宁夏枸杞果实糖积累和蔗糖代谢相关酶活性的关系

通过对枸杞果实发育过程中果实生长模式、蔗糖、果糖、葡萄糖和淀粉含量及糖代谢相关酶活性的测定,研究了宁夏枸杞果实生长发育过程中糖的代谢积累与相关酶活性的关系.结果表明:(1)宁夏枸杞果实发育呈双S"曲线,果实主要以积累己糖为主.(2)蔗糖磷酸合成酶(SPS)活性在果实发育初期处于下降的趋势,在花后19d开始上升,果实转色后又逐渐下降;蔗糖合成酶(SS)活性总体表现为SS分解方向的活性大于SS合成方向的活性,说明枸杞果实发育过程中,SS的活性主要以分解方向的为主;酸性转化酶(AI)和中性转化酶(NI)的活性随果实发育呈上升趋势,但在果实成熟后期有所下降,且AI和NI活性高于合成酶类的活性,较高的转化酶类活性促进了果实内部己糖的积累.(3)在枸杞果实生长发育中,葡萄糖和果糖含量与AI和NI均呈极显著正相关,而与其它酶不具有相关性.说明AI和NI在宁夏枸杞果实的糖代谢中起着主要的调控作用.     

水杨酸、乙酰水杨酸对番茄幼苗叶片中PPO和POD的诱导作用

以番茄品种改良美国908和合作906为试验材料,研究了水杨酸(SA)和乙酰水杨酸(ASA)喷雾处理6-7叶期幼苗后,叶片内多酚氧化酶(PPO)和过氧化物酶(POD)活性在120 h内的变化.结果显示:SA和ASA对2个番茄品种的适宜诱导浓度分别为1 mmol/L和1.39 mmol/L;SA和ASA对PPO活性的诱导效果无显著差异,但对POD活性的诱导效果SA极显著强于ASA;合作906的PPO活性增幅显著大于改良美国908,而POD活性增幅却显著小于改良美国908,且合作906对诱导处理反应更敏感.研究表明,SA和ASA能显著提高番茄幼苗叶片的PPO、POD活性,而酶活性变化在品种和诱导剂间有显著差异.     

肉苁蓉和寄主梭梭体内可溶性糖分积累与蔗糖代谢相关酶活性研究

通过测定不同发育时期肉苁蓉和寄主梭梭体内主要糖类物质含量和蔗糖代谢相关酶活性,以研究寄生植物与寄主植物的糖代谢及其关系。结果表明:未寄生肉苁蓉的梭梭以积累葡萄糖为主,而寄生肉苁蓉的梭梭在夏季休眠期以积累葡萄糖为主,进入秋季旺盛生长期时以积累蔗糖为主。肉苁蓉的糖分积累与梭梭不同,己糖含量约占可溶性总糖的62.45%,而蔗糖仅为可溶性总糖的4.98%,故肉苁蓉为己糖积累型。寄主梭梭同化枝内蔗糖磷酸合成酶活性较转化酶活性和蔗糖合成酶活性低,其中寄生肉苁蓉的梭梭的分解酶类活性高于未寄生肉苁蓉的梭梭。肉苁蓉体内转化酶活性较低,而蔗糖合成酶和蔗糖磷酸合成酶活性较高,且蔗糖合成酶活性高于蔗糖磷酸合成酶活性,表现为肉苁蓉中的分解酶类活性高于合成酶类活性,较高的分解酶类活性促进了蔗糖的分解,从而促进了糖分由寄主梭梭向肉苁蓉的不断转移。总体来看,肉苁蓉和寄主梭梭体内糖分的代谢主要以蔗糖合成酶为主,其它2种酶为辅协同参与调控。     

遮光灵武长枣果实糖积累和代谢相关酶活性特征

于灵武长枣盛花期对果实进行遮光处理,以自然照光为对照,通过测定果实生长指标、叶绿素含量、蔗糖代谢相关酶活性及其蔗糖代谢糖分含量等,研究果实光合作用在果实糖积累中的作用及对果实多糖和总糖含量积累的影响。结果表明:(1)遮光处理后,果实单粒重、单粒体积以及果实中叶绿素含量均降低。(2)遮光处理不同程度增加了果实中转化酶、蔗糖磷酸合成酶和蔗糖合成酶分解方向酶的活性,而降低了其蔗糖合成酶合成方向酶的活性。(3)遮光处理主要影响果实着色期和成熟期的糖含量,对果实发育初期糖含量影响较小;果实多糖的形成与果实所受光照状况具有一定的关系,而果实中总糖的积累与外界光照具有密切关系。可见,果实遮光处理影响了果实发育过程中蔗糖代谢相关酶的活性,从而影响果实糖分的代谢和积累。     

宁夏枸杞果实遮光处理对果实糖积累和相关酶活性的影响

在宁夏枸杞盛花期对果实进行遮光处理,以自然照光为对照,通过测定枸杞果实生长指标、果实叶绿素含量、蔗糖代谢糖分含量及其蔗糖代谢相关酶活性,以研究枸杞果实光合作用在枸杞果实糖积累中的效应及对枸杞果实多糖和总糖含量积累的影响。结果表明:(1)遮光后,果实单粒重和果实中叶绿素含量均降低,体积却有所增加,遮光处理主要影响果实着色期和成熟期的糖含量,对果实发育初期影响不大;(2)遮光处理不同程度增加了果实转化酶、蔗糖磷酸合成酶和蔗糖合成酶活性。枸杞果实多糖的形成与果实光照具有一定的关系,而总糖含量的积累与光照关系不大。     

不同果色枸杞果实糖积累特征及其与蔗糖代谢酶活性的关系

以‘宁杞1号’（红色）、‘宁夏黄果’（黄色）和‘黑果’（黑色）3份不同果色枸杞为试材,测定枸杞果实发育过程中糖含量与蔗糖代谢酶活性的变化,并分析糖含量与蔗糖代谢酶活性的相关性,以探讨不同果色枸杞糖积累差异的生理基础,为进一步阐明枸杞品质形成及调控机理提供理论依据。结果显示：（1）气相色谱（GC）法检测结果为 ‘宁杞1号’果实含8种糖,‘宁夏黄果’含7种糖,‘黑果’仅检测到4种糖;且成熟期枸杞果实均以果糖、葡萄糖和蔗糖为主。（2）在枸杞果实发育过程中,各材料果实的果糖和葡萄糖含量呈现逐渐升高趋势,果实发育的后期升高幅度高于初期;而各材料蔗糖和赤藓糖含量却呈现出不同的变化趋势,不同发育时期材料间差异各异。（3）不同果色枸杞蔗糖代谢酶活性在枸杞果实发育过程中差异较大,其中酸性转化酶（AI）在果实发育的初期活性较低,材料间差别小,但在果实发育的后期活性高,材料间差异较大;从枸杞果实发育色变期到成熟期,供试材料AI和蔗糖合成酶（SS）活性高于中性转化酶（NI）和磷酸蔗糖合成酶（SPS）;在整个果实发育过程中‘黑果’保持着较低果糖含量和蔗糖代谢酶活性。（4）3种果色枸杞果糖含量均与AI活性达到显著相关关系,红色与黑色枸杞己糖（果糖和葡萄糖）含量与NI达到显著相关关系。研究表明,不同果色枸杞果实中的糖种类与含量、蔗糖代谢酶活性差异较大,AI活性升高有利于枸杞果糖的积累,转化酶在枸杞果实己糖积累过程中发挥着重要的作用。     

昼间亚高温对花后番茄叶和果实中光合产物代谢的影响

于日光温室中栽培的番茄第一花序第一花开花和开花10d时分别作昼间35℃亚高温处理(以25℃为对照),检测不同生育期的番茄叶与果实中同化产物积累与代谢变化的结果表明:番茄开花后叶中果糖、葡萄糖和蔗糖含量均下降,花后亚高温处理时期越早,叶中糖含量越低;果实发育过程中的果糖、葡萄糖和蔗糖含量比25℃下的高,但成熟时趋于一致。叶和果实中蔗糖代谢相关酶的活性变化基本一致,酸性转化酶(AI)与中性转化酶(NI)活性下降,蔗糖合成酶(SS)和蔗糖磷酸合成酶(SPS)活性升高。     

外源ABA对冬小麦越冬期蔗糖代谢的影响

以抗寒品种‘东衣冬麦l号’和冷敏感品种‘济麦22’为试验材料,在三叶期时对叶片喷施ABA。在冬小麦越冬期间对叶片和分蘖节取样,研究外源ABA对越冬期低温下冬小麦的蔗糖含量及蔗糖代谢相关酶活性的影响。结果表明,外源ABA处理使低温下2个冬小麦品种积累了更多的蔗糖,尤其是‘东农冬麦1号’的分蘖节。零上低温时外源ABA促进了尿苷二磷酸一葡萄糖焦磷酸化酶（UGP）在蔗糖的合成中起主要作用,在零下低温时外源ABA则促进了UGP在蔗糖分解中起作用;外源ABA提高了‘东农冬麦1号’叶片和分蘖节以及‘济麦22’分蘖节中蔗糖磷酸合成酶、蔗糖合成酶的活性,但‘济麦22’叶片中这两种酶的活性则受到ABA的抑制;外源ABA也不同程度地促进了2＋-小麦品种叶片和‘济麦22’分蘖节中酸性转化酶和碱性转化酶活性的提高,但却抑制了‘东农冬麦1号’分蘖节中两种酶活性的提高,表明抗寒性强的‘东农冬麦1号’对外源ABA可能更加敏感,其越冬器官分蘖节保持了较高的蔗糖水平,其蔗糖合成能力的提高将有利于冬小麦植株抵御低温,进而维持＋a＋k-的存活。     

乙酰水杨酸处理对猕猴桃果实成熟衰老的影响及其作用机理

以不同后熟软化阶段猕猴桃果肉组织圆片为材料 ,在 2 0℃下用 1.0mmol L(pH 3.5 )的乙酰水杨酸(ASP)分别处理 4、12和 2 4h后 ,分析其对果实成熟衰老相关因子的影响。结果表明 ,随着果实成熟衰老 ,内源游离SA下降 ,LOX活性增加 ,超氧自由基 (O- ·2 )生成速率增加 ,乙烯释放量加大 ;ASP处理促使组织内源SA水平的增加 ,降低了O- ·2 生成速率 ,抑制了LOX、ACC合成酶和ACC氧化酶的活性以及乙烯的生成。推测ASP可能作为O- ·2 等自由基清除剂 ,通过负反馈调控LOX途径 ,延缓果实的成熟衰老     

苗期喷施表油菜素内酯对番茄叶中蔗糖代谢的影响

以番茄品种“辽园多丽”为材料,在人工气候室内模拟外界自然条件,研究苗期（四叶期）喷施表油菜素内酯（epi—BL）对番茄叶中蔗糖代谢影响的结果表明：喷施epi—BL的番茄幼苗叶中果糖和葡萄糖含量提高,而蔗糖的含量下降,可溶性酸性转化酶和蔗糖合成酶的活性以及可溶性酸性转化酶和蔗糖合成酶在mRNA水平上的表达增强;但epi-BL对番茄幼苗叶的中性转化酶辛口蔗糖磷酸合成酶活性影响不大。     

昼间亚高温下番茄叶中糖含量与蔗糖代谢相关酶的活性日变化

研究番茄品种‘辽园多丽’幼苗在昼间35℃亚高温条件下叶中糖含量及蔗糖代谢相关酶活性日变化的结果表明,昼间亚高温处理后的幼苗叶中果糖、葡萄糖和淀粉含量下降,蔗糖含量升高。与蔗糖代谢相关的酶活性有明显的昼夜节律性变化,转化酶、蔗糖合成酶呈现昼间活性低、夜间活性高的节律性,而蔗糖磷酸合成酶活性在进入夜间时立刻升高。35℃昼间亚高温处理后的幼苗叶中,转化酶活性下降,蔗糖合成酶活性明显升高,蔗糖磷酸合成酶活性则略有升高。     

Ca2+对离体培养的番茄花柄脱落的影响以及脱落过程中离区内钙形态的变化

在自然条件下,Ca~(2 )对离体培养的番茄花柄脱落有抑制作用,而对经乙烯处理的则有显著的促进。无论是在自然还是乙烯条件下,未经任何处理的番茄花柄脱落过程中总钙与果胶酸钙含量下降,而水溶性钙含量升高,Ca~(2 )在不同程度上提高脱落过程中离区总钙、果胶酸钙和水溶性钙含量,尤其是在乙烯下的效果更显著,而经EGTA处理的则相反。     

串番茄果实货架期间与耐贮性有关的生理特性的变化

串番茄品种随着货架期延长,果实硬度、果肉硬度、原果胶含量逐渐下降;可溶性果胶含量逐渐上升;多聚半乳糖醛酸酶(PG)活性呈峰值变化,变化幅度小于普通番茄.     

1-甲基环丙烯采后处理对樱桃番茄果实成熟过程的影响

研究了不同浓度(0、0.035、0.07和0.11μL/L)的乙烯受体竞争性抑制剂1-甲基环丙烯(1-MCP)采后处理对绿熟期樱桃番茄的乙烯合成、果实软化、果实色素(叶绿素、茄红素、β-胡萝卜素)含量消长的影响.0.07 μL/L及其以上浓度的1-MCP降低了前期乙烯合成,同时推迟了乙烯释放高峰,但0.035 μL/L浓度的1-MCP处理并不能抑制内源乙烯合成.1-MCP显著延迟了果实软化和叶绿素降解,但并不影响这两个过程的启动.茄红素合成的启动和积累均受到了1-MCP抑制,而1-MCP并不推迟β-胡萝卜素合成的启动,只抑制其积累.这些结果提示了乙烯调节成熟生理过程的不同机制.对于绿熟期的樱桃番茄,0.07～0.11μL/L的1-MCP是实用的有效处理浓度.1-MCP有效浓度可能用于了解果实的乙烯受体水平和乙烯敏感性.     

Plant Regeneration from Cotyledon Protoplasts of Tomato (Lycopersicon esculentum L.)

otyledon protoplasts of tomato (Lycopersicon esculentum L.) isolated from 2–3 week grown seedlings were cultured in MS liquid medium (2,4-D 1, 6-BA 0.1 mg/l) and fresh medium added subsequently. After 6 weeks culture, the cell clusters were transferred to semisolid medium (the additive same as in liquid medium, agar 0.3%). When the calli grew to 0.5 cm in diameter, transfer them to MS medium (6-BA 2, IAA 0.2 mg/l) for differentiation. The regenerated plants were obtained. After comparing different culture methods, tomato protoplasts grew better in double layers than in agar plate and hanging drops.     

Does an antagonistic relationship between ABA and ethylene mediate shoot growth when tomato (Lycopersicon esculentum Mill.) plants encounter compacted soil?

This study tested the hypothesis that antagonistic interactions between abscisic acid (ABA) and ethylene mediate the effects of soil compaction on shoot growth. Isogenic wild‐type (Ailsa Craig), ABA‐deficient (notabilis) and a transgenic (ACO1_AS) tomato genotype with a reduced capacity to synthesize ethylene were examined. Exogenous ABA was also applied. Leaf area was comparable when Ailsa Craig and ACO1_AS were grown in uncompacted (1·1 g cm^?3) or compacted (1·5 g cm^?3) soil, but was lower in notabilis. However, a 1·1/1·5 g cm^?3 split‐pot treatment invoked marked genotypic differences, whereby leaf area was comparable to 1·1 g cm^?3 control plants in ACO1_AS but was intermediate between the 1·1 and 1·5 g cm^?3 treatments in Ailsa Craig and notabilis. ABA may be discounted as the root‐sourced signal responsible for reducing leaf area when the roots encountered compacted soil as Ailsa Craig and ACO1_AS showed differing responses despite similar increases in xylem sap ABA concentration; leaf area was invariably lower in notabilis. These genotypic differences were correlated with ethylene evolution; thus the greater leaf area in ACO1_AS was associated with its reduced ability to synthesize ethylene, whereas the reductions in leaf expansion observed when Ailsa Craig and notabilis encountered compacted soil were accompanied by increased ethylene production. Application of ABA had little effect on ACO1_AS, but promoted a recovery of leaf expansion in notabilis, and more surprisingly in Ailsa Craig. These results suggest that antagonistic interactions between ABA and ethylene may regulate leaf expansion when the root system simultaneously encounters uncompacted and compacted soil.     

Relationship between the Changes of Acid Phosphatase Activities and Pi -uptake of Tomato Seedlings during Phosphate Starvation

The acid phosphatase activities from roots and both stems and leaves of tomato seedlings all in-creased markedly under phosphate starvation. Phosphate starvation also increased the activities of acid phos-phatase from cell surface of, and released by roots of tomato seedlings. The kinetic analysis of acid phos-phatase of roots of tomato seedlings revealed that phosphate starvation increased the affinity of the enzyme to its substrate. The results also revealed that phosphate starvation had no effect on the optimum pH (pH 4.93) of the acid phosphatase of roots of tomato seedlings. It was also found that molybdate strongly inhibited not only the activities of acid phosphatase but also Pi- uptake rates of tomato seedlings.     

UV-B radiation causes early ripening and reduction in size of fruits in two lines of tomato (Lycopersicon esculentum Mill.)

An open-air experiment was performed in Pistoia (Italy) to investigate the possible protective role played by different contents of UV-B absorbing compounds to realistic UV-B supplementation and to study its effect on plant fruit production. A mutant line and its normal counterpart of Lycopersicon esculentum Mill, which differ in the content of UV-B absorbing compounds, were used. Additional UV-B radiation in the field was supplied to simulate a 20% stratospheric ozone depletion. Two groups of plants were grown: ‘control’, where plants received only natural solar UV-B radiation, and ‘UV-B’ treatment, where plants were grown under supplemental UV-B. The results of the experiment showed that the content of UV-B absorbing compounds of treated plants did not differ from that of the control in both lines. This indicates that natural sunlight, in Mediterranean areas, is saturating for synthesis of these compounds also in plants with normal content of UV-B absorbing compounds. Consequently, plants are not able to produce significant additional amounts of them, in response to a realistic UV-B supplementation, in order to protect the plant from additional UV-B radiation. No different responses to the UV-B supplementation were found between the two lines. The most significant UV-B effect was an earlier reddening of fruits in comparison with the ‘control’ accompanied by a reduction in the size of mature fruits. No significant effects of UV-B treatment were observed in biomass accumulation, leaf ontogeny, flowering or productivity.     

Utilization of Caffeic Acid Phenethyl Ester to Control Alternaria alternata Rot in Tomato (Lycopersicon esculentum Mill.) Fruit

Chemical fungicides that are related with resistant strains develop negative effects on human health and environment. Propolis is a resinous substance collected by bees with positive effects on human health and inhibitory activity against Alternaria alternata. Caffeic acid phenethyl ester (CAPE) is a component of the propolis. The objective of this experiment was to test the effect of CAPE on fungi infecting tomato fruit using as a model the pathosystem A. alternata‐tomato. CAPE was chemically synthesized in our laboratory and analysed with nuclear magnetic resonance spectroscopy. Different concentrations (0, 16, 32, 48, 64, 80, 90 and 100 μm ) of CAPE were tested on A. alternata growing in vitro. For the in vivo experiment, red ripe tomato fruit was inoculated with A. alternata and untreated or treated with 1, 50 and 100 μm of CAPE. After that, the fruit was stored at 25°C for up to 20 days. Colony size (CS) was recorded in vitro. In tomato fruits, the severity of infection (SI), respiration rate (RR), ethylene production (EP), pH, total soluble solids (TSS), weight loss (WL) and titratable acidity (TA) were evaluated during the storage time. CAPE melting point and spectral data probed to be the right molecule. In vitro, 64 and 100 μm of CAPE reduced CS by 30%. In vivo, 50 and 100 μm of CAPE reduced SI higher than the fungicide Captan^® with no effects on RR, EP, WL, pH, TSS and TA. It was concluded that CAPE controls A. alternata infection better than a commercial fungicide without negative effects on tomato fruit ripening and fruit quality.