低盐腌制对缙云梅干菜加工品质的影响

为研究低盐回卤腌制工艺对梅干菜加工品质的影响,对不同梅干菜原材料进行2.5%低盐腌制回卤加工,比较分析梅干菜加工产品的腌制出菜率、含盐量、亚硝酸盐含量和氨基酸含量等品质特点。结果表明,低盐回卤腌制加工明显降低了梅干菜的亚硝酸盐含量,甬雪3号的梅干菜中亚硝酸盐含量仅为1.89 mg·kg-1,高温加工后的制品中未检测到亚硝酸盐含量;氨基酸含量较高,总氨基酸含量为147.8~183.8 mg·kg-1,高于高盐腌制梅干菜的含量,其中鲜味氨基酸比例较高。腌制出菜率及田间性状分析发现,叶用芥菜分蘖能力及其茎叶比对梅干菜腌制产量具有明显影响,较高分蘖能力的高茎叶比芥菜品种有助于提高梅干菜腌制产量。此外,梅干菜品种会影响其加工产品可溶性糖、粗蛋白及粗纤维等含量。低盐回卤腌制加工工艺结合适当的叶用芥菜品种能够实现梅干菜的高效优质、安全生产,本研究为梅干菜加工提供了一定的技术支持和理论参考。     

腌制加工对不同品种叶用芥菜抗氧化物质含量和抗氧化活性的影响

本试验以4个不同品种叶用芥菜为材料,研究了腌制加工对叶用芥菜抗氧化物质含量(维生素C、总酚、总黄酮)和抗氧化活性(TEAC值和FRAP值)的影响。结果表明:与腌制前相比芥菜中抗氧化物质含量与抗氧化活性都有不同程度的下降。维生素C含量下降最为显著(P<0.01),幅度为40.70%~57.46%,总黄酮含量下降不显著,幅度为2.30%~10.62%,总酚介于二者之间;抗氧化活性的变化在品种间存在较大差异,雪里蕻和金丝芥腌制后抗氧化活性下降幅度未达到显著水平(TEAC 8.49%~10.83%,FRAP 9.03%~14.06%),而笋壳青菜和瘤子芥菜下降幅度达到显著水平(TEAC 14.45%~19.14%,FRAP 28.05%~35.77%,P<0.05)。总酚和总黄酮与抗氧化活性呈现极显著的正相关,总酚与TEAC和FRAP的R2分别为0.9482和0.9395,总黄酮与TEAC和FRAP的R2分别为0.8287和0.9129。维生素C与抗氧化活性的相关性较弱(TEAC,R2=0.2968,FRAP,R2=0.0979),酚类物质在腌制叶用芥菜抗氧化活性中起重要作用。     

高温诱导叶用莴苣抽薹过程中碳氮的变化分析

为了明确叶用莴苣高温抽薹的生理学基础,以叶用莴苣易抽薹品种G-B30、G-B31和耐抽薹品种G-B4、G-B20为试材,研究叶用莴苣高温抽薹过程中各糖组分、可溶性总糖、淀粉、可溶性蛋白含量以及碳氮比的动态变化。结果表明,经高温处理后,除G-B20外,其他3个品种的葡萄糖、蔗糖和果糖含量均表现为抽薹临界期低于未抽薹时期。2个易抽薹品种均在抽薹临界期可溶性总糖含量达到最低,2个耐抽薹品种在花芽分化始期可溶性总糖含量最低。淀粉含量在花芽分化始期达到最大值,抽薹时期含量又迅速下降。2个易抽薹品种抽薹后期的半乳糖、可溶性蛋白质含量显著高于抽薹前,并有大量积累的趋势,而2个耐抽薹品种相反。2个易抽薹品种的C/N在抽薹期最低,2个耐抽薹品种在高温处理过程中C/N不断升高。综上,高温诱导叶用莴苣抽薹过程中可溶性蛋白、半乳糖、淀粉大量积累,而可溶性糖、葡萄糖、果糖、蔗糖含量及C/N降低。本研究结果为进一步探究叶用莴苣高温抽薹的分子机理提供了参考依据。     

腌制叶用芥菜发酵菌分离鉴定及应用研究

为获得发酵性能优良的菌株,生产优质的发酵叶用芥菜,本研究从自然发酵的芥菜中分离发酵用菌株,通过测定乳酸菌的生长、产酸和亚硝酸盐降解能力以及酵母菌的产气、产酯能力和蛋白酶活性等发酵特性进行筛选,并对筛选获得的优良发酵菌加以应用。结果表明,筛选获得的2株乳酸菌L8短乳杆菌(Lactobacillus brevis)、L9植物乳杆菌(Lactobacillus plantarum)和1株酵母菌Y9酿酒酵母菌(Saccharomyces cerevisiae)在腌制叶用芥菜中的发酵性能优良。与自然发酵的叶用芥菜相比,接菌发酵叶用芥菜的pH值和亚硝酸盐含量分别减少了2.22%和88.13%;总酸含量、氨基酸态氮含量分别增加了9.02%和28.09%。接菌发酵提高了腌制芥菜的营养品质和安全性。本研究丰富了叶用芥菜的发酵菌种,为蔬菜发酵加工产业奠定了技术基础。     

Cd~(2+)处理对几种叶菜可食部分Cd含量及品质的影响

以5种叶菜为材料,采用水培和盆栽试验2种培养方式,测定不同浓度Cd2+处理下叶菜地上部(可食部分)生物量、Cd含量、硝酸盐及纤维素含量等生理与品质指标。结果表明:水培与盆栽培养条件下青菜、塌地乌、小白菜、菠菜及芥菜5种叶菜生物量随着Cd2+处理浓度增加显著降低(P0.05);可食部Cd含量显著升高(P0.05);高浓度水培与盆栽Cd2+处理(40mg.L-1和70mg.kg-1)下,5种叶菜中菠菜Cd含量相对较高,青菜Cd含量较低;随着Cd2+处理浓度增加,5种叶菜硝酸盐及纤维素含量升高,维生素C和可溶性糖含量下降,采用灰度关联综合分析表明,不同浓度Cd2+处理的5种叶菜中,青菜品质相对稳定及Cd含量较低,为Cd低积累品种。     

红柄叶用甜菜主要营养成分及抗氧化能力分析

为全面了解红柄叶用甜菜的营养价值,以红柄绿叶和红柄红叶类型的叶用甜菜为材料,分别对其8个品种、4个部位的色度、主要营养成分含量及抗氧化能力进行分析。结果表明,不同类型、品种和部位的叶用甜菜间均存在显著差异。红柄绿叶型甜菜的L*值、b*值、多酚含量和抗氧化能力均显著高于红柄红叶型,a*值、可溶性糖含量、花青素含量均显著低于红柄红叶型。就部位而言,嫩叶柄的L*值和a*值最大,嫩叶的b*值最大。在不同部位间,可溶性蛋白质、叶绿素、类胡萝卜素、花青素、多酚含量和抗氧化能力均呈现叶叶柄的趋势,可溶性糖则相反;在同一部位内,花青素、多酚含量和抗氧化能力均表现为老嫩,可溶性蛋白含量为嫩老,叶绿素、类胡萝卜素和可溶性糖在不同部位或类型间呈现不同的变化趋势。主成分分析结果表明,红柄叶用甜菜间的含量差异主要来自于部位因素,其次是类型因素。相关性分析表明,多酚对红柄叶用甜菜的抗氧化能力可能有较大贡献。本研究结果为人们日常膳食提供了一定参考,为红柄叶用甜菜的品种选育奠定了理论基础。     

有机无机复混肥对小白菜作用效果和机理的研究

采用田间小区试验研究了有机无机复混肥对小白菜C、N代谢关键酶活性及其产量与品质的影响。结果表明,施用有机无机复混肥能增强小白菜叶片中的蔗糖合成酶、蔗糖磷酸合成酶和硝酸还原酶活性,提高小白菜可食部分维生素C、可溶性糖、蛋白氮、天冬氨酸、丙氨酸、异亮氨酸和叶片中叶绿素的含量,增加小白菜产量,减少小白菜可食部分硝酸盐、亚硝酸盐的含量。     

淹涝胁迫和氮形态对苗期玉米糖、氮代谢底物量的影响

采用砂培培养方法,比较研究淹水和不同氮形态(铵态氮、硝态氮以及铵态氮︰硝态氮为1︰1)对苗期玉米根、茎鞘和叶的糖、氮代谢底物——可溶性糖、还原糖、硝态氮和游离氨基酸等物质含量的影响。结果表明,当淹涝胁迫持续7 d时,在非淹涝胁迫条件下,铵态氮处理的根、茎鞘和叶的可溶性糖和游离氨基酸含量均显著高于硝态氮处理(P<0.05);在淹涝胁迫条件下,硝态氮处理的根、茎鞘和叶的生物量干重显著低于铵态氮处理(P<0.05),其根和叶的生物量干重也显著低于铵态氮、硝态氮混合处理(P<0.05)。与非淹涝条件相比,在淹涝胁迫条件下,硝态氮处理的根系和叶的硝态氮含量显著降低(P<0.05),降低幅度分别高达62.6%和30.0%;此外,与非淹涝条件相比,在淹涝胁迫条件下,铵态氮处理的根的可溶性糖、还原糖以及游离氨基酸含量,茎鞘的可溶性糖和还原糖含量以及叶的可溶性糖和游离氨基酸含量均显著升高(P<0.05),而硝态氮处理仅根、茎鞘和叶的还原糖含量以及叶的游离氨基酸含量显著升高(P<0.05)。因此,在本试验条件下,由于糖、氮代谢底物含量充足,铵态氮处理的苗期玉米具有相对较强的耐淹涝胁迫能力。     

营养液中添加氯化钠降低硫浓度对韭菜硝酸盐累积的减控效应

  【目的】  韭菜易于吸收和累积硝酸盐,研究营养液中添加氯化钠 (NaCl) 和降低硫含量减少韭菜硝酸盐累积的效果,并从氮代谢途径初步探讨其减少硝酸盐累积的机理。  【方法】  采用新型韭菜专用营养液架床栽培系统进行了韭菜水培试验。在营养液中添加NaCl 12 mmol/L的同时,硫浓度设定为3、2、1和0 mmol/L 4个水平,分别用NaCl+S₃, NaCl+S₂, NaCl+S₁ 和 NaCl+S₀表示。韭菜生长30天后,取样分析了不同硫水平下韭菜中的硝酸盐含量及主要氮代谢途径中的氨基酸含量。  【结果】  在营养液硫供应水平3 mmol/L下,与营养液中不添加氯化钠处理 (CK) 相比,NaCl+S₃处理的韭菜硝酸盐累积降低了32.60%,地上部干重、可溶性糖和可溶性蛋白质含量、根系活力显著增加;NaCl+S₁处理的韭菜硝酸盐累积降低了53.30%,地上部干重、可溶性糖和可溶性蛋白质含量、根系活力显著增加。NaCl+S₁处理较NaCl+S₃处理更有利于降低硝酸盐含量。韭菜地上部的全氮含量无显著变化 (NaCl+S₃处理) 或略有增加 (NaCl+S₁处理),表明添加低浓度氯化钠并未限制氮素吸收。NaCl+S₃和NaCl+S₁处理下,硝态氮还原活性 (硝酸还原酶NR) 和转氨活性 (谷氨酸草酰乙酸转氨酶GOT、谷氨酸丙氨酸转氨酶GPT) 增加,尤其是初级同化活性 (谷氨酰胺合成酶GS) 分别大幅增加了43.57%和71.43%。NaCl+S₃和NaCl+S₁处理下,丝氨酸途径的游离氨基酸代谢和天冬氨酸途径的蛋白质合成得到增强,韭菜的游离氨基酸总量基本保持不变或略有增加,而蛋白质水解氨基酸总量显著增加。  【结论】  韭菜专用营养液中添加NaCl 12 mmol/L并将硫浓度降低到1 mmol/L,可显著提高根系和氮代谢关键酶活性,在一定程度上改变游离氨基酸代谢途径和蛋白质合成途径,进而在显著增加韭菜干物质的同时,大大降低硝酸盐累积。     

氮、硫配施对生姜产量和品质的影响

采用田间小区试验研究氮、硫配施对生姜生长发育及产量和品质的影响。结果表明,不同氮、硫配施比例对生姜产量和品质有显著影响。随施氮量的增加,生姜的株高、茎粗、分枝数和单株茎、叶鲜重随之提高,N600S50处理高于其它处理,而单株根茎鲜重则是N450S50处理最高。施氮量在450 kg·hm-2之内时,生姜产量随施氮量的增加而增加。相较于N0S0处理,不同施氮处理的增产率在33.1%~74.3%之间。同一施氮量下,增施硫肥可促进生姜生长发育,提高产量,增加幅度在2.1%~11.8%之间。生姜根茎的品质分析结果也表现出类似趋势。N450S50处理的还原糖、还原型Vc、姜精油和姜辣素含量均最高,分别为1.20%、91.8 mg·kg-1FW、4.28 m L·kg-1FW及13.5 mg·g-1;而粗蛋白和硝酸盐含量则N600S50处理较高,分别为9.71%和82.1 mg·kg-1FW。同一施氮量下,增施硫肥可明显提高还原糖、粗蛋白、还原型Vc、姜精油和姜辣素含量,降低硝酸盐含量。可见,适宜比例的氮硫配施可提高生姜产量,改善生姜品质。     

Effects of Nitrogen and Sulfur on Total Phenolics and Antioxidant Activity in Two Genotypes of Leaf Mustard

Leaf mustard (Brassica juncea Coss) is widely used for both fresh and processed markets in southern China. It contains high nutritional and medicinal compounds, which are important for maintaining optimum health. The objective of this study was to determine the influence of nitrogen (N) and sulfur (S) nutrition on total phenolics and antioxidant activity in two genotypes of leaf mustard (cvs. ‘Xuelihong’ and ‘Zhujie’). Plants were greenhouse-grown using nutrient solutions with two levels of nitrogen (10 and 25 mM) and three levels of sulfur (0.5, 1, and 2 mM). Total phenolic concentrations were considerably decreased by increasing nitrogen supply, whereas increased by increasing sulfur supply. Total phenolic concentrations in cv ‘Zhujie’ was higher than in cv ‘Xuelihong’. Three assays including 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, β -carotene bleaching (BCB), and ferric reducing antioxidant power (FRAP) were used to evaluate antioxidant activity. Increasing nitrogen supply reduced DPPH radical scavenging activity and FRAP value, but increased antioxidant activity using BCB assay. Increasing sulfur supply increased antioxidant activity with all three tests. The effects of genotype on DPPH radical scavenging activity and FRAP value were not significant, however, antioxidant activity using BCB assay was significantly higher in cv ‘Zhujie’ than in cv ‘Xuelihong’. A significantly positive correlation was found between DPPH radical scavenging activity and total phenolic concentrations in two genotypes, FRAP value and total phenolic concentrations in cv ‘Xuelihong’.     

Salicylic Acid–Induced Growth and Biochemical Changes in Salt‐Stressed Wheat

The interactive effect of salicylic acid and sodium chloride (NaCl) salinity on wheat (Triticum aestivum L.) cv. ‘Inqlab’ (salt‐sensitive) and cv. ‘S‐24’ (salt‐tolerant) was studied in a sand‐culture pot experiment in a net house. Wheat seeds soaked in water and 100 ppm salicylic acid solution for 6 h were sown in sand salinized with 0, 50, and 100 mM NaCl. Pots were irrigated with quarter‐strength Hoagland's nutrient solution. Fourteen‐day‐old seedlings were harvested, and growth parameters (leaf and root length, leaf and root dry weight) were recorded. Chlorophyll a and b content; soluble sugar (reducing, nonreducing, and total sugars) content; nitrate (NR) and nitrite reductase activity (NiR); soluble proteins, and total soluble amino acid content of fresh leaves were determined. Sodium chloride salinity significantly reduced growth parameters. Salicylic acid treatment alleviated the adverse salinity effect on growth. Salinity decreased the chlorophyll a and b content and chlorophyll a/b ratio in both varieties, but a decrease in the chlorophyll a/b ratio was less in salt‐tolerant wheat variety (‘S‐24’), which could be a useful marker for selecting a salt‐tolerant variety. Salinity (NaCl) stress considerably increased the accumulation of reducing sugars, nonreducing sugars, and total soluble sugars in leaves of 14‐day‐old wheat seedlings of both varieties. The salt‐tolerant variety (‘S‐24’) accumulated a higher sugar content, which also could be a useful marker for selecting a salt‐tolerant variety for slat‐affected areas. Salinity caused a reduction in nitrate reductase and nitrite reductase activity. The salt‐tolerant variety (‘S‐24’) showed resistance to a decrease of nitrate reductase activity under salinity. This could be a useful criterion for selecting salt‐tolerant varieties. In response to salinity, wheat seedlings accumulated soluble proteins and amino acids, which might reflect a salt‐protective mechanism.     

EFFECT OF POTASSIUM NUTRITION ON SOLUTE ACCUMULATION,ION COMPOSITION AND YIELD OF MAIZE HYBRIDS GROWN UNDER SALINE CONDITIONS

An experiment was conducted to study the response of two maize hybrids to external potassium (K) application under saline conditions. The data showed that there was an increase in the organic solute contents and sodium ion under salinity stress, though potassium, calcium, nitrogen and phosphorus were decreased. There was a non-significant effect of K application on glycinebetaine and total soluble sugar, however; the proline, protein and total free amino acids were increased with the application of external K. The enzymatic activity like nitrate reductase and nitrite reductase activity were severely reduced under salinity stress and improved by K application. The maize hybrids differed significantly for all the parameters discussed in the study except sugar, phosphorus and number of grain rows per cob. The increase in yield parameters was more pronounced under control than under saline conditions. The enhanced yield and yield components of these maize hybrids might be due to the quick response to external K application, resulting in high contents of leaf potassium, calcium, nitrogen and phosphorus. The results indicated that the maize hybrid ‘Pioneer32B33’ might perform better than ‘Dekalb979’ under saline conditions when sufficient potassium is applied in the rooting medium.     

水氮配施对绿洲温室黄瓜氮素代谢及产量品质的影响

为明确绿洲温室黄瓜的水氮适宜用量,以黄瓜品种"卓越99F1"为材料,采用田间随机区组排列设计,研究了不同水氮处理对黄瓜氮素代谢及产量品质的影响.结果表明:土壤含水量为田间持水量65％～80％、施氮量为234 kg·hm-2的处理,黄瓜植株体内硝酸还原酶、谷氨酰胺合成酶、谷氨酸草酰乙酸转氨酶和谷氨酸丙酮酸转氨酶活性最高;...     

氮形态和硫水平对烤烟氮、硫、钾等营养的影响

红壤和潮土培育烤烟,100%铵态氮、100%硝态氮和50%铵氮+50%硝氮等3种氮形态和2种硫施用量的盆栽试验研究表明,增加硝态氮肥供给比例,有利于烤烟生长,烟株叶片干重、株高、干径增加。施硫增加,各叶位全硫含量均显著增加,下部叶片明显累积较多的硫。硝态氮处理红壤和潮土生长烟叶硫含量降低。烟叶氮含量也受供氮形态影响,硝态氮供给比例增加,烟叶全氮含量均较高。供硫增加,烟叶钾含量下降;100%铵氮处理烟叶钾累积较多,NH4+没有抑制K的吸收。     

无机硒肥对土壤有效氮含量及菠菜品质的影响

【目的】研究不同浓度亚硒酸钠(Na_2SeO_3)对土壤脲酶活性、铵态氮(NH_4^+-N)和硝态氮(NO_3~–-N)含量及菠菜品质的影响,综合分析Na_2SeO_3在土壤-根部-作物之间被吸收、转运、转化的可能路径,为生物强化生产富硒农产品及调控硒的安全水平提供参考。【方法】进行连续42天盆栽试验,共设置4个处理,每千克土施Na_2SeO_3 0 (对照)、1、10、30 mg,分别于定植后的14、28、42天测定菠菜叶可溶性糖、可溶性蛋白、维生素C、硝酸盐含量,并测定土壤铵态氮、硝态氮含量及土壤脲酶活性等指标。【结果】在菠菜生长期间,≤10mg/kg Na_2SeO_3处理可使土壤脲酶活性表现为先被激活后减弱至对照水平,土壤硝态氮含量也表现出相同的变化趋势,但铵态氮变化趋势正好相反;30 mg/kg Na_2SeO_3处理对土壤脲酶活性没有明显的影响,在整个培养时期与对照水平相当,土壤NH_4^+-N含量后期明显减少,转化成的NO_3~–-N含量明显增加,有利于菠菜吸收利用。同等Na_2SeO_3添加量条件下,Na_2SeO_3对三个取样时间菠菜叶的硝酸盐、维生素C (Vc)、可溶性蛋白、可溶性糖含量影响各异。1 mg/kg Na_2SeO_3处理组可使菠菜叶的硝酸盐含量明显增加,Vc含量先增后减,可溶性蛋白含量减少,可溶性糖含量没有变化;10 mg/kg处理组可使菠菜叶中的硝酸盐、可溶性糖含量表现为先增后减,Vc含量、可溶性蛋白含量均有不同程度增加;30 mg/kg处理组可使菠菜叶的硝酸盐含量先增后减,可溶性蛋白、可溶性糖含量减少,Vc含量没有变化。【结论】不同浓度亚硒酸钠对土壤有效氮及菠菜品质有不同程度的影响。富硒作物生产中无机硒肥施用量要综合考虑硒在作物体内的转化率及硒对作物品质影响的各项因素而确定。     

镁肥对葡萄叶片糖、淀粉和蛋白质及果实品质的影响

探讨大田条件下,施镁对缺镁葡萄叶片糖、淀粉和蛋白质及果实品质的影响,为葡萄科学施肥提供理论依据。采用裂区试验,主区设4个土施硫酸镁梯度,为0、112.5、150、187.5 kg/hm~2,副区设3个叶面喷施硫酸镁浓度,分别是0%、0.2%、0.4%。结果发现:土施和叶面喷施镁肥能够显著提高叶片镁含量,提升硝酸还原酶活性,增加可溶性蛋白和可溶性糖含量,并促进淀粉转运,减少其在叶片中的积累,最终增加果皮花色素含量,使果皮显著变红,并提高果实可溶性固形物含量,降低可滴定酸含量,提升了果实外在和内在品质。土施150 kg/hm~2同时叶面喷施0.4%硫酸镁肥时,叶片镁含量处于适量标准,硝酸还原酶活性高,叶片可溶性蛋白和糖含量高,果皮红,果实糖高酸低,施镁效果最好。