Formation in vitro of ripe tomato fruits from thin layer explants of flower pedicels

Thin longitudinal sections cut from pedicels of fifteen cultivars of tomato (Lycopersicon esculentum) were grown in vitro on Murashige-Skoog medium supplemented with various concentrations of different auxins and cytokinins. Isatin (an auxin precursor slowly converted to an active auxin) was the most effective source of auxin for the formation of buds without prior root formation, while zeatin was the most effective cytokinin for growth and development of the buds. Flower buds and ripe fruits developed consistently from explants of the cultivar Pixie Hybrid II treated with 10 M isatin plus 3 M zeatin as the cytokinin. Fruits developed parthenocarpically, grew to a diameter of about 15 mm, ripened promptly, and possessed normal color and flavor.Abbreviations BAP benzylaminopurine - IAA indole-3-acetic acid - IBA indole-3-butyric acid - IPA isopentyladenosine - NAA -napthaleneacetic acid     

Recent advances in the cryopreservation of shoot-derived germplasm of economically important fruit trees of Actinidia, Diospyros, Malus, Olea, Prunus, Pyrus and Vitis

This paper presents the advances made over the last decade in cryopreservation of economically important vegetatively propagated fruit trees. Cryopreservation protocols have been established using both dormant buds sampled on field-grown plants and shoot tips sampled on in vitro plantlets. In the case of dormant buds, scions are partially dehydrated by storage at − 5 °C, and then cooled slowly to − 30 °C using low cooling rates (c.a. 1 °C/h) before immersion in liquid nitrogen. After slow rewarming and rehydration of samples, regrowth takes place either through grafting of buds on rootstocks or excision of apices and inoculation in vitro. In the case of shoot tips of in vitro plantlets, the cryopreservation techniques employed are the following: controlled rate cooling procedures involving slow prefreezing followed by immersion in liquid nitrogen or vitrification-based procedures including encapsulation–dehydration, vitrification, encapsulation–vitrification and droplet-vitrification. The current status of cryopreservation for a series of fruit tree species including Actinidia, Diospyros, Malus, Olea, Prunus, Pyrus and Vitis is presented. Routine application of cryopreservation for long-term germplasm storage in genebanks is currently limited to apple and pear, for which large cryopreserved collections have been established at NCGRP, Fort Collins (USA), using dormant buds and in vitro shoot tips, respectively. However, there are a growing number of examples of pilot scale testing experiments under way for different species in various countries. Progress in the further development and application of cryopreservation techniques will be made through a better understanding of the mechanisms involved in the induction of tolerance to dehydration and cryopreservation in frozen explants.     

茎尖和芽的超低温保存

介绍了植物茎尖和芽超低温保存的意义和现状。影响超低温保存的一些主要因素及其所采取的措施,主要包括预培养、低温锻炼、使用冰冻保护剂以及适当采用不同的降温方法和化冻洗涤方法,并就今后的研究提出了一些看法。     

Stunting and flower buds deficiency of Lilium sp.: a new phytoplasma associated disease

The presence of phytoplasmas in Lilium sp. showing severely stunted growth, leaf malformation and flower buds deficiency was demonstrated for the first time using polymerase chain reaction assays with primers amplifying phytoplasma 16S rDNA regions. These phytoplasmas were found in leaves as well as roots and bulb scales of symptomatic and CMV and/or LSV affected and asymptomatic virus-free lilies.     

水曲柳腋芽离体快繁研究初报

以水曲柳带顶芽、腋芽茎段为外植体进行离体培养,研究其适宜的灭菌方法、基本培养基种类和激素对腋芽萌发、丛芽产生、芽苗增殖的影响。结果表明,水曲柳的腋芽茎段为快繁的适宜外植体,茎段灭菌以用0.05%HgCl₂处理2 min最好。在萌芽培养中,BA和2ip均可促进腋芽萌发,但以8 mg·L^-1 BA处理时萌发效果最好,萌发率达100％;将腋芽萌发后长成的新枝转入添加ZT的培养基中,出现丛芽,在添加1.0 mg·L^-1的ZT的培养基中增殖效果最好,增殖系数达到3.0。无论在萌芽培养还是增殖培养中均发现WPM培养基最适合水曲柳腋芽的离体快繁。     

毛药忍冬花蕾抗氧化活性部位化学成分研究

毛药忍冬(Lonicera serreana)为忍冬属(Lonicera)植物,其花和果实入药,具有清热解毒、凉散风热之功效,但至今缺乏系统化学成分及药理活性研究。为了寻找毛药忍冬中天然抗氧化活性成分,进一步开发利用忍冬属药用植物资源,该研究以DPPH自由基清除法为活性指导,首次对毛药忍冬干燥花蕾75%乙醇提取物的不同极性萃取部位进行抗氧化活性测试,结果发现乙酸乙酯萃取物表现出最强的抗氧化活性(平均清除率为89.45%)。进一步应用现代色谱手段(硅胶柱色谱、Sephadex LH-20凝胶柱色谱等),从毛药忍冬花蕾的乙酸乙酯萃取物中分离单体化合物,运用现代光谱分析技术(MS、1 H-NMR、13 C-NMR、COSY、HSQC、HMBC、ROESY),并结合文献数据鉴定化合物的化学结构。结果表明:从毛药忍冬干燥花蕾75%乙醇提取物中共分离得到9个化合物,分别鉴定为4个酚酸类化合物:绿原酸(1)、绿原酸甲酯(2)、绿原酸乙酯(3)、咖啡酸(4);4个黄酮类化合物:木犀草素(5)、木犀草素-7-O-β-D-葡萄糖苷(6)、槲皮素(7)、槲皮素-3-O-β-D-葡萄糖苷(8);1个甾醇类化合物:β-谷甾醇(9)。所有化合物均为从毛药忍冬花蕾中首次分离得到。研究结果可为抗氧化类相关产品的开发提供科学依据。     

Development and changes at settlement in the barbel structure of the reef fish,Upeneus tragula (Mullidae)

Synopsis The development of the sensory barbels of the tropical goatfish, Upeneus tragula (Mullidae), was examined from their first appearance early in planktonic life through to the reef-associated juvenile period. The structure of the barbel was examined histologically and found to represent an outgrowth of the gustatory (taste) system, composed of at least 50% sensory tissue at settlement. Abrupt changes in morphology were found to be coincident with the 6–12 h settlement period: barbels rapidly moved forward along the hyoid arch to abut the dentary; the length of the barbels increased by up to 52%; the epidermal layer increased to comprise 75% of the cross-sectional area; and the mean size of the taste bud cells increased by up to 100%. A strong relationship was found between barbel length and mean taste-bud size. This relationship was used to predict the mean taste-bud sizes for 237 newly-settled fish, collected as 12 samples over two recruitment seasons. Mean taste-bud size varied significantly among samples. Experiments examined whether food availability or temperature of the water within the pelagic phase influenced the size of the barbels at settlement. Food availability influenced the relationship between barbel length and fish size. Slower growing fish had larger barbels relative to fish length than those that grew faster. Temperature did not influence the relationship between barbel length and fish size. Variability in sensory development at settlement, and the factors which influence it, may have important ramifications for the potential success of the fish once on the reef.     

Theobroma cacao L.: an axillary bud in vitro propagation procedure

An axillary bud derived in vitro propagation procedure for Theobroma cacao is described. The method allows bud expansion and elongation, including leaf development, as early as 13 days after placing explants on establishment medium. Shoots have been maintained in culture vessels for six months with little evidence of decline. Propagules have been induced to form roots, hardened off, and moved to the greenhouse within six weeks of initial explant establishment. Some plants have been in the greenhouse for twelve months and are growing in an apparently normal manner. No major differences in response from UF-667 or EQX-100 derived seed-grown trees were found suggesting that the method may not be limited by genotype. Long-term growth without added plant growth regulators has been seen in over 2400 explants.Abbreviations NAA naphthaleneacetic acid - IBA indolebutyric acid - BAP benzylaminopurine - WPM Lloyd-McCown woody plant medium Published as paper No. 8148, Journal Series, Pennsylvania Agricultural Experiment Station     

Ethylene production by young Aranda orchid flowers and buds

A high rate of ethylene production was observed in buds and young flowers of Aranda orchid, which increased with bud growth, reaching a high value in half-opened flower. This was followed by a gradual decline but it increased again when the flowers showed sign of senescence. Aminooxylacetic acid (AOA) inhibited ethylene production and bud expansion of Aranda buds.