青椒保鲜剂研究与配制

采用采后生理调节与抑菌防腐相结合的方法,通过单因素筛选,多因素优化组合,研究配制青椒保鲜剂。研究表明,青椒的成熟衰老与乙烯作用关系密切,乙烯合成抑制剂或促衰老类植物生长调节剂可通过青椒的果柄和萼片进入果实内部,可延长青椒的贮藏期和保鲜期。研制的青椒保鲜剂与对照青椒保鲜剂相比,在8～15 ℃贮藏条件下,贮藏25 d、50 d,0级果率分别提高33.1 %、17.9 %,商品果率分别提高4.3 %、6.5 %,腐烂指数分别降低66.7 %、34.0 %;与空白对照相比在8 ℃贮藏2个月,0级果率、商品果率分别提高47.6 %、26.9 %,腐烂指数降低78.7 %。     

夏橙果实发育后期及返青期类胡萝卜素积累及乙烯的调控

 【目的】明确夏橙发育后期转黄及返青过程中类胡萝卜素积累及关键合成酶基因表达的变化及乙烯的调控作用。【方法】将夏橙果实发育的后期和成熟过程分为转黄期（P1—P4）及返青期（P5—P7）共7个时期,通过比色法和Northern-blotting法分析发育后期成熟过程中及乙烯作用下果皮中类胡萝卜素的含量及其合成关键酶PSY、PDS和ZDS基因表达水平的变化。【结果】证实P1—P7发育过程中果皮发生由青至黄,继而返青的颜色变化,与果皮中类胡萝卜素积累及其合成途径中PSY、PDS和ZDS基因表达水平的变化趋势一致。乙烯可促进转黄期夏橙果皮中类胡萝卜素积累及PSY基因的表达,而对PDS和ZDS基因表达的影响不显著。乙烯处理不影响返青期果实中类胡萝卜素的积累,但能够阻碍果实成熟后期PSY和PDS基因表达水平的减弱。【结论】夏橙果实在发育后期及成熟过程中,乙烯在转黄期及返青期对类胡萝卜素积累及PSY和PDS基因表达的影响不同,暗示乙烯的调控作用还受果实发育相关因子的影响。在夏橙转黄期可以用乙烯促进转黄着色,而在返青期利用乙烯不能达到脱绿的效果。     

‘大久保’桃常温贮藏过程中香气成分变化及其与乙烯释放的关系

 以‘大久保’桃为材料,研究了果实在采后常温贮藏过程中特征香气及乙烯释放量和相关酶活性的变化。结果表明：果实中“青草型”香气成分含量的降低对风味的影响大于“花香型”香气成分的增加对风味的影响,以“青草型”与“花香型”香气成分的比值为衡量指标,比值最低时风味最佳。乙烯释放量与醛类物质含量和“青草型”香气成分含量呈显著负相关,ACC氧化酶与LOX酶共同调控乙烯的合成,进而调节香气的释放,影响果实的风味。     

三种微生物肥料固氮活性的检测及方案

本项研究采用目前国际上普遍公认的研究生物固氮活性的方法（乙炔还原－气相色谱法）对３种微生物固氮菌肥的固氮活性进行检测，并尽可能地排除检测过程中可能导致乙炔还原生成的乙烯和多种导致乙烯产生的非固氮菌因素，从而保证分析数据的真实性．在系统设计方案的基础上，对不同产地的３种固氮菌肥进行了认真的检测．     

乙烯分解纳米光催化反应器关键性能参数研究

果品与蔬菜在采后贮藏过程中所产生和释放的乙烯是加速成熟、衰老和腐烂的重要环境因子。该研究采用纳米光催化技术开发设计了一种可以去除气调库中乙烯的玻璃管光催化反应器，并对其主要性能参数进行了模拟测试与分析。结果表明：气体流量、玻璃管直径与长度以及光源种类均是影响光催化反应器乙烯分解性能的主要因素。在该试验条件下，气体流量在40～80 L/h的范围内较佳；玻璃管的适宜内径为50 mm；在相同功率条件下黑光灯的光催化效果优于紫光灯。光催化反应器可以多级串联使用，以便提高系统的乙烯分解能力。这些研究结果为气调库用光催化乙烯分解装置设计提供了基础设计参数和指标。     

Ozone sensitivity of Phaseolus vulgaris in relation to cultivar differences,growth stage and growing conditions

Exposure of Phaseolus vulgaris cv. Lit to ambient ozone caused a 14% pod yield reduction in 1994. This yield loss was assessed by comparing plants that were protected against ozone by treatment with EDU (ethylenediurea) with unprotected plants, both cultivated in pots with a continuous water supply. The plants had experienced an AOT40 of 8135 ppb.h during their growth. However, plant response to ozone depends on a large number of environmental and plant-specific conditions. Visible injury increased mainly after flowering and was much less severe on soil-grown bean cultivars (Lit, Stella and Groffy) not receiving additional water. Ozone fumigations in closed chambers before or after flowering proved that the growth stage during which the plants are exposed also plays a very important role with regard to injury development. Plants seem to be more susceptible during the generative growth stage and the relative cultivar sensitivity was related to the developmental stage during fumigation. However with regard to yield effects the timing of the ozone exposure seems to be less important.     

钙和ABA在番茄果实乙烯生物合成中的相互作用

研究了钙和ABA对不同成熟阶段和不同成熟模式番茄(Lycopersicon esculentum cv．Lichun)果实乙烯生成的影响，分析两者在乙烯生物合成系统中的相互作用。普通番茄绿熟果实组织圆片在用100μmol／L ABA和100mmol/L钙处理后，乙烯生成均很快增加。当用这两种试剂同时处理番茄果实圆片时，乙烯生成增加量明显比单一处理增加量大，表明两者在对绿熟番茄果实乙烯生成的影响中有协同作用关系。钙离子鳌合剂EGTA(乙二醇双乙胺醚-N，N’-四乙酸)对乙烯生成有抑制作用，用ABA和EGTA同时处理番茄圆片时，乙烯的生成量比EGTA单一处理的生成量要高。当用这些试剂处理未成熟番茄果实则产生不同的效果，ABA明显抑制乙烯生成，而钙却依然促进乙烯的生物合成，ABA和钙同时处理果实时，乙烯生成量介于二者单一处理之间，表明ABA和钙在未成熟番茄果实乙烯生成中表现出相互抑制作用。在转反义ACS番茄中，ABA和钙抑制未成熟果实的乙烯生成，而都促进了绿熟果实的乙烯生成。这表明ABA和钙在番茄果实不同成熟阶段和不同成熟模式的乙烯生物合成过程中有着不同的相互作用关系。     

老化处理对几种牧草种子乙烯释放量的影响

探讨了不同老化处理对紫花苜蓿、光叶紫花苕、老芒麦和苏丹草种子萌发过程中乙烯释放量的影响 ,及乙烯释放量和发芽率的关系。结果表明 :35℃高温、10 %种子含水量条件下 ,不同贮藏时间的老化处理对 4种牧草种子乙烯释放量有显著影响 ,所有供试种随种子劣变 ,乙烯释放量下降 ,且释放高峰推迟。在测定期内 (2 2 h) 2种豆科牧草种子乙烯释放量和高峰出现的时间分别高于和早于 2种禾本科牧草 ;未处理种样平均每百粒种子乙烯释放总量 ,按供试种样计算为光叶紫花苕 (56 .0 nl) >紫花苜蓿 (2 0 .0 nl) >苏丹草 (17.4 nl) >老芒麦(10 .7nl) ,而按发芽种子计算为光叶紫花苕 (6 7.5nl) >紫花苜蓿 (2 5.8nl) >老芒麦(2 2 .3nl) >苏丹草 (2 0 .2 nl)。 4种牧草种子乙烯释放量与发芽率呈极显著的正相关 (p<0 .0 5) ,其决定系数 (r2 )从高自低依次为紫花苜蓿 0 .980、光叶紫花苕 0 .96 0、老芒麦 0 .952和苏丹草 0 .94 1。     

Changes in ripening behavior of ‘d'Anjou’ pears (Pyrus communis L.) after cold storage

‘d'Anjou’ pear fruit, harvested at optimum maturity with flesh firmness of 6.8 kg, were stored at ?1.1°C. Fruit were ripened at 20°C for 15 days following storage for 1–8 months. Dessert qualities were evaluated organoleptically on Day 10 of each ripening period. Changes in fruit firmness, extractable juice, titratable acids, solubl solids, respiration, ethylene production and internal ethylene were determined daily during each ripening period. Fruit firmness declined continually from 6.8 kg at harvest to 4.5 kg after 8 months of storage. Fruit stored for 2–8 months softened with a similar pattern during a 15-day ripening period at 20°C, while fruit stored for 1 month softened at a slower rate during ripening to 3.2 kg, with a coarse and dry texture after 15 days at 20°C. Fruit stored for 2–4 months ripened with the desirable buttery and juicy texture, while those stored for more than 5 months ripened with a coarse or mealy and dry texture. The buttery and juicy texture was highly correlated with a lower extractable juice, which could be used for quantitative determination of storage life based on ripened fruit quality. Changes in titratable acids and soluble solids during each ripening period were not associated with changes in dessert qualities of the ripened pears. Rates of respiration, ethylene production and internal ethylene during ripening at 20°C varied with duration of storage, but were not associated with changes in dessert qualities of the ripened fruit.     

Identification of the ethylene precursor, 1-aminocyclopropane-1-carboxylic acid (ACC), in pollen

Within 15 min after application of pollen to the stigma of carnation flowers (Dianthus caryophyllus L. cultivar ‘White Sim’), ethylene (C₂H₄) production by the gynoecium had increased substantially. Pollen germination did not start until 1 h after pollination. Analysis of materials removed from pollen by a brief rinse with an aqueous solvent showed the presence of high concentrations of the C₂H₄ precursor, 1-aminocyclopropane-1-carboxylic acid (ACC). This compound, which was found to be present in pollen from a number of flower species and which increased in concentration as the anthers developed, may be an important mediator of the early response of flowers to pollination.