细叶旱芹地上部化感物质粗分离物对4种草坪草及5种牧草的化感作用

采用滤纸培养皿法,以发芽率、发芽势、根长和苗长为指标,研究细叶旱芹(Cyclospermum leptophyllum(Pers.) Sprague ex Britton et P. Wilson)地上部化感物质对4种草坪草和5种牧草受体植物的种子萌发和幼苗生长的影响。结果表明,细叶旱芹地上部化感物质对4种草坪草和5种牧草的种子萌发和幼苗生长均有抑制作用,其中对种子发芽势抑制最明显,抑制率最高达96.3%;其次是对幼苗根长的抑制作用,抑制率最高达91.1%。通过比较种子萌发和幼苗生长的测定指标,得出5种馏分对草坪草的化感作用为石油醚相>氯仿相>正丁醇相>乙酸乙酯相>水相,而对牧草的化感作用为石油醚相>乙酸乙酯相>氯仿相>正丁醇相>水相。说明不同受体植物对相同萃取相组分的化感作用强弱存在差异,细叶旱芹地上部化感物质主要存在于石油醚馏分中,可进一步从中分离提取活性物质。     

儿茶素的药理作用研究综述

目的研究表儿茶素(EC)对小鼠急性肺损伤(ALI)炎症反应的调节作用。方法采用吸入式气管滴注法在BALB/c小鼠中建立ALI模型,H8LE染色观察肺组织病理学变化,并结合基于超高效液相色谱与四极杆—飞行时间质谱联用技术(HILIC UHPLC-Q-TOF MS)的非靶向代谢组学方法对小鼠肺组织进行研究。结果对比空白对照组,LPS处理后的小鼠肺组织发生严重的炎症变化,而EC预处理组炎症现象比LPS组轻。经肺组织代谢轮廓分析发现：二十羟基花生四烯酸、色氨酸、苯丙氨酸、酪氨酸、ATP、磷酸胆碱、二十碳四烯酸、磷酸、烯醇和二磷酸葡萄糖等差异物与小鼠急性肺损伤内源性代谢密切相关,且涉及甘油酯代谢、糖酵解、甘油磷脂代谢、苯丙氨酸、酪氨酸和色氨酸生物合成、抗坏血酸代谢和胆碱代谢等6条代谢路径。结论运用代谢组学方法探讨了EC干预小鼠ALI的差异代谢物变化情况,为表儿茶素抗炎特性的研究提供了理论依据。     

蝙蝠葛果实脂肪酸和氨基酸成分分析

首次对秦岭所产的治疗心血管疾病的药用植物蝙蝠葛果实中的脂肪酸成分采用GC-MS法进行了分析,检测并鉴定出11种脂肪酸,占脂肪酸总含量的99.99%。其中不饱和脂肪酸含量高达94.27%,主要成分为亚油酸,油酸和亚麻酸,其相对含量分别为47.65%,24.75%,19.82%。说明蝙蝠葛果实可能会成为良好的不饱和脂肪酸来源。对蝙蝠葛果实中氨基酸的含量及种类进行了测定,共测得17种氨基酸,氨基酸的总质量浓度为4.872 g.kg-1。其中谷氨酸含量最高(0.7833 g.kg-1),胱氨酸含量最低(0.03257 g.kg-1)。     

陕北安塞县马家沟流域近20 a来土地利用变化分析

汶川地震触发了大量次生山地灾害,震后山地灾害活动风险对灾区的发展规划决策有着重要的参考价值。通过对四川境内震后灾区基础资料的分析和研究,分别对灾区的44个县(市)进行了山地灾害危险性、易损性和风险评价,并以震后灾害点密度对危险性评价结果进行了验证,结果发现二者之间具有线性函数关系。评价结果表明,高度危险区集中于龙门山断裂附近,并且呈现明显的带状分布,面积比例为39.8%;极高易损和高度易损区则主要分布于成都、绵阳、德阳、雅安等大城市周边地区,面积比例为13.1%;高度风险区则主要位于龙门山腹地向山前平原的过渡带,属于高度危险和高度易损的结合部位,面积比例为11.0%。高风险区是今后恢复重建和发展规划中需要重点关注的地区;中度风险区由于灾后恢复重建的推进,其承灾体的易损性将会上升,容易导致其向高度风险转化,也要给予重视。     

免耕与土壤侵蚀研究进展

综述了国内外免耕控制土壤侵蚀的机理研究以及对土壤性质的影响,并提出免耕在我国的应用方向。     

A rapid multiplication system for ‘Candidatus Liberibacter asiaticus’ through regeneration of axillary buds in vitro

‘Candidatus Liberibacter asiaticus (CLas)’, which causes citrus Huanglongbing (HLB) disease, has not been successfully cultured in vitro to date. Here, a rapid multiplication system for CLas was established through in vitro regeneration of axillary buds from CLas-infected ‘Changyecheng’ sweet orange (Citrus sinensis Osbeck). Stem segments with a single axillary bud were cultured in vitro to allow CLas to multiply in the regenerating axillary buds. A high CLas titer was detected in the regenerated shoots on an optimized medium at 30 days after germination (DAG). This titer was 28.2-fold higher than in the midribs from CLas-infected trees growing in the greenhouse. To minimize contamination during in vitro regeneration, CLas-infected axillary buds were micrografted onto seedlings of ‘Changyecheng’ sweet orange and cultured in a liquid medium. In this culture, the titers of CLas in regenerated shoots rapidly increased from 7.5×10⁴ to 1.4×10⁸ cells μg^–1 of citrus DNA during the first 40 DAG. The percentages of shoots with >1×10⁸ CLas cells μg^–1 DNA were 30 and 40% at 30 and 40 DAG, respectively. Direct tissue blot immunoassay (DTBIA) indicated that the distribution of CLas was much more uniform in regenerated plantlets than in CLas-infected trees growing in the greenhouse. The disease symptoms in the plantlets were die-back, stunted growth, leaf necrosis/yellowing, and defoliation. The death rate of the plantlets was 82.0% at 60 DAG. Our results show that CLas can effectively multiply in citrus plantlests in vitro. This method will be useful for studying plant-HLB interactions and for rapid screening of therapeutic compounds against CLas in citrus.     

病原菌诱导黄瓜对其主要病害的抗病反应

以5种黄瓜主要病原菌作为诱导抗病因子,研究其对黄瓜主要病害的作用,结果发现黄瓜经病原菌诱导后,可以产生对诱导病原菌及其它病原菌引起病害的交互保护作用,并且诱导的交互保护作用与诱导浓度、诱导间隔期、不同品种存在相关性.诱导效果不随诱导接种浓度的升高而升高.在黑星病菌对霜霉病菌的诱导作用中,以浓度为1×102个/ml的黑星病菌孢子悬浮液的诱导效果最好,诱导间隔期为48h黄瓜黑星病菌对霜霉病的交互保护作用最明显,抗性品种的交互保护作用明显好于感病品种;炭疽病菌可诱导黄瓜有效抑制褐斑病的发生,但挑战接种褐斑病菌后,却促进了炭疽病的发生.诱导接种炭疽病菌后再挑战接种褐斑病菌12d,对褐斑病的防效为92.07%.     

甘蓝型油菜有、无花瓣近等基因系花器官的比较研究

比较甘蓝型油菜有、无花瓣近等基因系花器官的形态差异，结果表明，无花瓣品系在花蕾、花萼、雌蕊长度上与有花瓣品系无差异，仅雄蕊长度有所下降；无花瓣品系因缺少花瓣，花蕾重量仅为有花瓣品系的55．89％，但花萼、雄蕊、雌蕊重量差异不大，其中花萼和雄蕊重量略有下降，而雌蕊重量则上升。无花瓣品系花器官各部分与有花瓣品系间的差异主要表现在花瓣缺失上，而花萼、雄蕊、雌蕊、花粉、柱头和蜜腺等形态均无明显差异，因此，该油菜花瓣缺失类型可能与拟南芥等植物花器官发育的ABC模型不符。     

Effects of astragaloside on the levels of sex hormone and oxidative stress injury in rats with polycystic ovary syndrome

AIM To investigate the effects of astragaloside on the levels of sex hormone and oxidative stress in rats with polycystic ovary syndrome （PCOS）. METHODS Female SD rats （n=60） were randomly divided into normal control group, model group, Diane-35 （0.339 2 mg/kg） group, low dose astragaloside （12.5 mg/kg） group and high dose astragaloside （50 mg/kg） group, with 12 rats in each group. The PCOS model was induced by letrozole （1 mg/kg）, which was administered by gavage once a day for 3 weeks. After administration, the estrus cycle of the rats was observed by vaginal smear, and the ovarian index was calculated. HE staining was used to observe the histopathological changes of the ovaries. Serum levels of the sex hormones testosterone （T）, estradiol （E₂）, luteinizing hormone （LH） and follicle-stimulating hormone （FSH） were measured by ELISA. The levels of superoxide dismutase （SOD）, malondialdehyde （MDA） and glutathione peroxidase （GSH-Px） in serum and ovarian tissue were detected by colorimetry, and the protein levels of steroidogenetic acute regulatory protein （StAR） and apoptosis-related proteins cleaved caspase-3, Bax and Bcl-2 in ovarian tissue were detected by Western blot. RESULT Compared with control group, the oestrous cycle of the rats in model group was disorder, and the ovarian index was increased, ovary was polycystic. The serum levels of T, LH and MDAwere significantly increased （P<0.05）, while the contents of E2, FSH and the activities of GSH-Px and SOD were significantly decreased （P<0.05）. The levels of MDA, StAR, cleaved caspase-3 and Bax proteins in ovarian tissue were significantly up-regulated （P<0.05）. GSH-Px and SOD activities and Bcl-2 protein levels were significantly down-regulated （P<0.05）. CONCLUSION Astragalosideeffectively balances the levels of sex hormone in PCOS rats and relieves the oxidative stress injury, the mechanism may be related to the inhibition of StAR expression.     

中国粮食安全现状与应对策略

粮食是人类生存与发展的基础,粮食安全目前已经纳入国家战略,在世界贸易摩擦不断加剧的新形势下,保障国家粮食安全是长期艰巨的任务。分析了我国粮食生产现状及存在的问题,并针对粮食总量和质量上存在的问题提出了应对策略。提出了加强耕地保护与环境治理,建立粮食加工监管全程追溯系统,深化粮食科研院所改革,构建上下协同、功能互补和配置高效的粮食科技协同创新体系,持续推进粮食品种与区域结构调整,开展粮食增产模式攻关等方法,从而促进粮食安全保障能力稳步提升。