乙烯与水稻细胞质雄性不育的关系

从幼穗发育的IV到VII期,水稻细胞质雄性不育系(珍汕97A)幼穗和叶片的ACC含量和乙烯释放速率均高于其保持系(珍汕97B)。外施乙烯释放剂乙烯利使保持系花粉可育度明显下降;外施ACC合成酶抑制剂AVG引起两系幼穗ACC含量和乙烯释放速率下降,并使不育系花粉育性得以部分恢复,而在外施AVG的同时再施以乙烯利则AVG的恢复作用消失。     

1-MCP对冬枣冷藏期间乙烯代谢及细胞膜脂过氧化作用的影响

[目的]探讨1-MCP对果实成熟衰老的调控机制,为控制果实成熟衰老进程提供理论依据。[方法]以冬枣为试材,以未经处理的冬枣为对照,测定在冷藏条件下不同浓度1-MCP处理后冬枣的呼吸强度、乙烯释放速率、MDA含量及ACS、ACO、SOD、CAT、POD等酶活性的变化。[结果]经测定,1-MCP在贮藏前期有效抑制了冬枣ACS活性,在贮藏后期有效抑制了冬枣ACO活性,处理果的呼吸强度和乙烯释放速率均低于对照,差异达到显著水平。同时,1-MCP处理有效地减少了MDA的积累,与对照比较,虽然1-MCP处理未改变SOD、CAT和POD的变化趋势,但却显著提高了它们的活性。[结论]1-MCP能有效降低非跃变型果实冬枣的膜脂过氧化水平、呼吸强度和乙烯释放速率,延缓果实衰老进程,并对乙烯的生物合成过程产生抑制。     

五种热带水果乙烯受体基因的SNP分析

根据乙烯受体基因的保守序列设计引物，分别从荔枝、香蕉、木瓜、芒果和莲雾等五种热带水果的基因组DNA中克隆出的乙烯受体基因的保守序列，序列长度分别为1440bp、1441bp、1439bp、1440bp和1440bp，序列分析表明，与栽培稻的ers基因相似性最高。五种热带水果乙烯受体基因保守序列存在明显的单核苷酸变异，在19个核苷酸位点存在SNPs(single nucleotide polymorphisms)，其中12个SNPs存在于内含子中，7个SNPs存在于编码序列区。在编码序列区的SNPs，荔枝与其他4种热带水果相比具有较高的单核苷酸多态性，荔枝有4个核苷酸的变异，其余4种热带水果仅有一个核苷酸变异。编码区序列中的单核苷酸的改变，除了第783位核苷酸的不同没有引起氨基酸改变外，其余均导致编码氨基酸的改变。     

转基因番茄果实成熟与乙烯含量的关系

为探索番茄果实成熟与乙烯的关系,测定了转反义NR和ACC基因突变体番茄果实不同发育期乙烯释放量的变化,结果显示:(1)NR2、NR17和NR18号转反义NR基因果实各期的乙烯含量变化规律与普通果实相同。(2)转反义 NR基因番茄果实与转反义ACC基因番茄果实不同,前者果实能正常成熟、但成熟延迟,后者不能正常成熟。(3)在转反义NR基因果实发育各期中,粉红期乙烯释放量最高。(4)转反义NR基因果实成熟各期乙烯的释放量均明显低于普通果实。说明乙烯受体蛋白基因——NR基因的表达在被抑制后,也反过来抑制了番茄果实乙烯的释放。(5)转反义NR基因果实在常温下贮藏,贮藏期延长了43d。     

番茄乙烯受体基因反义表达对果实成熟的影响

 以乙烯受体基因LeETR1和LeETR2的转反义基因株系ale1和ale2为材料, 对果实成熟特性进行了研究。转基因番茄果实与对照相比, 呼吸速率下降, 但乙烯释放速率增加1～4倍, 呼吸高峰和乙烯跃变高峰出现的时间没有改变, 表明果实成熟起始时间没有改变。ale1果实成熟后期着色速度减慢, 红熟果色泽a值、番茄红素和类胡萝卜素含量都显著低于对照; 但果实多聚半乳糖醛酸酶活性上升和硬度下降速度都显著高于对照。这说明LeETR1基因与果实成熟品质特征的形成可能存在比较复杂的关系。     

乙烯在植物生长发育和抗病反应中的作用及其生物合成的反义抑制

乙烯是迄今为止所发现的 5大类植物激素之一 ,它广泛存在于植物体中 ,对植物的生长发育 ,特别是植物的成熟和衰老起着十分重要的调节作用。研究还发现 ,乙烯参与逆境条件 (热害、冷害、旱害、涝害、盐害、紫外线和重金属离子等 )下植物的胁迫反应 ,影响到植物体内一系列胁迫反应的开始和植物抗性的变化。近年来又发现乙烯参与植物的抗病反应 ,尤其是转反义乙烯形成酶基因植物的抗病性研究倍受重视。人们虽然在转反义乙烯形成酶基因植物的抗病性方面做了大量的工作 ,积累了相当多的资料 ,发现植物的抗病性与乙烯密切相关 ,但由于该研究尚处在初期 ,研究还不系统 ,乙烯在植物抗病反应中的作用机理也不十分清楚 ,因此需要系统整理和更加深入细致的研究。反义基因技术的成功应用 ,不仅为深入研究乙烯在植物体内的作用机理提供了方便 ,也为培育植物新品种提供了快速有效且专一性极强的育种新途径。本文将系统介绍乙烯在植物生长发育中的作用以及利用反义基因技术控制乙烯的生物合成、从而达到控制植物生长和发育之目的研究进展 ,重点叙述乙烯在植物抗病作用以及转反义乙烯形成酶基因植物的抗病性研究的最新进展 ,同时对倍受重视的反义基因技术的原理及特点也做较为全面和细致的介绍。     

Effect of fruit maturity on efficiency of 1-methylcyclopropene to delay the ripening of bananas

Three bunches of unripe ‘Williams’ banana fruit of different maturity, 173, 156 and 71 days from bunch emergence, were harvested. Fruit from the top, bottom and middle hands from each bunch were fumigated for 24 h with 1-methylcyclopropene (1-MCP) at 0, 5, 50 or 500 nl l⁻¹ at 20^oC. All fruit were then stored at 20^oC in air containing 0.1 μl l⁻¹ ethylene and the time taken for each fruit to ripen (green life) was noted. The green life of fruit treated with 500 nl l⁻¹ 1-MCP varied with fruit maturity. In the two most mature bunches it was 27.9±2.3 days, 4-fold longer than fruit fumigated with 0 nl l⁻¹ 1-MCP (6.7±0.6 days). In the least mature bunch, green life was 39.7±3.0 days, 1.5-fold longer than fruit fumigated with 0 nl l⁻¹ 1-MCP (25.7±2.5 days). Most fruit treated with 500 nl l⁻¹ 1-MCP showed an unacceptable uneven skin colouration when ripe. There was no significant effect on green life of 1-MCP at 50 nl l⁻¹ and 5 nl l⁻¹. Other fruit from these bunches were not exposed to 1-MCP and were held in ethylene-free air until ripe. In the two most mature bunches, these fruit had a significantly shorter green life (11.2±5.6 days in hand 1; 18.9±4.1 days in hands 4 and 6) than fruit that were fumigated with 500 nl l⁻¹ 1-MCP. In the least mature bunch, however, these fruit had a significantly longer green life (56.0±5.9 days) than 1-MCP treated fruit. Since the effectiveness of 1-MCP varied with fruit maturity and in any commercial consignment there is a mixture of fruit maturity, it is concluded that 1-MCP has limited commercial potential for the storage of unripe ‘Williams’ bananas.     

Plant oil emulsion modifies internal atmosphere, delays fruit ripening, and inhibits internal browning in Chinese pears

'Laiyang Chili’ and ‘Ya Li’ (Pyrus bertschneideri Reld) pears were treated with 3, 6, and 9% emulsions of commercial or refined (reduced -tocopherol levels) plant (soybean, corn, peanut, linseed, and cottonseed) oils at harvest an stored at 0°C for 6 months. Effects of oil treatments on ethylene production, respiration, fruit firmness, fruit color, soluble solid content (SSC), titratable acids (TA), internal browning (IB), and internal CO₂, O₂, and ethanol were studied. At the same concentration, oil treatments induced similar responses regardless of their sources or their -tocopherol concentrations. In both cultivars, ethylene production and respiration in fruit treated with 9% oils were lower in early storage and higher in late storage than that in the controls. Oils at 6% reduced IB, at 9% inhibited IB completely, and at 3% was not effective after 6 months at 0°C and 7 days at 20°C. Plant oil treatment maintained fruit color, firmness, SSC, and TA in a concentration-dependent manner during storage. In the first 4 months storage, 9% corn oil-treated fruit contained similar partial pressure of CO₂ and O₂ as the controls. After 5 months storage, oil-treated fruit contained higher partial pressure of CO₂ and lower levels of O₂ than the controls. When held at 20°C for 7 days, changes of internal CO₂ and O₂ were slower but partial pressure of CO₂ were higher, and O₂ were lower, in 9% corn oil-treated fruit than in the controls. Internal ethanol was not affected by oil treatment compared with control, either during storage or 7 days at 20°C. No off-flavor was detected in either oil-treated and control fruit by sensory evaluation.     

乙烯抑制剂在采后观赏植物中的应用研究进展

乙烯作为植物衰老激素在观赏植物及切花开花衰老过程中起着关键性的调节作用。利用乙烯抑制剂控制乙烯作用就成为延长观赏植物观赏寿命和提高其观赏价值的主要途径和经济有效的方法,是采后观赏植物研究的主要方向之一。在此,综述了近年来在采后观赏植物研究和生产实践中广为应用的几种乙烯抑制剂,并简要说明了其特点和作用原理。     

植物切花乙烯致衰机理与化学调节

乙烯是引起切花采后衰老的主要激素。综述了针对植物体内乙烯的生物合成途径及其作用机理的研究现状，从保持切花体内水分平衡、降低呼吸速率、抑制乙烯的产生和作用等方面提出了利用糖类、有机酸、STS、GA3、1—MCP等化学物质调控切花衰老的主要措施，并对切花保鲜的研究方向进行了展望。