土壤干旱对葡萄果实中黄烷醇类多酚时空积累及隐色花色素还原酶活性、组织定位的影响

【目的】葡萄果实发育过程中,土壤干旱对黄烷醇类多酚时空积累及其合成关键酶隐色花色素还原酶（leucoanthocyanidin reductase, LAR）活性和组织定位的影响。【方法】以5年生赤霞珠葡萄为试材,采用避雨棚和断根沟措施模拟土壤干旱,跟踪果实发育进程,采用分光光度计法、免疫组织定位等方法,就黄烷醇类多酚的时空积累及其合成关键酶LAR活性和组织定位进行研究。【结果】土壤干旱明显抑制葡萄果实生长,促进果实总酚积累,特别是在幼果期,土壤干旱明显促进葡萄果实总酚积累。土壤干旱未改变黄烷醇类多酚和总黄烷-3-醇的时空积累模式,但对其积累具有一定的诱导作用,且这一诱导作用具有明显的器官和发育阶段依赖性。土壤干旱明显诱导幼果期葡萄果皮和果肉中LAR酶活性增强,对LAR1、LAR2分布无明显作用,但诱导其积累,特别是在果肉维管束中,土壤干旱明显诱导LAR1、LAR2蛋白积累。【结论】土壤干旱诱导果实中LAR1、LAR2蛋白积累,进而导致LAR酶活性增强,最终表现为促进相应发育阶段、部位黄烷醇类多酚积累。     

过量表达LAR3和Bbchit1以提高毛白杨对叶枯病的抗性

利用转基因技术将多种抗病基因共同转入毛白杨中以提高其抗性,从而获得毛白杨抗病新品种是目前解决杨树真菌病害的主要研究方向之一。本研究通过根癌农杆菌介导的二次遗传转化,将来源于球孢白僵菌几丁质酶基因Bbchit1转入过量表达无色花色素还原酶基因LAR3转基因毛白杨中,实时定量PCR显示Bbchit1与LAR3均能有效表达,离体抗病试验显示Bbchit1+LAR3共表达转基因毛白杨细胞粗提液对杨树叶枯病菌具有明显抑制作用,进一步将叶枯病菌接种在转基因和非转基因毛白杨叶片上培养30天,转基因植株的感病面积均低于非转基因植株且Bbchit1+LAR3共表达转基因株系抗病效果更明显。上述抗病试验结果表明:LAR3和Bbchit1在杨树中共表达可提高其对叶枯病的抗性。     

UV-C对葡萄果实发育过程中黄烷醇类多酚积累及隐色花色素还原酶表达的影响

【目的】阐明葡萄果实发育过程中,植株接受UV-C照射对果实中黄烷醇类多酚积累的作用。【方法】以5年生赤霞珠葡萄为试材,定期对植株进行UV-C照射,分别采用分光光度计法、Western Blot和Real time PCR法对黄烷醇类多酚积累及其生物合成关键酶LAR表达进行分析,从底物、酶活性、蛋白质含量及基因转录水平阐明UV-C对Vv lar1、lar2基因表达的影响。【结果】葡萄果实发育过程中,UV-C照射并未改变果实中黄烷醇类多酚的积累规律,但诱导黄烷醇类多酚积累,特别是在幼果期,UV-C照射明显诱导果实中黄烷醇类多酚的积累。UV-C照射诱导葡萄果实LAR酶活性升高,LAR1、LAR2蛋白含量增加,Vv lar1、Vv lar2转录增强。【结论】UV-C能够诱导Vv lar1、Vv lar2转录,合成新LAR1、LAR2蛋白,LAR酶活性增强,导致黄烷醇类多酚在葡萄果实中积累。     

弱光条件下黄瓜的生长解析

为了阐明弱光对黄瓜生长、发育的影响,育苗期进行3周遮光处理(自然光的53％),探讨弱光对RGR、NAR等的影响,其结果:(1)弱光促使茎部伸长,地上、地下部重显著减少,但叶片数差别不大,不同黄瓜品种对弱光的反应也不同;(2)处理期间遮光区的RGR低,处理结束后,随长势的恢复而提高;(3)弱先条件下的NAR显著下降,处理结束后,遮光区与对照区的差缩小了,品种间的NRA仍有差别;(4)弱光区的LAR比对照区高,出现了弱光反应。     

UV-C 对葡萄黄烷醇类多酚时空积累、LAR 活性和组织定位的影响

 以酿酒葡萄‘赤霞珠’（Vitis vinifera L.‘Cabernet Sauvignon’）为试材,在果实发育过程中定期对植株进行UV-C 照射,分别采用分光光度计法、免疫组织定位等方法,对黄烷醇类多酚时空积累及其合成关键酶LAR（leucoanthocyanidin reductase,LAR）活性和定位进行初步研究。结果表明：UV-C 诱导果皮和果肉中总酚、黄烷醇类多酚、总黄烷–3–醇的积累,LAR 酶活性增强,且这一诱导作用有明显的照射剂量、器官/组织和发育阶段依赖性。UV-C 照射并不改变LAR1、LAR2 酶蛋白在葡萄果实中的分布,但诱导酶蛋白积累,特别在果皮及果肉维管束中,UV-C 照射导致LAR1、LAR2 酶蛋白信号明显增强。所有结果表明,UV-C 照射诱导果皮和果肉维管束中LAR1、LAR2 酶蛋白增加,诱导LAR 酶活性增强,最终导致总黄烷–3–醇和黄烷醇类多酚特异性积累。     

Flavonols attenuate the immediate and late-phase asthmatic responses to aerosolized-ovalbumin exposure in the conscious guinea pig

We previously reported that quercetin and rutin have potent, anti-asthmatic activity, but the structure-activity relationships of flavonoids and anti-asthmatic agents are still poorly understood. In the current study, the effects of kaempferol, fisetin, and morin on the immediate-phase response (IAR) and late-phase response (LAR) caused by exposure to aerosolized-ovalbumin (OA) in OA-sensitized guinea pigs were evaluated by determining the specific airway resistance (sRaw), recruitment of leukocytes and chemical mediators in bronchoalveolar lavage fluid (BALF), histopathological surveys, and determination of neutrophil chemotaxis. Fisetin and kaempherol (30 mg/kg, p.o.) significantly (P < 0.01) inhibited sRaw by 47.93% and 30.05% in IAR, and 54.45% and 40.50% in LAR, when compared to vehicle control, respectively. Furthermore, all three studied flavonols (30 mg/kg, p.o.) significantly (P < 0.05) inhibited the recruitment of total, as well as subtypes of, leukocytes into the lung BALF. This recruitment inhibition corresponded to the inhibition of leukocyte infiltration, particularly of eosinophils and neutrophils, into the lung in pathological surveys and formly-methionyl-leucyl-phenylalanine (FMLP)-induced neutrophil chemotaxis studies. Kaempferol inhibited FMLP-induced neutrophil chemotaxis in a concentration-dependent manner in a tested range of 1–100 μM. Fisetin inhibited histamine content and peroxidase (EPO) activity in BALF in a dose-dependent manner. All three tested flavonols significantly (P < 0.01) inhibited histamine content at 10 mg/kg, and phospholipase A₂ (PLA₂) and EPO activities at 30 mg/kg (p.o.) in BALF. Kaempherol had a greater anti-asthmatic effect than other flavonols. Fisetin demonstrated the greatest inhibition of sRaw, whereas morin had lesser effects. These results indicate that the lower the molecular weight, the greater the anti-asthmatic activities of these compounds.     

Effects of the invasive tomato red spider mite (Acari: Tetranychidae) on growth and leaf yield of African nightshades

The tomato red spider mite, Tetranychus evansi Baker and Pritchard, is one of the most serious pests of solanaceous crops in Africa. Field experiments were conducted to investigate its effects on the growth and leaf yield of five African nightshade species viz. Solanum americanum, S. sarrachoides, S. scabrum, S. tarderemotum and S. villosum during the 2008 and 2009 growing seasons. Plants were infested with 2–4 day-old female spider mites which were allowed to multiply. The number of mite motiles increased throughout the growing season in unsprayed plots and this number varied significantly between the African nightshade species. Except for S. sarrachoides, leaf damage was high on the other four Solanum species irrespective of the spraying regime during both seasons. However, S. scabrum had a significantly greater leaf area ratio (ratio of leaf area to total plant weight) and specific leaf area (ratio of leaf area to total leaf dry weight) during both seasons. Overall yields were 1.5 times more in S. scabrum and S. sarrachoides compared to S. americanum, S. tarderemotum and S. villosum. Our results show that T. evansi infestation affects the leaf area ratio and specific leaf area of African nightshade species differentially which eventually determines the plant's overall leaf yield. These findings present an opportunity for evaluation and selection of African nightshade species that can withstand spider mite infestation in small holder farms for increased vegetable production in Africa.     

Effects of diurnal temperature alternations and light quality on growth,morphogenesis and carbohydrate content of Cucumis sativus L.

The effects of the difference (DIF) between day/night temperature (DT/NT) and end-of-day (EOD) light quality on growth, morphology, dry matter (DM) content and carbohydrate status in cucumber (Cucumis sativus L.) were examined. Plants were grown under a 12 h high light intensity period and DT/NT of 25/19 °C (positive DIF) or 19/25 °C (negative DIF) in combination with an exposure of 30 min EOD-red (EOD-R) or far-red (EOD-FR) light. A significant interaction between DIF and EOD light quality was found on morphology, DM and carbohydrate content in axial plant organs like stems and petioles, but not in leaf blades and roots. Positive DIF induced taller stems, and higher DM and carbohydrate content than negative DIF when the plants were grown under EOD-R. The stems developed under EOD-FR were tall and accumulated the highest content of DM and carbohydrates and only small differences were found between positive DIF and negative DIF. Under EOD-R a higher content of glucose and fructose was found under positive than negative DIF, while EOD-FR light resulted in a high glucose and fructose content under both positive and negative DIF and thereby equalized the effect of the two temperature treatments. The results show that positive DIF can induce similar responses in elongation growth, DM and carbohydrate accumulation as EOD-FR, and further that phytochrome status interact with the responses to alternating DT and NT.     

两个超级杂交水稻品种物质生产的特性

定量分析超级杂交水稻若干群体指标的动态特征,以期为其高产栽培提供依据。于2011年和2012年在大田条件下,以超级杂交水稻准两优527、Q优6号和对照品种II优838为试材,通过连续测定干物质和叶面积,建立了水稻群体干物质和相对叶面积指数动态模型,进而以群体干物质和相对叶面积指数模型为基础,分析了超级杂交水稻作物生长率、相对生长率、光合势、净同化率、叶面积比率动态变化特征。结果表明,超级杂交水稻快增期的干物质积累量及其占总生物量的比例均高于对照。作物生长率(CGR)随移栽后时间呈先升高后下降的单峰曲线变化,其快增期的CGR较大。与对照相比,超级杂交水稻相对生长率(RGR)表现出上升快、峰值大、下降快的特点。准两优527在移栽后23 d至成熟期高于对照,Q优6号的RGR在移栽后43 d以前低于对照,移栽后43 d至113 d高于对照,两者在移栽后113 d至成熟期的RGR相差不大。不同水稻净同化率(NAR)随移栽后时间呈先上升后下降的单峰曲线变化,最大NAR出现在移栽后43~53 d。总光合势与快增期光合势及与快增期绿叶面积持续时间均呈极显著正相关。2个超级杂交水稻叶面积比率(LAR)在移栽后23 d至43 d迅速下降,移栽后43 d至73 d缓慢下降,移栽后73 d至成熟期快速下降,其快增期的LAR较大。     

朱砂叶螨为害前后抗、感木薯品种叶组织中无色花青素还原酶活性差异分析

为了解木薯单宁酸合成关键酶无色花青素还原酶(leucoanthocyanidin reductase,LAR)在木薯抗螨中的功能与作用,本研究分析朱砂叶螨为害前后抗、感木薯品种不同叶龄组织LAR酶活性变化差异。结果表明:朱砂叶螨为害1、8 d时,高感木薯品种BRA900的未展开叶、展开幼嫩叶、顶芽下第3叶、中下部叶片的LAR酶活性分别为螨害前的1.38倍和1.44倍、1.33倍和1.48倍、1.42倍和1.43倍、0.82倍和0.50倍,除了中下部叶片螨害8 d的LAR酶活性显著降低外,其余叶片LAR酶活性在螨害前后均无显著差异(p<0.05);朱砂叶螨为害1、8 d时,高抗木薯品种C1115的未展开叶、展开幼嫩叶、顶芽下第3叶、中下部叶片的LAR酶活性则分别比螨害前显著提高2.13倍和2.41倍、2.02倍和2.09倍、2.02倍和2.04倍、2.01倍和2.03倍(p<0.05)。上述结果为阐明LAR酶活性显著提高与木薯品种抗螨能力的相关性及田间朱砂叶螨主要为害木薯中下部叶片提供了初步证据。