激光辐照洋葱L1代的生理效应研究

采用ＣＯ２和Ｈｅ－Ｎｅ两种激光的三种剂量,分别辐照两个洋葱品种的湿种子,采用生理生化的方法,从过氧化氢酶、叶绿素、总糖总量等三个方面考查研究洋葱Ｌ１各处理的生物学效应。结果表明：Ｈｅ－Ｎｅ激光辐照洋葱Ｌ１代的过氧化氢酶、叶绿素、总糖含量的变异大于ＣＯ２激光辐照,可作为激光诱导变洋葱育种参考。     

Aspects of interspecific hybridization within edible <Emphasis Type="Italic">Alliaceae</Emphasis>

Crossing experiments within the genus Allium have been carried out for many years. Usually, with the aim of widening genetic variation, edible Alliaceae such as bulb onion, Japanese bunching onion, leek, garlic and shallot have been crossed with each other or with distant vegetable Allium crops. Interspecific hybridization, especially with wild relatives is considered as the best way of introgression desirable traits to the crops. By using sexual or somatic hybridization, many important characters, such as: disease and pest resistance, important metabolites and cytoplasmic male sterility have been transferred to other Allium crops. This review summarises some aspects of the directions of interspecific hybridization in edible Alliaceae and the significance and perspectives of using these hybrids in breeding programmes.     

Performance of down-flow hanging sponge (DHS) reactor coupled with up-flow anaerobic sludge blanket (UASB) reactor for treatment of onion dehydration wastewater

In this study, a promising system consisting of up-flow anaerobic sludge blanket (UASB) reactor followed by down-flow hanging sponge (DHS) reactor was investigated for onion dehydration wastewater treatment. Laboratory experiments were conducted at two different phases, i.e., phase (1) at overall hydraulic retention time (HRT) of 11 h (UASB reactor: 6 h and DHS reactor: 5 h) and phase (2) at overall HRT of 9.4 h (UASB reactor: 5.2 h and DHS reactor: 4.2 h). Long-term operation results of the proposed system showed that its overall TCOD, TBOD, TSS, TKN and NH₄N removal efficiencies were 92 ± 5, 95 ± 2, 95 ± 2, 72 ± 6 and 99 ± 1.3%, respectively (phase 1). Corresponding values for the 2nd phase were 85.4 ± 5, 86 ± 3, 87 ± 6, 65 ± 8 and 95 ± 2.8%. Based on the available results, the proposed system could be more viable option for treatment of wastewater generated from onion dehydration industry in regions with tropical or sub-tropical climates and with stringent discharge standards.     

Quercetin-4′-glucoside: a physiological inhibitor of the activities of dominant glutathione <Emphasis Type="Italic">S</Emphasis>-transferases in onion (<Emphasis Type="Italic">Allium cepa</Emphasis> L.) bulb

The onion (Allium cepa L.) bulb has a high level of glutathione S-transferase (GST) activity, and it is a rich source of sulfur compounds as well as flavonoids. To investigate interactions between onion bulb GSTs and metabolites, we separated onion bulb GSTs (GSTa and GSTb as minor GSTs and GSTc, GSTd and GSTe as dominant GSTs) by DEAE-cellulose chromatography. In Western blot analysis with anti-CmGSTF1 antiserum, GSTc and GSTd fractions showed a thick band. A cDNA (AcGSTF1) corresponding to GSTc was immunoscreened with the same antiserum from an onion bulb cDNA library and its bacterial expression product was also subjected to investigation. Among the sulfur compounds, nonphysiological compounds, S-hexyl glutathione (GSH) and S-butyl GSH, showed strong inhibitory effects on 1-chloro-2,4-dinitrobenezene (CDNB)-conjugating activities of GSTa, GSTb and GSTe. However, physiological sulfur compounds, S-methyl GSH, S-propyl GSH, S-lactoyl GSH and S-ethyl-l-cysteine sulfoxide, had small or almost no inhibitory effects. Therefore, onion sulfur compounds might have the least possibility to be substantial inhibitors of onion GSTs. On the other hand, the activities of GSTc, GSTd and AcGSTF1 were strongly inhibited by flavonoids, quercetin, luteolin, apigenin and kaempferol. Ethylacetate (EtOAc) extract of onion bulb contained quercetin-4′-glucoside as a major inhibitory substance. The strong inhibitory effects of quercetin-4′-glucoside on GSTc and GSTd as well as on AcGSTF1 (50% inhibitory concentration (IC₅₀): 9.5, 7.5 and 11.2 μM, respectively) along with its high concentration (226 μM) in the onion bulb indicates that quercetin-4′-glucoside is a physiological inhibitor of dominant GSTs in the onion bulb.