Variation of total FOS,total IOS,inulin and their related-metabolizing enzymes in burdock roots (Arctium lappa L.) stored under different temperatures

Burdock roots were stored for six weeks at three temperatures, 0, 15 and 20 °C, and activity of sucrose hydrolase (SH), 1-kestose hydrolase (1-KH), inulin hydrolase (InH), sucrose:sucrose 1-fructosyltransferase (1-SST) and fructan:fructan 1-fructoslytransferase (1-FFT) were assessed. Simultaneously, total fructooligosaccharides (FOS), total inulooligosaccharides (IOS) and inulin were also assessed during storage. During storage, SH showed an irregular variation at 15 and 20 °C, and was significantly higher at 0 °C showing a continuous increase during the storage period. 1-KH decreased progressively at 15 and 20 °C, but showed a sharp increase at 0 °C after two weeks and decreased afterwards. InH showed a different although more regular pattern by decreasing progressively at 0, 15 and 20 °C. However, the decrease was more significant at 15 and 20 °C during the first two weeks, while at 0 °C the decrease was significant after four weeks storage. 1-SST and 1-FFT activities decreased progressively in a pseudo-linear regression during storage, and showed similar patterns. At 15 and 20 °C, total FOS increased during the first three weeks then decreased, while at 0 °C FOS increased progressively during storage. Total IOS increased during storage, however, this increase was much higher at 0 °C than that observed at 15 and 20 °C. Inulin content decreased during storage and final content was lower at 20 °C. The inulin to total FOS plus total IOS ratio decreased sharply during the first two weeks of storage, then progressively during the last four weeks, while the ratio of hydrolyzing to synthesizing activities was quite stable at 15 and 20 °C, but showed a peak at 0 °C after two weeks. The results suggest that carbohydrate metabolism in stored burdock depends partly on temperature and other physiological factors.     

高等植物果聚糖合成途径、相关基因和功能的研究进展

果聚糖是由蔗糖与一个或多个果糖基相连接的聚合物,是一类重要的碳水化合物和渗透调节物质,可提高植物的抗逆性;果聚糖还是一类重要的功能性食品,对人体健康有多种促进作用。植物是果聚糖的主要来源,其合成过程涉及到多种果糖基转移酶,不同的果糖基转移酶组合形成不同类型的果聚糖。较为系统地综述了高等植物果聚糖合成的代谢路径、相关基因、果聚糖的功能及应用前景等方面的研究进展。     

盐胁迫对苗期番茄蔗糖代谢的影响

研究了不同浓度盐胁迫下番茄苗期蔗糖代谢相关酶（转化酶、蔗糖合成酶、蔗糖磷酸合成酶）的活性变化与糖积累的关系。结果表明：盐胁迫在一定程度上可以提高番茄幼苗体内的果糖和葡萄糖含量,降低蔗糖的含量。短期盐胁迫可以提高番茄幼苗体内转化酶的活性,使相应的可溶性酸性转化酶mRNA水平提高,处理后期转化酶活性及可溶性酸性转化酶mRNA水平下降;蔗糖合成酶和蔗糖磷酸合成酶的活性降低,但与对照之间的差异不显著;表明盐胁迫主要通过调节转化酶表达与活性变化来影响番茄苗期的蔗糖代谢水平。     

乐都紫皮大蒜叶片生长发育与果聚糖代谢的关系

为了探讨高原大蒜生长特性及其果聚糖代谢规律,分析叶片生长发育与果聚糖代谢的关系,本研究以"乐都紫皮大蒜"为材料,对不同发育期的大蒜叶片生长情况、生理指标及其果聚糖代谢关键基因的表达特征进行了解析。结果表明:随着生育期的延续,大蒜植株的最大叶长、最大叶宽和单株叶片数均稳步增加。叶片生理指标呈现先升高后降低的趋势,总叶绿素含量在花芽分化之前快速上升,在抽薹期达到最大值2.32 mg/g FW;组织含水量在鳞茎膨大初期达到最大值89.06%,随后急剧降低。在整个发育过程中,大蒜叶片蔗糖:蔗糖1-果糖基转移酶基因(1-SST)和果聚糖外切水解酶基因(1-FEH)表达量存在显著差异,从幼苗期至鳞茎膨大初期,1-SST基因表达量显著高于1-FEH。1-SST的表达在全生育期表现为"升高-降低"的趋势,在抽薹期,1-SST的表达量达到峰值,比幼苗期提高了17.51倍;1-FEH在全生育期的表达量均较低,呈现起伏波动的趋势,在收获期表达量最高,是苗期的2.41倍。综合分析说明,大蒜叶片叶绿素和果聚糖的合成高峰主要在抽薹期,抽薹期是大蒜叶片生长发育和果聚糖代谢的关键时期,大蒜可通过叶绿素的合成以及1-SST和1-FEH的差异表达进一步影响鳞茎果聚糖的累积。     

己糖激酶调控‘赤霞珠’酿酒葡萄蔗糖分解代谢

以酿酒葡萄(Vitis viniferaL.)‘赤霞珠’果实为试材,研究己糖激酶与蔗糖分解代谢关键酶[可溶性酸性转化酶和蔗糖合酶(分解方向)]在果实发育过程中的关系,以期为己糖激酶对蔗糖分解代谢的调控提供知识。利用高效液相色谱(HPLC)分析了发育期‘赤霞珠’葡萄果实中蔗糖、葡萄糖和果糖的含量,测定了其己糖激酶、酸性转化酶和蔗糖合酶活性变化趋势。研究表明,果实整个发育过程中,蔗糖含量极微,己糖激酶表现出与葡萄糖、果糖相反的梯度变化;葡萄糖和果糖含量低时,可溶性酸性转化酶和蔗糖合酶的活性开始上升;葡萄糖和果糖含量高时,可溶性酸性转化酶和蔗糖合酶的活性降低。相关性分析表明,蔗糖含量与葡萄糖含量、果糖含量显著相关,葡萄糖和果糖含量与可溶性酸性转化酶、蔗糖合酶活性负相关,己糖激酶活性与所有因子负相关,但无显著相关。讨论后得出己糖激酶可能通过其催化活性调控葡萄糖和果糖的积累并反馈调节可溶性酸性转化酶和蔗糖合酶。     

Harvest Dates, Fertilizer and Varietal Effects on Yield, Concentration and Molecular Distribution of Fructan in Jerusalem Artichoke (Helianthus tuberosus L.)

In a pot experiment two varieties of Jerusalem artichoke ( Helianths tuberosus L., cv. Topianka and cv. Violet de Rennes ) were exposed to different supplies of N, P and K. Nitrogen supply increased tuber yield more than the productivity of aerial parts. Violet de Rennes responded better to N than Topianka. Nutrient regimes without P or K addition but including N to some extent depressed the yields of tubers only (by 8–23 %). Carbohydrate concentrations (78–81 % of d.m.) and molecular fructan distributions were neither influenced by fertilizer regimes nor by mineral concentrations in the tubers.
Genotypic differences were significant for yield, for concentrations of N, P, Ca, S and Cu, and for fructan concentration in the tubers. At harvest time the fructose/glucose ratio in tubers of Violet de Rennes was about 10 % higher than in Topianka and remained on a higher level during storage.
Harvest time had the greatest influence on carbohydrate composition. Depolymerization of fructan proceeded at a high rate in November and slowed down during subsequent storage, accompanied by a decline in polydispersity. Simultaneously osmolanty increased, resulting in a freezing point depression of < 0.5 °C.     

KH2PO4对设施油桃果实糖积累及代谢相关酶活性的影响

以设施栽培的艳光油桃为试材,研究了设施栽培条件下,喷施KH2PO4处理对油桃果实中糖积累和蔗糖代谢相关酶活性的影响。结果表明,幼果期喷施KH2PO4处理,果实葡萄糖和果糖含量明显增加,蔗糖含量没有明显变化,成熟期三种糖含量与对照均无明显差异;果实着色前KH2PO4处理显著增加了果实中蔗糖含量,但对葡萄糖和果糖含量无明显影响。幼果期和着色前喷施KH2PO4均显著提高了果实中蔗糖代谢酶活性。说明KH2PO4处理是通过全面提高果实中蔗糖代谢酶活性,起到提高库强作用,从而增加果实含糖量。     

Carbohydrates Accumulation and Remobilization in Wheat Plants as Influenced by Combined Waterlogging and Shading Stress During Grain Filling

Wheat plants were subjected to combined waterlogging and shading stress (WS) at 0–7, 8–15, 16–23 and 24–31 days after anthesis (DAA), respectively. Compared to the non‐stressed plants, WS significantly decreased the final grain yield. Grain number was dramatically lowered by WS imposed at 0–7 DAA but hardly affected by other WS treatments; while the thousand‐kernel‐weight was unaffected by WS imposed at 0–7 DAA and lowered by other WS treatments. Photosynthate accumulation in the stem was decreased by WS imposed at 0–7 and 8–15 DAA, but was unaffected by WS imposed at later stages. Grain‐filling rate was decreased, although the apparent remobilization of carbohydrate reserves from stem to grain was stimulated under WS. The carbohydrate reserves stored in the lower stem internodes were activated earlier and remobilized much more than those in the upper internodes; however, the proportion of the apparent remobilized reserves among the different stem internodes was consistent for all treatments. WS decreased contents of fructans, fructose and sucrose in the stem, which coincided with increased activity of fructan exohydrolase and decreased activities of sucrose‐1‐fructosyltransferase and fructan‐1‐fructosyltransferse. The results indicate that post‐anthesis WS stimulated carbohydrate reserves remobilization by modifying the activities of the fructans‐catalysing enzymes in the stem.     

甜高粱茎秆贮存过程中蔗糖代谢及其相关酶活性的变化研究

为明确甜高粱茎秆贮存过程中蔗糖降解的关键酶,以期通过对蔗糖降解关键酶的分子调控解决甜高粱茎秆贮存过程中蔗糖易降解的难题。采用高效液相色谱法和酶学测定方法对3个品种甜高粱在采后75天贮藏期内,茎秆中的蔗糖、果糖、葡萄糖含量和可溶性酸性转化酶(SAI)、中性转化酶(NI)和蔗糖合成酶(SS)分解蔗糖的酶活性变化进行了测定。结果表明：在采后75天贮藏期内,‘辽甜1号’、‘辽甜4号’和‘辽甜6号’甜高粱的茎秆中,糖分降解迅速,总糖损失近一半,分别为68.2-31.9（g/100g干基）、43.0-18.1（g/100g干基）和59.6-25.3（g/100g干基）。3个品种果糖、葡萄糖和蔗糖含量呈总体下降趋势,并呈现贮藏期开始时糖分降低很快,而后缓慢降低的趋势。可溶性酸性转化酶活性在茎秆贮藏15天时增幅较大,而后以微小幅度持续增加,一直保持较高的酶活性。中性转化酶活性一直以微小幅度持续增加,酶活性较低,变化不大。蔗糖合成酶分解方向的活性则更低,且变化不大。这表明可溶性酸性转化酶可能与甜高粱茎秆贮存过程中蔗糖降解密切相关。     

Respiration rate,ethylene production and biochemical variations of ackee fruit arils (Blighia sapida Köenig) stored under three temperature regimes

The storage of fruit is characterized by many physiological and biochemical changes, and this study aimed to study respiration rate, ethylene production, and other biochemical variations of ackee fruit arils (Blighia sapida), cheese variety, stored at 5, 10 and 20 °C during eight days. During storage, respiration rate decreased but ethylene production increased. Glucose, fructose, sucrose, and short chain fructooligosaccharides – 1-kestose, nystose and DP-5 – and total phenolic compounds also decreased, however, the decrease was much higher at 20 °C. The L*, a*, b, C* and H* values showed that lower temperatures preserved much better colour and visual quality, and arils stored at 5 °C were rated excellent compared to those stored at 10 and 20 °C. The quality of arils stored at 10 °C also was more than satisfactory, while arils stored at 20 °C were completely spoiled after 8 days and showed high weight losses compared to arils stored at 5 and 10 °C, which did not show any spoilage and very low weight losses. In conclusion, the results demonstrated that ackee fruit arils can be stored in very good conditions for a minimum of eight days under low temperature regimes, although at 5 °C arils showed the best shelf-life.     

Sucrose Accumulation in Sugar Beet Under Drought Stress

Drought stress may affect sucrose accumulation of sugar beet by restricting leaf development and storage root growth. The objective of this study was to identify changes occurring in the storage root of Beta beets in growth characteristics and ions and compatible solutes accumulation under drought with regard to sucrose accumulation. Two pot experiments were conducted: (1) sugar beet well supplied with water (100 % water capacity), under continuous moderate (50 %) and severe drought stress (30 %), (2) sugar beet and fodder beet well supplied with water (100 %) and under continuous severe drought stress (30 %). Under drought stress, the ratio of storage root to leaf dry matter of sugar beet decreased indicating a different partitioning of the assimilates. The sucrose concentration of the storage root was reduced. In the root, the number of cambium rings was only slightly affected, although drought stress was implemented already 6 weeks after sowing. In contrast, the distance between adjacent rings and the cell size was considerably restricted, which points to a reduced expansion of existing sink tissues. The daily rate of sucrose accumulation in the root showed a maximum between 16 and 20 weeks after sowing in well‐watered plants, but it was considerably reduced under drought stress. The concentration of compatible solutes (K, Na, amino acids, glycine betaine, glucose and fructose) decreased during growth, while it was enhanced because of drought. However, when sucrose concentration was added, a constant sum of all examined solutes was found throughout the vegetation period. It was similar in sugar beet and in fodder beet despite different concentrations of single solutes, and the total sum was not affected by water supply. A close negative relationship between the concentration of compatible solutes and sucrose occurred. It is therefore concluded that the accumulation of compatible solutes in the storage root of Beta beets under drought might be a physiological constraint limiting sucrose accumulation.     

1-MCP对凯特杏果实采后糖酸组分与含量的影响

探讨了1-MCP处理对凯特杏果实采后糖酸组分及其含量的影响。试验结果表明,绿熟期的凯特杏果实糖分以蔗糖含量最高,果糖含量最低;有机酸以柠檬酸为主,苹果酸次之,属柠檬酸型。用1．0μL/L 1-MCP处理可抑制杏果实采后可溶性糖的积累,其蔗糖、葡萄糖、果糖与总糖含量均低于对照;同时,1-MCP处理能显著地抑制杏果实抗坏血酸含量的减少,抑制贮藏末期柠檬酸、苹果酸、酒石酸和总酸量的下降与琥珀酸的升高。1-MCP处理改变杏果实采后糖酸代谢可能是提高果实贮藏品质的主要原因。     

柑橘果实发育成熟中果肉游离糖、 肌肌醇及钾含量的变化

以龟井（无籽）温州蜜柑和鄂柑1号（有籽）橘为试材，对果实发育成熟过程中果肉游离糖（果糖、葡萄糖和蔗糖）、肌肌醇及钾含量变化进行了测定。结果表明：(1)果实增大初期鄂柑1号果肉果糖和葡萄糖含量明显上升，蔗糖变化小，肌肌醇却趋下降，进入果实增大中后期，蔗糖含量显著上升，其它变化小；而龟井的果糖、葡萄糖和蔗糖均于果实增大初期和中期出现明显积累，肌肌醇除在增大中期出现一峰值外趋于平稳；采前果实发育期两品种总糖含量变化趋势均与各自的蔗糖较一致；(2)采后贮藏期内两品种果肉总糖和肌肌醇含量均趋于稳定，而二者的果糖、葡萄糖和蔗糖含量变化趋势却均趋相反；(3)两品种果肉钾含量均在果实增大期内出现明显上升并居相对较高水平。     

高效液相色谱法测定甜高粱茎秆中三种糖含量

采用高效液相色谱法（HPLC）对新高粱3号和新高粱4号两种甜高粱茎秆在采后220天贮藏期内,不同贮藏方式下（去叶立放、去叶平放、带叶立放、带叶平放、金字塔型）茎秆中果糖、葡萄糖、蔗糖含量进行了测定。结果表明：在0-220d贮藏期间内,所有贮藏方式下,3号和4号甜高粱茎秆中果糖、葡萄糖、蔗糖含量均呈下降趋势。同一种贮藏方式下3号甜高粱茎秆的果糖、葡萄糖、蔗糖含量始终比4号茎秆高。在整个贮藏期内3号和4号甜高粱茎秆果糖、葡萄糖、蔗糖含量由高到低依次为整秆去叶立放＞整秆去叶平放＞整秆带叶立放＞整秆带叶平放＞金字塔五层＞金字塔四层＞金字塔三层＞金字塔二层＞金字塔一层。     

冷热破碎工艺对小包装番茄酱贮藏期间非酶褐变的影响

为探究冷破碎工艺和热破碎工艺对番茄酱贮藏期间非酶褐变的影响,将制备的番茄酱在20℃和35℃条件下进行12个月的贮藏。通过对番茄酱的褐变指数、还原糖、番茄红素、5-HMF、VC含量、氨基酸态氮含量、可滴定酸含量和pH变化的测定以及相关性分析得出美拉德反应与VC氧化分解反应是导致番茄酱在贮藏期间发生非酶褐变的主要原因,番茄红素不是引起番茄酱色泽变化的主要原因,美拉德反应的主要产物是5-HMF。经过液相色谱分析,番茄酱中糖类主要由果糖、葡萄糖和蔗糖组成,冷破、热破番茄酱中的三种糖类含量有差异。通过模拟体系,进一步确定了美拉德反应是导致番茄酱在贮藏期间发生非酶褐变的根本原因,且糖是5-HMF生成的必要条件,5-HMF的产生主要由果糖决定,VC氧化分解反应对5-HMF的生成贡献微弱。因冷破碎工艺温度较低,产品果糖含量较多,更容易褐变,所以冷破番茄酱的贮藏环境应尽可能的保证低温。     

Dehydration accelerates respiration in postharvest sugarbeet roots

Sugarbeet (Beta vulgaris L.) roots lose water during storage and often become severely dehydrated after prolonged storage and at the outer regions of storage piles which have greater wind and sun exposure. Sucrose loss is known to be elevated in dehydrated roots, although the metabolic processes responsible for this loss are unknown. To identify processes that contribute to sucrose loss in dehydrated roots, respiration rate, cellular electrolyte leakage, and sucrolytic enzyme activities were determined in roots of two varieties (VDH 66156 and Beta 4797R) during 4 weeks of 10 °C storage at high (85%) and low (40%) relative humidities. Roots stored at 40% relative humidity dehydrated significantly and lost almost 50% of their weight after 4 weeks of storage. Electrolyte leakage increased in these roots, indicating that dehydration damaged cellular membranes. Respiration rate generally increased in roots stored at 40% relative humidity compared to roots stored at 85% relative humidity. The increase in respiration rate was positively correlated with root weight loss and electrolyte leakage. Respiration rate was most closely associated with electrolyte leakage, however, suggesting that elevations in respiration rate were not due to dehydration, but to the membrane damage that occurred in response to dehydration. Activities of the sucrose-degrading enzymes, sucrose synthase, alkaline invertase and soluble acid invertase, were unaltered by dehydration. Alterations in sucrolytic enzyme activities, therefore, were not needed to provide for the increased demand for respiratory substrates in dehydrated roots. These results suggest that storage at low relative humidity alters the postharvest physiology of sugarbeet roots by increasing the rate of weight loss, reducing membrane integrity, and accelerating root respiration rate.     

套袋对红富士苹果山梨醇代谢和相关酶活性的影响

以红富士为试材,研究了套袋对苹果果实糖含量和山梨醇代谢相关酶活性的影响。结果表明：在整个发育过程中,套袋苹果果实的蔗糖、葡萄糖和果糖含量及SDH的活性变化趋势与对照基本一致。与对照相比,套袋后,苹果果实的蔗糖、葡萄糖和果糖含量均出现不同程度的降低,而山梨醇含量有一定的增加。套袋处理降低苹果果实的SDH活性,但SOX活性在发育后期有一定的增加。相关分析表明,苹果果实的果糖积累主要与SDH活性密切相关。由此推断,套袋通过降低苹果果实的山梨醇代谢而影响苹果果实的糖积累。     

离子色谱法测定贮藏期间菠萝果实的糖分变化

优化了应用离子色谱检测巴厘菠萝果实糖分组成与含量的方法,经优化的测定分析条件为：Carb0PacPAl（2×250mm）分离柱,淋洗液40mmol／LNaOH溶液,流速0．25mL·min^-1,柱温30℃;用该方法对经果蜡处理的巴厘菠萝果实贮藏期间的糖分组成和含量进行了有效分离与测定。结果表明,果蜡处理组与对照组菠萝果实的糖分都是以蔗糖为主,其次为葡萄糖和果糖;贮藏期间,处理与对照组果实主要的3种糖含量均呈不断下降趋势．但果蜡处理组果实的葡萄糖和蔗糖含量总体上明显高于对照．表明果蜡处理对保持菠萝采后品质有一定作用。     

Comparison of the antioxidant enzymes of broccoli after cold or heat shock treatment at different storage temperatures

An experiment was conducted to study the association between cold shock treatment (CST) (0 °C, 1 h) and heat shock treatment (HST) (55 °C, 30 s) on antioxidant enzymes of broccoli at different storage temperatures (20, 10, or 5 °C). There was no difference in antioxidant enzyme activities between CST and HST under storage at 20 °C; superoxide dismutase (SOD) and catalase (CAT) activities were increased in comparison with the controls. However, activities of antioxidant enzymes, except for ascorbate peroxidase (APX), with CST were higher than those with HST during storage at 10 °C, while there were opposite results except for CAT activity at 5 °C. These results suggest that CST and HST have the same effect on the antioxidant enzymes of broccoli during 20 °C storage, but have different effects at below 10 °C, which become more pronounced as the temperature is lowered.