The Effect of Detopping the Field Bean Plants (Vicia faba L. minor) and Lack of the Pod Setting on the Symbiosis with Root Nodule Bacteria

The plants of field bean var. Nadwiślaνski were detopped after about 1 month since the beginning of flowering and after that all flower buds were removed from some plants. The effect of a change in the trophic balance on the setting and subsequent growth of root nodules was studied.
The removal of pods had the greater effect on the increase in the weight of the remaining organs than the detopping of plants. Detopping retarded the ageing of the plants and delayed the phase of the greatest reduction of the number of pods. The detopping of plants revealed their considerable compensative possibilities in terms of production of the pod weight and the potential of leaves for biomass production. The data obtained indicate that plant detopping may disturb the root–bacteria exchange of signals, necessary to initiate the nodule development, while the further growth of nodules depends, above all, on the amount of available photosynthates.
A very high correlation between the dry weight of the whole plant to the dry weight of leaves ratio and the weight of nodules was observed. It proves the importance of the trophic balance of the plant for the root nodule weight production.     

亚麻细菌病发生及防治技术研究

从亚麻细菌病的发生、发展、危害及病原茵特性到病害综合防治，进行了系统研究，明确了该病的发生与品种抗性、耕作栽培等诸方面的关系，为病害防治提供了理论依据；明确了种子带茵是该病害主要侵染源和传播途径，同时建立综合防病体系。     

一株克氏原螯虾病原——霍乱弧菌的分离鉴定

从尾扇边缘溃烂的克氏原螯虾中分离到一株优势菌LK-18,并对该菌株进行种属鉴定和致病性分析。通过菌落形态观察、16S rRNA测序、血清型分析及基因特性鉴定对细菌的类别进行初步判断,并采用浸泡感染、肌肉注射和腹腔注射等方式进行人工感染实验对细菌的致病性进行评估。经16S rRNA测序分析和4个管家基因（atpA、pyrH、recA、gyrB）串联分析,该菌株最终被鉴定并命名为Vibrio cholerae LK-18。V. cholerae LK-18经PCR鉴定不属于O1和O139血清型,但含hly毒力基因和几丁质分解相关的几丁质酶（chitinase,Chi）基因。人工感染实验虽未能重现烂尾症状,但从克氏原螯虾烂尾组织中分离的V. cholerae LK-18具有致病性,能够引起克氏原螯虾的死亡。研究结果表明霍乱弧菌LK-18是一种致病菌,不仅扩大了非O1/O139群霍乱弧菌的感染宿主范围,同时预警霍乱弧菌有导致克氏原螯虾养殖业暴发疾病的可能,因此要提前做好该疾病的预防工作,从而避免霍乱弧菌感染带来的损失。     

烤烟总氮含量和氮碱比与物理性状的关系分析

试验以我国主产烟区的主栽烤烟品种K326为材料,测定X2F(下橘二)等级共计124份样品的总氮、烟碱含量和物理性状,系统地分析总氮含量、氮碱比与物理性状的相互关系。结果表明,总氮含量、氮碱比和物理性状在样品间存在着广泛的变异。总氮含量随单叶重、叶长、叶面密度的增加而逐步下降;氮碱比随叶长、叶宽的增加而上升,随叶面密度的增加而逐渐下降。总氮与叶长、叶面密度的关系可分别用逆函数■=0.827 38.047/x、复合函数■=1.880×0.996x描述;氮碱比与叶宽、叶面密度的关系可分别用复合函数■=0.413×1.023x描述、幂函数描述■=2.791x-0.354。     

Screening for New Cosmeceuticals from Brown Algae Fucus vesiculosus with Antioxidant and Photo-Protecting Properties

Phlorotannins play a role in biological functions to protect the cells against UV and oxidative damage in brown algae. We hypothesized that these compounds can function as photo-protectors and antioxidants in skin care formulations. Two types of extracts (water (FV-WE) and 67% v/v ethanol (FV-EE)) from Fucus vesiculosus were obtained with a phlorotannin content between 7−14% in dry extract. Exposure to sun light during growth was included as a factor on the phlorotannin content but did not influence the phlorotannin content. However, green colored F. vesiculosus had lower total phenolic content (TPC) (FV-WE = 6.9 g GAE 100 g⁻¹ dw, FV-EE = 7.8 g GAE 100 g⁻¹ dw) compared to those with a yellow/brownish color (FV-WE = 10.4–13.7 g GAE 100 g⁻¹ dw, FV-EE = 11.2–14.0 g GAE 100 g⁻¹ dw). UVA and UVB photo protective capabilities of the extracts through different biological effective protection factors (BEPFs) were evaluated using in vitro methods; the Mansur method for sun protection factor (SPF) and calculation of effective solar absorption radiation (%ESAR) to determine SPF and UVA protection factor (UVA-PF) of the extract and in seaweed enriched lotion. The SPF was negligible, when evaluating FV-WE in lotion (10 and 20% w/w). Moreover, %ESAR of the FV-WE showed SPF and some UVA-PF, but not enough to give sufficient SPF in lotions (10% w/w). It was concluded that the concentration of UV protecting compounds in the extracts was too low to and that further fractionation and purification of phlorotannins is needed to increase the SPF.     

Continuous Production of Biogenic Magnetite Nanoparticles by the Marine Bacterium Magnetovibrio blakemorei Strain MV-1T with a Nitrous Oxide Injection Strategy

Magnetotactic bacteria (MTB) produce magnetosomes, which are membrane-embedded magnetic nanoparticles. Despite their technological applicability, the production of magnetite magnetosomes depends on the cultivation of MTB, which results in low yields. Thus, strategies for the large-scale cultivation of MTB need to be improved. Here, we describe a new approach for bioreactor cultivation of Magnetovibrio blakemorei strain MV-1^T. Firstly, a fed-batch with a supplementation of iron source and N₂O injection in 24-h pulses was established. After 120 h of cultivation, the production of magnetite reached 24.5 mg∙L⁻¹. The maximum productivity (16.8 mg∙L⁻¹∙day⁻¹) was reached between 48 and 72 h. However, the productivity and mean number of magnetosomes per cell decreased after 72 h. Therefore, continuous culture in the chemostat was established. In the continuous process, magnetite production and productivity were 27.1 mg∙L⁻¹ and 22.7 mg∙L⁻¹∙day⁻¹, respectively, at 120 h. This new approach prevented a decrease in magnetite production in comparison to the fed-batch strategy.     

水稻内生细菌B196的鉴定及其对水稻纹枯病的防治作用

从水稻体内分离得到的细菌菌株B196对水稻纹枯病菌Rhizoctonia solani的生长有较强抑制作用.通过形态学和生理生化鉴定及16S rDNA序列分析,将菌株B196鉴定为巨大芽孢杆菌Bacillus megaterium.采用浸种和喷雾的方法将菌株B196接种到水稻植株后,均能在稻株体内回收到该菌株,表明菌株B196能在水稻体内定殖.菌株B196对水稻纹枯病的盆栽和田间防效分别为64.29%和55.13%.     

用免疫分离法检测稻种上的白叶枯病菌

 免疫分离法是一种新型的、高度灵敏和准确的种菌带菌检验法,它结合了利用专化性抗血清的选择法吸附作用和活细菌可形成菌落的两方面的优点,从种苗材料中分离到目标细菌,用纯菌测试它的回收率为50~70%,最低检出率为50~100个菌/ml,人工喷接种和病田收获的病种带菌率达87%,平均每粒自然病种上的细菌数在100个左右。免疫分离所得菌落经致病性测定,大多数为白叶枯菌。     

内生枯草芽孢杆菌B215对香蕉弯孢霉叶斑病抑制作用初探

通过香蕉内生枯草芽孢杆菌菌株B215对峙培养及其菌体代谢物的活性测定结果表明,B215菌株对香蕉弯孢霉叶斑病原真菌具有很强的拈抗作用,其对峙培养能明显抑制靶标菌菌丝向四周均匀扩展,抑菌带宽度为0.4 cm;菌株滤液的EC50值达5.10%,主要是以代谢产物中的抗菌物质造成孢子和菌丝膨大成球状畸形,原生质外泄,孢子崩溃干瘪,致使病菌丧失侵染和繁殖能力.