研制绿色杀虫剂的理论基础与研究现状——兼论植物对昆虫的化学防御

在长期的进化过程中 ,植物演化出了 3种防御昆虫侵害的化学防御方式 :(1)引起昆虫忌避和抑制其取食 ;(2 )影响昆虫对食物的消化和利用 ;(3)使昆虫中毒或死亡或延迟其生长发育 .植物含有的多种多样的化合物 (其中以次生性代谢物质为主 )可以通过影响昆虫的神经系统、呼吸系统、肌肉系统、消化系统、生殖系统与生长发育而达到杀灭害虫、保护自己的目的 .这是研制高效低毒新型杀虫剂———绿色杀虫剂的理论基础 .近年来对绿色杀虫剂的研制与开发越来越深入 ,并且取得了可喜的进展 .     

Plant thionins – the structural perspective

Thionins belong to a rapidly growing family of biologically active peptides in the plant kingdom. Thionins are small (∼5 kDA), cysteine-rich peptides with toxic and antimicrobial properties. They show a broad cellular toxicity against wide range of organisms and eukaryotic cell lines; while possessing some selectivity. Thionins are believed to be involved in protection against plant pathogens, including bacteria and fungi, by working directly at the membrane. The direct mechanism of action is still surrounded by controversy. Here the results of structural studies are reviewed and confronted with recent results of biophysical studies aimed at defining the function of thionins. The proposed toxicity mechanisms are reviewed and the attempt to reconcile competing hypotheses with a wealth of structural and functional studies is made. Received 3 December 2005; received after revision 6 February 2006; accepted 18 March 2006     

Host plant utilization and population abundance of three tropical species of Cassidinae (Coleoptera: Chrysomelidae)

Considering the little information on the biology and phenology of Chrysomelidae beetles and interaction with their host plants, we have followed the populations of Stolas chalybea, S. areolata and Anacassis phaeopoda for 2 years in order to obtain basic biological data on them and to describe their occurrence throughout the year. After emerging from the eggs, larvae of the three studied species remained aggregated, although the size of the groups decreased as the larvae developed. Egg clusters and young larvae of the two Stolas species were more frequently found on the underside of leaves of their host plants and mature larvae of S. areolata were only observed on the upper side of leaves. Adults of the three species were always isolated and both Stolas species were more frequently found on the upper side of leaves. The number of new branches on the host plant and some other plant physical characteristics were significantly related to Cassidinae abundance. The three studied species became active with the end of the dry season, reproduced more intensely during the rainy season and reduced their activity with the lowering of temperature and rainfall. The beetles also showed a lower peak of egg laying at the end of diapause of adults. This pattern of occurrence was very similar to the occurrence of leaves, especially the newest ones, on their host plants. Significant positive correlations between Cassidinae numbers and temperature showed that this parameter could influence ovipositing and mating activities.     

Polar transport of the plant hormone auxin – the role of PIN-FORMED (PIN) proteins

The PIN-FORMED (PIN) protein family is a group of plant transmembrane proteins with a predicted function as secondary transporters. PINs have been shown to play a rate-limiting role in the catalysis of efflux of the plant growth regulator auxin from cells, and their asymmetrical cellular localization determines the direction of cell-to-cell auxin flow. There is a functional redundancy of PINs and their biochemical activity is regulated at many levels. PINs constitute a flexible network underlying the directional auxin flux (polar auxin transport) which provides cells in any part of the plant body with particular positional and temporal information. Thus, the PIN network, together with downstream auxin signalling system(s), coordinates plant development. This review summarizes recent progress in the elucidation of the role of PIN proteins in polar auxin transport at the cellular level, with emphasis on their structure and evolution and regulation of their function. Received 28 December 2006; received after revision 16 February 2007; accepted 26 March 2007     

高粱3853-1与高粱3801-2生理指标及抗性分析

在正常及低温胁迫条件下,对高粱3853—1与高粱3801—2苗期超氧化物歧化酶（SOD）、过氧化氢酶（CAT）及游离脯氨酸、可溶性糖、丙二醛（MDA）等指标进行了测定与分析,结果表明：在正常生长环境下,高粱3853—1的SOD与CAT的活性以及游离脯氨酸和可溶性糖的含量均大于高粱3801-2,MDA的含量低于高粱3801—2;在低温胁迫下,高粱3853—1与高粱3801—2叶片中MDA的含量增高．其余4项指标都比正常环境下低;高粱3853-1叶片中SOD与CAT的活性、可溶性糖及游离脯氨酸的含量均高于高粱3801—2;与高粱3801—2相比较,高粱3853—1有较强的抗性．     

《植物生理学》实验教学的改革与实践

实验教学是高校教学体系的重要组成部分,实验教学改革是教学改革重要的环节。根据多年的实验教学实际,以加强教材建设、改革实验课程体系、加强实验教学课程规范化管理和改革实验考试制度等实践环节为核心,对《植物生理学》实验教学进行了改革和探索,收到了较好的教学效果,提高了学生的综合素质和实验动手能力,同时也提高了该课程的教学质量。     

球虫感染对雏鸡若干血液生理指标的影响

为了解混合球虫感染对雏鸡血液生理指标的影响,选择78只14日龄雏鸡随机分为6组,进行人工感染球虫试验。其中组为对照组,不感染球虫, ～组分别人工感染0.6×105,1.2×105,1.8×105,2.4×105,3.0×105个孢子化球虫卵囊,观察雏鸡临床症状及测定血液中的红细胞、白细胞、血红蛋白含量等指标。结果表明:雏鸡随感染强度增加临床症状加重, 组、组死亡率均为23.08%,其余各组未见死亡。各感染组雏鸡血液从第4天起Hb显著下降,第6天降至最低,且各期的Hb随感染球虫数量的增加呈下降趋势;感染后第6天,红细胞总数均有所下降, 组、组与对照组比较差异显著;白细胞总数均有所上升, 组、组、组淋巴细胞百分率显著增加,嗜中性白细胞百分率显著降低,而嗜酸性、嗜碱性及单核细胞百分率无明显差异。     

硒对蛭石培养大豆生理生化特性的影响

采用蛭石培养大豆,并施以不同浓度的硒处理,对大豆的表观性状、生物学性状、生理性状进行了研究.结果表明,蛭石中补以适宜浓度的硒,能够促进大豆植株生长,硒浓度过高,大豆的生长会受到抑制;可溶性蛋白和可溶性糖的含量均较对照组有所提高,一定浓度的硒能够增强大豆的抗逆性能;蛭石中硒浓度高于5μg.mL-1时,脯氨酸含量上升,提高了大豆的抗逆性,而硒浓度在0.1～5μg.mL-1范围内时,MDA含量均低于对照,补硒浓度达到10μg.mL-1时,MDA的含量高于对照和低浓度硒处理,所以低浓度的硒(补硒浓度小于10μg.mL-1)有利于降低过氧化产物MDA的生成,对大豆有一定的抗氧化作用;当硒浓度低于10μg.mL-1时,叶绿素含量均高于对照组,说明适量的硒有利于促进光合作用,从而利于大豆的生长.     

昆虫化学生态学与植物保护

在生态安全条件下进行植物保护，推行植物免害工程是实现可持续发展的有效途径之一。笔综述了昆虫化学生态学中昆虫与植物之间、昆虫与天敌间的化学联系，信息素与植物挥发性物质在昆虫对寄主植物定位、定居、取食和繁殖中的作用，非寄主植物对植食性昆虫寄主选择的影响等领域的研究进展，以及利用植物次生性化合物进行害虫治理的应用现状。展示了昆虫化学生态学在未来植物保护中的应用前景及昆虫化学生态学的研究方向。     

微生物复合菌剂的生物安全评价

微生物复合菌剂在石油污染土壤生物修复中的应用潜力在不断扩大,有着广阔的发展前景,但同时对人体健康和生态环境的安全问题也存在较大的不确定性和潜在风险.文章中采用八株降油菌制成混合菌剂,通过动物试验和陆生植物生长试验,对微生物复合菌剂进行生物安全评价.结果表明,试验用微生物复合菌剂对动物皮肤无刺激性,对植物生长无毒害作用,具有相对安全性.