Endogenous polyamines in apple and their relationship to fruit set and fruit growth

The distribution of free and bound polyamines was investigated from blooming until harvest on flower, fruitlets and fruits of Malus domestica Borkh cv. Golden Delicious, Relationships between polyamines and fruit set and growth were also investigated. The level of free polyamines was high only during the first weeks after full bloom and then decreased gradually. The amount of bound trichloroacetic acid-insoluble polyamines was much higher than free polyamines. Bound spermine in particular showed a high value for almost 40 days after full bloom, while spermidine and putrescine were no longer detectable even a few days after full bloom.
In relation to fruit set, it was possible to observe that abscission peaks took place when free polyamine levels were low or decreasing. Insofar as fruit growth is concerned, the most substantial variations in polyamine levels occurred very early in the season when fruit dry weight and protein amount were also changing rapidly and fruit diameter was almost impossible to measure.     

Biochemical basis of high-temperature inhibition of ethylene biosynthesis in ripening tomato fruits

Biggs, M. S., Woodson, W. R. and Handa, A. K. 1988. Biochemical basis of high-temperature inhibition of ethylene biosynthesis in ripening tomato fruits. Physiol. Plant. 72: 572578
Incubation of fruits of tomato ( Lycopersicon esculentum Mill. cv. Rutgers) at 34°C or above resulted in a marked decrease in ripening-associated ethylene production. High temperature inhibition of ethylene biosynthesis was not associated with permanent tissue damage, since ethylene production recovered following transfer of fruits to a permissive temperature. Determination of pericarp enzyme activities involved in ethylene biosynthesis following transfer of fruits from 25°C to 35 or 40°C revealed that 1-aminocyclopropane-l-carboxylic acid (ACC) synthase (EC 4.4.1.14) activity declined rapidly while ethylene forming enzyme (EFE) activity declined slowly. Removal of high temperature stress resulted in more rapid recovery of ACC synthase activity relative to EFE activity. Levels of ACC in pericarp tissue reflected the activity of ACC synthase before, during, and after heat stress. Recovery of ethylene production following transfer of pericarp discs from high to permissive temperature was inhibited in the presence of cycloheximide, indicating the necessity for protein synthesis. Ethylene production by wounded tomato pericarp tissue was not as inhibited by high temperature as ripening-associated ethylene production by whole fruits.     

苹果圆片诱导呼吸和乙烯产生的研究

跃变期前苹果圆片陈化后发生显著的伤诱导呼吸,乙烯也大量增生。Ag~+和AVG都明显抑制诱导呼吸发生,表明伤诱导乙烯对于诱导呼吸发生有重要作用。ACT、CHI和CHL强烈抑制乙烯和诱导呼吸。GA、IAA和ABA不同程度促进乙烯产生,但GA和IAA抑制,而ABA促进诱导呼吸。对诱导呼吸、乙烯产生和蛋白质合成作用的关系及激素对它们的调节进行了讨论。     

三七植物各部位的研究和开发利用

本文报道了对三七根、绒根、根茎、茎叶、花蕾,果实,果梗等的化学成分研究;皂甙提取分离方法;皂甙及黄酮类成分的生理活性及新药开发利用等的研究概况。     

影响柑桔树开花结果性能的生态生理因素

本文报道1988年和1989年春夏之际异常和正常的桔园小气候环境对柑桔树开花结果物候期、抽梢生长、幼果发育、生理落果、当年果实产量和品质等性能的影响。结果表明,柑桔树的座果率受许多生态生理因素制约,但第一次生理落果主要与开花期桔园的小气候环境有关,第二次生理落果则与树体营养生理代谢密切相关。据此提出了预测预报柑桔树第二次生理落果的指标及其防御措施。     

龙眼果实防腐保鲜技术研究

近几年来,我们探讨了不同的贮藏温度、化学防腐剂、气体组分、包装容器及包装方法对不同品种龙眼果实的防腐保鲜效果。结果表明:龙眼品种间的耐贮性有很大差异,按耐贮性排列:泉州本>乌龙岭>普明庵>福眼>赤壳>水涨;最佳的保鲜贮藏温度为3～4℃;仲丁胺、仲丁胺+赤霉素、多菌灵、甲基托布津、苯甲酸、特克多、FISB-1和FISB-2等不同化学防腐剂对泉州本的防腐效果,以FISB-1和FISB-2防腐效果最佳,贮藏40天,好果率分别为95.0％和95.2％,其他防腐剂处理的好果率为80.7％～86.5％;气调贮藏,CO_2为4％～6％,O_2为6％～8％的气体组分可延长贮藏寿命,降低龙眼果实自身损耗;包装容器以塑料周转箱套薄膜袋气调贮藏效果最佳。     

Improved Microscopic Detection of Bacteriuria

A simple method is described which permits the microscopic detection of bacteria in sediments of urine and other fluids, including bacteria that have eluded detection by conventional means. The method introduces increased centrifugal force and stepwise chemical fixation and then conventional staining. It is rapid, economical, and suitable for use in a physician's office. Use of this method immediately reveals those bacteria reported as “significant” by the conventional laboratory culture. More importantly, it immediately reveals the presence of bacteria, living or dead, which are missed by the conventional culture and by the conventional Gram staining procedure. These bacteria usually can be grown in special media and they appear to be related to systemic disease as evidenced by the clinical response to appropriate antibiotics.     

Characterization and in vitro selection for iron efficiency inPyrus andCydonia

Summary Responses to low Fe were characterized in tissue cultures ofPyrus amygdaliformis andCydonia oblonga (quince), two species used as rootstocks for pear. Cultured shoots and plantlets ofP. amygdaliformis had a higher chlorophyll concentration and Fe²⁺/total Fe ratio than those ofC. oblonga when grown under low Fe conditions. This tolerance to low Fe was correlated with high Fe³⁺-reducing ability and medium acidification. The adaptive responses were manifested in roots of plantlets, shoot bases, root cultures, and cell suspension cultures. Shoots were regenerated from leaves of quince and subjected to Fe-deficient conditions. Two somaclonal variants (IE-1 and IE-2) were recovered; each displayed higher ability to reduce Fe³⁺ and acidify the medium. These variants may be useful as rootstocks for regions with calcareous soils, which limit Fe availability.     

β-oxidation enzymes and the carnitine-dependent oxidation of palmitate and palmitoyl CoA in mitochondria from avocado

Two sites for the β-oxidation of fatty acids in avocado (Persea americana L.) mesocarp exist. One site is the microbody, the other the mitochondrion. It is apparent that the mitochondrial membrane barrier, which remains intact after sucrose density gradient centrifugation, prevents rapid access of acyl CoA substrates to matrix β-oxidation sites. Thus, intact mitochondria showed little β-oxidation enzyme activity. Rupturing of the mitochondrial membrane allowed rapid access of the acyl CoA substrates to matrix sites. Consequently, in ruptured mitochondria, high O₂-oxidation enzyme activities were measured. O₂ uptake studies further distinguished the two organellar sites of β-oxidation. During palmitoyl CoA oxidation, O₂ uptake was reduced by catalase and increased by KCN in the microbodies, whilst mitochondrial O₂ uptake was unaffected by catalase and reduced by KCN. This reflected the differing fates of FADH₂, produced during the first β-oxidation step, in the two organelles. In addition, only the mitochondrial β-oxidation of fatty acids was carnitine-dependent.