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.     

赖氨酸修饰对梯棱羊肚菌黑色素结构和理化特性的影响

为了进一步提高梯棱羊肚菌黑色素的提取率及溶解性,本试验采用单因素、Plackett-Burman试验、响应面试验对纤维素酶-超声波协同提取梯棱羊肚菌黑色素的提取工艺进行优化研究。通过赖氨酸修饰,并对修饰前后的梯棱羊肚菌黑色素进行结构表征、理化性质及稳定性研究。结果表明,在NaOH浓度为1.54 mol/L,纤维素酶添加量为20 mg/g,纤维素酶酶解时间为78.6 min,料液比为1:30,酶解温度为40 ℃,超声时间为80 min条件下提取的梯棱羊肚菌黑色素最优。未修饰的梯棱羊肚菌黑色素不溶于水,色价值为480.24,修饰后的黑色素溶解度为1 016 g/L,色价值为1 771.18,比未修饰的黑色素在溶解性、色价值方面均有所提高。此外,在不同的温度、光照、pH条件下,修饰前后的梯棱羊肚菌黑色素均比较稳定。以上研究结果为梯棱羊肚菌黑色素的高效提取及其产品的开发利用奠定了理论基础。     

不同调酸剂对种植玉米红壤微生物群落的影响

为研究红壤微生物丰度和群落组成对不同调酸剂的响应,分析影响碳/氮关键代谢过程微生物的变化,通过盆栽实验,设置不施肥（CK）、钙镁复合剂（L）、钙镁复合剂配施猪粪（ML）和钙镁复合剂配施秸秆（SL）4个处理,采用宏基因组测序技术,分析土壤细菌、真菌和古菌以及碳/氮代谢关键过程微生物。结果表明：L、ML和SL处理显著提高土壤pH值和交换性钙/镁,显著降低土壤交换性酸。调酸剂增加了细菌优势菌中的变形菌门相对丰度,降低了绿弯菌门和酸杆菌门相对丰度;降低了真菌优势菌中的毛霉菌门相对丰度;增加了古菌优势菌中的广古菌门和深古菌门的相对丰度,降低了奇古菌门的相对丰度。冗余分析结果显示,速效钾是影响土壤细菌和真菌群落结构的主要环境因子,土壤pH和有机碳是影响土壤真菌和古菌群落结构组成的关键因子。碳代谢过程的贡献度方面,变形菌门的贡献度在SL处理中最高,放线菌门和芽单胞菌门的贡献度在ML处理中最高。氮代谢过程中,各处理绿弯菌门对硝化作用的贡献率均超过80%。调酸降低了绿弯菌门和酸杆菌门在反硝化与硝酸盐异化还原过程中的贡献度,L与SL处理的变形菌门贡献度低于ML处理,而ML处理的放线菌门贡献度高于L与SL处...     

外源阿魏酸抑制鲜切苹果褐变机制研究

苹果在鲜切过程中易因遭受机械损伤而引发褐变,严重影响其感官品质、风味和商品价值。采用不同浓度外源阿魏酸溶液对鲜切‘红富士’苹果进行浸泡处理,以研究其抑制鲜切苹果褐变的机制。结果表明：1、5、8、10 g/L 的阿魏酸浸泡处理均能有效抑制鲜切苹果褐变,10 g/L 阿魏酸浸泡处理10 min 对鲜切苹果褐变的抑制效果最优;10 g/L 阿魏酸处理显著提高了鲜切苹果超氧化物歧化酶（SOD）活性及1,1-二苯基-2-三硝基苯肼（DPPH）自由基、2,2-联氨-双-3-乙基苯并噻唑啉-6-磺酸（ABTS）阳离子自由基的清除率,抑制了贮藏后期多酚氧化酶（PPO）活性,降低了表儿茶素等单一酚的含量,提高了对香豆酸的含量;添加5 mg/mL 表儿茶素会促进苹果浆液褐变,而添加5、10、20、40 mg/mL 对香豆酸均能抑制苹果浆液褐变。综上所述,外源阿魏酸处理可通过提高SOD 活性、抗氧化能力、内源褐变抑制物含量以及降低褐变底物含量来减轻鲜切苹果褐变。     

减氮对麦玉轮作农田土壤反硝化细菌群落结构和多样性的影响

探究减氮对华北地区麦玉轮作农田土壤反硝化细菌群落结构和多样性影响,为华北地区麦玉轮作农田氮肥管理提供技术支持,本研究以不施氮为对照（CK）,设置 2个施氮量,分别为常规施氮量（纯氮 300 kg·hm^-2,N2）、减氮 20%（纯氮 240 kg·hm^-2,N1）,提取土壤DNA,用nirS（细胞色素cd1-亚硝酸还原酶）、nirK（Cu-亚硝酸还原酶）引物扩增后采用MiSeq PE300测序技术,研究施氮量对麦玉轮作农田土壤性状及nirS、nirK反硝化细菌群落结构及多样性的影响。结果表明,3个处理nirS、nirK反硝化细菌α-多样性指数无显著差异,nirS反硝化细菌α-多样性高于nirK。减氮显著影响nirS、nirK反硝化细菌物种组成。减氮对nirS、nirK反硝化细菌门水平及nirK纲水平物种组成无显著影响,但显著降低了nirS反硝化细菌Deltaproteobacteria（δ-变形菌纲）相对丰度;减氮显著影响nirS、nirK属水平物种组成。硝态氮、速效磷、pH值是影响土壤nirS反硝化细菌属水平群落结构主要环境因子;pH值是影响土壤nirK反硝化细菌属水平群落结构的主要环境因子。研究表明,适量减氮不影响反硝化细菌α-多样性,但显著影响反硝化细菌属水平群落组成和群落结构,减氮主要是通过影响土壤性状及微生物群落结构进而影响农田土壤N₂O排放。     

剩余污泥腐植酸的提取和对作物幼苗建成的影响

为解决IHSS （国际腐植酸协会）推荐法提取剩余污泥腐植酸参数不明确和剩余污泥腐植酸提取研究中缺乏其毒性效应评价等问题,利用响应曲面法得到剩余污泥腐植酸提取的最佳条件,并分析了腐植酸理化特性及其对作物幼苗建成的影响。结果表明,腐植酸提取的最佳条件：碱浓度为0.19 mol·L^-1,碱泥比（mL∶g）为11.6,振荡时间为3.8 h,提取量为96.1 mg·g^-1。相较于推荐法的腐植酸提取量增加了118%。提取所得腐植酸的元素分析显示,O/C为0.84,H/C为0.14,C/N为4.43;傅里叶变换红外光谱和凝胶渗透色谱分析显示,剩余污泥腐植酸存在羧基、醇羟基和酚羟基等含氧官能团,重均分子量为8 856 Da。此外,在500 mg·L^-1施用条件下,该腐植酸对大白菜和萝卜种子发芽率和子叶光合色素含量均无显著影响,而对大白菜种子胚根伸长具有显著促进作用。综上,通过优化提取条件可显著提高腐植酸提取量,剩余污泥腐植酸腐殖化程度与芳香化程度均较高,分子量较小,生物活性较强,且低浓度下对作物早期生长无不良影响。     

Effects of dietary vitamin E and fat supplementation in growing-finishing swine fed to a heavy slaughter weight of 150 kg: II. Tissue fatty acid profile,vitamin E concentrations,and antioxidant capacity of plasma and tissue

The study aimed to assess the effects of vitamin E (VE) supplementation and fat source on fatty acid (FA) composition, VE concentrations, and antioxidant capacity in plasma and tissues of pigs fed to a heavy slaughter weight (150 kg). A total of 64 pigs (32 barrows, 32 gilts; 28.41 ± 0.83 kg) were blocked by sex and weight, and randomly assigned to one of eight dietary treatments (n = 8 per treatment) in a 4 × 2 factorial arrangement. Fat sources included corn starch (CS), 5% tallow (TW), 5% distiller’s corn oil (DCO), and 5% coconut oil (CN); VE supplementation levels were 11 and 200 ppm. Five-phase diets were formulated to meet requirement estimates of NRC (2012) and fed to pigs for each period of 25 kg from 25 to 150 kg. Increasing VE supplementation level increased C16:1 (P < 0.05) content but decreased C20:0 (P < 0.05) content in backfat and belly fat, while in liver, it increased C17:0 (P < 0.05) but decreased C18:0 (P < 0.05). Compared to the pigs fed the CS diet, the pigs fed the CN diet had greater (P < 0.05) content of total saturated FA, the pigs fed the DCO diet had greater (P < 0.05) content of total polyunsaturated FA content and iodine value, and the pigs fed the TW diet had greater (P < 0.05) content of total monounsaturated FA in backfat, belly fat, and liver. Plasma VE concentrations increased linearly (P < 0.05) with increasing length of feeding but faster (P < 0.05) in the pigs fed the CN and TW diets compared with the CS and DCO diets within the 200 ppm VE level; the pigs fed the DCO diet had the highest plasma VE concentrations (P < 0.05) from Phase 2 to Phase 5 within the 11 ppm VE level. The VE concentrations in liver and loin muscle (P < 0.05) increased with increasing dietary VE level from 11 to 200 ppm, but it was not affected by dietary fat source. There was no effect of VE supplementation and fat source on antioxidant capacity in plasma and liver except that pigs fed the DCO diet had greater liver SOD activity (P < 0.05) than the pigs fed the CN diet. In conclusion, dietary VE supplementation did not affect FA profile in backfat, belly fat, and liver consistently, while dietary FA composition with different fat sources affected much of the FA profile in backfat, belly fat, and liver. The higher level of VE supplementation increased liver and muscle VE concentrations and dietary fat sources affected plasma VE concentrations differently (P < 0.05), wherein the TW and CN diets increased the VE absorption greater than the DCO diet.