NYH-1型~(14)C核素高灵敏探测装置

本文描述了可测量低活度1 4 C核素的高灵敏探测装置。在FH 36 7探头的基础上进行了改装 ,更换了闪烁介质 ,增加了物质屏蔽和反符合屏蔽以及相应的电子线路。本装置对1 4 C的探测效率 ,植物干样为 6 93% ,土壤样为 3 2 % ,装置的本底计数为 2 35cpm     

应用~(15)N稀释法筛选高固氮能力的大豆品种

应用＾１５Ｎ稀释法筛选出了具有高固氮能力的大豆品种和品系,大豆品系１００５,８５０２,２０９６,１４５４,９４用东农４２是高固氮品系,它们的固氮效率高达７０％,大豆品系１４５４和１５５５即高产又高固氮。根据方差分析,不同大豆品种或品系固氮效率差异显,固氮效率与产量无相关关系,与成熟期呈正相关,成熟期越长,固氮效率越高。有１０年品种或品系在１９９２和１９９４年两次进行试验,尽管两年的降雨情况有较大     

用~(15)N示踪法研究不同土壤水分条件下小麦对氮的吸收利用

本研究结果表明,同一施氮量处理小麦地上生物量、茎叶产量和籽粒产量随土壤水分含量的增加而提高,在同一土壤含水量下,这３ 种产量则随氮素肥料施用量的增加而增加。小麦成熟后地上部吸收总氮量的方差分析显示出施氮处理和水分处理对小麦吸氮量的影响达到显著水平,同一施氮处理小麦地上部吸氮总量随土壤含水量的增加而增加,在３ 种土壤水分含量条件下,小麦的吸氮量均随施尿素氮肥量的增加而提高。施尿素处理的土壤Ａ 值随土壤含水量的增加而降低;尿素与猪粪配施处理的土壤Ａ 值则随土壤含水量的增加而增加。在相同施肥量下,尿素氮的利用率随土壤含水量的增加而提高,当田间持水量分别为５０ ％ 、７０ ％ 和９０ ％ 时,小麦对土壤中氮素利用率分别为１３３０ ％ 、２７９７ ％ 和３２２６ ％ ,尿素与猪粪配施处理在３ 种土壤水分条件下的氮肥利用率分别为１９９６ ％ 、２９９０ ％ 和３４３９ ％ 。说明在水分缺乏的情况下,尿素氮的利用率受土壤水分条件的制约,土壤水分充足及无机氮肥与有机肥配施可以提高氮肥的利用率。     

粪产碱菌耐铵工程菌与水稻联合共生固氮作用

粪产碱菌（ Ａａｅｃａｌｉｓｆａｅｃａｌｉｓ） 在ＬＷ 培养基下能产生植物激素ＩＡＡ。盆栽结果表明,接种Ａ．ｆａｅｃａｌｉｓ 显著提高了水稻的生长,接种Ａ１５０１ 和Ａ１５１３ 的水稻稻谷产量分别比未接种提高了８５％ 和１０３ ％ ,用１５ Ｎ 同位素稀释法估测水稻地上部总氮中来源联合固氮的百分率达９００ ％ 和１１５ ％ ,其结果与水稻地上部（ 茎叶及稻谷） 总氮量的增加幅度（８６ ％ 和１１６ ％ ）基本一致。研究还表明Ａ１５１３ 耐铵工程菌的产ＩＡＡ作用以及对水稻的生长和产量、联合固氮作用均优于原始菌株Ａ１５０１ 。     

灰葡萄孢菌nit突变体的诱导及其在营养体亲和性测定中的应用初探

 从山西运城、临汾、长治、晋中、大同等地保护地黄瓜灰霉病病株上采集、分离的分属于3个不同菌丝融合群的8个灰葡萄孢菌单孢菌株,经氯酸盐诱导处理,共获得了抗氯酸盐的硝酸盐利用缺陷突变体(nit突变体)59株,其中nit1型38株,nit3型10株,nitM型11株。所有nit突变株分别在PDA斜面转管培养3次(21 d)后,除6株恢复成野生菌株外,其余多数nit突变菌株表现稳定。来源于同一野生菌株的不同类型nit突变体间或同一菌丝融合群不同野生菌株的nit突变体间可产生互补反应而形成异核体,其中以nitM型突变株互补性最好,在利用nit突变体测定灰葡萄孢菌营养体亲和性时应作为标准菌株。来源于不同菌丝融合群的nit突变体间不能产生互补反应。     

玉蜀黍赤霉有性重组体的诱导及其生物学特性

 本研究以硝酸盐营养缺陷型突变体(nit)和多菌灵抗性为遗传标记,在5个所选菌株中设计了3个玉蜀黍赤霉病菌Gibberella zeae的杂交组合,使各菌株之间进行杂交,从而诱导有性重组体。从各杂交组合的后代中任意挑选出3个有性重组体,比较了这些有性重组体与其亲本在无性和有性阶段的主要生物学性状。结果表明,玉蜀黍赤霉中的nit基因及对杀菌剂多菌灵的抗药性基因可以通过有性杂交的方式重组,即发生了有性重组。有性重组体与其亲本在菌落生长、培养性状和致病性方面没有显著差异;但某些有性重组体中,产孢量和产子囊壳能力方面存在一定差异。总体看来,有性重组体仍然保持了较高的适合度。因此,可以认为有性重组在玉蜀黍赤霉群体对多菌灵抗药性发生发展以及群体遗传进化中可能起着重要的作用。     

Mating Behaviour and Vegetative Compatibility in Spanish Populations of Botryotinia fuckeliana

Mating behaviour and vegetative compatibility were studied in Spanish populations of Botryotinia fuckeliana. Fifty-seven isolates out of the 61 tested were sexually fertile with one or more of the reference strains of known mating type (MAT1-1 or MAT1-2). Thirty-nine isolates were heterothallic, giving fertile crosses when mated with the MAT1-1 (24 isolates) or the MAT1-2 (15 isolates) reference strain. Eighteen isolates crossed successfully with both MAT1-1 and MAT1-2 reference strains, and were referred to as homothallic or MAT1-1/2. Both mating types were widespread, being represented in isolates from two regions, from the same and different greenhouses, from different hosts, and from different years of isolation. Isolates were paired on Malt Extract Agar + NaCl to evaluate vegetative compatibility. Most of the paired isolates were unable to fuse and showed a different reaction of incompatibility. Nitrate-non-utilising (nit) mutants were selected by growth on a medium amended with 30–50gl^–1 potassium chlorate. Over 600 chlorate-resistant sectors were recovered from 40 isolates at a mean frequency of 0.15–2.39 sectors per colony, but only 11% were identified as nit mutants by their thin growth with no aerial mycelium on minimal medium. However, most of these nit mutants reverted to wild type during six months of storage on chlorate-amended medium. Genetic complementation between nit mutants occurred only in two cases between mutants from the same isolate.     

Distinguishing characteristics and vegetative compatibility of Colletotrichum kahawe in comparison with other related species from coffee

On the basis of pathogenicity tests on green berries or hypocotyls of coffee and by morphological and biochemical characteristics in culture, 31 isolates of Colletotrichum were classified into C. kahawe (24 isolates), C. gloeosporioides (six isolates) or C. acutatum (one isolate). Within these groups of isolates, vegetative compatibility groups (VCGs) were determined by complementation tests with mutants in the nitrate assimilation pathway. There were distinct incompatibility barriers between the three species. Among the C. gloeosporioides group, the three isolates tested were self-compatible but incompatible with each other. Within C. kahawe , 18 isolates were self-compatible and only one main VCG was detected. However, partial compatibility in C. kahawe was also indicated by variation in the intensity of heterokaryon formation between different pairs of isolates and between different types of mutant. The existence of only one VCG in C. kahawe is consistent with the low level of variation found in previous work on DNA polymorphism.     

杨树溃疡病菌3菌株营养体亲和性的研究

对杨树溃疡病菌3株系氯酸钾诱变、突变体氮源利用和VCG测定表明，该病菌A、B菌株属同一VCG群，地理来源一致；C菌株为另一VCG群。探讨了3株系分化的生理及营养体亲和的遗传基础。     

免耕稻茬麦植株、土壤系统氮素平衡研究

研究表明，免耕稻茬麦吸收积累的氮素４９．４％来自肥料氮，氮肥的当季利用率为４５．９８％，植株对其依赖和谐高于旱作水浇麦。肥料氮土壤残留率为２７．８７％，回收率为７３．８４％，损失率为２６．１６％。百公斤籽粒和生物产量吸氮量分别为３．７０和１．４４ｋｇ。肥料氮的７２．４％分配到籽粒中，高于总氮的分配比例。返青、拔节、三叶及种肥的吸收率依次为９．７２％、１１．３５％、１０．７９％和７．０２％。三叶期液