功能研究体系。为大豆产量和品质基因工程改良提供技术手段和理论基础。结果如下： 以大豆下胚轴为外植体，对分生组织产生不定芽的频率进行了研究。培养基中添加高浓度BAP（6-benzylaminopurine）可以诱导外植体分生组织增殖产生不定芽的发生率;在培养基中添加银离子可以明显地促进大豆单个外植体多芽的产生，使得诱导不定芽总数目显著增加;不同基因型大豆再生不定芽能力有着较大区别，黑农44，黑农37，合丰35，合丰39等品种再生能力强;相对于大豆子叶节等再生系统，大豆下胚轴体系具有高效高频的再生特点（总的再生频率高于80%），且重复性好，容易操作。 以大豆下胚轴为外植体，用含有GUS报告基因的根癌农杆菌对其进行遗传转化，并重点对农杆菌菌液浓度、农杆菌侵染时间、乙酰丁香酮（AS）和抗氧化剂浓度等因素对农杆菌大豆转化效率的影响进行了研究。组织化学染色结果显示GUS基因在外植体顶端表达强烈，表达位置主要位于初生芽基部周围的分生组织。 农杆菌浸染时间以 4h 为最佳，此时的GUS瞬时表达频率可达73.0%;培养基中添加浓度为200μmol/L的乙酰丁香酮，可以显著增加GUS瞬时表达频率。抗氧化剂可以显著降低共培养阶段外植体的褐化和坏死率，进而显著提高农杆菌转化效率。用根癌农杆菌转化大豆下胚轴的方法得到了表达GUS基因转基因大豆株系。 利用大豆油酸去饱和酶基因(FAD2-1;Genbank, L43920)在第315-852碱基之间的基因片断构建了反向重复的RNAi表达载体，以农杆菌介导大豆下胚轴转化方法进行转化，并且获得转基因植株。经过PCR，Southern杂交和转基因后代的脂肪酸分析，表明沉默结构已经成功整合到大豆基因组中，并成功抑制了内源基因的表达。与栽培大豆品种相比较，转基因大豆种子的脂肪酸组成发生显著变化，油酸含量由栽培大豆的18.1％增加到71.5％¬-81.9％;亚油酸含量从栽培大豆的46.4％降到了约3.4％。 栽培大豆种子中油酸去饱和比率（ODP, oleic desaturation proportion）为0.76 到 0.84，转基因大豆种子的油酸去饱和比率降为0.06-0.26，表明Δ12-去饱和酶活性降低了74%-94%。上述结果表明，我们构建的RNAi反向重复序列沉默结构高效地抑制了大豆种子FAD2-1基因。 在本研究中，我们通过外源GUS基因的表达和内源FAD2基因的抑制，成功地建立了以大豆下胚轴为外植体的高效农杆菌介导大豆转化体系，并获得了相应的转基因株系。本研究对我国大豆品种基因工程改良以及进一步大豆功能基因组研究有重要参考价值。 四合木茎积累三脂酰甘油特征 四合木(Tetraena mongotica Maxim)是蒺藜科(Zygophyllaceac)四合木属唯一的种，是地球上最具代表性的古老残遗濒危珍稀植物。由于四合木极易燃烧，当地居民称其为“油柴”。 通过对四合木内可能存在的“油”成分进行了分析，我们发现其茎组织含有大量的三脂酰甘油（Triacylglycerols），含量达到46 mg/g DM。在韧皮部中更高，达到90 mg/g DM。我们通过半薄切片对四合木中三脂酰甘油在不同组织的分布和存在形式进行了研究，发现三脂酰甘油主要以油体形式存在于木质部和韧皮部的薄壁组织中。在韧皮部中，几乎所有的薄壁细胞都含有大量的油体。 三脂酰甘油在植物的生长发育中起着非常重要的作用。作为植物生长发育所需的碳源和能量，三脂酰甘油一般储存在植物的种子和果实中。虽然也有关于其在茎和叶中发现的报道，但是含量很少。四合木茎组织含有大量的三脂酰甘油，这种现象可能与四合木茎中存在茎特异油脂合成酶系统有关。因此，克隆相关基因并在作物中表达，将对能源植物的开发具有重要意义。

Foraging behaviours of Diachasmimorpha kraussii (Fullaway) (Hymenoptera: Braconidae) and its host Bactrocera tryoni (Froggatt) (Diptera: Tephritidae) in a nectarine (Prunus persica (L.) Batsch var. nectarina (Aiton) Maxim) orchard

Diachasmimorpha kraussii is a larval parasitoid of dacine fruit flies. Host utilisation behaviour, including field foraging behaviour, is poorly known in this species. The diurnal foraging behaviour of D. kraussii and one of its common hosts, Bactrocera tryoni, in a nectarine orchard was concurrently recorded. Observations of mating, resting, feeding and oviposition were taken two-hourly on 42 trees, commencing at 07:00 h and terminating at 17:30 h, for 17 days. Resting and oviposition were common events within the orchard for both species, while mating behaviours were not recorded in the orchard for either species. Feeding was not observed for D. kraussii and was rare for B. tryoni. At the level of the individual tree there was a very weak, but significant correlation between parasitoid and fly abundance over a day, but when broken down to the individual observation periods the correlations were absent, or were weakly significant in an inconsistent manner (i.e. sometimes positively correlated, sometimes negatively correlated). At the orchard level, abundance of the parasitoid was not correlated with adult fly abundance. Results suggest that D. kraussii forage independently to adult B. tryoni, a result consistent with a prediction that their foraging is largely driven by larval or plant damage cues.

Przewalskin A: A new C-23 terpenoid with a 6/6/7 carbon ring skeleton from Salvia przewalskii maxim

Przewalskin A (1), a novel C-23 terpenoid with a 6/6/7 carbon ring skeleton, was isolated from Salvia przewalskii. Its structure was determined by comprehensive 1D NMR, 2D NMR, and MS spectroscopic analysis and subsequently confirmed by a single-crystal X

Przewalskin B, a novel diterpenoid with an unprecedented skeleton from Salvia przewalskii maxim

[GRAPHIC] Przewalskin B (1), a novel diterpenoid possessing a unique skeleton, was isolated from a Chinese medicinal plant Salvia przewalskii. Its structure and relative stereochemistry were elucidated by extensive NMR analysis and a single-crystal X-ray

科尔沁沙地南缘樟子松(Pinussylvestrisvar.mongolica)人工林天然更新障碍

针对科尔沁沙地南缘樟子松人工林不能天然更新的特征,从森林天然更新的必要条件出发,通过种子萌发、幼苗存活与生长所需条件的系列试验,探讨了科尔沁沙地南缘樟子松人工林不能天然更新的障碍特征。结果表明,沙地樟子松人工林不能天然更新的主要原因有:(1)由于土壤的干旱胁迫使沙地樟子松人工林中天然下种的种子很少有萌发的机会,尤其是在春季;(2)在水分条件相对充足的季节(秋季),樟子松种子能够萌发,但萌发产生的更新幼苗数量极少,即便这些更新幼苗得以存活,但由于沙地表层(0~5cm)与樟子松共生的外生菌根菌几乎不能存活而导致幼苗根系无法形成菌根,从而致使存活的樟子松幼苗抗旱、抗病能力非常弱,不能越冬,即不能更新。

Identification of herb Acanthopanax senticosus (Rupr. Et Maxim.) harms by capillary electrophoresis with electrochemical detection

In this paper, a rapid, high efficient, sensitive and inexpensive approach based on a combination of simple ultrasonic extract and capillary electrophoresis (CE) separation with electrochemical detection (ED), is described to identify herbs by comparing their CE-ED profiles (namely, CE-ED electropherograms). The proposed method takes advantage of ultrasmall sample volume, low consumption of organic solvent, simple sample pretreatment and easy cleanup procedure. It was applied to analyze the CE-ED profiles of stems of herb Acanthopanax senticosus (Rupr. Et Maxim.) Harms from different sources and different parts (roots, rhizomes, stems and leaves) of this herb. By comparing peak number, peak height and peak height ratio, we found that the CE-ED profiles showed big differences for the herbs from the different sources and the different parts of this herb. In addition, the distribution of bioactive compounds (isofraxidin, rutin and chlorogenic acid) in the different parts of this herb and their content variations affected by the source were studied with the CE-ED method. Based on their own unique CE-ED profiles, these herbs from the different sources and the different parts of this herb could be easily distinguished. Therefore, the proposed approach could be used as a rapid, high efficient and sensitive method for the identification of herbal medicines.

Examination of Antioxidative System's Responses in the Different Phases of Drought Stress and During Recovery in Desert Plant Reaumuria soongorica (Pall.) Maxim

The aim of this study was to test the protective roles of superoxide dismutases (SODs), guaiacol peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR) against oxidative damage and their activities in different phases of the dry down process in Reaumuria soongorica (Pall.) Maxim. leaves. Drought stress was imposed during 100 consecutive days and rewatering after 16, 72, and 100 days. The concentration of hydrogen peroxide (H2O2), malondialdehyde, and SODs activities were elevated significantly with progressing drought stress. POD and CAT activities increased markedly in the early phase of drought and decreased significantly with further drought stress continuation, and POD activity was unable to recover after rewatering. Ascorbate, reduced glutathione, APX, and GR activities declined in the initial stages of drought process, elevated significantly with further increasing water deficit progression and recovered after rewatering. These results indicate that: (1) iron SODs-removing superoxide anion is very effective during the whole drought stress; (2) CAT scavenges H2O2 in the early phase of drought and enzymes of ascorbate-glutathione cycle scavenge H2O2 in further increasing drought stress; and (3) POD does not contribute to protect against oxidative damage caused by H2O2 under drought stress.