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1.
黄瓜叶片和韧皮部汁液中碳水化合物及相关酶的日变化   总被引:3,自引:0,他引:3  
 以黄瓜叶片和韧皮部汁液为对象, 研究1个昼夜周期中各种碳水化合物含量及相关酶活性的变化。结果表明夜间至上午10: 00, 葡萄糖和果糖是叶片中主要的可溶性糖, 而下午13: 00至16: 00,水苏糖成为成熟叶片中含量最高的可溶性糖, 这种变化主要由叶片中水苏糖含量剧烈的昼夜变化引起; 当黄瓜同化物从源叶向外运输时, 韧皮部汁液中的可溶性糖以水苏糖为主, 运输完毕后则以蔗糖为主; 黄瓜成熟叶片在夜间以淀粉、葡萄糖、果糖、水苏糖、蔗糖等各种形式贮藏尚未运出的同化物, 而此时韧皮部汁液中葡萄糖、果糖、水苏糖的含量极低, 可能有特定的源库调节机制阻止叶片中的可溶性糖在夜间进一步向韧皮部中装载。  相似文献   

2.
试验中发现,黄瓜幼苗遮光叶片蔗糖含量略高于未遮光对照叶片,而棉籽糖、肌醇半乳糖苷和水苏糖含量显著低于对照叶片。叶片中肌醇半乳糖苷合成酶活性和基因转录水平变化趋势一致,遮光叶片显著低于对照叶片;棉籽糖合成酶活性差异不显著,但是遮光叶片棉籽糖合成酶基因转录水平显著低于对照叶片;遮光叶片水苏糖合成酶活性显著低于对照,且相关基因转录水平变化与酶活性变化一致;此外蔗糖非发酵相关蛋白激酶1基因(SnRK1)表达水平在遮荫处理6 h时显著高于对照。表明在遮光胁迫下,黄瓜幼苗通过调控肌醇半乳糖苷合成酶、水苏糖合成酶和蔗糖非发酵相关蛋白激酶1相关基因表达和酶活性,维持叶片蔗糖含量,提供生长所需能量,保证叶片存活。  相似文献   

3.
以从各地搜集的6 个越瓜品种为试材,对越瓜果实糖含量及蔗糖代谢相关酶进行了研究。结果表明:不同越瓜品种之间糖含量差异较大,凤台越瓜、田集越瓜、刘集越瓜3 个品种可溶性固形物含量及糖含量较高;随着果实的发育蔗糖磷酸合成酶活性呈递增趋势,且在果实各个发育期田集越瓜的蔗糖磷酸合成酶活性均最高;而转化酶活性则随着果实发育呈下降趋势,凤台越瓜和田集越瓜的酸性转化酶及中性转化酶活性在各个发育期均最低;中性转化酶在毛集越瓜、潘集越瓜、青皮越瓜、刘集越瓜中相对较高,且随着果实发育活性下降,至果实成熟时活性达到最小值;除刘集越瓜外,其他品种的蔗糖代谢酶活性在果实不同发育期均没有明显变化。以上结果表明,不同越瓜品种蔗糖含量差异是由蔗糖磷酸合成酶、酸性转化酶和中性转化酶活性共同决定的,其中酸性转化酶在越瓜蔗糖积累中占主导地位。  相似文献   

4.
核桃果肉发育过程中糖含量及相关酶活性的变化   总被引:11,自引:2,他引:11  
 以普通核桃为试材,研究了核桃果肉发育过程中糖含量及其相关酶活性的变化。结果表明:总糖含量呈现逐渐增长趋势,在果实油脂转化期(约花后90 d)达到极大值;淀粉含量呈波动状态。各种可溶性糖含量变化各异,果糖在果实发育前期含量最高,后期有所降低;葡萄糖含量变化不大; 蔗糖含量前期极低,后期逐渐增加。酸性转化酶和淀粉酶前期活性很强,后期降低;蔗糖合成酶(合成方向)和蔗糖磷酸合成酶的活性变化趋势相似,前期弱后期强。  相似文献   

5.
苹果加工品种的糖积累与蔗糖代谢相关酶活性   总被引:8,自引:1,他引:8  
以苹果加工品种瑞林、瑞丹、瑞星为试材研究了发育过程中不同品种苹果果实中糖积累和糖代谢相关酶活性的变化。结果表明,瑞林以积累果糖为主,成熟果实的果糖含量占总糖的53.58%,葡萄糖占24.85%;瑞丹以积累果糖为主、其次是蔗糖,2者分别占总糖的45.52%和35.39%;瑞星是蔗糖/果糖积累并重型品种,蔗糖含量占47.94%,果糖占总糖的46.65%。瑞星蔗糖积累早于其他品种并呈持续上升趋势,而瑞林果糖积累开始早,蔗糖积累缓慢。各品种蔗糖含量与酸性转化酶活性呈负相关,瑞星的酸性转化酶活性明显低于其他品种,而瑞林则表现出较高的酸性转化酶活性。发育后期各品种蔗糖含量升高与酶的净合成活性升高有关。  相似文献   

6.
The quality of fruits and vegetables is mainly dependant on the sweetness determined by the level of soluble sugars such as glucose, fructose and sucrose. Other fruit quality parameters include Brix content, acidity, aroma, color, size and shape. Total sugar content in fruits and vegetables is a function of genetic, nutritional, environmental and developmental factors. Understanding the factors controlling sweetness is important to design strategies for enhancing quality of fruits and vegetables. Modifying the activity of enzymes in carbohydrate metabolism such as sucrose synthase (SuSy), acid invertase, ADP-glucose pyrophosphorylase (AGPase), sucrose phosphate synthase (SPS) and sucrose transporters were found to influence carbohydrate partitioning and sucrose accumulation in sink tissues of several food crops. Plant based taste-modifying sweet proteins such as brazzein, cucurmin, mabinlin, monellin, miraculin, neoculin and thaumatin have potential application for developing transgenic plants to improve the sweetness and quality of fruits and vegetables. The present review envisages various cultural, breeding and molecular approaches used for enhancing sugar content and sweetness in fruits and vegetables.  相似文献   

7.
Summary

This study served to reveal the effects and mechanism of low night-temperatures on the metabolism of raffinose-family oligosaccharides in melon (Cucumis melo L.) leaves. We investigated the carbohydrate contents and sugar-metabolising enzyme activities in leaves under normal (15°C; control) and two low night-temperature (12°C or 9°C) conditions during fruit expansion. The results showed that the greatest difference in carbohydrate metabolism occurred between 9°C at night and the 15°C control. Compared to the normal night temperature, total carbohydrate accumulation, in particular raffinose, increased and the ratio of raffinose to total carbohydrates exhibited the greatest increase in melon leaves treated at 9°C at night, while the ratio of sucrose to total carbohydrates declined at the end of the same treatment. These data suggested that 9°C at night played an important role in partitioning carbon from sucrose to raffinose-family oligosaccharides (RFO), and that raffinose may serve dual purposes in stress protection and carbon storage. Meanwhile, the activities of sugar-metabolising enzymes were notably affected by 9°C at night. Sucrose synthase (SS), sucrose phosphate synthase (SPS) and, in particular, galactinol and stachyose synthase activities decreased markedly, while acid invertase (AI) and neutral invertase (NI) activities increased sharply, which restricted sucrose and RFO synthesis. Overall, these data suggest that the decline in stachyose and galactinol synthase activities were the main limiting factor for RFO synthesis in melon leaves at 9°C at night. They also indicated that the reduction in stachyose metabolism may be an important factor during the development of unmarketable fruit.  相似文献   

8.
 以‘巨玫瑰’葡萄(Vitis vinifera L. × V. labrusca L.)为试材,从始熟期开始研究了根域限制栽培对果实可溶性糖积累及相关代谢酶活性的影响。结果表明:‘巨玫瑰’葡萄果实中主要以葡萄糖和果糖积累为主。从始熟期开始果实中的葡萄糖和果糖含量持续增加,与此同时,酸性转化酶(AI)的活性也随果实发育进程而逐步增强。AI活性与果实中含量最多的葡萄糖和果糖含量显著相关。中性转化酶(NI)和蔗糖合成酶(SS)的分解方向的活性只是在始熟期3周后开始增加,且活性低于AI。蔗糖合成酶(SS)的合成方向和蔗糖磷酸合成酶(SPS)的活性在始熟期开始后稍有增加,此后保持平稳,且活性远远低于蔗糖分解相关酶AI、NI和SS的分解方向活性。根域限制栽培可以显著提高‘巨玫瑰’果实中可溶性糖的含量、糖积累期间的AI活性和成熟时的NI活性,但对其他酶活性影响不显著。由此推断AI是葡萄果实糖积累的最重要的调节因子,也是根域限制提高果实糖含量的关键代谢酶。  相似文献   

9.
Six banana varieties: 3 ‘dessert’ ones: ‘IDN 110’; ‘Kirun’; and ‘Grande Naine’, and 3 ‘cooking’ ones: ‘Galéo’; ‘Sowmuk’; and ‘French’ were used to investigate the relationship between sugar profiles and activities of sucrose-phosphate synthase (SPS, EC 2.4.1.14), sucrose synthase (SuSy, EC 2.4.1.13) working in the hydrolytic way, invertases (EC 3.2.1.26) (neutral (NIV) and acid (AIV)). Expression of a Musa cell-wall invertase (MaCwINV1/pBANUU103) gene was additionally studied during fruit development and ripening ex planta after ethylene treatment of two of these varieties. Close amounts of soluble sugars (sucrose + glucose + fructose) were measured in the different varieties at ripe stage. SPS activity was either almost constant or increased continuously or transitorily during ripening of all varieties, concomitantly to total soluble sugar (sucrose + glucose + fructose) accumulation. Together with previous data obtained from ‘Cavendish’, our data lead us, (i) to strengthen the hypothesis that this enzyme is likely to have a major role in the synthesis of sucrose during ripening of banana and (ii) to underline the complexity of the mode of SPS activity regulation already pointed out. Interestingly, for the first time in banana, two diploid and cooking varieties: ‘Galéo’ and ‘Sowmuk’ were found almost sucrose-free, in good agreement with a 6.4-fold higher mostly vacuolar AIV activity than that of the two desserts and diploid ones. Otherwise, expression of a MaCwINV1/pBANUU103 (cell wall) gene was followed in the two most contrasted varieties in matter of sucrose content: ‘Sowmuk’ almost sucrose-free, and ‘IDN 110’ accumulating high level of sucrose. Compared to ‘IDN110’, the mRNA level of MaCwINV1/pBANUU103 gene was higher (up to 173-fold) in ‘Sowmuk’ concomitantly with the low level of sucrose of ‘Sowmuk’. Our data let us to conclude that the AIV is probably one of the main determinants involved in the regulation of sucrose level during banana fruit ripening, even if the form, vacuolar or cell wall-linked is not determined yet. Otherwise, the MaCwINV1/pBANUU103 gene appears as a putative candidate gene that could contribute to regulate this level.  相似文献   

10.
荔枝果实的糖积累与相关酶活性   总被引:57,自引:4,他引:57  
 以‘糯米糍’和‘妃子笑’两个品种为试材, 对比研究两者在果实发育和成熟过程中假种皮中糖积累和转化及其与糖代谢相关酶类———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) 活性的关系。结果表明: 1. 糯米糍荔枝以积累蔗糖为主, 蔗糖/ 还原糖比值约为1. 5 ; 妃子笑荔枝以积累还原糖为主, 蔗糖/ 还原糖比值仅约为0. 4 ; 2. 荔枝糖积累与库活力密切相关, 但不同品种库活力的主要构成酶类不同, 糯米糍主要是SS , 而妃子笑则主要是NI + SS; 3. 不同的糖代谢酶活性决定了糖组分的不同, 积累蔗糖为主的糯米糍具有高的SS 和SPS 活性, 而转化酶活性较低; 以积累还原糖为主的妃子笑的SS 和SPS 活性较低, 而转化酶活性较高。  相似文献   

11.
蔗糖代谢相关酶在卡因菠萝果实糖积累中的作用   总被引:12,自引:1,他引:12  
以菠萝品种卡因为材料,测定了不同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-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,卡因果实的发育呈单"S型"曲线,在幼果期到果实迅速生长期,果糖和葡萄糖积累较多,蔗糖积累缓慢,此期蔗糖积累较少与高活性蔗糖转化酶有关;进入成熟期,果实中蔗糖迅速积累,而己糖略有上升,果实蔗糖的显著增加主要与SS和SPS活性有关.酸性转化酶和中性转化酶前期活性很强,后期降低;蔗糖合成酶(合成方向)和蔗糖磷酸合成酶的活性变化趋势相似,前期弱后期强.经过相关性分析:果实中蔗糖含量与SS和SPS活性存在极显著的正相关性(相关系数分别为r=0.97273**和r=-0.91004**),而与NI活性呈极显著负相关(r=-0.76419**),与AI的活性呈显著负相关(r=-0.60594*).  相似文献   

12.
蔗糖代谢相关酶在温州蜜柑果实糖积累中的作用   总被引:129,自引:16,他引:113  
 在不同发育时期测定了宫川温州蜜柑果实中蔗糖、葡萄糖和果糖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, 并对果实中糖积累与酶活性的关系进行了分析。结果表明: 蔗糖代谢相关酶的综合作用(蔗糖代谢相关酶的净活性) 是影响果实糖积累的重要因子之一。膨大期末至着色期初是果实中糖积累和蔗糖代谢相关酶的净活性变化的转折时期。着色期前果实中蔗糖代谢相关酶的净活性为负值, 蔗糖缓慢积累; 进入着色期蔗糖代谢相关酶的净活性转为正值,蔗糖积累迅速。完熟期果皮组织中蔗糖代谢相关酶的净活性为负值, 己糖积累明显高于可食组织。  相似文献   

13.
Changes in fruit growth rate, carbohydrate content (glucose, fructose, sucrose and starch) and enzyme activity (sucrose synthase, UDPglucose pyrophosphorylase, fructokinase, glucokinase, sucrose phosphate synthase, ADPglucose pyrophosphorylase and invertases), in the external pericarp of kiwifruit, were measured throughout the growing season. Sucrose synthase showed the highest activity among the sucrose cleaving enzymes during large part of the growing season. The activity of invertases were much lower than that of sucrose synthase until ripening started. Sucrose synthase showed a tight although not linear relationship with the fruit RGR. Furthermore, sucrose synthase showed linear and significant correlations with the activities of both fructokinase and UDPglucose pyrophosphorylase indicating a strong co-regulation of the activities of these three enzymes involved in sucrose cleavage and sink strength, in kiwifruit. Sucrose synthase is suggested to be the dominating enzyme in the cleavage of imported carbon in kiwifruit, in tight coordination with fructokinase and UDPglucose pyrophosphorylase.  相似文献   

14.
One cold-sensitive cultivar (Jinyan 4) and two cold-tolerant inbred lines (NY-1 and XC-1) of cucumber (Cucumis sativus L.) were subjected to temperatures of 28 °C/22 °C (day/night, control) or 28 °C/12 °C (day/night, cold treatment) in a 10 h photoperiod (7:00–17:00). Under control conditions, cucumber fruits grew fast during afternoon and early night, and slow during late night and morning. Under 28 °C/12 °C conditions, the two cold-tolerant inbred lines maintained relatively higher fruit growth rates than the cold-sensitive cultivar by different mechanisms. Compared to Jinyan 4, NY-1 fruits had higher growth rates during cold nights while XC-1 fruits grew faster during the next day. Under the 28 °C/12 °C temperature regime, the assimilate accumulation in the fruits of all tested genotypes followed a similar trend with the corresponding fruit growth rates. After a cold night treatment, the net CO2 assimilation rates of one- and two-fruit plants, which had increased sink demand, were higher than that of plants without fruits in all tested genotypes. This response indicates that feedback inhibition might be an important reason for the reduction of photosynthesis on the next day. In addition, after a cold night treatment, the levels of exportable sugars (sucrose and stachyose) in mature leaves of XC-1 were higher than those measured in Jinyan 4 and NY-1, which might explain why XC-1 fruits had faster assimilate accumulation rates in the next morning. Higher activity of sucrose-phosphate synthase, a key enzyme of sucrose and stachyose biosynthesis, constituted an additional evidence that faster sucrose and stachyose biosynthesis in mature leaves may occur in XC-1 than in Jinyan 4 and NY-1 at that time. In conclusion, our results showed that cucumber genotypes may use different mechanisms to enhance their cold tolerance.  相似文献   

15.
在苹果果实生长早期进行水分胁迫处理,研究水分胁迫期间及胁迫解除之后源叶中的不同种类碳同化物含量及相关酶活性的变化,结果表明,水分胁迫条件下源叶中总可溶性糖和还原糖积累,山梨醇含量升高;前两个干旱胁迫周期源叶中淀粉含量显著降低;水分胁迫对还原糖的影响主要是增加葡萄糖和果糖的含量,葡萄糖含量在中度胁迫时开始增加,严重胁迫时急剧升高,但果糖含量仅在轻度胁迫时显著高于对照,对蔗糖含量的影响较小。水分胁迫解除后,水分胁迫株叶片中除葡萄糖能保持一个显著高于对照的水平外,其余的糖和山梨醇均迅速地回落到正常灌溉的对照水平。同时,树体承受水分胁迫期间,源叶中的6-磷酸醛糖还原酶(A6PR)、山梨醇脱氢酶(SDH)、磷酸蔗糖合成酶(SPS)、蔗糖合成酶(SS)、中性转化酶、酸性转化酶、ADPG焦磷酸化酶(ADPGPPase)和淀粉酶等均有可能得到显著增加,并且水分胁迫解除后各种酶在短期内仍维持一个较高的活性。  相似文献   

16.
Salicylic acid (SA) plays a critical role in plant development and defense responses to biotic and abiotic stresses. Sugars can act as osmotic adjustors or nutrient and metabolic signals in the activation of plant defense responses. To uncover the effects of SA on sugar metabolism, we assayed the altered components and levels of sugars in cucumber seedlings treated with SA. After SA treatment, the levels of glucose, fructose, raffinose and stachyose were increased in both leaves and roots. In contrast, sucrose and starch responded differently in leaves and root, decreasing in leaves but accumulating in roots. These changes could be due to the effects of SA on the activities of metabolism-related enzymes. In leaves, SA promoted the activities of sucrose phosphate synthase (SPS), sucrose synthase (SS) and amylases, while the SA-treated root showed a reduced amylase activity and an unchanged activity in SPS. The changes in various sugar contents resulted in the accumulation of soluble sugars in SA-treated cucumber seedlings, especially non-reducing sugars in roots. These increased sugars could function as osmotic regulators and facilitate water uptake and retention in plant cells, thereby conferring seedlings an enhanced tolerance to salinity stresses caused by NaCl treatment. Taken together, our findings provide an important insight into the effects of SA on sugar metabolism, and a protective mechanism for SA against water deficiency is discussed.  相似文献   

17.
甜瓜果实发育过程中糖积累与蔗糖代谢相关酶的关系   总被引:18,自引:0,他引:18  
以伊丽莎白和乌引1号2个厚皮甜瓜品种为试材,测定了不同发育时期果实中的糖、淀粉含量以及蔗糖代谢相关酶—酸性转化酶(AI)、中性转化酶(NI)、蔗糖磷酸合成酶(SPS)和蔗糖合成酶(SS)的活性变化等,并对甜瓜果实糖积累的生理机制进行了系统分析。结果表明:(1)2个品种果实中糖积累动态十分相似,即成熟期之前,糖积累缓慢,特别是蔗糖几乎很少积累;进入成熟期,果实中蔗糖迅速积累,而单糖略有下降。(2)AI、NI的活性变化对2种甜瓜果实中糖的积累和构成具有重要影响,SS对2种甜瓜果实中糖积累的作用较小,SPS活性升高与成熟期伊丽莎白果实中蔗糖的积累相一致。(3)果实中糖的积累与淀粉含量变化无明显关系。  相似文献   

18.
 试验研究了嫁接对日光温室栽培的网纹甜瓜果实发育、糖含量及蔗糖代谢相关酶活性的影响。结果表明: 嫁接加快了果实的膨大速度, 但对中果肉厚度影响不大; 降低了网纹甜瓜中果肉内的果糖、葡萄糖含量; 改变了网纹甜瓜蔗糖积累模式, 嫁接网纹甜瓜中果肉内蔗糖积累时间较自根提前了7 d左右,蔗糖含量高于自根; 但嫁接降低了网纹甜瓜中果肉的总糖含量及酸性转化酶(AI) 和中性转化酶(NI) 活性, 提高了蔗糖磷酸合成酶( SPS) 和蔗糖合成酶( SS) 活性。  相似文献   

19.
牡丹开花和衰老期间花瓣糖代谢的研究   总被引:4,自引:3,他引:1  
 以牡丹( Paeonia suffruticosa) 品种‘洛阳红’和‘胡红’为材料, 研究了花开放和衰老过程中花瓣可溶性糖及其代谢相关酶活性的变化。结果表明: 伴随花瓣的迅速生长展开, 总可溶性糖呈现迅速增加的趋势, 特别是己糖(葡萄糖和果糖) 含量显著增加, 盛开后己糖水平达到最高, 而蔗糖含量呈现逐渐下降的变化。己糖和蔗糖降解指数(SDI) 与花枝质量呈现极显著的正相关; 花瓣酸性转化酶活性维持较高水平, 开花过程中活性逐渐升高, 开放后逐渐下降。经主成分回归分析, 可溶性糖的代谢依赖于酸性转化酶、中性转化酶、蔗糖合成酶和蔗糖磷酸合成酶的共同作用。结果提示, 牡丹花瓣中己糖的积累在花开放和衰老过程中起着重要作用。  相似文献   

20.
番茄不同部位中糖含量和相关酶活性的研究   总被引:25,自引:2,他引:25  
 试验将番茄光合产物运转途径上叶片(源) 、运输系统以及果实(库) 区分开, 分别测定其糖的组成和含量以及糖代谢相关酶的活性。结果表明: 番茄光合产物运转途径上从“源”到“库”各部位糖的组成和含量不同。叶肉中果糖的含量最高, 蔗糖的含量最低; 中筋中以果糖和葡萄糖为主; 叶柄维管束中葡萄糖含量最高, 蔗糖含量次之, 果糖含量最低。节间和果柄维管束中主要含有蔗糖。果实维管束以及果实内各部位中则主要含有葡萄糖和果糖, 且两者含量无显著差异, 蔗糖含量很低。萼片中葡萄糖含量最高, 蔗糖含量最低; 果蒂中3种糖含量均较高且无显著差异。番茄叶肉及光合产物运转组织中转化酶活性很低, 而在库器官的非维管组织中转化酶活性较高。果蒂中的蔗糖合成酶( SS) 活性最高, 其次是叶肉和运转组织, 果实内各部位中SS活性较低。在合成蔗糖的器官—叶肉中, 有较高的蔗糖磷酸合成酶( SPS) 活性, 运转组织中的SPS活性较叶肉中降低, 但果柄维管束和果实维管束中则表现出较高SPS活性, 果肉、果胶质胎座及心室隔壁中的SPS活性最低。  相似文献   

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