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1.
玉米生长生理生态学模拟模型   总被引:9,自引:0,他引:9  
建立了玉米(Zea mays L.)生长生理生态学模拟模型(MPESM)。模型由5个子模型组成:1)气象资料形成子模型,2)水分影响子模型,3)氮素影响子模型,4)玉米发育子模型,5)玉米生长子模型。MPESM具有5个主要功能:1)模拟环境条件(气象因子、土壤湿度和氮素供应)对玉米生长和发育的影响,2)模拟玉米的发育进程,3)模拟玉米的生长过程,4)模拟玉米产量形成过程,5)玉米最优化栽培管理决策  相似文献   

2.
不同温湿度组合对安微虫瘟霉诱发桃蚜病害的影响   总被引:2,自引:0,他引:2  
刘彩玲  冯明光 《昆虫学报》2000,43(4):380-387
用孢子浴方法,对42批次桃蚜Myzus persicae(30-60头/批)接种大剂量(孢子79-90个/mm^2)安徽虫瘟霉Zoophthora amhuiensis的分生孢子,在20℃下保湿24h后转入不同温度(10℃、15℃、20℃、25℃、30℃及自然变温下1.5-16.6℃和8.5-20.2℃)和温度(50%、65%、80%、90%95%及100%RH)的组合条件下观察桃蚜的反应。结果表  相似文献   

3.
1980—2005年松嫩平原土壤湿度对气候变化的响应   总被引:7,自引:0,他引:7  
基于松嫩平原16个农业气象站1980—2005年作物生长季的旬土壤湿度、月气温和月降水量观测资料,采用统计分析方法,分析了研究区表层(0~30 cm)土壤湿度的时空变化特征及其对气温、降水量等气候变化的响应.结果表明:1980—2005年间,松嫩平原不同区域作物生长季表层土壤湿度均呈减小趋势,松嫩平原表层土壤存在干旱化趋向,其中,西部和南部地区尤为明显;20世纪90年代以前,研究区表层土壤处于比较湿润阶段,之后土壤湿度持续降低,并发生了偏干现象;研究期间,松嫩平原作物生长季平均气温呈周期性波动上升,每6 a一个周期,期间小幅波动,1992年开始明显上升;生长季降水量的年际变幅较大,存在一个4~5 a的波动周期;研究区作物生长季表层土壤湿度与气温呈极显著负相关关系,与降水量呈极显著正相关关系(P<0.01).气温和降水量是影响松嫩平原作物生长季表层土壤湿度变化的主要气候因素.  相似文献   

4.
若尔盖地区25万年以来的植被与气候   总被引:20,自引:0,他引:20  
本文根据RM孔上部60m210个样品的花粉分析结果,探讨了若尔盖地区25万年以来的植被演替和气候变化。研究结果表明,若尔盖地区过去25万年的植被演替和气候变化可划分为7个阶段。在约250-195KaB.P.(7阶段),植被以亚高山莎草草甸为主,气温和降水与现在接近。在195-128KaB.P.(6阶段)和32-11KaB.P.(2阶段),植被主要是荒漠草原,反映寒冷干旱的冰期气候,年平均气温比现在低5-6℃,年降水量仅为现在的60-80%左右。128-71KaB.P.(5阶段)是过去25万年中水热条件最好的时期,植被主要是亚高山暗针叶林和亚高山草甸,大部分时间的气温比现在高1℃左右,降水量稍高于现在;但在此阶段的气温和降水仍有较大的波动,5e、5c和5a阶段的气温和降水高于5b和5d阶段。71-58KaB.P.(4阶段)的植被主要是高山草甸为主,年平均气温比今低3-5℃,年降水量约为现在的80%,在58-32KaB.P.(3阶段),早期植被以亚高山暗针叶林和草甸为主,晚期主要是亚高山禾草草甸,气温和降水均明显高于4阶段,在晚期气温呈非线性逐渐下降的趋势。  相似文献   

5.
蝴蝶兰根段的组织培养   总被引:38,自引:2,他引:36  
1 植物名称 蝴蝶兰(PhalaenopsisMellerGold“NFS”)。2 材料类别 根段。3 培养条件 (1)愈伤组织的诱导及分化培养基:B5+NAA1.5mg·L-1(单位下同)+KT0.2+CM150ml·L-1+3%蔗糖;(2)原球茎增殖培养基:B5+GA0.05+CH120+3%蔗糖;(3)小苗生长培养基:1/2MS+20%香蕉泥+2%蔗糖;(4)诱导生根培养基:1/2MS+IBA0.3+2%蔗糖。上述培养基均加0.2%活性炭,0.58%琼脂粉,pH为5.5;培养基在121℃高…  相似文献   

6.
测定水稻、玉米和狼尾草花粉在低温(5℃)低湿(45%)、低温(5℃)高湿(80%)、高温(35℃)低湿(45%)和高温(35℃)高湿(90%)4种贮藏条件下的活力表明:低温高湿下花粉活力保持的时间最长;狼尾草花粉比水稻、玉米花粉耐贮藏,在低湿高湿条件下贮藏30d后,仍有38.3%的萌发率;狼尾草花粉中蛋白质含量较高,淀粉含量较低。  相似文献   

7.
安祖花在低温贮藏过程中,其还原糖(果糖和葡萄糖)含量随呼吸速率的提高而逐渐降低。在4℃条件下,呼吸速率降低,还原糖含量下降的速度减慢。火焰苞色泽的变化与含糖量没有直接关系。 4℃条件下贮藏超过 3 d,然后移至 20℃,会加速花色的坏变。贮藏前,先用2.5%二甲亚砜(DM-SO)处理,然后在4℃、14℃条件下贮藏 15 d,并没有明显地抑制花色的坏变。  相似文献   

8.
超干贮藏杜仲种子的研究   总被引:12,自引:0,他引:12  
林坚  郑光华 《植物学通报》1996,13(A00):58-62
杜仲种子含水量降至3.5%以下,其耐藏力增强。经50℃10天人工加速老化后,表现出较强的抗老化能力。室温贮藏2年后,与5℃、-20℃条件贮藏种子相比,发芽率、根长及活力指数等均无显著性差异。超干种子比对照种子(含水量7.5%,室温贮藏)电导率降低45%;脂质过氧化产物丙二醛(MDA)的积累减少;对脱氢酶活性的保持能力比常规种子增强。超干种子幼苗的吸氧量高于对照种子。经过氧化物酶同工酶谱分析,超干种  相似文献   

9.
盐胁迫下丛枝菌根真菌对玉米水分和养分状况的影响   总被引:31,自引:4,他引:27  
在NaCl胁迫下无论接种AM真菌与否玉米植株生物产量均减少,但不接种处理的减少幅度比较种处理的高10个百分点左右,盐胁迫下接种AM真菌的玉米根系和地上部的干重、叶片水热均高于不接种处理、叶片脯氨酸含量低于不接种处理,在盐胁迫下真菌菌丝对玉米植株营养的贡献由45.3%降为42.6%,AM真菌对植株生长的效应反而由30.9%提高到63.5%,说明AM真菌主米耐盐性的机理与改善植株的水分状况和P营养状况  相似文献   

10.
本文研究模拟高原低氧下新生和胚胎大鼠发育时,下丘脑内促肾上腺皮质激素(CRF)及垂体环磷酸腺苷(cAMP)水平的变化。结果表明:5km海拔高度抑制下丘脑CRF的发育,当发育至25天和30天时,CRF含量分别为对照组的64.8%和57.9%。此时,体重分别为47.8%和52.9%。30天时,cAMP为20.8%。本研究还显示,在7km海拔高度,已怀孕大鼠难以完成正常的妊娠和胎儿发育过程,5km海拔高度暴露17天时,胚胎脑内CRF含量高于对照。  相似文献   

11.
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.  相似文献   

12.
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  相似文献   

13.
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.  相似文献   

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17.
鸡传染性法氏囊病病毒研究进展   总被引:3,自引:0,他引:3  
闫笑  李天宪 《中国病毒学》2003,18(2):191-195
传染性法氏囊病(Infection bursal disease, IBD)是由鸡传染性法氏囊病毒(Infectious bursal disease virus, IBDV)引起的鸡和火鸡的一种高度接触性传染病,给世界各国的禽养殖业带来了巨大损失.自IBDV发现至今新的变异株不断出现,分子结构的改变导致病毒致病力的改变及宿主对疫苗应答的改变,使得传统的疫苗已不能控制其流行,因此各国学者对其基因组结构和功能进行了广泛深入的研究,并积极研制新型有效的疫苗以达到防治的目的.  相似文献   

18.
In conclusion, the novel visual RT-LAMP assay is a simple, rapid, and sensitive approach for detection of SARS-CoV-2, and it is ready for application in primary care and community hospitals or health care centers, and even patients' own houses in response to the current SARS-CoV-2 epidemic because the assay does not require sophisticated equipment and skilled personnel. Furthermore, it is also ready to be used in fields for screening samples from wild animals and environments to facilitate the identification of potential intermediate hosts that mediate the cross-species transmission of SARS-CoV-2 from bats to humans.  相似文献   

19.
Shen  Jia-Yuan  Li  Man  Xie  Lyu  Mao  Jia-Rong  Zhou  Hong-Ning  Wang  Pei-Gang  Jiang  Jin-Yong  An  Jing 《中国病毒学》2021,36(1):145-148
正Dear Editor,Chikungunya virus (CHIKV), an arbovirus in the family of Togaviridae, genus Alphavirus, is transmitted by the A.aegyptii or A. albopictus mosquito, and causes disease in humans characterized by fever, rash, and arthralgia (Silva and Dermody 2017; Suhrbier 2019). It was first reported in 1953 in Tanzania, and caused only a few outbreaks and sporadic cases in Africa and Asia in last century. However, in the epidemic in 2004, CHIKV acquired mutations that conferred enhanced transmission by the A. albopictus mosquito(Schuffenecker et al. 2006). Since then, it has successively caused outbreaks in Africa, the Indian Ocean, South East Asia, the South America, and Europe (Zeller et al. 2016).  相似文献   

20.
Highlights
1. The N-terminal tail of histone H3 is specifically cleaved during EV71 infection.
2. Viral protease 3C is identified as a protease responsible for proteolytically processing the N-terminal H3 tail.
3. Our finding reveals a new epigenetic regulatory mechanism for Enterovirus 71 in virus-host interactions.  相似文献   

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