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.     

龙柚果肉糖积累与蔗糖代谢相关酶活性的研究

本文探讨龙柚果实发育过程中果肉糖积累与蔗糖代谢相关酶活性的变化。结果表明,在龙柚果实发育过程中,3种可溶性糖含量同步上升,在果实膨大期和成熟期,以蔗糖积累为主。在龙柚糖积累过程中,蔗糖合成酶(SS)和蔗糖磷酸合成酶(SPS)活性较高;而蔗糖中性转化酶(NI)活性则随着蔗糖的积累而降低。     

枇杷果实发育过程中糖积累及相关酶活性变化研究

以'青种'、'霸红'和'鸡蛋白'3个枇杷品种为材料,测定不同果实发育时期果实中蔗糖、葡萄糖和果糖含量以及蔗糖代谢相关酶即酸性转化酶(AI)、中性转化酶(NI)、蔗糖合成酶(SS)和蔗糖磷酸合成酶(SPS)的活性,并对果实中糖积累与酶活性的关系进行了分析.结果表明:在果实膨大期(5月3日)之前,3种枇杷果实的蔗糖、葡萄糖和果糖积累缓慢,之后则迅速积累,存在着明显的转折点;果实成熟(5月23日)之后糖分积累速度趋于平稳.3种枇杷果实在发育过程中转化酶、蔗糖合成酶和蔗糖磷酸合成酶的活性变化与3种糖积累的动态变化趋势相一致.NI和AI活性在果实膨大期之前都较低且没有明显的变化,之后均快速上升;SS和SPS的活性在果实膨大期之前都很低且几乎无变化,随后'鸡蛋白'的活性迅速上升至果实成熟之后便缓慢上升,而'青种'和'霸红'随果实成熟度的增加而升高,但均低于'鸡蛋白'.可见,枇杷果实膨大期是糖分积累代谢活跃期,其糖积累受蔗糖代谢相关酶综合调控.     

套袋对梨果实发育过程中糖组分及其相关酶活性的影响

以翠冠和黄金梨为试材,测定套袋和未套袋(对照)梨果实发育时期果实中蔗糖、葡萄糖、果糖和山梨醇含量以及蔗糖代谢相关酶酸性转化酶(AI)、中性转化酶(NI)、蔗糖合成酶(SS)和蔗糖磷酸合成酶(SPS)的活性,并对果实中糖组分积累与酶活性的关系进行了分析.结果表明:(1)两梨品种套袋果实在发育过程中蔗糖、葡萄糖、果糖、山梨醇和糖代谢相关酶活性变化趋势与对照基本一致,套袋果实糖含量均低于对照但差异不显著,而各相关酶活性在两类果实间差异表现各异.(2)在梨果实发育早期,果实中以分解酶类为主,糖分积累低;发育后期以合成酶类为主,糖分积累多.(3)两品种套袋和对照果实AI活性与葡萄糖含量均呈显著或极显著正相关,SS合成方向活性与蔗糖含量均为极显著正相关,且翠冠对照果SPS活性与蔗糖含量呈极显著正相关.可见,套袋通过提高果实发育早期转化酶(Inv)活性,降低果实后期蔗糖磷酸合成酶(SPS)、蔗糖合成酶(SS)的活性来影响糖分积累,从而影响梨果品质.     

‘台农1号’芒果果实发育过程中的糖分积累与相关酶活性研究

以‘台农1号’芒果为材料,测定了果实生长发育过程中淀粉、蔗糖、葡萄糖和果糖含量以及淀粉酶、蔗糖代谢相关酶———酸性转化酶(AI)、中性转化酶(NI)、蔗糖合成酶(SS)和蔗糖磷酸合成酶(SPS)的活性,并对果实中糖组分与酶活性的关系进行了分析.结果显示,(1)台农1号芒果果实属于单S型生长曲线,发育前期主要积累淀粉、葡萄糖和果糖,果实成熟软化时,淀粉酶活性降至最低,淀粉水解,蔗糖快速积累.(2)酸性转化酶活性在果实整个发育过程中维持最高,完熟时略有降低;蔗糖磷酸合成酶在果实发育前期略有降低,完熟时升至最高;蔗糖合成酶和中性转化酶活性在整个发育期一直很低且较稳定.(3)淀粉含量与淀粉酶活性呈显著正相关,与SPS活性呈极显著负相关,蔗糖、葡萄糖含量均与SPS、SS呈显著、极显著的正相关;果糖含量与SS呈极显著的正相关.研究表明,芒果成熟时淀粉分解、酸性转化酶活性的降低,且蔗糖合成酶和蔗糖磷酸合成酶活性的增加是引起果实蔗糖积累的主要因子.     

糖代谢相关酶在灵武长枣叶片和果柄糖积累中的作用

以不同发育时期灵武长枣为试材,测定果实生长发育过程中叶片、果柄可溶性糖含量及蔗糖代谢相关酶活性的变化,探讨果实生长发育过程中叶片、果柄糖的积累与蔗糖代谢相关酶活性的关系。结果表明:(1)灵武长枣叶片、果柄均主要以积累蔗糖为主,叶片、果柄中葡萄糖和果糖含量的变化平缓且随果实发育略有上升,蔗糖含量则呈先下降后迅速上升的趋势,且蔗糖含量始终高于葡萄糖和果糖的含量。(2)在果实的整个发育期,叶片和果柄的酸性转化酶(AI)活性均远高于中性转化酶(NI),AI在前期升高后变化较平稳,而蔗糖合成酶(SS)和蔗糖磷酸合成酶(SPS)活性的变化各不相同。(3)SS分解方向酶活性(SSd)对叶片和果柄蔗糖的积累具有重要的调节作用。研究认为,蔗糖合成酶分解方向酶活性(SSd)对灵武长枣叶片和果柄蔗糖的积累起主要的调控作用。     

河套蜜瓜果实发育过程中糖积累与蔗糖代谢相关酶的关系

以河套蜜瓜为试材,采用外部形态观测与内部生理指标测定相结合的方法,对其果实发育过程中果实生长模式以及果实中蔗糖、果糖、葡萄糖和淀粉含量以及蔗糖代谢相关酶活性进行测定,以揭示河套蜜瓜果实生长发育过程中糖的代谢积累与相关酶的关系.结果显示:(1)河套蜜瓜果实生长速率呈单"S"曲线,果实发育早期以积累葡萄糖为主,进入成熟期后蔗糖积累量迅速增加,最终由蔗糖和己糖共同构成果实品质.(2)在河套蜜瓜果实成熟期前,蔗糖磷酸合成酶(SPS)活性维持较低水平,进入成熟期后,SPS活性迅速升高;蔗糖合成酶(SS)活性在成熟期前为分解活性大于合成活性,成熟期后表现为合成活性大于分解活性;在整个果实发育期,酸性转化酶(AI)活性较低,中性转化酶(NI)活性始终高于AI.(3)在果实整个发育期,蔗糖含量与蔗糖代谢酶的净活力呈极显著正相关,蔗糖代谢相关酶共同作用决定果实中蔗糖含量.研究表明,在河套蜜瓜果实发育前期,以蔗糖分解代谢为主,且蔗糖合成酶和中性转化酶是催化蔗糖分解的关键酶;果实成熟期间,蔗糖代谢转为合成方向为主,蔗糖合成酶和蔗糖磷酸合成酶在蔗糖积累中起主导作用.     

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。     

苹果果实糖积累特性与品质形成的关系

以'富士'和'国光'苹果为研究对象,对其果实发育过程中糖含量及其代谢关键酶活性的变化进行测定分析,以揭示糖分积累代谢特性对果实品质形成的影响.结果表明:(1)'富士'和'国光'均为己糖积累型果实, '富士'果实以积累果糖最多,果糖/葡萄糖(F/G)值为1.56,而'国光'以积累葡萄糖最多,F/G值仅为0.68;蔗糖在两品种中含量和所占比例均很低,在近成熟期'富士'高于'国光'.(2)'富士'果实蔗糖磷酸合成酶(SPS)和蔗糖合成酶(SS)活性均随果实糖的累积量增加而显著升高,酸性转化酶(AI)活性也渐趋升高,而中性转化酶(NI)活性波动不大,且其糖累积与AI和SPS活性相关性最大,而与NI相关性不大,SS的作用主要表现在发育后期;在 '国光'果实糖积累过程中SPS起主导作用,SS和NI的作用主要表现在发育前期,而AI的作用不大.(3)'富士'和'国光'果实淀粉含量变化趋势相同,在淀粉积累高峰之后,'富士'果实淀粉降解速度更快,其淀粉含量迅速下降且低于'国光',此时其相应淀粉酶活性也高于'国光'.研究发现,'富士'和'国光'果实糖积累和淀粉代谢均存在显著差异,从而直接或间接地影响着果实糖代谢过程,进而导致果实品质的显著差异.     

睡莲叶脐着生胎芽与叶片不同部位碳水化合物代谢的关系

为了解睡莲叶脐胎芽的发育机理,以广热带亚属胎生睡莲‘玛格丽特’和‘鲁比’为材料,非胎生睡莲‘粉星’为对照,采用石蜡切片技术观察叶脐胎芽发育4个时期的形态变化,并比较胎生与非胎生睡莲叶片不同部位碳水化合物代谢的差异性。结果表明: 叶片展开后,胎生睡莲叶脐表皮以下细胞不断分裂和生长,形成排列紧密的细胞群,并逐渐向上凸起呈球形,非胎生睡莲叶脐则无任何变化。随着叶片的不断发育,除蔗糖和酶活性以外,各生理指标在胎生睡莲叶片中的含量均表现为先升后降,显著高于非胎生睡莲;从不同部位来看,碳水化合物含量总体表现为叶片>叶脐>叶柄(淀粉含量除外,其叶脐高于叶片和叶柄);不同品种蔗糖代谢酶活性表现为蔗糖合成酶(SS)和酸性转化酶(AI)活性高于蔗糖磷酸合成酶(SPS)和中性转化酶(NI)活性,胎生睡莲不同组织中的SPS和NI活性均显著高于非胎生睡莲,但SS和AI活性在胎生睡莲中并未表现出明显的品种优势;AI活性在品种间差异大,NI活性在品种间差异较小,且在不同组织中均处于较低水平。相关性分析表明,‘鲁比’叶片的蔗糖含量与SPS和AI呈极显著正相关,与NI呈显著正相关,且蔗糖含量的积累主要增加了睡莲叶片的SS和NI活性,有利于促进胎芽的形成。     

Response of sucrose metabolizing enzyme activity to CPPU and p-CPA treatments in excised discs of muskmelon

We investigated the effects of 1-(2-chloro-4-pyridyl)-3-phenylurea(CPPU) and para-chlorophenoxyacetic acid(p-CPA) treatments on the sucrose metabolism-relatedenzymeactivities in excised mesocarp discs of muskmelon fruit at different growthstages. Both a CPPU and a p-CPA treatment applied to discsprepared at 5 and at 20 days after anthesis (DAA) increased acid invertase (AI)activity and neutral invertase (NI) activity, but neither treatment affectedthese activities in the discs prepared at 45 DAA. Both plant growth substancesincreased the activity of sucrose phosphate synthase (SPS) in the discs at 5and20 DAA, but neither affected it in the 45 DAA discs. The sucrose synthase (SS)activity was markedly increased by p-CPA treatment in the20 and 45 DAA discs, but was not affected at 5 DAA. CPPU treatment did notactivate SS of discs throughout the growth stage.     

外源水杨酸对氯化钠胁迫下番茄幼苗糖代谢的影响

采用营养液水培法,用100、300和500 mg·L^-1不同浓度的水杨酸（SA）处理‘辽园多丽’番茄幼苗,测定在NaCl胁迫下番茄幼苗叶片果糖、葡萄糖、蔗糖含量和蔗谢代谢相关酶活性（酸性转化酶AI、中性转化酶NI、蔗糖磷酸合成酶SPS、蔗糖合成酶活性SS）的变化.结果表明：SA处理叶片可以维持或提高NaCl胁迫条件下番茄幼苗叶片果糖、葡萄糖含量及AI、NI、SPS和SS活性,其最高值分别比单纯NaCl处理植株增加30.0%、31.1%、24.7%、27.9%、22.0%和24.5%;但对NaCl胁迫条件下番茄幼苗叶片蔗糖含量的影响不大.表明水杨酸可以通过提高NaCl胁迫下番茄叶片转化酶活性来提高番茄叶片果糖和葡萄糖含量,从而缓解NaCl胁迫对番茄的伤害,其中以500 mg·L^-1的SA处理效果较理想.     

Activity of sucrose hydrolysing enzymes and sugar accumulation during tomato fruit development

Relationships between the assimilate import rate and the activity of acid invertase and/or sucrose synthase have been investigated in the pericarp, locule and placenta of tomato fruit during development to establish the possible role of sucrose cleavage as the control step for the import of sucrose into these sink tissues. The rate of sucrose cleavage was estimated from the activities of these two enzymes as well as the ratio of hexoses to sucrose (i.e. the sucrose degradation index, SDI) in the tissues of the fruit, based on the assumption that the accumulation of hexoses is the consequence of imported sucrose being degraded by either or both of these two enzymes. The results showed that the change of sucrose synthase activity during fruit development was positively related to both the rate of dry matter accumulation in the fruit tissue and SDI. Although the role of acid invertase in regulating the rate of import during development remains uncertain, the actions of sucrose synthase on sucrose cleavage may regulate the import and compartmentation of sucrose in the early stage of tomato fruit development.     

Carbohydrate availability affects growth and metabolism in peach fruit

Along with sucrose, sorbitol represents the main photosynthetic product and form of translocated carbon in peach. This study aimed at determining whether peach fruit carbohydrate metabolism is affected by changes in source–sink balance , and specifically whether sorbitol or sucrose availability regulates fruit enzyme activities and growth. In various trials, different levels of assimilate availability to growing fruits were induced in vivo by varying crop load of entire trees, leaf : fruit ratio (L:F) of fruiting shoots, or by interrupting the phloem stream (girdling) to individual fruits. In vitro, fruit tissue was incubated in presence/absence of sorbitol and sucrose. Relative growth rate (RGR), enzyme activities and carbohydrates were measured at different fruit growth stages of various peach cultivars in different years. At stage III, high crop load induced higher acid invertase (AI, EC 3.2.1.26) activities and hexose : sucrose ratios. Both sorbitol and sucrose contents were proportional to L:F, while sorbitol dehydrogenase (SDH, EC 1.1.1.14) activity was the only enzyme activity directly related to L:F in both fruit growth stages. Girdling reduced fruit RGR and all major carbohydrates after 4 days and SDH activity already after 48 h, but it did not affect sucrose synthase (SS, EC 2.4.1.13), AI and neutral invertase (NI, EC 3.2.1.27). Fruit incubation in sorbitol for 24 h induced higher SDH activities than in buffer alone. In general, assimilate availability affected both sorbitol and sucrose metabolism in peach fruit, and sorbitol may function as a signal for modulating SDH activity. Under highly competitive conditions, AI activity may be enhanced by assimilate depletion, providing a mechanism to increase fruit sink strength by increasing hexose concentrations.