Effect of ethylene on polygalacturonase, lipoxygenase and expansin in ripening of tomato fruits

Fruit ripening is a complex process and is regulated by many factors.Ethylene and polygalacturonase (PG),lipoxygenase (LOX),expansin (EXP) are all critical regulating factors in fruit ripening and softening process.With antisense,ACS tomato,Nr mutant tomato and cultivated tomato as materials,Northern blot hybridization showed that PG,LeEXP1 and LOX expressed differently in different parts of cultivated tomato fruit during ripening,which was related to fruit ripening.The ripening process of columella and radial pericarp was faster than pericarp.In both Nr mutant and antisense ACS transgenic tomato fruit,expression levels of PG,LeEXP1 and LOX were generally lower than those in cultivated fruit but still related to fruit ripening.The expression levels of PG,LeEXP1 and LOX increased in the mature green tomato fruits after 0.5 h treatment with ethylene ( 100 μL/L).These results indicate that gene expression of PG,LeEXP1 and LOXwere positively regulated by ethylene.The time and cumulative effect of the concentration exists in the expression of PG regulated by ethylene.The regulation of LOX expression mainly depended on the fruit development after great amount of ethylene was produced.PG played a major role in ripening and softening of tomato fruit,and cooperated with the regulation of EXP and LOX.     

拉曼光谱法检测微量乙烯气体

首次利用激光拉曼技术对微量乙烯气体进行测试和分析,得到500 cm-1~3500 cm-1内乙烯气体的拉曼光谱。结果表明,乙烯气体的拉曼光谱有明显特征峰,这一性质为进一步研究果蔬散发乙烯气体的检测提供了依据。     

中华猕猴桃果实成熟过程中膜脂过氧化变化研究

研究中华猕猴桃果实成熟过程中脂过氧化的变化，结果表明：MDA含量呈上升趋势，SOD、Vc含量呈下降趋势。SOD、POD酶活性出现二次高峰，SOD、POD活性第一次峰出现时，果实内MDA含量下降；第二次峰出现时MDA含量变化不大，两品种比较，果实内Vc含量高，膜脂过氧化水平低时，果实成熟慢。     

采后枇杷果实品质及相关酶活性变化的研究

研究了20℃下贮藏过程两个枇杷品种果实品质及相关酶活性的变化。结果表明:解放钟与早钟6号枇杷果实贮藏期间,可溶性固形物和蛋白质含量逐渐下降。在贮藏前10d,果实硬度变化不明显,早钟6号枇杷果实硬度还略有增大现象;贮藏后期,枇杷果实硬度逐渐减小。类胡萝卜素与木质素含量在贮藏期内均表现为先升高后逐渐下降趋势,而在采后前期果实PAL和POD活性均持续增加,与木质素含量变化具有一定的相关性,表明在20℃下PAL和POD在枇杷果实木质素的代谢中起着重要作用。     

京白梨果实软化特性与贮藏保鲜技术研究进展

对京白梨果实后熟软化机理、采收期确定、低温气调贮藏、臭氧处理、辐射处理、涂被剂防腐剂涂油处理以及1-MCP处理等贮藏保鲜技术的研究进展进行了综述,并从果实贮藏特性、产地贮藏条件和基因工程等方面提出了研究展望.     

Characteristics of transgenic tomatoes antisensed for the ethylene receptor genes LeERT1 and LeERT2

Two stable transformed lines containing antisense LeERT1 or LeERT2 sequences and their hybridized line were investigated to determine the effect of LeERT1 and LeERT2 specificity in the ethylene receptor family in tomato （Lycopersicon esculenturn Mill.） on ethylene signaling. The transgenic line alel containing antisense LeER T1 displayed shorter length of seedling grown in the dark and adult plant in the light, severe epinastic petiole, and accelerated abscission of petiole explant and senescence of flower explant, compared with its wild type B 1. The transgenic line ale2 containing antisense LeERT2 also exhibited shorter hypocotyls and slightly accelerated abscission. The phenotypes of cross line dale of LeERT1 and LeERT2 were close to alel in many aspects. These results suggested that LeERT1 probably plays a relatively important role in ethylene signaling of tomato growth and development.     

1-MCP对南果梨15℃贮藏保鲜效果的影响

研究了1-MCP处理对南果梨15℃贮藏期间品质和生理特性的影响.结果表明,1-MCP处理可以明显抑制南果梨果实硬度的下降,保持可溶性固形物含量,推迟乙烯释放峰值出现的时间,抑制果胶酶活性的剧烈变化,延缓南果梨的后熟,延长贮藏期.     

Effect of physiological harvest stages on the composition of bioactive compounds in Cavendish bananas

The combined influence of maturation, ripening, and climate on the profile of bioactive compounds was studied in banana (Musa acuminata, AAA, Cavendish, cv. Grande Naine). Their bioactive compounds were determined by the Folin-Ciocalteu assay and high-performance thin layer chromatographic (HPTLC) method. The polyphenol content of bananas harvested after 400 degree days remained unchanged during ripening, while bananas harvested after 600 and 900 degree days exhibited a significant polyphenol increase. Although dopamine was the polyphenol with the highest concentration in banana peels during the green developmental stage and ripening, its kinetics differed from the total polyphenol profile. Our results showed that this matrix of choice (maturation, ripening, and climate) may allow selection of the banana (M. acuminata, AAA, Cavendish, cv. Grande Naine) status that will produce optimal concentrations of identified compounds with human health relevance.     

我国高等教育内涵式发展路径探析

近十年的扩招之后,高等教育告别"摊大饼"式的粗放发展模式,走向以提高办学水平和人才培养质量为核心的内涵式发展轨道。内涵发展是我国高等教育大众化成熟发展的重要标志,是高等教育普及化过程中必须坚持的理念和方向。新的形势下,走内涵式发展道路,要求各高校进一步理清发展思路,搞好顶层设计,认真解决"办什么学和如何办学"这个根本问题;认识和把握发展机遇,促进事业快速发展;完善经费保障机制,规避财务风险,确保持续稳定发展;落实人才强校战略,建设高素质教师队伍,筑牢发展根基;加强科学管理,抓重点,讲规范,求实效,实现高等教育又好又快发展。     

美国四年制公立院校办学成本递增的特点与启示

美国四年制公立院校办学成本的递增折射出高校办学成本递增的一般特点,表现为办学成本的增长快于一般物价水平的增长,办学总成本的增幅快于生均教育成本的增幅,学生资助增幅快于教学费用增幅以及不同层次院校成本递增具有一定的差异性等方面。驱动办学成本递增的因素有入学规模、学术竞争、组织效率、教育产业属性、学生资助等。我国应加大高等教育投入、促进院校之间的适度办学竞争、加强学校成本管理、创新产权制度、完善学费和资助政策,以提高我国高等教育的质量和效率。     

1-甲基环丙烯在果蔬采后生理与保鲜上的研究

1-甲基环丙烯(1-MCP)是一种新型乙烯抑制剂,能不可逆地结合到细胞的乙烯结合位点上,有效地抑制植物对内源或外源乙烯的敏感性,在园艺商业上具有很大的潜在应用价值.本文综述了1-MCP在水果、蔬菜采后与贮藏保鲜基础研究和应用研究方面的进展,并探讨了1-MCP在生产上应用时应注意的问题及其前景.     

High pressure treatment of Swiss cheese slurries (I): Inactivation of selected microorganisms after treatment and during accelerated ripening

Cheese slurries, made from fresh Swiss cheese curd, were treated at 345 or 550 MPa for 10 or 30 minutes in an isostatic press at 25°C. The slurries were ripened at 30 °C for 0,3 and 5 days. The growths of coliforms, yeasts and molds, starter bacteria (Lactococci andStreptococci), non-starter lactic acid bacteria (Lactobacilli), and presumptive coagulase-positiveStaphylococcus were determined. An electronic nose was used to evaluate aroma development of the cheese slurries. Commercial Swiss cheeses with different ages were used as aroma references. The degree of inactivation of organisms was found to be a function of pressure intensity, exposure time, type of organism, and cheese slurry pH. In general, slurries treated at a higher pressure and with a longer exposure time showed a greater reduction in numbers and had less out-growth of organisms during ripening.Coliforms, yeasts and molds were completely inactivated at the pressures and time used. Starter bacteria appeared to be more resistant to being inactivated by high pressure treatment and had a greater out-growth rate thanLactobacilli andStaphylococci. Based on canonical analysis, nineteen samples for each batch were assigned to three groups. In general, higher intensity of pressure or longer exposure time caused less aroma development in the cheese slurries. When the cheese curd was incubated overnight prior to making the cheese slurries, stronger slurries with stronger aroma were observed. This study provided an explanation of the relative importance of relationships among high pressure treatment, starter bacteria, and aroma development during accelerated ripening.     

Heat transfer and parametric studies of an encapsulated phase change material based cool thermal energy storage system

INTRODUCTION Cool thermal energy storage (CTES) using the latent heat concept as an alternative to sensible heat storage offers a good option because of its high storage density and the nearly constant temperature heat removal characteristics during the discharging cycle. Since the principle of latent cool storage nec- essarily involves a change of state, heat transfer must occur in different modes depending on the state of charging and discharging. During the periods of low cooling dema…     

枇杷果实采后生理与贮藏保鲜

综述枇杷果实采后生理,涉及果实呼吸速率、乙烯产生、细胞膜透性、主要营养成分构成、果实硬度变化及冷藏果实果肉木质化发生;讨论枇杷果实耐贮运品种选择,采前田间管理,采收,选别和分级,包装和贮藏保鲜技术;并指出枇杷今后需要进一步研究的领域。     

沙田柚果实贮藏期水分变化与枯水的关系

沙田柚采后经预贮10d贮藏于常温室内.用~3H_2O对标记定期测定果蒂部、果皮、果肉(汁胞)的放射性比活度和果实的失重率、果汁率、不同组织含水量、呼吸速率及营养物质含量变化,结果表明,沙田柚贮藏期间,果瓣之间、果肉和果皮之间水分是相互流动的.果实枯水时,水分从果肉到果皮的转移速度大于正常果.沙田柚果实枯水的原因可能是果肉营养物质消耗和果皮组织相对再生长同步进行.