Differential effects of -mannose and 2-deoxy- -glucose on attempted powdery mildew fungal infection of inappropriate and appropriate ramineae

Barley, oat and wheat were used as both inappropriate hosts (IH) and appropriate hosts (AH) for three formae speciales of the fungus Blumeria graminis, the causal agent of powdery mildew disease. Treatment with either the glucose analog 2-deoxy- -glucose (DDG) or with -mannose dramatically suppressed penetration resistance in IH and to a much lesser extent in AH combinations. Other effects of DDG and -mannose were strikingly dissimilar. DDG greatly reduced localized autofluorescence at fungal attack sites on epidermal cells, and prevented hypersensitive epidermal cell death (HR). -mannose had little effect on autofluorescence or HR. DDG arrested the development of fungal haustoria and apparently prohibited biotrophy leading to secondary hyphae. -mannose allowed haustorial development and functional biotrophy leading to the production of elongating secondary hyphae. This suggests that B. graminis is in some way capable of utilizing -mannose as a carbon substrate. Results with IH combinations paralleled those of known mlo -barley responses to DDG and -mannose. Results are discussed in relation to specific physiological processes known to be influenced by either DDG or by -mannose, or by both compounds.     

20%多效唑·甲哌Wong微乳剂防止小麦倒伏和增产机理研究

冬小麦二棱期喷施植物生长调节剂20%多效唑·甲哌鎓微乳剂375 mL/hm2,可以显著抑制茎秆基部节间伸长,增加各节间充实度,其中赤霉素(Gas)和生长素(IAA)降低,可显著增强小麦抗倒伏能力和降低田间倒伏率.处理还协调了穗数、穗粒数和粒重的关系,增产幅度6.2%～28.6%.增产原因可能在于促进籽粒灌浆强,增加籽粒中内源Gas、IAA、细胞分裂素(CTKs)的水平,增强了籽粒库活性,同时促进茎叶中干物质向籽粒运转.     

细胞骨架解聚药物对小麦与叶锈菌互作诱发的细胞过敏性反应的影响

 小麦(Triticum aestivum)品种洛夫林10和叶锈菌小种366组成不亲和组合,小麦叶片发生过敏性坏死反应(HR)是小麦抵抗叶锈菌侵染的重要因素。在接种前给小麦叶片分别预注射微管解聚药物磺草硝(oryzalin)和微丝解聚药物细胞松弛素D (cytochalasin D,CD),结果表明2种药物注射使得寄主因叶锈菌侵染诱导的细胞过敏性坏死数目明显减少,并且注射药物的浓度越大,寄主细胞发生HR的数量越少。说明肌动蛋白和微管蛋白的聚合状态是诱发小麦叶片发生HR防卫反应所必需的,细胞骨架在小麦抵抗叶锈菌侵染过程中可能起着重要作用。     

Development and fecundity ofSitobion avenae on some wheat cultivars under laboratory conditions

Nymphal development time and fecundity ofSitobion avenae (F.) (Homoptera: Aphididae) were determined on nine widespread wheat varieties cultivated in Tekirdağ Region in Turkey. Tests were carried out in controlled environment chambers (25±1°C, 65±5% r.h.; 16:8, L:D). Development time (±S.E.) ranged from 5.75±0.25 to 7.20±0.20 days. Fecundity per female ofS. avenae was found to be the highest (12.87±1.50) on wheat cv. ‘Sana’. In this investigation cvs. ‘MV-17’, ‘Miryana’, ‘Pehlivan’ and ‘Saraybosna’ were particularly resistant againstS. avenae. http://www.phytoparasitica.org posting July 8, 2002.     

香菇杂交新菌株1363号的选育研究

采用单孢杂交的方法培育出香菇新菌株 136 3号。它具有产量高 ,质量好 ,遗传性状稳定 ,抗逆性状强等优点。     

中国的一个新记录属——冠生刺菌属

基于采自滇中哀牢山区的标本 ,报道我国的一个新记录属———冠生刺菌属CreolophusP .Karst.,并根据其主要特征把齿耳属SteccherinumGray的肉齿耳S .cir rhatum (Pers.exFr .)Teng归并到Creolophus属中。同时对有争议的相似种C .cirrhatus (Pers .exFr .)Karst.和C .corrugatum (Fr.)P .Karst.(=HydnumcorrugatumFr.)进行了比较研究 ,根据盖缘是否具有生殖能力的菌刺 ,提出两者应作为不同的种来处理。     

Olive processing wastes for weed control

The herbicidal effect of olive processing wastes (OPW) on some weed species in wheat, maize and sunflower was investigated in the Aegean region of Turkey. In trials with maize and sunflower, OPW was applied as an air‐dried solid form at 3 and 4.5 kg m^?2. It provided an effectiveness level on Portulaca oleracea of 63–98%. In trials with wheat, OPW was applied as solid and liquid forms, each at two different doses, namely 4.5 and 6 kg m^?2 (solid), and 5 and 10 L m^?2 (liquid). Solid OPW provided a reduction in total weed coverage of 75% and 81% at doses of 4.5 and 6 kg m^?2, respectively. The weed coverage reduction by liquid OPW was 39% and 62% with 5 and 10 L m^?2, respectively. Apart from 12–26% reduction of the number of germinating seeds, OPW showed no toxic effects on maize and sunflower. Wheat was affected in the initial stages but no adverse effect was detected at harvest. It can be concluded that the herbicidal effect of OPW may be considered as an alternative to chemical weed control in some important summer crops (maize and sunflower) and for most of the weeds in winter wheat.     

Effect of take-all root infections on nitrate uptake in winter wheat

The effect of take-all root lesions on nitrate uptake of wheat was investigated in two experiments under controlled conditions. Plants were supplied with a nutrient solution labelled with ¹⁵N during stem elongation and flowering to assess the distribution of the isotopic tracer in the different plant organs, and particularly in root segments located on both sides of take-all lesions. The ¹⁵N atom percentage excess measured in root segments located below lesions longer than 1 cm was reduced on average by half compared with that in healthy roots and root segments above lesions, reflecting a reduction in nitrogen uptake by these root segments. This reduction probably resulted from the invasion and breakdown of phloem vessels by the fungus hyphae, interrupting energy supply and thus the uptake process. Severely infected plants showed an increase in the uptake rate per unit of efficient root, which appeared to be a compensatory response to reduction of efficient root biomass in order to satisfy shoot nitrogen demand. However, this compensatory response was insufficient to ensure nitrogen accumulation equivalent to that of healthy plants, as reductions in nitrogen accumulated in roots and aerial parts at flowering were up to 56 and 49%, respectively, for plants with more than 50% of the root system below lesions longer than 1 cm.     

小麦高温抗条锈性的组织病理学和超微结构变化

为了进一步弄清高温抗条锈病的抗性机制，利用荧光显微技术和电镜技术研究了高温抗条锈性品种小偃6号的组织病理学特征和超微结构变化。结果表明：在高温抗条锈性表达时，病斑周围寄主细胞发生坏死和木质化，在高温处理24h，坏死细胞和木质化细胞数分别为初期的17．1和23．8倍。从超微结构观察，在高温抗条锈性表达时，侵染点附近寄主细胞壁表面凹凸不平、粗糙，细胞壁的厚度也较健康细胞厚。之后，细胞内的细胞器消解，仅有沿细胞壁分布的原生质和残存的一些颗粒状物质。     

哈茨木霉几丁质酶诱导及其对水稻纹枯病菌的拮抗作用

 在实验室条件下分别以几丁质和水稻纹枯病菌(Rhizoctonia solani)细胞壁作唯一碳源诱导哈茨木霉(Trichoderma harzianum)菌株NF9、TC3和P1产生几丁质酶,用硫酸铵沉淀法制备几丁质酶粗提液。上述木霉菌株内切几丁质酶活性(对胶体几丁质浑浊度的减少率)分别为79.8%、74.4%和76.0%,均显著高于非诱导的阳性对照。培养第5 d几丁质诱导的木霉菌株NF9和TC3内切几丁质酶活性显著高于由水稻纹枯病菌细胞壁诱导的酶活性。体外测定表明,通过诱导的木霉菌株TC3、NF9和P1几丁质酶粗提液对水稻纹枯病病菌的拮抗圈直径可达38、21和23 mm,与非诱导的阳性对照比较有显著性差异。对木霉几丁质酶拮抗作用的特点及生防应用进行了讨论。