盐胁迫和干旱胁迫对蓝花子种子萌发和幼苗生长的影响

将蓝花子培养在含有不同浓度的NaCl和甘露醇的MS培养基上,研究蓝花子在不同浓度的NaCl和甘露醇处理下的发芽势、发芽率、相对发芽率、叶绿素含量以及过氧化物酶活性等,揭示蓝花子对盐胁迫和干旱胁迫的耐受能力。结果表明:蓝花子的发芽率、株高、根长、叶绿素以及过氧化物酶活性都随NaCl浓度的升高而显著下降;在甘露醇胁迫时,蓝花子幼苗的根长、叶绿素含量以及POD酶活性都随甘露醇浓度的升高表现为先升高后降低的趋势。说明同十字花科其它植物相比蓝花子对盐胁迫十分敏感,而对干旱胁迫却能表现出比较明显的耐受性。     

Effect of mannitol pretreatment to improve green plant regeneration on isolated microspore culture in Triticum turgidum ssp. durum cv. 'Jennah Khetifa'

The use of doubled haploids improves the efficiency of cultivar development in many crops and can be helpful in genetic and molecular studies. The major problem with this approach is the low efficiency of green plant regeneration. We describe here an efficient method for inducing embryos and regenerating green plants directly from isolated microspores of durum wheat cv. ‘Jennah Khetifa’. Tillers from donor plants were pretreated in 0.3 m mannitol and were stored at 4°C at various times: 3, 5, 6, 7, 8, 10 and 12 days. Our results showed clearly that the novel pretreatment combined mannitol 0.3 m and cold for 7 days had a strong effect on the number of embryos produced and regenerated green plants. Under this condition 13 475 mature embryos were produced from 2 693 500 microspores. Moreover, 85 green plants were obtained. High green plants regeneration frequency was recorded. As an average 11.55 green plants were produced per 100 000 microspores (about the equivalent of six plants per spike). Therefore, this study showed clearly that our results are the best ones published until now in durum wheat.     

Dietary mannitol increased the absorption of calcium and magnesium in rats

The effect of mannitol on bone‐related mineral absorption and retention and the mechanism was investigated in this study. Fourteen 8‐week‐old male Wistar rats in experiment 1 and same number and age cecectomized Wistar male rats in experiment 2 were divided into two subgroups of seven animals, respectively, fed diets containing 0 or 4% mannitol for 28 days. Mineral balance tests were determined twice during days 8–12 and days 22–26, and the rats were slaughtered on day 28 both in experiment 1 and experiment 2. The whole caecum and colon were collected with the content to analyse tissue weight, content weight, content's pH and moisture, organic acids' concentration and mineral levels. In experiment 1, Ca absorption and retention and Mg absorption were significantly increased by mannitol feeding during days 8–12. Caecal total weight, tissue weight and content weight were increased, the pH of caecum and colon was reduced, and the concentrations of caecal short‐chain fatty acids (SCFAs) were modified by mannitol feeding. In experiment 2, during days 8–12 and days 22–26, Ca absorption and retention were significantly lowered by mannitol feeding in cecectomized rats; however, mannitol feeding decreased Mg absorption during days 8–12, but did not impact Mg retention. Colonic total weight, tissue weight and content weight were significantly increased, and colonic pH was reduced by mannitol feeding. In conclusion, dietary mannitol increased the absorption of Ca and Mg and the caecum markedly contributed to this promoting effect of mannitol.     

甘露醇和生长抑制剂对文心兰离体保存的影响

以文心兰无菌苗为离体保存材料,研究培养基中添加不同浓度甘露醇、矮壮素及脱落酸对文心兰试管苗离体保存的影响.结果表明:在培养温度(24±3)℃,保存前6个月光照强度2 000～2 500 lx,后6个月光照强度500～1 000 lx,光照时间12 h·d-1的培养条件下,MS+6-BA 0.5 mg·L-1+NAA 0...     

Tissue culture storage of potato germplasm. 2. Use of growth retardants

Summary The interval between transfers of organ cultures from seventeen potato cultivars has been extended from several weeks to twelve months by the addition of growth retardants to the medium. The presence of abscisic acid or mannitol in the medium increased the survival of cultures from 15 to 60% after twelve months, and in combination with a reduced temperature regime up to 73% of cultures survived. B995 and Phosphon D added to the medium had less effect and trans-cinnamic acid was ineffective. In the presence of abscisic acid and mannitol cultures became stunted with short internodes and poor root development but normal growth occurred on transfer to retardant-free medium

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Zusammenfassung Das Intervall zwischen den Uebertragungen von Organkulturen, die von siebzehn Kartoffelsorten stammen, wurde von vier Wochen auf zw?lf Monate oder l?nger ausgedehnt. Die fünfzehn Züchtungen schlossen Muster von vier Ploidygraden ein und deckten den Schwankungsbereich innerhalb kultivierter Kartoffeln. Nodienkulturen wurden routinem?ssig alle vier Wochen übertragen und auf N?hrboden nach Murashige & Skoog (1962) ohne Hormone bei 22 °C bei einer Photoperiode von 16 Stunden herangezogen. Die nach der Lagerung überlebenden Pflanzen wurden auf frischen N?hrboden übertragen und dienten der Produktion der neuen Anzucht. Der durchschnittliche Prozentsatz Ueberlebende nach 12monatiger Lagerung bei 22 °C wurde von 17 % auf 66 % bzw. 61 % mit 5 mg/l bzw. 10 mg/l Abscisins?ure im N?hrboden verbessert. Eine Erh?hung des osmotischen Druckes durch die Beifügung von Mannit erm?glichte das Ueberleben in einem ?hnlichen Ausmass, 3 % und 6 % Mannit erh?hte die Zahl der Ueberlebenden auf 64 % und 61 %. Die andern Hemmstoffe waren weniger wirksam. Nach 6 Monaten Lagerung war die Ueberlebensrate von 45 % auf 60 % mit 50 mg/l B995 und 10 mg/l Maleins?urehydrazid und auf 85% mit 1 und 3 mg/l Phosphon D verbessert; trans-Zimts?ure war unwirksam. Eine Kombination von erh?htem N?hrbodenvolumen (3,5 ml auf 60 ml) mit 20 mg/l Abscisins?ure im N?hrboden verbesserte die Ueberlebensrate von 26 % auf 73 % nach 12 Monaten Lagerung. 73 % der Kulturen wurden auch mit 10 mg/l Abscisins?ure in Verbindung mit einem zyklischen Temperaturregime erzielt. Wirksame Konzentrationen von Hemmstoffen erzeugten eine anomale Pflanzenmorphologie. Die Pfl?nzchen waren verkümmert mit kurzen Internodien und schwacher Wurzelentwicklung. Durch die Uebertragung auf frischen, hemmstoffreien N?hrboden wurde jedoch ein normales Wachstum erzielt. Die Beifügung von Hemmstoffen, besonders Abscisins?ure und Mannit, erlaubt die Lagerung von Kartoffelkulturen bei normalen Raumtemperaturen für Kulturen (22 °C) und ist auch in Kombination mit reduzierten Temperaturen wirksam.

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Résumé L'intervalle entre la mise en culture d'organes issus de dix-sept variétés de pomme de terre et leur transfert a été étendu de quatre semaines à douze mois ou plus. Ces quinze variétés comprenaient quatre niveaux de plo?die et couvraient la gamme des variations observées à l'intérieur des pommes de terre cultivées. Les explantats issus des cultures ont été transférés régulièrement toutes les quatre semaines et cultivés sur le milieu de Murashige & Skoog (1962) sans hormones, à 22 °C sous une photopériode de 16 heures. Les cultures étaient faites une à quatre semaines avant leur transfert dans les conditions expérimentales. La survie des explantats s'est exprimée par la production d'une nouvelle croissance sur le milieu frais. Le pourcentrage moyen de survie après une conservation de 12 mois à 22 °C était amélioré de 17 à 66 % et 61 % avec respectivement 5 mg/l et 10 mg/l d'acide absissique dans le milieu. Une augmentation de la pression osmotique occasionnée par l'addition de mannitol a amélioré la survie dans des proportions analogues, de 3 et 6 % à 64 et 61 %. Les autres retardateurs de croissance ont été moins efficaces. Après 6 mois de conservation le taux de survie est passé de 45 à 60 % avec 50 mg/l de B995 et 10 mg/l d'hydrazide maléique et à 85 % avec 1 et 3 mg/l de phosphon D; l'acide trans-cinnamique n'a pas été efficace. L'augmentation de la quantité de milieu (de 3.5 ml à 60 ml) combinée avec l'addition de 20 mg d'acide absissique a amélioré le taux de survie de 26 à 73% après 12 mois, et 73 % également avec 10 mg/l lorsque le cycle des températures a été alterné. La concentration des retardateurs de croissance avait pour effet de donner des anomalies morphologiques aux cultures. Les plantules étaient rabougries avec de courts entre-noeuds et peu de racines. Le transfert de celles-ci sur un milieu frais sans retardateur de croissance leur rendait une croissance normale. L'addition de retardateurs de croissance, notamment d'acide absissique et de mannitol, convient à la pomme de terre pour la conservation des cultures à la température ambiante (22 °C) et est également efficace dans le cas de températures plus basses.

     

应用中空纤维超滤膜分离纯化甘露醇

采用中空纤维超滤膜分离技术对海带中提取的甘露醇进行纯化精制，以去除其中的褐藻糖胶和低分子褐藻胶等有机杂质。经应用自行设计的超滤装置对天然甘露醇进行纯化，取得了良好的效果，产品质量明显提高，且每吨甘露醇成本仅增加103元，显著地提高了该产品在国内外市场上的竞争能力。     

Extracellular fluid volume measurements in tissues of the rainbow trout (Oncorhynchus mykiss)in vivo and their effects on intracellular pH and ion calculations

Extracellular fluid volume (ECFV) estimates were determined in various tissues and whole body of resting, chronically cannulated rainbow trout (Oncorhynchus mykiss). Fish were infused with¹⁴C-inulin,³H-polyethylene glycol (PEG, M.W. 4000),³H-mannitol, or¹⁴C-mannitol, and values of ECFV determined from tissue: plasma water distribution ratios after 6 h or 13 h equilibration. Overall,³H-PEG provided the most conservative and reliable estimates after 13 h equilibration, with ECFV values in the order: brain < white muscle < red muscle < liver < heart < gill tissue.¹⁴C-inulin yielded generally similar values to³H-PEG at 13 h, but probably overestimated ECFV in liver.³H-mannitol and¹⁴C-mannitol spaces were similar to each other and far greater than³H-PEG or¹⁴C-inulin values in most tissues.³H-mannitol values increased significantly between 6 h and 13 h, in contrast to¹⁴C-inulin. Mannitol clearly overestimated ECFV in liver and gill, and probably also heart and whole body, but may have provided more realistic estimates in brain due to better penetration of the blood-brain barrier. The Cl^–/K⁺ space technique overestimated ECFV in gills, but was satisfactory in white muscle. Measurements and model calculations evaluated sources of error in intracellular pH (by¹⁴C-DMO) and ion determinations. Trapped red cells in the gills have negligible influence. Errors in ECFV are much more influential in a tissue with a high ECFV (gills) than a low ECFV (white muscle).³H-PEG is the marker of choice for intracellular pH determinations. However, even when³H-PEG is used, the potential for absolute errors in intracellular ion concentrations remains high.     

蓝莓Vco-miR_n10的克隆及对干旱的响应分析

【目的】MicroRNA（miRNA）是一类内源单链非编码的小分子 RNA，在动植物中参与转录后基因 表达调控。Vco-miR_n10 是蓝莓中的新型 miRNA，目前尚未见该 miRNA 功能方面的报道。本研究对蓝莓 VcomiR_n10 进行了初步功能分析。【方法】基于前期蓝莓小 RNA 高通量测序结果，对鉴定到的蓝莓新型 miRNA （Vco-miR_n10）的前体序列（224 nt）进行克隆与测序，并利用 mfold 在线软件对其前体序列的二级结构进行 预测。采用 Gateway 系统构建了 35Spro:: pre-Vco-miR_n10 表达载体并转入野生型拟南芥中，对其正常生长及 300 mmol/L 甘露醇处理条件下的表型进行观察与分析。【结果】克隆获得了 Vco-miR_n10 的前体序列，该序列能够折 叠形成较完美的茎环结构且仅有 2 个错配碱基对。Vco-miR_n10 的成熟体序列位于 3'' 茎臂上。观察正常生长条 件下的转基因植株并无显著的表型变化。而在 300 mmol/L 甘露醇模拟的干旱条件下，Vco-miR_n10-24 与 VcomiR_n10-52 的发芽率（33.53%、37.69%）和绿苗率均显著低于野生型（发芽率 67.72%、绿苗率 66.33%）。【结 论】蓝莓 Vco-miR_n10 能够响应甘露醇模拟的干旱胁迫，并降低拟南芥对干旱的耐受能力，影响发芽率和绿苗率， 说明蓝莓 Vco-miR_n10 可能在植物响应干旱胁迫过程中发挥一定的调控功能。     

Inoculation with the native Rhizobium gallicum 8a3 improves osmotic stress tolerance in common bean drought-sensitive cultivar

Abstract

Symbiotic nitrogen fixation potential in common bean is considered to be low in comparison with other grain legumes. However, it may be possible to improve the nitrogen fixation potential of common bean using efficient rhizobia. In order to improve osmotic stress tolerance of a drought-sensitive common bean cultivar (COCOT) consumed in Tunisia, plants were inoculated either by the reference strain Rhizobium tropici CIAT 899 or by inoculation with rhizobia isolated from native soils Rhizobium gallicum 8a3. Fifteen days after sowing, osmotic stress was applied by means of 25 mM mannitol (low stress level) or by 75 mM mannitol (high stress level). Fifteen days after treatment plants were harvested and different physiological and biochemical parameters were analysed. Results showed no significant differences between the studied symbioses under control conditions. However after exposure to osmotic stress our results showed better tolerance of COCOT to osmotic stress when inoculated with the native R. gallicum 8a3. This can be partially explained by better water-use efficiency in both leaves and nodules, better relative water content in nodules and better efficiency in utilization of rhizobial symbiosis as compared with COCOT-CIAT 899 symbiosis. Hence, the present study suggested the better use of native soil isolated strains for the inoculation of common bean in order to improve its performance and nitrogen fixation potential under stressful conditions.     

甘露醇和蔗糖对菊花低温离体保存的影响

离体保存技术在植物种质资源保存方面具有独特优势和重要意义。为改善菊花离体保存技术,本研究以4个不同生长势的菊花品种为试验材料,在7±2℃条件下研究渗透调节物质甘露醇和蔗糖对不同菊花品种离体保存的影响,观察统计不同浓度蔗糖和甘露醇处理下菊花离体保存试管苗不同阶段的存活率和绿叶数,并对保存后试管苗的叶和茎段的组织结构、恢复生长能力和遗传稳定性进行了观察和鉴定。结果表明,保存12个月后,在MS培养基中添加15 g·L^-1甘露醇处理对南农橙乒乓和小洋菊试管苗的离体保存效果最佳,存活率分别达86.67%和93.33%;20 g·L^-1甘露醇处理对蒙娜丽莎黄和橙安娜保存效果最优,存活率分别达到80.00%和93.33%。60 g·L^-1蔗糖处理,南农橙乒乓和小洋菊保存12个月存活率均达到70%以上,但相比甘露醇处理,其绿叶数少、生长状况差;高浓度蔗糖(45～90 g·L^-1)对蒙娜丽莎黄和橙安娜保存效果不佳。保存12个月后,20 g·L^-1甘露醇处理的蒙娜丽莎黄和橙安娜、15 g·L^-1甘露醇处理的小洋菊和南农橙兵兵的叶片和茎段细胞间隙减小,细胞密度增加,试管苗恢复正常培养45 d后不同品种菊花生长良好,株高、叶片数、茎粗、节间长等形态指标及SSR分子标记图谱与对照相比无显著差异,保持了良好的遗传稳定性。本研究为菊花种质资源的低温离体保存提供了理论依据与技术支撑。