Temperature,ethylene and the postharvest performance of cut snapdragons (Antirrhinum majus)

The effects of temperature and ethylene on the quality of snapdragon flowers (Antirrhinum majus L. cvs. ‘Potomac Pink’ and ‘Rocket’) after harvest were investigated. The flowers were stored dry or wet at 6 temperatures ranging from 0 to 12.5 °C for 5 days. Vase life and gravitropic bending were measured at 20 °C after storage. Respiration rates of flowers at 8 different temperatures (0, 2.5, 5, 7.5, 10, 12.5, 15 and 20 °C) were measured continually using a computerized system. The respiration of cut snapdragon flowers increased exponentially as the temperature increased from 0 to 20 °C, with a mean Q₁₀ of 2.6. The vase life of flowers of the ‘Potomac Pink’ cultivar stored dry at 0 °C was 10.8 days, similar to that of freshly harvested controls (10.6 days), and 4.4 days longer than that of flowers stored at 7.5 °C. When spikes were placed horizontally at 20 °C, growth became negatively gravitropic within 20 min. Bending was significantly higher than controls (stored vertically) in all flowers stored horizontally at temperatures above 5 °C. Vase life of flowers stored for 5 days at a range of temperatures then placed in an interior environment was directly correlated with respiration rate at the storage temperature. Wet storage of cut snapdragon flowers reduced the loss of quality at storage temperatures above 5 °C but the vase life of flowers stored in water at 12.5 °C was less than half that of flowers stored dry at 0 °C. Ethylene treatment caused 100% floret abscission which was prevented by pre-treatment either with 1-methycyclopropene (1-MCP) or with silver thiosulfate (STS), but neither of these inhibitors prevented gravitropic bending.     

UV-327合成中溶剂的选择

以甲苯、氯苯、乙二醇单甲醚分别作为单组分溶剂,又用乙醇分别与上述溶剂按一定比例配制成3种混合溶剂,用葡萄糖和锌粉为还原剂,以4-氯-2-硝基苯胺为原料,经重氮、偶合和二次还原合成紫外线吸试剂UV-327。结果表明,在该工艺的第2次还原中,混合溶剂比单组分溶剂效果好,用乙醇与氯苯配成的混合溶剂较好,溶剂回收率大于85%。通过HPLC,1H-NMR,IR和紫外光谱对目标产品进行了分析。该方法以4-氯-2-硝基苯胺计,总收率>83%,目标产品纯度为99.76%。     

桃沙红果实α-甘露糖苷酶基因(α-man)克隆及其在软化过程中的表达分析

α-甘露糖苷酶(α-man)是植物体内N聚糖加工的关键酶,在控制果实软化和延长货架期方面起重要作用.明确α-man在桃果实软化中的生理功能及其调控机制对进一步阐明桃果实的成熟软化机理具有重要意义.以商业成熟期桃(Prunus persica)沙红果实为材料,采用RT-PCR和RACE相结合的方法,克隆桃果实中α-man基因全长cDNA,并利用实时荧光PCR定量技术,检测了采后乙烯利和1-methylcyclo-propene(1-MCP)处理沙红果实软化过程中α-man基因的表达差异.结果表明:桃果实α-man基因的cDNA全长长3 491 bp,包含一个3 075 bp完整的开放阅读框,编码1 024个氨基酸(Genbank登录号:JX310861),N端含有NXT/S的糖基化位点,属糖基水解酶38家族.实时荧光PCR定量技术检测发现对照果实在贮藏第2天出现α-man的表达高峰;外源乙烯处理α-man基因表达高峰提前ld出现,且峰值显著高于对照果实;而1-MCP处理可使α-man基因的表达高峰延迟1d,且后期α-man基因的表达受到极显著抑制.据此推断桃果实α-man基因可能受乙烯生成和乙烯信号转导途径的调控,参与桃果实的软化过程.     

采后果蔬贮藏过程中多胺与乙烯的关系

综述了多胺与乙烯对采后果蔬的生理效应及相关研究进展,介绍了多胺的生物合成与氧化分解途径,分析了多胺与乙烯生物合成的关系,讨论了果蔬贮藏过程中多胺与乙烯二者的相互作用,并对其研究前景进行了展望。     

结实期土壤水分和灌溉方式对水稻产量与品质的影响及其生理原因

以水稻品种武育粳3号(粳稻)和扬稻6号(籼稻)为材料, 研究了结实期土壤水分和灌溉方式对产量、米质、籽粒中淀粉合成关键酶活性和内源乙烯释放速率的影响及它们之间的关系。结果表明, 与WW(保持水层, well-watered)或CI(常规灌溉, conventional irrigation)相比, 土壤轻度落干(MD, moderate soil-drying, 土壤水势保持在–10 ~ –30 kPa)和轻干湿交替灌溉(W-MD, alternate wetting and moderate-drying irrigation, 土壤落干至土水势为–25 kPa时复水)显著提高了千粒重、稻米的最高黏度和崩解值, 显著降低了垩白度和消减值; 土壤干旱(SD, severe soil-drying, 土壤水势保持在– 40~ – 60 kPa)和重干湿交替灌溉(W-SD, alternate wetting and severe-drying irrigation, 土壤落干至土水势为– 50 kPa时复水)则使稻米品质变劣。MD和W-MD处理显著降低了籽粒乙烯释放速率, 增加了灌浆中后期籽粒中蔗糖合酶(SuS)、腺苷二磷酸葡萄糖焦磷酸化酶(AGP)、淀粉合酶(StS)和淀粉分支酶(SBE)活性, SD和W-SD处理则提高了籽粒内源乙烯释放速率, 降低了上述各酶的活性。说明结实期土壤轻度落干或轻干－湿交替灌溉可以改善稻米品质, 籽粒SuS、AGP、StS和SBE活性的增强和内源乙烯水平的降低是稻米品质改善的重要生理原因。     

草莓乙烯受体FaEtr2基因的克隆及其反义表达载体的构建

为了构建草莓乙烯受体FaEtr2基因的反义表达载体,在已报道的FaEtr2基因序列的基础上,设计特异引物,克隆草莓乙烯受体FaEtr2基因部分特异序列,将该片段反向插入植物表达载体pBI121的CaMV 35S启动子和NOS终止子之间,构建了反义表达载体pBI121Etr2。通过双酶切鉴定后,导入农杆菌EHA105中,酶切和PCR鉴定表明质粒已导入到农杆菌中。本研究为后期该反义基因转化草莓品种以改良草莓果实耐贮运性打下基础。     

水稻籽粒中乙烯和ACC对土壤水分的反应及其与籽粒灌浆的关系

以武运粳8号(粳稻)和扬稻6号(籼稻)为材,自抽穗后9 d至成熟期进行保持浅水层(WW)、土壤轻度落干(MD)和土壤水分严重亏缺(SD)3种处理。观察在不同土壤水分条件下灌浆期籽粒中乙烯和1-氨基环丙烷1-羧酸（ACC）浓度的变化及其与籽粒灌浆的关系,并使用化学调控物质进行验证。结果表明,MD显著提高籽粒灌浆速率和粒重,SD明显降低籽粒灌浆速率和粒重。籽粒中乙烯释放速率和ACC浓度在MD中降低,在SD中增加。籽粒乙烯释放速率及根系伤流液中ACC浓度与籽粒中ACC浓度呈极显著的正相关。籽粒灌浆速率与乙烯释放速率呈极显著负相关。在花后9~13 d喷施乙烯合成的抑制物质氨基－乙氧基乙烯基甘氨酸(AVG),明显降低籽粒中ACC的浓度和乙烯的释放速率,显著提高了籽粒灌浆速率和粒重以及籽粒中的蔗糖合成酶（SuSase）、ADP葡萄糖焦磷酸化酶（AGPase）和可溶性淀粉合成酶（SSSase）活性;喷施乙烯释放的促进物质乙烯利,结果则相反。表明结实期土壤轻度落干或适度干旱处理可以抑制水稻体内乙烯的产生,促进籽粒灌浆。     

Effect of high temperature stress on ethylene biosynthesis, respiration and ripening of ‘Hayward’ kiwifruit

Temperatures up to 35°C have been shown to increase ethylene production and ripening of propylene-treated kiwifruit (Stavroulakis, G., Sfakiotakis, E.M., 1993. We attempted to study the regulation by high stress temperature of the propylene induced ethylene biosynthesis and ripening in ‘Hayward’ kiwifruit. ‘Hayward’ kiwifruit were treated with 130 μl/l propylene at temperatures from 30 to 45°C up to 120 h. Ethylene biosynthesis pathway and fruit ripening were investigated. Propylene induced normal ripening of kiwifruit at 30–34°C. Fruit failed to ripe normally at 38°C and above 40°C ripening was inhibited. Propylene induced autocatalytic ethylene production after a lag period of 24 h at 30–34°C. Ethylene production was drastically reduced at 38°C and almost nil at 40°C. The 1-aminocyclopropane-1-carboxylic acid (ACC) content was similar at 30–38°C and was very low at 40°C. The 1-aminocyclopropane-1-carboxylate synthase (ACC synthase) and 1-aminocyclopropane-1-carboxylate oxidase (ACC oxidase) activities decreased with a temperature increase above 30°C, but ACC oxidase decreased at a faster rate than ACC synthase. Fruit not treated with propylene showed no ripening response or ethylene production. However, kiwifruit respiration rate increased with temperature up to 45°C, reaching the respiration peak in 10 h. At temperatures up to 38°C, propylene treatment enhanced the respiration rate. After 48 h at 45°C, fruit showed injury symptoms and a larger decrease in CO₂. The results suggest that high temperature stress inhibits ripening by inhibiting ethylene production and sensitivity while respiration proceeds until the breakdown of tissues.     

植物内源激素对小麦叶片衰老的调控机理研究

对小麦灌浆期不同叶位叶片的５大类激素含量测定结果表明,正在衰老叶片的乙烯和脱落酸（ＡＢＡ）含量明显增加,前期和中期的功能期叶片细胞分裂素（玉米素和玉米素核苷,Ｚ＋ＺＲ）和赤霉素（ＧＡ３）含量较高,生长素（ＩＡＡ）在功能期和后期衰老的叶片中含量较高。因此可以将这４种激素分为２大类,即乙烯和ＡＢＡ诱发和促进叶片衰老,另一类的Ｚ＋ＺＲ和ＧＡ３则维持叶片功能,抑制衰老。但ＩＡＡ表现了具有前期保持叶片生长发育和后期促进衰老的双重作用,在不同叶片中,春６叶（旗叶）则比较复杂。旗叶与睛相比表现了特殊性,这可能与其特殊的功能有关。     

Effects of Ca2+/CaM Messenger System Inhibitors on Ethylene-Induced Increase in Lycopene Content

The changes of lycopene content during ripening and senescence of tomato fruit and the relationship between ethylene glycol-bis (EGTA, Ca2+ chelator), verapamil (Vp, Ca2+ channel blockers), trifluoperazine (TFP), chloropromaize (CPZ) (CaM antagonism) and ethylene-induced increase in lycopene content in tomato fruit were investigated. Lycopene content accumulated obviously during ripening and senescence of tomato fruit after harvest at pink stage. Low temperature inhibited but ethylene enhanced the lycopene content.Meanwhile, ethylene also promoted calmodulin (CaM) content in tomato fruit, which was related to the concentration of ethylene. When EGTA, Vp, TFP and CPZ with ethylene were used to treat tomato fruit, ethylene-induced increase in lycopene content could be reversed, indicating that blocking Ca2+ channel in plasma membrane or chelating extracellular Ca2+ or inhibiting the activity of CaM could decrease the action of ethylene, and suggesting that Ca2+-CaM messenger system may be involved in lycopene increase inducedby ethylene.