小麦条锈菌侵染高温抗病品种组织病理学研究

条锈菌 ( Puccinia striiformis W.)侵染高温抗病品种后 ,抗性表达后与表达前比较 ,条锈菌产孢量显著减少 ,产孢期缩短 ,但孢子萌发率不受表达前后限制。组织病理学观察发现 ,高温抗性表达前 ,寄主内菌落面积大且增长快 ,吸器母细胞数目多 ,后期可产生少量寄主坏死细胞 ,但不足以抑制菌丝的扩展 ;高温抗性表达后 ,接种后 48h即产生典型的寄主细胞坏死 ,后期寄主坏死细胞连片 ,菌落扩展明显受抑 ,菌落稀且面积小     

盐分和贮藏对矮沙冬青种子萌发的影响

本文以濒危植物矮沙冬青(Ammmopiptanthus nanus(M.Pop.) Cheng f.)的种子为试材,研究不同贮藏条件和盐分胁迫对其发芽率、发芽指数和活力指数的影响,结果表明:矮沙冬青种子为正常型种子,室温贮藏18个月仍有较高的种子活力,5℃低温贮藏可明显提高矮沙冬青种子活力及萌发整齐度,加速种子萌发进程。矮沙冬青种子萌发期具有一定的耐盐性,耐盐极限浓度为0.3 mol/L,耐盐致死浓度为0.45 mol/L,其种子萌发率、下胚轴长、发芽指数、活力指数与盐浓度均呈极显著负相关。     

重瓣榆叶梅茎段组织培养体系的建立

以重瓣榆叶梅带腋芽的茎段作为试验材料,研究了不同外植体消毒方式、初代培养基激素配比和生根培养基激素配比对重瓣榆叶梅组织培养的影响。结果表明:1)先用75%酒精处理30 s,再使用0.1%升汞溶液消毒8 min或以2%次氯酸钠溶液消毒12 min,外植体感染率最低;2)茎段初代培养最佳培养基为MS+6-BA2.0 mg/L+NAA 0.05 mg/L,诱导率为89.30%;3)最佳增殖培养基为MS+6-BA 2.0 mg/L+NAA 0.1 mg/L+KT1.0 mg/L,增殖倍数为4.4,且生长状况良好;4)1/2MS+IBA 0.2 mg/L为最佳生根培养基;5)该研究建立了重瓣榆叶梅组培再生体系,为工厂化育苗与大面积推广奠定了基础。     

The importance of abortive stoma penetration in the partial resistance and nonhost reaction of adult barley and wheat plants to leaf rust fungi

Summary Early stages of the infection process of Puccinia hordei isolate 1.2.1 and of a P. recondita f.sp. tritici isolate were studied on adult plants of four barley lines and one wheat line. Two of the barley lines are extremely susceptible to P. hordei, the other two have a very high level of partial resistance.A histological study based on a trypan blue staining indicated that stoma penetration by P. hordei isolate 1.2.1 was equally successful on the susceptible as on the partially resistant adult barley plants. Abortion of substomatal vesicles was rare in all lines. These results do not support a hypothesis that mechanisms of partial resistance in adult plants differ from those in seedlings by a substantial abortive stoma penetration.Also in the nonhost combinations wheat-P. hordei and barley-P. recondita f.sp. tritici inhibition of stoma penetration and of substomatal vesicle development appears to play a biologically insignificant role in adult plants.The proportion of stoma penetration on the leaf sheaths of two of the barley lines was as high as on the leaf blades of the flag leaf and the leaf below the flag leaf. There was no evidence for stomatal exclusion as a crucial factor in the relatively low infectibility of leaf sheaths to leaf-blade specialized rust species.     

不同条件下韭菜汁对香蕉枯萎病菌4号小种活性抑制的研究

研究了不同温度、pH值、杀虫剂和杀菌剂的影响下,韭菜汁对香蕉枯萎病菌4号小种的抑制作用,以确定韭菜汁在不同条件影响下对病菌的活力。结果表明,在试验的各温度处理后,55℃以上的温度对韭菜汁的成分有破坏作用,菌落的生长受到显著影响。韭菜根汁对病菌孢子的抑制作用不受pH值的影响。酸性至弱碱性情况下,韭菜茎汁对病菌孢子萌发的抑制率为100%;在强碱性条件下,韭菜茎汁中物质的活性促进了孢子的萌发。供试杀虫剂和杀菌剂对韭菜汁的成分无明显破坏作用。     

山莓叶中茶多酚的提取工艺研究

用正交实验方法研究了从山莓叶中提取茶多酚的提取工艺,得到了提取茶多酚的最佳工艺条件。该工艺条件具有操作简单、产量高、无毒无污染、成本低等特点。     

野生黄木香的离体培养及其再生体系研究

以野生黄木香茎段为外植体,探讨了不同生长调节物质对其不定芽诱导、增殖和生根的影响,并建立了野生黄木香的高效再生体系。结果表明,利于野生黄木香分化的诱导培养基为M S+A gNO33.0 m g/L+6-BA1.5 m g/L+NAA 0.5 m g/L+琼脂6.5 g/L+蔗糖30 g/L;以M S+A gNO33.0 m g/L+6-BA 1.5 m g/L+NAA0.05 m g/L+琼脂6.5 g/L+蔗糖30 g/L为增殖培养基时的增殖效果最好,增殖倍数为5.5;黄木香高效的再生体系为1/2 M S+A gNO34.5 m g/L+IBA 0.2 m g/L+质量分数0.2%活性炭+琼脂4.0 g/L+蔗糖20 g/L,其生根率可达95%。     

Allelopathic potential of itchgrass (Rottboellia exaltata L. f.) powder incorporated into soil

Itchgrass ( Rottboellia exaltata L. f.) is a widespread weed in northern Thailand. The farmers in this area have been using itchgrass as a mulching material in order to control other weeds in vegetable fields. Laboratory experiments were undertaken to investigate the phytotoxic activity of itchgrass powder incorporated into soil in order to evaluate the allelopathic activity in the field. The phytotoxic activity on the growth of radish seedlings ( Raphanus sativa L. var. radicula ), used as a test plant, was more pronounced in the root than in the shoot growth. The phytotoxic activity was found to be similar for the soils incorporated with the shoot or the root powder of itchgrass. The growth of the radish seedlings grown in sea sand and watered with soil water obtained from the soil previously incorporated with itchgrass powder showed a similar inhibition to those planted in the treated soil. The phytotoxic activity on the growth of the radish seedlings in the soil incorporated with the powder decreased over time. It is suggested that itchgrass releases phytotoxic compound(s) into soil water and the concentration of the active compound(s) in the soil water decreases over time.     

碱性肥料对香蕉枯萎病发生及土壤微生物群落的影响

【目的】针对我国香蕉主产区蕉园土壤酸化、 微生物环境恶化,香蕉枯萎病严重泛滥和肆虐,严重威胁产业等问题,通过施用碱性肥料改善蕉园土壤酸性及微生物环境,从而降低香蕉枯萎病发病率,促进香蕉健康生长。【方法】以重病区蕉园土壤为对象,采用盆栽试验,研究碱性肥料对土壤微生物及香蕉枯萎病发生情况的影响。试验设碱性肥料(AF)和常规肥料(CCF)2种肥料处理,每种肥料设低量(L1)、 中量(L2)和高量(L3)3个施肥量,同一施肥量处理的氮、 磷、 钾总用量相等。于2013年3月6日移栽香蕉苗到营养钵, 130 d后待各处理香蕉发病明显时采集土壤及植株样品进行各项指标测定。【结果】 1)施碱性肥料能显著降低香蕉枯萎病的发病率,常规肥料处理的香蕉发病率为78%,而碱性肥料处理的仅为33%。2)碱性肥料对土壤微生物群落有明显的影响,土壤中的真菌数量AF处理明显少于CCF处理,而细菌、 放线菌数量则显著高于CCF处理,因此AF处理土壤的香蕉尖孢镰刀菌明显减少。3)试验期间碱性肥料能显著提高土壤pH值,较常规肥料处理提高了0.75个pH单位,而土壤EC值比常规肥料处理低47.76 μS/cm。4)土壤pH值与土壤中古巴专化型尖孢镰刀菌(FOC)的数量及香蕉发病率呈显著负相关; 细菌数量与FOC数量、 香蕉枯萎病发病率、 病情指数之间呈显著的负相关; 土壤中FOC和真菌数量与香蕉发病率呈显著正相关。5)香蕉生物量随着碱性肥料和常规肥料用量的增大而增加,但碱性肥料的效果更加明显。【结论】应用碱性肥料不仅可以为香蕉提供氮、 磷、 钾养分,而且能改良蕉园土壤酸性从而改善土壤微生物群落结构及环境,有效防控香蕉枯萎病的发生。     

香蕉枯萎病菌cyp1基因的克隆与序列分析

为了解亲环素基因(cyp1,其编码亲和蛋白)在尖孢镰刀菌古巴专化型生理小种1号和生理小种4号之间及与其他镰刀菌之间的差异,分析cyp1基因与两生理小种之间的寄主选择性差异的关系,通过比对现有镰刀菌属的亲环素基因序列,设计并合成引物,采用PCR和RT-PCR方法扩增了尖孢镰刀菌古巴专化型生理小种1号和生理小种4号2个生理小种的cyp1基因,并测序进行比较分析,同时对编码蛋白进行了氨基酸序列比对和功能分析。结果表明,2个生理小种cyp1基因全长均为1066bp,开放阅读框均为675bp,编码224个氨基酸,基因序列间差异性为0.8%,编码蛋白间仅存在1个氨基酸的差异;两生理小种的cyp1基因序列与镰刀菌属其他专化型或不同种间存在差异性,与不同属之间其他种间的差异最大达50%,比对蛋白序列发现仅存在0.85%的差异,这进一步证明亲和蛋白在真菌中较保守。从cyp1基因序列及其编码蛋白的氨基酸序列在两生理小种之间的差异性分析结果推测,2个生理小种寄主选择性差异与cyp1基因并无明显对应关系,这为进一步研究cyp1基因功能奠定了基础。