不同变种甜瓜糖分积累及蔗糖代谢酶活性动态变化

为了解不同类型甜瓜糖分积累及糖代谢特点,选用厚皮甜瓜品种X228、普通甜瓜品种B154及越瓜品种H227为材料,定期取样测定果实成熟过程中的葡萄糖、果糖、蔗糖含量和蔗糖代谢相关酶活性,研究不同变种甜瓜果实发育过程中糖分积累及相关酶动态变化差异。结果表明,授粉15 d至果实成熟期间,3个甜瓜品种的果实葡萄糖与果糖含量的变化均较小,品种间差异不显著。3个甜瓜品种果实蔗糖含量存在显著性差异,其中H227果实几乎无蔗糖积累,葡萄糖和果糖是果实的主要糖组分;B154和X228果实蔗糖含量随着果实发育而快速增加,蔗糖积累存在明显的转折点,蔗糖是B154和X228这2个品种成熟果实中最主要的糖组分,且果实蔗糖含量提高的同时蔗糖磷酸合成酶(SPS)活性上升、酸性转化酶(AI)活性降低,蔗糖合成酶(SS)合成方向的活性与蔗糖含量关系不显著。根据蔗糖含量的差异,可将甜瓜分为蔗糖积累型和低蔗糖积累型两类,前者果实蔗糖含量的上升被认为是SPS活性上升与转化酶(特别是AI)活性下降共同作用的结果,后者果实内极低的蔗糖含量被认为是SPS活性较低导致的。本研究结果为甜瓜种质资源创新利用和甜瓜果实糖分积累调控研究奠定了理论基础。     

套黄、白袋凯特芒果采后果实糖代谢的比较研究

为探究果实生长期间套不同颜色纸袋对芒果采后果实软鼻病和贮藏特性的影响,本试验以套黄、白袋凯特芒果(Mangifera indica L.cv. Keitt)为试验材料,比较研究了两种套袋果实采后软鼻病发病率、硬度及糖代谢的差异。结果表明,在常温贮藏下(10 d),套黄袋芒果采后果实的软鼻病发病率显著低于套白袋芒果(P<0.05),而且采后果实果肉的淀粉酶、酸性转化酶(AI)、中性转化酶(NI)和蔗糖磷酸合成酶(SPS)活性均显著低于套白袋芒果(P<0.05),因而缓解了果实淀粉含量的下降速率和蔗糖积累的速率,延缓了果实的软化成熟进程,提高了采后果实的耐贮性。另外,套袋影响采后芒果果肉的蔗糖糖代谢可能与果实软鼻病的病情发展相关。本研究为选取合理有效的芒果套袋材料提供了一定的参考依据。     

鸡粪的施用对薄皮甜瓜果实糖积累及糖代谢相关酶活性的影响

为了探讨鸡粪以及鸡粪与尿素配施对薄皮甜瓜果实糖积累及糖代谢相关酶活性的影响,本试验以薄皮甜瓜DX108为试验材料,以尿素为氮源的处理为对照(CK),研究了相同施氮量条件下,鸡粪与尿素配施(A)以及鸡粪(B)对甜瓜果实葡萄糖、果糖和蔗糖含量的影响,分析了蔗糖磷酸合成酶(SPS)、蔗糖合成酶(SS,蔗糖合成与分解方向)、酸性转化酶(AI)和中性转化酶(NI)的活性。结果表明,与CK相比,B、A明显促进了果实中果糖、蔗糖及葡萄糖积累,尤其是显著增加了成熟果实中这3种糖的含量。相关性分析表明,CK的甜瓜果实蔗糖积累与AI活性呈显著负相关,葡萄糖与SPS和SS(蔗糖合成酶)合成方向酶活性呈显著正相关;A和B果实中蔗糖、葡萄糖和果糖积累(除B中葡萄糖积累)与SPS、NI活性呈显著或极显著正相关,与SS分解方向酶活性呈极显著负相关,而A果实中葡萄糖积累与SPS和NI活性呈极显著正相关。综上所述,A和B提高了果实中SPS、NI活性,降低了SS分解方向酶活性,进而促进了糖的积累。本研究结果为有机肥替代化学氮肥在甜瓜生产上的应用提供了理论依据。     

番木瓜酸性转化酶基因家族预测及生物信息学初步分析

酸性转化酶参与了番木瓜果实中蔗糖的韧皮部卸载,调控果实中糖类的积累。本文利用番木瓜基因组数据库信息,发现了番木瓜基因组中含有6个酸性转化酶基因,分别为细胞壁转化酶基因（CpCWINV1-3）和液泡转化酶基因（CpVINV1-3）。这些基因由3-7个外显子组成,其中CpCWINV1、CpVINV1和CpVINV2的N端均具有一个跨膜区域。蛋白质3D结构预测分析表明,CpCWINV1、CpVINV1和CpVINV2具有典型的N端β-螺旋桨模块（β-propeller module）和C端β-三明治模块（β-sandwich module）,而CpCWINV3和CpVINV3的桨叶I上,均没有保守区NDPNG/A;CpCWINV2和CpVINV3均缺失了β-三明治模块。推测番木瓜细胞壁转化酶CpCWINV1、液泡转化酶CpVINV1和CpVINV2能正确履行催化蔗糖分解的功能。本研究有助于我们进一步揭示酸性转化酶在番木瓜果实发育及糖类积累过程中的作用。     

Carbohydrate content and metabolism as related to maturity and chilling sensitivity of cv. Fortune mandarins.

Fruits of cv. Fortune mandarin were periodically harvested throughout the ripening period to evaluate changes in carbohydrate content and metabolism in flavedo tissue and to determine the potential role of carbohydrates in the tolerance of citrus fruit to chilling injury (CI). Sucrose showed little change in the flavedo during the season, but fructose and glucose increased, in nearly equal amounts, throughout the fall and winter, reaching a maximum in January. Starch levels were less abundant than soluble carbohydrates and rose continuously until March. Sucrose phosphate synthase (SPS; EC 4.1.14) activity decreased from December throughout ripening. Changes in sucrose synthase (SS; EC 2.4.1.13) and acid and alkaline invertase (Inv; EC 3.2.1.26) activities correlated with changes in the reducing sugars, but acid invertase was less active than the other sucrose-metabolizing enzymes. Carbohydrate changes in the flavedo of Fortune mandarins with fruit maturity appear not to be related to the chilling tolerance of fruits during cold storage.     

Changes in invertase activities and reducing sugar content in sweetpotato stored at different temperatures

Cured sweetpotato roots were stored at different temperatures (4.5, 15.6, and 24 degrees C) for 7 weeks and assayed for invertase activities and reducing sugar levels during two separate years. Invertase activities and reducing sugar concentration significantly increased in the roots kept at low temperature. Of the three types of invertases assayed, acid invertase specific activity was the highest. Acid invertase was the most influential in determining reducing sugar levels in stored sweetpotato. Cultivar differences were found in invertase specific activities and reducing sugar concentration. Reducing sugar content was highly correlated to acid and total invertase activity, regardless of cultivar.     

硼钙营养对不同品种柑桔糖代谢的影响

连续 2年对胡柚和柑桔进行叶面喷施硼 (B)、钙 (Ca)及硼加钙 (B +Ca)溶液试验 ,以探讨B、Ca及其互作对柑桔果实糖酸代谢的影响。结果表明 ,硼 (B)、硼加钙 (B +Ca)处理能提高柑桔果实成熟前的还原糖、滴定酸含量 ,降低果实收获期的还原糖和滴定酸含量 ,并提高了果实成熟期总糖含量 ;增强柑桔果实发育初期酸性转化酶活性和果实发育后期中性转化酶活性 ;钙 (Ca)处理对柑桔糖代谢的影响效果不明显     

Physical characters and antioxidant, sugar, and mineral nutrient contents in fruit from 29 apricot (Prunus armeniaca L.) cultivars and hybrids

Fruit physical and chemical characters of 29 apricot cultivars of Greek and American origin and their hybrids were evaluated using correlation and principal component analysis. A remarkable variation was observed in the total phenol content (0.3-7.4 mg gallic acid equivalent g(-1) FW) and total antioxidant capacity (0.026-1.858 mg ascorbic acid equivalent g(-1) FW), with the American origin cultivars Robada and NJA(2) and the new cultivar Nike exhibiting the greatest values. The cultivar Tomcot and hybrid 467/99 had the highest content of total carotene (37.8 microg beta-carotene equivalent g(-1) FW), which was up to four times greater as compared with the rest of studied genotypes. The dominant sugar in fruit tissue was sucrose, followed second by glucose and third by sorbitol and fructose-inositol. The new cultivars Nike, Niobe, and Neraida contained relatively higher contents of sucrose and total sugars, while Ninfa and P. Tirynthos contained relatively higher contents of K, Ca, and Mg. Correlation analysis suggested that late-harvesting cultivars/hybrids had greater fruit developmental times (r = 0.817) and contained higher sugar (r = 0.704) and less Mg contents (r= -0.742) in fruit tissue. The total antioxidant capacity was better correlated with the total phenol content (r = 0.954) as compared with the total carotenoid content (r = 0.482). Weak correlations were found between the fruit skin color and the antioxidant contents in flesh tissue. Multivariate analysis allowed the grouping of variables, with more important variables being the harvest date, fruit developmental time, skin Chroma, sorbitol, and total sugar, K and Mg contents. Plotting the genotypes in a dendrogram revealed cases of homonymy between parents and hybrids, although independent segregation of the measured traits after hybridization was also found.     

Comparison of leaf and fruit metabolism in two tomato (Solanum lycopersicum L.) genotypes varying in total soluble solids

Sink and source activity in two tomato (Solanum lycopersicum L.) genotypes that vary in fruit Brix were investigated to identify differences that potentially underscore this trait. Solara (Brix 9%) accumulated almost twice the glucose, fructose, and sucrose in ripe fruit and had a higher horticultural yield (25% greater) compared to Moneymaker (Brix 5%). 14C-glucose feeding suggested large disparities in sucrose metabolism in ripe fruit between genotypes. Biochemical pathways in the leaf adjacent to a fruiting truss at night were also analyzed since in many species, this is the period when leaf reserves are mobilized to feed the plant. Surprisingly, leaf metabolism, i.e., starch and sugar content, the levels of polar metabolites assayed by GC-TOF MS and 14CO2-pulse-chase fluxes in detached leaves, did not change between the day and night in either genotype. Solara has a higher morphological source-to-sink ratio, and this may contribute to higher Brix in that genotype.     

Developmental and varietal differences in volatile ester formation and acetyl-CoA: alcohol acetyl transferase activities in apple (Malus domestica Borkh.) fruit

Apple (Malus domestica Borkh.) cultivars differ in their aroma and composition of volatile acetates in their fruit flesh and peel. Cv. Fuji flesh contains substantial levels of 2-methyl butyl acetate (fruity banana-like odor), while the flesh of cv. Granny Smith apples lacks this compound. Granny Smith apples accumulate mainly hexyl acetate (apple-pear odor) in their peel. Feeding experiments indicated that Fuji apples were able to convert hexanol and 2-methyl butanol to their respective acetate derivatives in vivo, while Granny Smith apples could only convert exogenous hexanol to hexyl acetate. Differential substrate specificities of the in vitro acetyl-CoA:alcohol acetyl transferase (AAT) activities were also detected among cultivars. In Granny Smith apples, the AAT activity was detected only in the peel, and its specificity was almost exclusively restricted to hexanol and cis-3-hexenol. In Fuji apples, the AAT activity was detected in both peel and flesh and apparently accepted a broader range of alcohols as substrates than the Granny Smith enzyme activity. Our data strongly suggest that different AAT activities are operational in apple tissues and cultivars and that these differences contribute to the variation observed in the accumulation of volatile acetates.     

Occurrence and distribution of organochlorine pesticides (OCPs) in tomato (Lycopersicon esculentum) crops from organic production

Organochlorine pesticides (OCPs) were quantified by GC-ECD in tomato (Lycopersicon esculentum) during a vegetation period. Plants were harvested at 15, 60, and 151 days after seed germination. Leaves, stem, roots, and fruit (peel and flesh) were analyzed separately. The results showed that tomato plants were able to accumulate OCPs from soils, and a trend to reach the equilibrium among tissues at mature stages was also observed. Endosulfans comprised the main OCP group, probably due to its spray during summer months in the surrounding areas. Banned pesticides such as DDTs, heptachlor, and dieldrin were found. OCPs levels in the fruit were below the maximum residues limits (MRL) considered by the Codex Alimentarius. DDE/DDT and alpha-/gamma-HCH ratios of <1 would indicate recent inputs of DDT and lindane in the environment. The occurrence of OCPs in the study farm, where agrochemicals have never been used, is a result of atmospheric deposition of those pesticides.     

气温升高与干旱对灵武长枣果实糖积累、蔗糖代谢关键酶及相关基因表达的影响

为探究灵武长枣果实糖积累、蔗糖代谢关键酶及相关基因表达水平对气温升高与干旱的响应,以6年生灵武长枣为试验材料,设置大气环境温度和土壤含水量双因素试验,研究了果实不同成熟期葡萄糖、果糖、蔗糖、淀粉含量及转化酶(AI,NI)、蔗糖合成酶(SS-s,SS-c)、蔗糖磷酸合成酶(SPS)等关键酶活性变化,并从分子水平分析基因表达特性。结果表明,与自然大气温度(T1)环境相比,升高大气温度(T2)环境下灵武长枣果实的葡萄糖、果糖、蔗糖、淀粉含量及NI、SPS、SS-s活性分别增加0.18%~22.02%、0.97%~21.97%、0.43%~85.30%、5.39%~49.06%、0.60%~28.53%、0.01%~31.21%、0.77%~25.31%;与正常土壤供水条件(D1)相比,中度干旱条件(D2)下,灵武长枣果实的果糖、蔗糖、淀粉含量及NI、SS-c活性平均分别增加44.26%、49.56%、38.20%、56.04%、45.36%;大气温度升高2.0℃左右时,ZjNI基因中ZjNI 1和ZjNI 2分别上调14.25和14.52倍;气温升高伴随重度干旱条件下,ZjSPS基因中ZjSPS 1和ZjSPS 4分别上调24.36和93.70倍;ZjSS基因中ZjSS 1和ZjSS 3分别上调131.29倍和81.38倍。综上所述,干旱条件对灵武长枣果实糖含量和关键酶活性的影响显著;气温升高可减缓中度干旱对糖积累的促进作用,加剧重度干旱对糖积累的抑制作用;气温升高伴随干旱可促使蔗糖代谢关键酶基因表达上调。结果表明,大气温度上升和干旱显著影响灵武长枣果实营养品质。本研究可为宁夏灵武长枣生产实践应对全球气候变化提供理论指导与科技支撑。     

钾素对食用型甘薯糖代谢相关酶活性的影响

为了探讨钾素提高甘薯块根可溶性糖含量的生理基础。选用典型的食用型甘薯品种北京553,设置不同施钾处理,于2009～2010年2个生长季在山东农业大学农学试验站进行试验。采用甘薯块根膨大过程中定期取样的方法,测定块根可溶性糖和淀粉含量及相关酶活性、功能叶蔗糖含量及相关酶活性。结果表明,与对照比较,施用钾肥能显著提高块根产量、可溶性糖及各糖组分含量,其中K2O用量为24 g/m2处理增幅最大,为最适用量。进一步研究发现,适宜供钾处理显著提高了功能叶磷酸蔗糖合成酶活性和蔗糖含量,生育期内平均增幅分别为10.31%和34.13%,同时提高了块根中蔗糖合成酶、不溶性酸性转化酶的活性,生育期内平均增幅为16.47%和3.66%,在提高源端光合产物供应的同时促进蔗糖在库端的卸载,促进块根中淀粉和可溶性糖的积累;适宜供钾处理还提高了块根中-和-淀粉酶的活性,生育期内平均增幅分别为26.06%和14.64%,促进淀粉向可溶性糖转化。此外,适宜供钾处理还显著提高了生长前期和后期块根中可溶性酸性转化酶活性、以及生长后期块根中蔗糖-蔗糖果糖基转移酶活性,促进了葡萄糖、果糖和果聚糖在块根中的积累。在甘薯收获期,块根可溶性糖和淀粉含量分别提高了13.52%和3.02%。即钾肥能够增加块根中蔗糖的供应量、促进块根对蔗糖的吸收、促进淀粉水解,是其提高块根可溶性糖含量的生理原因。     

Effects of genotype, latitude, and weather conditions on the composition of sugars, sugar alcohols, fruit acids, and ascorbic acid in sea buckthorn (Hippophaë rhamnoides ssp. mongolica) berry juice

Sea buckthorn berries (Hippopha? rhamnoides ssp. mongolica) of nine varieties were collected from three growth locations in five inconsecutive years (n = 152) to study the compositional differences of sugars, sugar alcohols, fruit acids, and ascorbic acid in berries of different genotypes. Fructose and glucose (major sugars) were highest in Chuiskaya and Vitaminaya among the varieties studied, respectively. Malic acid and quinic acid (major acids) were highest in Pertsik and Vitaminaya, respectively. Ascorbic acid was highest in Oranzhevaya and lowest in Vitaminaya. Berry samples of nine varieties collected from two growth locations in five years (n = 124) were combined to study the effects of latitude and weather conditions on the composition of H. rhamnoides ssp. mongolica. Sea buckthorn berries grown at lower latitude had higher levels of total sugar and sugar/acid ratio and a lower level of total acid and were supposed to have better sensory properties than those grown at higher latitude. Glucose, quinic acid, and ascorbic acid were hardly influenced by weather conditions. The other components showed various correlations with temperature, radiation, precipitation, and humidity variables. In addition, fructose, sucrose, and myo-inositol correlated positively with each other and showed negative correlation with malic acid on the basis of all the samples studied (n = 152).     

Purification and biochemical characterization of insoluble acid invertase (INAC-INV) from pea seedlings

Invertase (EC 3.2.1.26) catalyzes the hydrolysis of sucrose into D-glucose and D-fructose. Insoluble acid invertase (INAC-INV) was purified from pea (Pisum sativum L.) by sequential procedures entailing ammonium sulfate precipitation, ion exchange chromatography, absorption chromatography, reactive green-19 affinity chromatography, and gel filtration. The purified INAC-INV had a pH optimum of 4.0 and a temperature optimum of 45 °C. The effects of various concentrations of Tris-HCl, HgCl(2), and CuSO(4) on the activities of the purified invertase were examined. INAC-INV was not affected by Tris-HCl and HgCl(2). INAC-INV activity was inhibited by 6.2 mM CuSO(4) up to 50%. The enzymes display typical hyperbolic saturation kinetics for sucrose hydrolysis. The K(m) and V(max) values of INAC-INV were determined to be 4.41 mM and 8.41 U (mg protein)(-1) min(-1), respectively. INAC-INV is a true member of the β-fructofuranosidases, which can react with sucrose and raffinose as substrates. SDS-PAGE and immunoblotting were used to determine the molecular mass of INAC-INV to be 69 kDa. The isoelectric point of INAC-INV was estimated to be about pH 8.0. Taken together, INAC-INV is a pea seedling invertase with a stable and optimum activity at lower acid pH and at higher temperature than other invertases.     

庆阳市日光温室小果型西瓜品种筛选

为筛选出适宜在庆阳市种植的小果型西瓜品种,丰富庆阳市日光温室栽培小果型西瓜品种资源。引进了13个国内外小果型西瓜品种进行了试种,并对各引进品种的植株形态、果实形态、果肉风味和产量进行了评价。结果表明,13个参试品种生长特征及果实品质差异显著,其中鼎优美颜中心糖含量最高,达143.3 g/kg;红小玉的边糖含量最高,为123.3 g/kg,且中心糖与边糖差最小。综合分析,鼎优美颜与红小玉果型精致小巧、果皮薄、果肉脆甜多汁、纤维含量少,可作为日光温室栽培种在庆阳市种植。     

Genetic variability in apple fruit polyphenol composition in Malus × domestica and Malus sieversii germplasm grown in New Zealand

Variations in the concentrations of flavan-3-ol, oligomeric procyanidin, chlorogenic acid, dihydrochalcone, flavonol, and anthocyanin polyphenol groups and total polyphenols were examined in the fruit peel and cortical flesh of 93 (80 Malus × domestica and 13 Malus sieversii) apple genotypes in at least 1 year between 2003 and 2005 grown at one site in New Zealand (NZ). Differences among genotypes accounted for 46-97% of the total variation in the concentrations of total polyphenols and each of the individual phenol groups in the flesh and peel in both species, whereas effects of year and genotype × year were minimal, except for peel flavonols in M. × domestica and flesh flavonols in both species. In these cases, differences among genotypes accounted for less than 30% of the total variation, which was less than the variation found for the interaction between genotype and year. Total polyphenol concentrations among genotypes were spread over a 7- and 9-fold range in the flesh and a 4- and 3-fold range in the peel of M. sieversii and M. × domestica, respectively, with the spread in concentrations of individual polyphenol groups in each tissue and within each species varying from a 2-fold to over a 500-fold range. Higher concentrations were generally found in M. sieversii. In M. × domestica, cultivars and breeding selections originating in NZ had lower average flesh and peel total polyphenols and chlorogenic acid than older cultivars previously imported into NZ from overseas countries.     

不同土壤水分下限对大棚滴灌甜瓜产量和品质的影响

以厚皮甜瓜品种伊莉莎白为材料,研究大棚滴灌条件下营养生长期不同土壤水分下限(75%田间持水量,I75;65%田间持水量,I65;55%田间持水量,I55;45%田间持水量,I45)对甜瓜生长、产量、品质以及灌溉水分利用效率的影响,并以沟灌(G75)作为对照。结果表明,株高、茎粗、叶面积和地上部干重均随着营养生长期土壤水分下限的降低而减小。I75果实横径、皮厚和肉厚均最大,果形指数最小;I65果实纵径最大。果实品质方面,总可溶性固形物(TSS)含量为:I65>I55>I75>I45;可溶性糖含量为:I55>I65>I45>I75;维生素C(Vc)含量为:I55>I65>I75>I45;可溶性蛋白质含量为:I55>I65>I45>I75;游离氨基酸总量为:I45>I65>I55>I75。I75的产量和平均单果重最高;I65的灌溉水分利用效率最高,达到29.16kg/m3,相比沟灌对照提高76.4%,可节水58.1%,而平均单果重仅比对照下降3.2%。综合考虑产量和品质,可以选择65%田间持水量作为武汉地区厚皮甜瓜营养生长期适宜的土壤水分下限指标。     

外源褪黑素对低温胁迫下桃果实蔗糖代谢的影响

为探究外源褪黑素减轻桃果实低温冷害发生的机制,以湖景蜜露水蜜桃果实为材料,研究了100μmol·L~(-1)外源褪黑素处理对桃果实采后4℃贮藏期间可溶性糖含量及蔗糖代谢相关酶基因表达的影响。结果表明,100μmol·L~(-1)外源褪黑素能显著减轻果实冷害的症状,保持较高水平的蔗糖和葡萄糖含量。RT-q PCR分析表明,外源褪黑素处理抑制了蔗糖代谢相关酶基因Pp SPS3、Pp SPP1、Pp SUS1、Pp SUS5、PpHK1、Pp FK1和Pp FK3的表达,提高了蔗糖合成相关酶基因Pp SPS1、Pp SPS2、Pp SUT1和Pp NI1的表达水平,维持果实较高的蔗糖和葡萄糖含量,从而提高了桃果实的抗冷性和贮藏品质。本研究结果为揭示外源褪黑素减轻桃果实低温冷害发生的机制提供了新的思路。