Pollen morphology and taxonomic implications of Muscari Miller (Hyacinthaceae) species from Sicily

Pollen morphology of the native Sicilian species of the genus Muscari, one of which is endemic to Sicily, belonging to the subgenera Muscari, Leopoldia and Pseudomuscari, was studied using a light microscope and a scanning electron microscope. Pollen grains are monads, heteropolar and monosulcate; the exine is semitectate reticulate and perforate. The sulcus extends from distal to proximal face and its length is not directly proportional to the size of the granules and varies from one species to another.     

Light pollution may create demographic traps for nocturnal insects

Light pollution impacts both intra- and inter-specific interactions, such as interactions between mates and predator–prey interactions. In mobile organisms attracted to artificial lights, the effect of light pollution on these interactions may be intensified. If organisms are repelled by artificial lights, effects of light pollution on intra- and inter-specific interactions may be diminished as organisms move away. However, organisms repelled by artificial lights would likely lose suitable habitat as light pollution expands. Thus, we investigated how light pollution affects both net attraction or repulsion of organisms and effects on intra- and inter-specific interactions. In manipulative field studies using fireflies, we found that Photuris versicolor and Photinus pyralis fireflies were lured to artificial (LED) light at night and that both species were less likely to engage in courtship dialogues (bioluminescent flashing) in light-polluted field plots. Light pollution also lowered the mating success of P. pyralis. P. versicolor is known to prey upon P. pyralis by mimicking the flash patterns of P. pyralis, but we did not find an effect of light pollution on Photuris–Photinus predator–prey interactions. Our study suggests, that for some nocturnal insects, light-polluted areas may act as demographic traps, i.e., areas where immigration exceeds emigration and inhibition of courtship dialogues and mating reduces reproduction. Examining multiple factors affecting population growth in concert is needed to understand and mitigate impacts of light pollution on wildlife.     

不同光质对甘蓝型油菜幼苗的生长和生理特性的影响

以甘蓝型油菜品种‘宁油12’为试材,采用单因素随机区组设计的盆栽试验,将直播后长至子叶展平时的油菜幼苗转入荧光灯(FL,对照)、蓝光(B)、蓝红组合1∶1(BR1∶1)、蓝红组合1∶8(BR1∶8)和红光(R)下进行照射,考察不同光质对甘蓝型油菜生长指标、根系活力、叶绿素含量和光合产物等的光效应,筛选适合甘蓝型油菜工厂化育苗的人工光源,为油菜的工厂化育苗的光源合理利用提供理论指导和技术支持。结果表明:(1)油菜幼苗的鲜质量、干质量、根长、株高、茎粗和叶面积在BR1∶8处理下最大,并显著高于对照FL;(2)BR1∶8处理下的幼苗根系活力最强,其次为B处理,二者都显著高于对照FL;(3)幼苗叶片叶绿素a、叶绿素b、叶绿素总量和类胡萝卜素的含量在各光质处理下变化趋势一致,即B处理最大,其次是BR1∶8处理,二者均显著高于BR1∶1、R和FL处理,但BR1∶1、R和FL处理间均无显著差异;(4)BR1∶8处理幼苗叶片的可溶性糖、淀粉和游离氨基酸含量最高,且都显著高于BR1∶1、R和FL处理;B处理幼苗叶片的蔗糖、可溶性蛋白和抗坏血酸含量最高,且显著高于BR1∶1、R和FL处理;BR1∶8处理叶片的可溶性碳和氮含量最高,其次为B处理,并显著高于BR1∶1、R和FL处理;而对照FL处理的碳氮比最大,显著高于其他处理。研究认为,蓝红组合光(1∶8)能显著提高甘蓝型油菜叶片可溶性糖、可溶性淀粉、游离氨基酸、可溶糖总碳和总氮的含量,而蓝光则能显著促进叶片光合色素、蔗糖、可溶性蛋白和抗坏血酸的积累,有效促使幼苗快速、健壮生长,生产中可采用蓝红组合光(1∶8)和蓝光作为甘蓝型油菜育苗的人工光源。     

Effect of pinealectomy on the circadian clock of the chick retina under different monochromatic lights

The avian circadian rhythm pacemaker is composed of the retina, pineal gland and suprachiasmatic nucleus. As an intact input-pacemaker-output system, each of these structures is linked within a neuroendocrine loop to influence downstream processes and peripheral oscillations. While our previous study found that monochromatic light affected the circadian rhythms of clock genes in the chick retina, the effect of the pineal gland on the response of the retinal circadian clock under monochromatic light still remains unclear. In this study, a total of 144 chicks, including sham-operated and pinealectomized groups, were exposed to white, red, green or blue light. After 2 weeks of light illumination, the circadian expression of six core clock genes (cClock, cBmal1, cCry1, cCry2, cPer2 and cPer3), melanopsin (cOpn4-1, cOpn4-2), Arylalkylamine N-acetyltransferase (cAanat) and melatonin was examined in the retina. The cBmal1, cCry1, cPer2, cPer3, cOpn4-1, cOpn4-2 and cAanat genes as well as melatonin had circadian rhythmic expression in both the sham-operated and pinealectomized groups under different monochromatic lights, while cClock and cCry2 had arrhythmic 24 h profiles in all of the light-treated groups. After pinealectomy, the rhythmicity of the clock genes, melanopsins, cAanat and melatonin in the chick retina did not change, especially the mesors, amplitudes and phases of cBmal1, cOpn4-1, cOpn4-2, cAanat and melatonin. Compared to the white light group, however, green light increased the mRNA expression of the positive-regulating clock genes cBmal1, cAanat, cOpn4-1 and cOpn4-2 as well as the melatonin content in pinealectomized chicks, whereas red light decreased their expression. These results suggest that the chick retina is a relatively independent circadian oscillator from the pineal gland, whose circadian rhythmicity (including photoreception, molecular clock and melatonin output) is not altered after pinealectomization. Moreover, green light increases ocular cAanat expression and melatonin synthesis by accelerating the expression of melanopsin and positive-regulating clock genes cBmal1 and cClock.     

几种常用益生元不同配伍对三株益生菌体外生长的调节作用

目的 探讨几种常用益生元经过不同配伍组合后对3种常用益生菌体外生长的调节作用。方法 使用基础培养基分别培养3株益生菌,观察不同益生元配伍组合对3株益生菌的体外调节作用。依据不同的益生元组分配伍以及浓度制作含不同益生元组分的基础培养基体外培养3株益生菌,分别在培养的0、6、12、18和24 h取样进行平板活菌计数同时观察菌体形态。配置不同浓度的含葡萄糖基础培养基作为对照,研究不同益生元组分配伍组合对3株益生菌体外生长的调节作用。结果 低聚半乳糖、低聚果糖、低聚异麦芽糖（组合2‒0.5%）配伍以及低聚半乳糖、低聚果糖、低聚木糖（组合4‒1.0%）配伍相较于相同糖浓度的葡萄糖基础培养基对嗜酸乳杆菌NCFM活菌计数有促进作用（P<0.05）。低聚半乳糖、低聚果糖、低聚木糖（组合4‒0.5%）配伍相较于相同糖浓度的葡萄糖基础培养基对乳双歧杆菌HN019活菌计数有促进作用（P<0.05）。低聚半乳糖、低聚果糖、低聚异麦芽糖（组合2‒1.0%）配伍以及低聚半乳糖、低聚果糖、水苏糖（组合3‒0.5%）配伍相较于相同糖浓度的葡萄糖基础培养基对乳双歧杆菌Bi-07活菌计数有促进作用（P<0.05）。结论 低聚半乳糖、低聚果糖和低聚木糖组合对嗜酸乳杆菌NCFM和乳双歧杆菌HN019的增殖具有促进作用。低聚半乳糖、低聚果糖和低聚异麦芽糖组合对嗜酸乳杆菌NCFM和乳双歧杆菌Bi-07的增殖具有促进作用。低聚半乳糖、低聚果糖和水苏糖组合对乳双歧杆菌Bi-07的增殖具有促进作用。     

Production of eicosapentaenoic acid (EPA) in Monodus subterraneus grown in a helical tubular photobioreactor as affected by cell density and light intensity

The effect of cell density (1–4.5 g L^-1) and light intensity (44 and 82 mol m^-2 s^-1) on fatty acid composition andeicosapentaenoic acid (EPA, 20:5 3) production was studied ina semi-continuous culture of Monodus subterraneus grown in a helicaltubular photobioreactor (`Biocoil') under laboratory conditions. Under lowlight, the highest proportion of EPA (31.5% of total fatty acids) and EPAcontent (3.5% of dry weight), biomass productivity (1.3 g L^-124 h^-1) and EPA productivity (44 mg L^-1 24 h^-1)occurred at optimal cell density of about 1.7 g L^-1. Cell densityhad no effect on the total fatty acid (TFA) content and was maintained atca. 11% of dry weight. Under high light, the highest proportion ofEPA to fatty acids (31.8%), the total fatty acids content (13.4%) andEPA content (4.3% of dry weight) occurred at cell density of about 3.4gL^-1. But the highest biomass productivity (1.7 g L^-124 h^-1) and EPA productivity (56 mg L^-1 24 h^-1) wereobtained at a cell density of 1.6 and 2.6g L^-1, respectively. Ourresults suggest that manipulating the cell density and light intensity canmodify the composition of fatty acid and production of eicosapentaenoicacid (EPA) in M. subterraneus.     

Phototropism of rice (Oryza sativa L.) coleoptiles: fluence-response relationships, kinetics and photogravitropic equilibrium

Phototropism of rice (Oryza sativa L.) coleoptiles induced by unilateral blue light was characterized using red-light-grown seedlings. Phototropic fluence-response relationships, investigated mainly with submerged coleoptiles, revealed three response types previously identified in oat and maize coleoptiles: two pulse-induced positive phototropisms and a phototropism that depended on stimulation time. The effective ranges of fluences and fluence rates were comparable to those reported for maize. Compared with oats and maize, however, curvature responses in rice were much smaller and coleoptiles straightened faster after establishing the maximal curvature. When stimulated continuously, submerged coleoptiles developed curvature slowly over a period of 6 h, whereas air-grown coleoptiles, which showed smaller phototropic responsiveness, established a photogravitropic equilibrium from about 4 h of stimulation. The plot of the equilibrium angle against log fluence rates yielded a bell-shaped optimum curve that spanned over a relatively wide fluence-rate range; a maximal curvature of 25° occurred at a fluence rate of 1 μmol · m⁻² · s⁻¹. This optimum curve apparently reflects the light sensitivity of the steady-state phototropic response. Received: 28 June 1996 / Accepted: 30 July 1996