二化螟水稻种群与茭白种群光周期反应的比较

本文报道了用水稻和茭白分别饲养二化螟水稻种群和茭白种群的光周期反应。光周期反应曲线显示,用水稻饲养茭白种群或用茭白饲养水稻种群,无论是在短光照还是在长光照条件下,绝大多数幼虫被诱导进入滞育,丧失了各自原有的光周期反应特性,表明这两个种群已分化到仅适应其本身寄主的程度。用水稻饲养的茭白种群仅有5%～6%的个体化蛹,且其幼虫期较用茭白饲养的延长了15～18天;而用茭白饲养的水稻种群有30%～40%的个体化蛹,其幼虫期与水稻饲养的仅相差3～8天。茭白种群用水稻饲养时32日龄幼虫体重仅为茭白饲养的53.1%,而水稻种群用水稻饲养时32日龄幼虫体重为茭白饲养的79.5%。这些结果表明,茭白种群不适应取食水稻,而水稻种群对取食茭白则有一定的适应能力。根据这些结果,我们认为：（1）这两个种群已出现种下分化的迹象;（2）茭白种植不会对水稻田二化螟的发生产生大的影响。     

二化螟越冬种群∶年龄结构对其冬后取食和化蛹动态的影响

调查了不同类型稻田及茭白田中二化螟的越冬年龄结构,比较了不同龄期幼虫之间的在冬后取食与化蛹动态方面的差异。结果表明,越冬虫龄以双季晚稻田中明显较低,中稻田与茭白田中相对较高。出现取食的个体比例在４－５龄幼虫之间差别不大;但取食的开始时间在龄期之间具明显差异,以４龄个体最早取食。未取食个体的化蛹进度明显快于取食个体;未取食个体中以４龄幼虫的化肾时间较早。     

二化螟越冬幼虫三种寄生蜂发生动态

本文报道浙江部分地区二化螟Chilo suppressalis越冬幼虫寄生蜂的主要种类、寄生率以及它们在冬前与冬后的羽化动态.在兰溪,寄生蜂对二化螟越冬幼虫的寄生率较低,常见种类仅有二化螟绒茧蜂.在安吉与嘉兴两地,除二化螟绒茧蜂为主外,稻螟小腹茧蜂和中华钝唇姬蜂也较为常见,三者对双季晚稻田二化螟越冬幼虫寄生率为18～19%.明显高于单季晚稻田的寄生率(8～15%).3种寄生蜂的羽化动态有较大差异,二化螟绒茧蜂和稻螟小腹茧蜂在进入11月后即不再羽化,而中华钝唇姬蜂的羽化则持续到11月中旬之后;越冬后,后者的羽化时间明显早于前两者.     

葱斑潜蝇生物学特性研究

葱斑潜蝇在山东1年发生6－7代,以蛹于10月在地表5cm左右土中越冬。4月下旬越冬代蛹开始羽化,羽化高峰在5－6月,4月下旬始幼虫,5月中旬出现第1代成虫,世代重叠发生,盛发期在6－9月,完成1代需17－31天,其中卵期2－5天,幼虫期3－9天,蛹期11－18天,成虫活动高度多在1m以下,取食,产卵喜在大葱心部第2,3叶,平均单雌产率109．3粒。幼虫潜食主植物的叶片而形成潜道。温度20－32℃、湿度60％－90％利于其生长发育,危害和繁殖。恒温下测得全世代的的发育起点温度为10．0℃,有效积温为361．1日度,土壤含水量5％－15％适宜蛹羽化。寄生性天敌有幼虫幼虫期寄生的姬小蜂6种,寄生率达40％;幼虫一蛹期寄生的金小蜂1种、茧蜂2种,寄生率为28．4％－79．4％。     

杀虫剂不同处理对二化螟为害、防治效果及水稻产量的影响

近年来,二化螟发生出现各代均偏重或大发生的新特点。为探索杀虫剂防治二化螟的新策略,采用田间小区试验在早晚稻田中分别研究5%氟虫腈加25%灭.水胺的不同施药时期和次数对二化螟幼虫的为害和防治效果及对水稻产量的影响。在试验地,二化螟第1和第2代发生在早稻田,第3和第4代发生在晚稻田。试验结果表明,在第1和第3代二化螟幼虫孵化高峰施药1次、隔10d再施药1次对早稻田和晚稻田的幼虫防效显著,分别达到了92.4%和92.6%。在早、晚稻田分别发生的第1和第3代2龄幼虫高峰期施药1次、同时在次代孵化高峰期再施药1次,均可显著降低虫伤株率和白穗株率,提高保穗效果,并显著提高单位面积上的水稻产量(3.98%~4.20%)。因此,对第1至第4代二化螟幼虫均进行1次药剂防治是二化螟各代均大发生的新形势下的防治策略。     

湖北省钟祥市粘虫发生规律研究

为了明确粘虫Mythimna separata(Walker)在湖北省钟祥市的发生规律,对小麦玉米轮作田粘虫成虫和幼虫种群的发生动态、粘虫雌蛾卵巢发育进度以及粘虫越冬虫量作了调查,分析了粘虫种群虫源性质。结果表明,钟祥市为1代粘虫多发区,其虫源为外地迁入的越冬代成虫,1代粘虫危害高峰期在4月中下旬,羽化盛期在5月中下旬,羽化后以迁出为主。第2代粘虫发生量很小,羽化后基本全部迁出;在田间未调查到第3代粘虫幼虫,本区发现的第3代成虫可能为由北方南迁的过境种群;第4代粘虫发生量也很小,羽化后全部迁出,不在本区繁殖危害。在田间未调查到准备越冬的粘虫。     

湖北省钟祥市粘虫发生规律研究

为了明确粘虫Mythimna separata(Walker)在湖北省钟祥市的发生规律,对小麦玉米轮作田粘虫成虫和幼虫种群的发生动态、粘虫雌蛾卵巢发育进度以及粘虫越冬虫量作了调查,分析了粘虫种群虫源性质。结果表明,钟祥市为1代粘虫多发区,其虫源为外地迁入的越冬代成虫,1代粘虫危害高峰期在4月中下旬,羽化盛期在5月中下旬,羽化后以迁出为主。第2代粘虫发生量很小,羽化后基本全部迁出;在田间未调查到第3代粘虫幼虫,本区发现的第3代成虫可能为由北方南迁的过境种群;第4代粘虫发生量也很小,羽化后全部迁出,不在本区繁殖危害。在田间未调查到准备越冬的粘虫。     

千屈菜一种新害虫——肾毒蛾

肾毒蛾Cifuna locuples Walker是2007年在武汉发现危害千屈菜(Lythrumsalicaria L.)的一种新害虫,幼虫能取食千屈菜叶片和花朵。室外观察和室内饲养结果表明,肾毒蛾在武汉市1年发生3代,以低龄幼虫越冬,次年3～4月开始为害。5月初越冬代成虫出现,6月下旬第1代成虫羽化,8月中旬第2代成虫羽化。成虫羽化1d后即可分多次产卵于叶背,卵粒数十几到两百多粒。幼虫有5龄,初孵幼虫群集为害,2龄以后分散取食,4～5龄取食量大。幼虫在叶背吐丝结稀疏的薄茧化蛹。     

利用茭白、荸荠及水稻饲养二化螟的技术研究

分别用水稻苗、茭白、水稻 +荸荠 3种方法 ,喂饲二化螟Chilosupperssalis初孵幼虫 ,比较室内 3种饲养方法对二化螟生长发育和繁殖力的影响 ,从而为二化螟的实验室饲养提供方法和依据。其中 ,在整个幼虫期用茭白饲养的二化螟幼虫发育历期和化蛹历期最短 ,分别为 ( 1 7 8± 0 5 )d和 ( 9 8± 0 8)d ,而用水稻苗饲养的二化螟幼虫发育历期和化蛹历期最长 ,分别为 ( 3 0 4± 1 2 )d和 ( 2 0 0± 1 6)d。水稻苗喂饲二化螟的雌雄蛹的比例较低 ,仅为 0 44;荸荠有利于雌性个体的分化 ,用水稻 +荸荠相结合喂饲二化螟的雌雄蛹比例为 1 1 8。用荸荠喂饲的蛹最重 (雌和雄蛹重分别为 71和 5 1mg 头 )。 3种饲养方法对二化螟的产卵率和孵化率无显著影响 ,但是 ,用水稻饲养二化螟蛹的羽化率比其它 2种饲养方法显著降低。由此可见 ,用茭白、水稻苗 +荸荠饲养方法进行二化螟饲养是切实可行的 ,它们有利于二化螟的生长发育。     

金绿宽盾蝽的生物学特性

金绿宽盾蝽Poecilocoris lewisi Distant在北京1年1代,以5龄若虫在侧柏(Platycladus orientalis Franco)附近的落叶和石块下越冬,翌年4月上中旬陆续从越冬处爬出,取食侧柏嫩叶。5月中旬5龄若虫开始羽化,6月初为羽化高峰期,6月中下旬羽化期结束,5月到8月为成虫期,7月底到8月中旬交配产卵,8、9月份若虫由1龄发育至5龄,9月中下旬为5龄若虫高峰期,11月5龄若虫开始转移越冬。     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Entwicklungsgeschichte und Ultrastruktur von Pollenkitt und Exine bei nahe verwandten entomophilen und anemophilen Angiospermensippen derAlismataceae,Liliaceae, Juncaceae,Cyperaceae, Poaceae undAraceae

Some closely related members of the monocotyledonous familiesAlismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae andAraceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate (ambophilous or amphiphilous) monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly dry and powdery pollen of anemophilous plants always contains a variable amount of inactive pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout.

     

Identification and Characterization of the First Equine Parainfluenza Virus 5

正Dear Editor,Parainfluenza virus 5 (PIV5), known as canine parainfluenza virus in the veterinary field, is a negative-sense,nonsegmented, single-stranded RNA virus belonging to the Paramyxoviridae family (Chen 2018). The virus was first reported in primary monkey kidney cells in 1954 (Hsiung1972), then it has been frequently discovered in various