羊肚菌菌丝间融合与不融合现象研究

用平板、空试管、断培养基等方法培养羊肚菌菌丝,在显微镜下原位直接观察菌丝间的融合和非融合现象。观察六妹羊肚菌Morchella sextelata、梯棱羊肚菌M. importuna、七妹羊肚菌M. septimelata、Mel-21和秋天羊肚菌M. galilaea、Mes-16、Mes-19、Mes-20、Mes-21等9个物种,共100多个菌株菌丝间2 000多个接触点;并历经6年时间,用300多个菌株在国内外100多个地点超过500公顷面积进行出菇试验。结果发现:同一单孢菌株的菌丝分枝间有少量部位的可自体融合,融合点不产生新的分枝菌丝;同一物种的不同单孢菌株间菌丝不融合,同一物种的多孢菌株培养物内部相互不融合;不同物种间的菌丝都不融合;不融合的菌丝接触点出现Ⅱ型、X型、Y型、T型、π型等状况交叉而过,细胞接触而不融合;未见菌丝间的有性融合;菌丝接触后出现死亡、缠绕、卷曲、打结、膨大等现象;羊肚菌菌丝体纯培养物可以形成分生孢子和菌核。出菇试验结果表明,腐生型羊肚菌物种的出菇率,超过200个单孢菌株100%,超过100个多孢菌株100%,超过50个纯组织分离物小于50%,超过30个组孢混合菌株小于50%;出菇菌株在形态和产量有显著差异。共生型羊肚菌的菌种都不出菇。能出菇的同一物种的多孢菌株出菇后表现出子实体形态多样性,不同物种混合播种后出菇的子实体为原来物种的形态特征。结论:羊肚菌单孢培养物菌丝间不发生有性融合,单个孢子自身可孕,完全能够单孢出菇。     

三唑类杀菌剂对苹果轮纹病菌超微结构的影响

为了研究三唑类杀菌剂对苹果轮纹病菌形态和结构的影响,选择在生产上常用的防治苹果轮纹病的三唑类杀菌剂:戊唑醇和苯醚甲环唑,对苹果轮纹病菌进行处理。用光学显微镜和扫描电镜技术研究新型三唑类杀菌剂对苹果轮纹病菌发育的组织学和超微形态结构的影响。结果表明:光学显微镜和扫描电镜观察发现三唑类杀菌剂处理能导致苹果轮纹病菌发生一系列变化:菌丝的生长明显受到抑制,不再匍匐生长,而是向上生长。菌丝干瘪、畸形,分枝增多,分枝有长有短,很不规则,且不均匀膨大。一些菌丝出现不同程度的龟裂现象。这些变化会导致苹果轮纹病菌菌丝的生长严重受阻,最终菌丝细胞解体死亡。     

VA菌根真菌对植物养分吸收与传递的影响

VA菌根是泡囊-丛枝内生菌根菌与高等植物根系形成的共生体.VA菌丝增加根系的吸收面积,促进植物对矿质养分(尤其是磷和微量元素)的吸收,增强植物抵抗养分胁迫的能力,减少氮、磷肥的使用量和流失,从而避免水体富营养化.VA菌丝可以形成菌丝桥,在不同植株间传递养分,成为生态系统养分循环的重要通道.     

根间菌丝桥对三叶草生长及磷营养状况的影响

用五室方法研究了不同收获期三叶草根间菌丝桥对受体植株生长及体内磷营养状况的影响。结果表明三叶草根问菌丝矫形成以后,受体三叶草的生物量和体内磷的含量和浓度均有所增加,且与对照处理间的差异随接种时间的延长表现的更为明显。     

姬松茸菌丝及担孢子核观察

用荧光染色法观察姬松茸菌丝体和担孢子的核,用扫描电镜观察姬松茸担孢子着生情况。结果表明：姬松茸菌丝体为多核,未见到锁状联合;姬松茸担孢子56．3％为双核,17．6％为单核;姬松茸每个担子上着生4个或3个担孢子。     

Arbuscular mycorrhizal fungi and soil aggregation in a no‐tillage system with crop rotation

Crop rotation adoption in no‐tillage systems (NTS) has been recommended to increase the biological activity and soil aggregation, suppress soil and plant pathogens, and increase the productivity aiming at the sustainability of agricultural areas. In this context, this study aimed to assess the effect of crop rotation on the arbuscular mycorrhizal fungi (AMF) community and soil aggregation in a soil cultivated for nine years under NTS. Treatments consisted of combinations of three summer crop sequences and seven winter crops. Summer crop sequences consisted of corn (Zea mays L.) monoculture, soybean (Glycine max L. Merrill) monoculture, and soybean–corn rotation. Winter crops consisted of corn, sorghum (Sorghum bicolor (L.) Moench), sunflower (Helianthus annuus L.), sunn hemp (Crotalaria juncea L.), pigeon pea (Cajanus cajan (L.) Millsp.), oilseed radish (Raphanus sativus L.), and millet (Pennisetum americanum (L.) Leeke). Soil samples were collected at a depth of 0–0.10 m for analyses of soil chemical, physical, and biological attributes. Spore abundance, total glomalin, and soil aggregate stability index were higher in the soil under corn monoculture. The highest values of aggregate mean weight diameter were observed in the soybean–corn rotation (3.78 mm) and corn monoculture (3.70 mm), both differing from soybean monoculture (3.15 mm), while winter crops showed significant differences only between sorghum (3.96 mm) and pigeon pea (3.25 mm). Two processes were identified in the soil under summer crop sequences. The first process was observed in PC1 (spore abundance, total glomalin, easily extractable glomalin, pH, P, and Mg²⁺) and was related to AMF; the second process occurred in PC2 (aggregate mean weight diameter, soil aggregate stability index, K⁺, and organic matter) and was related to soil aggregation. The nine‐year no‐tillage system under the same crop rotation adoption influenced AMF abundance in the soil, especially with corn cultivation in the summer crop sequence, which promoted an increased total external mycelium length and number of spores of AMF. In addition, it favored an increased soil organic matter content, which is directly related to the formation and stability of soil aggregates in these managements.     

镉胁迫对姬松茸菌丝生理指标与镉吸收的影响

为了比较镉胁迫对不同姬松茸菌株(J1、J77)菌丝生长与镉吸收的影响,通过室内培育试验,设立0～75 mg·kg-1的不同镉胁迫浓度梯度,测定其对姬松茸菌丝生理指标与镉含量的影响。结果显示,不同镉浓度胁迫处理对J77和J1菌丝抗氧化系统的影响各异。当镉浓度为5 mg·L~(-1)时,J1与J77菌丝SOD酶活性分别增加121.5%、157.5%;当镉浓度高于5 mg·L~(-1)时,两个菌株菌丝SOD酶活性均开始降低。在10～75 mg·L~(-1)中高镉浓度胁迫范围,J77、J1菌丝的POD酶活性分别减少92.7%、95.3%。在5～50 mg·L~(-1)镉浓度胁迫范围,J77、J1菌丝的CAT酶活性分别减少40.9%、60.4%,随着镉胁迫浓度增加,J1的镉毒害更为严重。在0～2 mg·L~(-1)镉浓度范围内,J1与J77菌丝的APX酶活性分别增加7.9、13倍,两菌株相差近5倍,J77菌丝APX酶活性反应大于J1菌丝。不同浓度镉胁迫处理条件下(0～75 mg·L~(-1)),J1菌丝丙二醛(MDA)显示了较大幅度的提升,氧化程度比较剧烈,而J77在整个过程则提升幅度较缓,氧化应激程度相对较低。当镉胁迫浓度为10 mg·L~(-1)时,J1菌丝MDA含量比对照高1.6倍并达到最大值;当镉浓度为15mg·L~(-1)时,J77菌丝MDA含量比对照高60%并达到最大值,J1、J77的MDA最大值相差近1倍,J1菌丝细胞膜过氧化反应比J77更为强烈。在0～75 mg·L~(-1)浓度范围内,J77与J1菌丝中镉含量的浓度均随着外源镉含量的提高而增加。当镉浓度在2.5～50 mg·L~(-1)范围内,J1、J77菌丝镉含量分别增长了17.2、19.1倍;但就镉吸收累积量而言,J1菌丝比J77菌丝镉含量高近2.3倍;J77不仅对高镉胁迫的耐受程度高于J1,而且J77抵制镉吸收能力高于J1。结果表明,姬松茸J1和J77菌丝SOD、POD、CAT、APX酶活性及MDA含量随镉含量变化均表现为"低促高抑"的现象,J77菌丝镉含量低于J1,J77具有抵制镉吸收的潜力。     

赤霉素和α—萘乙酸对羊肚菌菌丝生长的影响

采用不同浓度的赤霉素（GA）和α-萘乙酸（NAA）配制成综合马铃薯培养基对羊肚菌菌丝体生长情况进行了研究。结果表明：2种激素对其都有不同程度的促进作用。GA在0．5－10μg/mL浓度下有明显的促进作用，其中以5μg/mL处理促进作用最强（P＜0．001）；NAA也有促进作用，以其5μg/mL处理第6d时促进作用最强（P＜0．05）；GA对羊肚菌菌丝体生长的促进作用明显优于NAA。     

Differences of hyphal and soil phosphatase activities in drought-stressed mycorrhizal trifoliate orange (Poncirus trifoliata) seedlings

Differences of hyphal and soil phosphatase activities between mycorrhizal and non-mycorrhizal plants were less studied under drought-stressed (DS) conditions. In a pot experiment, fungal alkaline phosphatase (FALP), and succinate dehydrogenase (FSDH), soil phosphatase activity, both soil and plant P contents were compared in 6.5-month-old trifoliate orange (Poncirus trifoliata) seedlings under 80 days of DS with or without inoculations by arbuscular mycorrhizal fungi (AMF, Glomus diaphanum, Glomus mosseae or Glomus versiforme). Plant growth and biomass production under DS were significantly higher in mycorrhizal than in non-mycorrhizal seedlings. Both the FALP and the FSDH activities under DS were significantly reduced in these three Glomus inoculated seedlings. In general, similar soil neutral and alkaline phosphatase activities, but significantly higher soil acid and total phosphatase activities, were exhibited in mycorrhizal than in non-mycorrhizal seedlings under both the well-watered (WW) and the DS. Both leaf and root P contents were significantly higher in the AM colonized seedlings, but soil available P contents were lower in the growth media with AM seedlings. Our results showed that higher hyphal enzymes’ activities, soil acid and total phosphatase activities, and plant P contents in AM colonized seedlings, particularly in Glomus mosseae-colonized seedlings and/or under DS, would result in a better growth of the host plants, which might be the basis for enhancing drought tolerance in plants.     

Chalastospora gossypii in a Maine Coon cat: case report and literature review

A 15-y-old castrated male Maine Coon cat was evaluated for an ulcerated soft tissue mass on the right hindlimb that had been observed for 4 mo and had grown rapidly. A 3 × 3 cm soft, raised, amorphous, and ulcerated subcutaneous mass was observed on the lateral right metatarsus. In-house cytology via fine-needle aspiration was nondiagnostic. Incisional biopsy of the mass and further staging was declined, and amputation was elected. The amputated limb was submitted for histopathology, which revealed severe chronic nodular granulomatous dermatitis and multifocal granulomatous popliteal lymphadenitis with large numbers of intralesional fungal hyphae. Fungal PCR and sequencing on formalin-fixed, paraffin-embedded tissue identified Chalastospora gossypii. No adjunctive therapy was elected at the time. The patient has done well clinically 1 y post-operatively. C. gossypii is a rare microfungus found worldwide and is considered a minor pathogen of several plants. To our knowledge, infection by this fungus has not been reported previously in veterinary species. Features in our case are comparable to other mycotic infections. Nodular granulomatous mycotic dermatitis and cellulitis, although uncommon, should be a differential for soft tissue masses in veterinary species; C. gossypii is a novel isolate.