Lemon,Citrus aurantifolia,peel and Bacillus licheniformis protected common carp,Cyprinus carpio,from Aeromonas hydrophila infection by improving the humoral and skin mucosal immunity,and antioxidative responses

The role of dietary lemon peel (LM) and/or Bacillus licheniformis (BL) on the growth, immunity, and resistance against Aeromonas hydrophila in common carp, Cyprinus carpio was investigated in this study. LM and BL were included in diets at 0% (T0), 10⁸ CFU/g BL (T1), 1.5% LM and 10⁸ CFU/g BL (T2), and 3% LM and 10⁸ CFU/g BL (T3). Fish fed with T1, T2, or T3 had higher weight gain, specific growth rate, white blood cells count, and blood total protein with lower feed conversion ratio than T0 group (p < .05). The albumin increased significantly (p < .05) in fish fed both BL and LM (T3). The serum superoxide dismutase (SOD), catalase, lysozyme, and bactericidal activities were significantly increased in fish fed both BL and LM (T2 and T3), while serum glutathione peroxidase increased in fish fed BL (T2) (p < .05). Fish fed T1, T2, and T3 diets displayed higher SOD and lower malondialdehyde than fish fed T0 (p < .05). After the A. hydrophila challenge, the mortality rate was significantly lower in T1, T2, and T3 groups than the T0 group (p < .05). The obtained results revealed that LM and BL could be used to increase resistance against A. hydrophila infection in carp. However, further field studies should be performed to confirm the obtained results.     

化肥减量配施有机肥对柠檬树体生长、果实产量及品质的影响

探讨化肥减施和配施有机肥改善土壤质量,减少化肥使用量,提高柠檬产量和品质,为云南柠檬园土壤环境改良和柠檬化肥减施增效提供技术依据。以‘云柠1号’柠檬为试材,利用田间小区试验,设置4个不同施肥处理,即100%化肥（常规施肥）、70%化肥+有机肥15 kg/株、50%化肥+有机肥15 kg/株及不施化肥处理+有机肥15 kg/株。分别测定不同施肥处理的柠檬树体生长参数、花枝成花数、果实品质、产量和叶绿素含量。结果表明,与常规施肥相比,70%化肥+有机肥15 kg/株处理下柠檬的生长参数、果实产量和品质有显著差异,该处理显著加快了柠檬树体的生长,获得了更高的产量和果实品质。与常规施肥相比,植株株高增高6.37%,嫁接口上、下5 cm处直径分别增粗13.05%、9.61%;单果重和产量分别增加15.19%、28.60%;果实出汁率、Vc含量和总糖含量分别增加6.68%、27.85%、6.20%,综合考虑产量、果实品质等因素,70%化肥+有机肥15 kg/株处理对柠檬增产、提质、增效的效果最佳。     

氮钾水平与全多酚对柠檬流胶病抗性的影响

Ｎ、Ｋ水平与柠檬抵御流胶病病原菌侵染能力有密切关系。在营养液中Ｎ浓度大于２４０ｍｇ／ｋｇ，树体对流胶病抵御能力降低；在Ｋ浓度小于２２０ｍｇ／ｋｇ范围内，提高Ｋ水平能明显提高树体抗流胶病的能力。叶片中全多酚的含量与树体抗流胶病能力强弱有关，在营养液中Ｎ浓度为２４０ｍｇ／ｋｇ，Ｋ浓度为２２０ｍｇ／ｋｇ时，叶片全多酚含量为９．１７ｍｇ／ｇ，树体具有较强的抗流胶病能力。     

云南省柠檬主产区土壤肥力特征与评价

土壤肥力在一定程度上决定了柠檬的产量和果实品质,为了探究云南省柠檬主要产区土壤肥力的特征,为柠檬种植园合理施肥提供理论依据。本研究对云南省5个州市的7个县(区)的20个柠檬主产区(乡镇)129个土壤样品进行分析测试,根据全国第二次土壤普查分级标准和Nemerow指数法评价不同主产区和不同海拔高度土壤肥力。结果表明：云南省7个县(区)柠檬采样区土壤综合肥力均达到Ⅰ级以上,土壤肥力总体较高,平均综合肥力指数为3.18,排名为元江县>施甸县>隆阳区>师宗县>澜沧县>陇川县>瑞丽市。单项肥力指数达到Ⅰ级(Pi≥1.7)17个,达到Ⅱ级(0.9≤Pi<1.7)30个,达到Ⅲ级(Pi<1.7)16个。在700~900m这一海拔区间土壤综合肥力最优,随着海拔的升高,土壤养分先下降后升高,海拔在1100~1300m为一个分水岭。     

云南柠檬灰霉病菌侵染能力及防控研究

柠檬灰霉病是由灰葡萄孢Botrytis cinerea引起的真菌性病害。灰霉病菌只侵染柠檬花、花蕾和幼果,柠檬果生长发育期不受侵染。在云南柠檬湿热种植区,柠檬春花、夏花、秋花和冬花四个开花物候期,灰霉病可以侵染柠檬春花、秋花和冬花,夏花几乎不受侵染。灰霉病主要侵染柠檬春花,病枝率为54.00%～76.00%,病情指数为35.00%～77.00%;其次为冬花,病枝率为16.00%～28.00%,病情指数为9.00%～16.00%;再次为秋花,病枝率为4.00%～8.00%,病情指数为2.00%～4.00%。柠檬完全花的柱头、花柱、花药、花丝、花瓣、子房、花萼、花梗和蜜盘9个部位均会受到灰霉病菌的侵染。柠檬灰霉病首先侵染柠檬花的柱头,接种24h即可侵染;接种48h小时后,柠檬花的花药、花瓣和花萼均出现灰霉病侵染症状。大田灰霉病防控时段及防控效果表明,柠檬的开花期是灰霉病防控的关键时期。在初花期、盛花期、谢花期整个开花期均进行药剂防控,以初花期开始进行药剂防控,并以盛花期加强药剂防控具有较好的防控效果。     

柠檬不同部位精油的成分分析及抑菌活性

采用水蒸气蒸馏法提取北京柠檬叶片、枝干和果皮的精油,并进行GC-MS分析,共鉴定出38种成分,其中叶片23种,枝干21种,果皮29种。3份精油主要挥发油成分均为D-柠檬烯,相对含量分别为52.85%、53.03%和51.23%;共有成分14种,特异性成分分别有4种、3种和14种。通过对3种食源性细菌的抑菌活性的测定,3份柠檬精油均有一定程度的抑菌作用,其中,叶片精油对大肠埃希氏菌和金黄色葡萄球菌抑菌效果最佳,且抑菌圈直径最大;果皮精油对伤寒沙门氏菌的抑菌效果最佳,抑菌圈最大。研究结果表明,柠檬不同部位精油活性成分含量差异较大,在对其开发利用时,可考虑各自优势,合理利用柠檬的叶片、枝干和果皮,为柠檬资源合理化和精细化的开发利用提供一定的科学依据。     

Characterisation of <Emphasis Type="Italic">Phoma tracheiphila</Emphasis> by RAPD-PCR,microsatellite-primed PCR and ITS rDNA sequencing and development of specific primers for <Emphasis Type="Italic">in planta</Emphasis> PCR detection

Thirty six isolates of Phoma tracheiphila from Italy, the causal agent of the mal secco disease on Citrus species, were characterised by different molecular tools in comparison with representative isolates of other phytopathogenic Phoma species. These included analysis of the distribution of RAPD and microsatellite markers and sequencing of the internal transcribed spacer (ITS) region of the nuclear rRNA genes. The results obtained with 12 RAPD primers (92 markers) and 7 microsatellite primers (56 markers) suggest that Italian isolates of P. tracheiphila are genetically homogeneous, leading to identical patterns upon amplification with all the tested primers. Accordingly, ITSI-5.8S-ITS2 sequences were highly conserved (98–100% identity along a 544-characters alignment) among all the isolates of P. tracheiphila. A neighbor-joining analysis of ITS sequences of P. tracheiphila in comparison with those of other Phoma species, as well as with alignable sequences from anamorphic and teleomorphic taxa retrieved in BLAST searches, revealed a close relationship between P. tracheiphila and Leptosphaeria congesta. A pair of P. tracheiphila-specific primers was designed on the consensus sequence (555 residues) obtained from the alignment of the newly generated P. tracheiphila ITS sequences. A PCR-based specific assay coupled to electrophoretic separation of amplicons made it possible to detect P. tracheiphila in naturally infected Citrus wood tissue collected from both symptomatic and symptomless plants. The limit of detection was 10 pg of genomic DNA and 5 fg of the ITS target sequence.     

摘心对柠檬苗新梢的影响

为探明不同摘心处理对柠檬苗生长的影响,以移栽1年生枳砧嫁接的柠檬苗为研究对象,嫁接3个月后分别进行自然生长（CK）,摘心留桩0.0cm,摘心留桩0.5cm,摘心留桩1.0cm处理。试验结果表明：摘心留桩1.0cm时,处理效果最佳,其抽梢数量、苗木基部粗度均优于摘心留桩0.0cm及自然生长（CK）,其苗高度也达到了优质苗木出圃移栽的规格。研究结果也显示,与自然生长（CK）相比,不同程度的摘心留桩均增加了侧芽萌发的数量、主干茎粗及侧枝生长的整齐度,但侧枝平均长度有所降低。     

Effect of salinity and arbuscular mycorrhizal fungi on growth and some physiological parameters of Citrus jambheri

Arbuscular mycorrhizal (AM) fungi alleviate the unfavorable effects of salinity stress on plant growth. A pot study was conducted to determine the effects of AM fungi and salt on growth and some physiological parameters of Citrus jambheri rootstock. Four levels of salinity (2, 4, 6, and 8 dS m^?1 as NaCl) and three mycorrhizal treatments (Glomus etunicatum, Glomus intraradices and non-mycorrhizal (NM) control) were used. As salinity increased, all measured characteristics of plants after 4.5-month growth except Na uptake, proline content, and electrolyte leakage decreased. Shoot dry weight and K uptake were significantly higher in G. intraradices-colonized seedlings than NM controls at all salinity levels. Root dry weight and shoot P uptake were significantly higher in G. etunicatum-colonized seedlings than NM controls at all salinity levels. G. intraradices-colonized seedlings had significantly higher proline content than NM controls and G. etunicatum-colonized seedlings at salinity levels of 4, 6 and 8 dS m^?1. The electrolyte leakage percentage was significantly lower in G. intraradices-colonized seedlings than NM controls at all salinity levels. The data demonstrated that mycorrhizal citrus seedlings exhibited greater tolerance to salt stress than NM seedlings and the enhanced proline content seems to be one of the mechanisms involved.