防止组织培养外植体接种后褐化的方法

防止组织培养外植体接种后褐化的方法组织培养外植体初始接种遇到最严重的问题是伤口酚类物质氧化变褐，而酚类物质及其氧化物对植物组织有害，因此必须去除。试用了四个苹果品种：ＧｒａｎｎｙＳｍｉｔｈ、Ｊｕｌｙｒｅｄ、Ｍｕｔｓｕ及短枝型金冠。研究表明下列方法可有...     

酚类物质及其对木本植物组织培养褐变影响的研究进展

褐变现象普遍存在于各种植物体的组织培养过程中,木本植物尤为严重。酚类化合物是植物组织培养过程中造成外植体褐变的底物。氧化酶类催化的酚氧化反应是褐变发生的直接原因。从酚类物质的合成与分类、代谢相关酶、测定与分析方法及其对木本植物组织培养褐变的影响等方面,综合阐述酚类物质影响木本植物组培褐变的问题,并对今后木本植物组织培养褐变的防治方法进行了展望,以期为木本植物组织培养的优化提供参考。     

蝴蝶兰褐变外植体的显微结构观察以及褐变成分的初步分析

 对蝴蝶兰褐变外植体进行扫描电镜和显微结构观察, 发现褐变叶片外植体的上表皮已经变形,维管束完全破坏, 被有毒的鞣质填充, 有些薄壁细胞中发现有不明物质沉积。初步分析褐变外植体分泌到培养基中的成分有缩合鞣质。外植体总酚含量和PAL活性随褐变程度加重逐渐增加, 两者呈现显著正相关。     

梨果实发育过程中褐变度、酚类物质及相关酶的变化研究

梨果肉褐变是影响其品质的重要问题,为深入探讨梨果肉褐变的生理机制,以易褐变品种‘宝珠’‘苹果梨’和不易褐变品种‘丰水’‘崇化大梨’为试验材料,测定其果实发育过程中褐变度、酚类物质及相关酶活性的变化。结果表明,梨果肉褐变程度、酚类物质含量和部分酶活性均随着果实的生长发育呈逐渐降低的趋势;从幼果至果实成熟,熊果苷、绿原酸、表儿茶素是果实中主要的酚类物质,三者含量占总酚含量的90%以上,2个易褐变品种‘宝珠’‘苹果梨’果实中熊果苷、绿原酸含量高于2个不易褐变品种‘丰水’‘崇化大梨’。从果实褐变度与酚类物质含量的相关性分析看,在幼果期,单个的酚类物质对果实褐变影响不大,在果实生长后期与果实褐变相关性强的酚类物质主要有熊果苷、儿茶素、绿原酸和咖啡酸。在整个果实发育期,易褐变品种的多酚氧化酶（PPO）活性、苯丙氨酸解氨酶（PAL）活性和总酚含量均高于不易褐变品种;幼果期易褐变品种果实PPO活性与不易褐变品种差异显著（P<0.05）,成熟期差异不显著。4个品种果实中PPO、PAL活性与大多数酚类物质含量均显著相关,对不同发育阶段果实褐变的研究要综合考虑PPO活性与总酚的含量。     

南果梨酶促褐变的生化机制

１９９７年秋，在沈阳农业大学以鞍山市郊产的南果梨为试材，研究了其在贮藏期间褐变的机理，测试结果表明，南果梨在贮藏期间先行酚类物质的合成，后发生降解，多酚氧化酶（ＰＰＯ）的活性呈先升后降趋势。酚类物质的减少和褐变同时发生，认为南果梨褐变是ＰＰＯ促进酚类物质氧化所致。已查明绿原酸是南果梨所含酚类物质的主要成分，是主要的褐变底物。     

荔枝幼叶愈伤组织诱导的研究

荔枝(Litchi chinensisSonn.)是无患子科(Sapindaceac)荔枝属植物。荔枝组织培养比较困难。荔枝内源酚类物质含量较高,外植体在培养期间易发生褐变,导致培养失败。目前,荔枝组织培养多选用胚性器官和组织作为外植体,如花药、幼胚等,用嫩叶作为外植体进行植株再生的极少。D·Puc     

梨果实酚类物质与酶促褐变底物的研究

 对我国分属不同栽培系统及种间杂交种的10个梨品种果实酚类物质含量进行了系统比较研究。结果表明：高相液相色谱法可检测到梨果中10种酚类物质,不同系统及品种的果实中酚类物质含量差异很大,其中绿原酸平均含量最高,香草醛、芦丁、表儿茶素、儿茶素含量较高,为主要的酚类物质;咖啡酸平均含量最低。对总多酚、绿原酸、表儿茶素、儿茶素、抗氧化活性与褐变的灰色关联分析表明：梨果实总多酚含量对褐变度影响最大,绿原酸含量对褐变度影响其次,果实抗氧化活性对褐变的影响最小。不同酚类物质中绿原酸含量最高,且与多酚氧化酶结合能力最强,为最主要的褐变底物。     

科技文摘

梨外植体组培褐变的影响因子及预防措施 以鸭梨、黄金梨、阿巴特梨和杜梨为试材,对梨组培过程中影响外植体褐化的因素及防褐措施进行了研究。结果表明,品种、采样时期以及外植体内酚类物质含量等因素都显著地影响材料褐化率。抗褐剂试验表明,培养基中添加0．2g／L的聚乙烯吡咯烷酮（PVP）或100mg／L抗坏血酸（Vc）,或将外植体在200mg／L抗坏血酸水溶液中浸泡30rain后接入添;gn2g／L活性炭的培养基,均能显著抑制鸭梨褐化的发生。低温试验表明,鸭梨外植体经4℃低温处理6h后接种,或接入初期在4℃低温中培养12～24h,褐化程度明显减轻。     

砂梨果肉褐变与酚类物质及相关酶活性的相关分析

【目的】为了探明砂梨褐变的内在机制,为砂梨贮藏与加工过程中品种选择和褐变控制提供理论依据,【方法】以11个砂梨品种的成熟果实为试材,测定总酚与酚类物质组成及含量、GSH含量、PPO、SOD、CAT、PAL、POD酶活性等相关指标。【结果】结果表明,不同品种酶促褐变程度有很大差别,‘新兴’和‘早生黄金’褐变较重,而‘秋黄’和‘丰水’较轻。绿原酸、儿茶素、芦丁和没食子酸是梨果肉中含量较高的酚类物质。总酚含量与果实褐变度相关性最高,绿原酸次之,儿茶素最低。【结论】梨果肉褐变相关酶活性与酚类物质组分及含量对其酶促褐变的影响程度因品种不同而存在差异。梨果肉酶促褐变与总酚和绿原酸含量的相关度高于与酶类的相关度。     

采后浸钙对雪花梨果肉褐变的影响

雪花梨果实采后常压浸泡６％ＣａＣｌ２１５分钟或减压浸泡４％ＣａＣｌ２２分钟能保持果肉较高水平的酚类物质（酚类物质与果肉钙含量呈显著正相关，ｒ＝０．８６３７），抑制ＦＰＰＯ（游离态多酚氧化酶）活性，维持细胞膜结构的完整性（果肉相对电导率与果肉钙含量呈显著负相关，ｒ＝－０．８７７５）。雪花梨果肉褐变与果肉钙含量及氮钙比有关，含钙量愈低或氮钙比愈高，果肉愈易褐变。重病果与健康果相比，其果肉钙含量低４４．６％，氮钙比高７５．３％。     

阿月浑子外植体褐变抑制方法

外植体褐变是阿月浑子组培的主要障碍之一。对阿月浑子外植体母树年龄、遮光、外植体枝条部位与采集季节、组培条件、添加剂以及多酚氧化酶活性等与外植体褐变的关系进行了研究,结果表明,阿月浑子外植体的褐变率夏季最高、秋季其次、春季最低,枝条中部最低,而枝条上端最高,1年生与7年生树褐变率差异不大,与母树是否遮光关系不明显,在培养基中添加抑制剂PVP能减轻褐变,而添加维生素C、Na2S2O3与活性碳的效果不显著,低光和低温对控制外植体褐变有显著效果,但从低温下转入常温后褐变率高于一直在常温下培养的,阿月浑子褐变率与多酚氧化酶活性关系不显著,可能主要决定于外植体多酚含量,但需要进一步实验数据支持。     

蝴蝶兰外植体褐变发生与总酚含量、PPO、POD和PAL的关系

 蝴蝶兰外植体在褐变发生前期PPO和POD活力皆升高, 褐变发生后酶活力下降。同工酶谱分析发现, 培养0 d的蝴蝶兰外植体PPO没有酶带出现, 而POD有1条弱带。离体培养2 d POD出现3条酶带, 第4天有新酶带Ⅰ发生, 随后消失, 其余3条带, 随培养天数的延长, 酶带活性渐弱。PPO同工酶谱在培养2 d出现3条酶带, 迁移率为0128的酶带Ⅲ在培养4 d活性较强, 随后3条酶带减弱。总酚含量和PAL活力随外植体褐变增强而逐渐增加, 两者呈现极显著正相关。     

蝴蝶兰外植体酚类物质和活性氧代谢与组培褐变的关系

（1Institute of Vegetables and Flowers,Chinese Academy of Agricultural Sciences,Beijing 100081,China;2College of Horticulture and Landscape Architecture,Southwest University,Chongqing 400716,China）     

‘薄壳香’核桃组培中的褐化及防止措施研究

 以‘薄壳香’核桃为试验材料, 对其组织培养过程中褐化的发生及防止措施作了探讨。结果证明: 褐化发生程度与培养温度、培养基中激素浓度和无机盐含量、外植体本身的生理状态等因素有关;较高培养温度、培养基中较高浓度无机盐、较高浓度激素及木质化程度高的外植体都会促进褐化的发生;培养基中加入抗氧化剂会抑制褐化的发生。     

Effects of explant position and dark treatment on bud formation in floret culture of Ponerorchis graminifolia Rchb.f

An efficient method of micropropagation was investigated for Ponerorchis graminifolia. Shoot apexes and florets with inflorescence nodes were used as explants for in vitro cultures. A high efficiency of bud formation was observed on half-strength MS medium containing 4.44 μM N⁶-benzyladenine (BA) and 0.54 μM α-naphthaleneacetic acid (NAA) using florets from upper positions of inflorescences as explants. However, the explants frequently exuded browning compounds into the media during culture. Dark treatment, a countermeasure, decreased exudation of the browning compounds during floret culture. When shoot apexes from dark treated florets were used as an explant material after the floret culture, the dark-pretreated shoot apexes developed 2.2 buds per explant, compared with 1.2 buds per explant from light pretreated shoot apexes, and showed decreased exudation of browning compounds. These results suggest that the most suitable explants for bud formation in P. graminifolia are top florets and shoot apexes derived from the floret culture with dark treatment.     

Shoot tip culture in mango: Influence of medium,genotype, explant factors,season and decontamination treatments on phenolic exudation,explant survival and axenic culture establishment

Summary

Attempts to establish shoot tip culture in mango (Mangifera indica L.) genotypes ‘Alphonso’, ‘Totapuri’, ‘Banganapalli’ and ‘Arka Anmol’ indicated that the problems of phenolic exudation, medium discoloration and explant browning were interrelated and influenced by a number of factors including medium, genotype, explant, season and decontamination treatments. Less phenolic exudation and better explant survival were observed in ½MS medium than full MS and in semi-solid than in liquid medium. Among explant factors, age and shading of shoots, length, thickness and scaling injuries on explant and lower cut petioles coming in contact with medium were important, but not the age of tree and the number of leaves on the shoot. Use of charcoal was beneficial but other adsorbents, antioxidants, dark incubation and submerged culture were not advantageous. The effect of season was prominent with least phenolics, minimum microbial contamination, best explant survival and genotype dependent growth response in current season’s semimature shoots collected during June-August. Deep seated microbial contaminants could not be checked completely. A scheme for establishing in vitro culture is suggested.     

激素配比及无机盐浓度对阿月浑子组培的影响

为提高组培苗的继代系数以及降低褐化率,进而为生根试验作基础,对阿月浑子组织培养试验中激素浓度的配此问题进行研究.运用正交设计、极差分析以及方差分析方法对阿月浑子组培苗诱导率、污染率、褐化率进行分析,试验结果表明:在茎段作为外植体的组培试验启动阶段中,最佳激素配比方案是6-BA 4.0 mg/L+IBA 0.05 mg/L+NAA0.02 mg/L;当培养基采用低无机盐质量浓度的DKW培养基,即1/2DKW时,外植体诱导分化较早,且褐化率低,污染率低,组培苗生长健壮.     

非洲菊组培快繁技术的优化

采用非洲菊幼嫩花托为外植体,比较研究了外源激素6-BA+ IAA、KT+IAA对不定芽诱导、增殖的影响.结果表明:以3.0 mg/L KT+0.3 mg/L IAA为诱导激素时,外植体的褐变数较少,不定芽的诱导率较高;以3.0 mg/L 6-BA+0.1 mg/L IAA为增殖激素时,丛生芽的增殖率较高,而以3.0 mg/L KT+0.1 mg/L IAA为增殖激素时,丛生芽的健壮度最高.     

Mango explant browning: Effect of ontogenic age,mycorrhization and pre-treatments

The in vitro performance of mango shoot culture is delimited by several factors, of which explant necrosis and media browning are considered as major constraints for successful exploitation of such an important commercial crop. Our results showed that source of explants had a significant effect on the performance of in vitro cultures of mango. The variations in survival of explants collected from glasshouse grown seedlings and field-grown stock plants indicated towards differences between their physiological/ontogenic age. Though, chronologically, both are young, the glasshouse grown shoots are ontogenetically younger and; therefore, responded better over field-grown shoots. Improved performance of explants harvested from mycorrhizal plants suggests integration of mycorrhizal biotechnology with tissue culture biotechnology in order to achieve better results as mycorrhiza being a well-known stress alleviator may help explants mitigate in vitro stresses. Furthermore, shoot tip explants of field-grown ‘Amrapali’ mango was assayed for their browning propensity at pre- and post-culture stages. Status of different bio-chemicals such as in vivo phenol, in vitro phenol exudation, phenylalanine ammonia lyase, peroxidase and polyphenol oxidase as affected by various pre-treatments were estimated to establish the relationship of these bio-chemicals with necrosis of mango shoot cultures. The different pre-treatments comprised etiolation of newly emerged shoots (5–7 days old) of stock plants using black polythene for 7 days, etiolation treatment + agitation of explants in antioxidant solution (antioxidants: ascorbic acid at 100 mg l⁻¹ + citric acid at 50 mg l⁻¹), etiolation treatment + agitation of explants in polyvinylpyrrolidone solution (PVP) at 0.2% and non-etiolated control. Of these, explants treated with PVP proved to be superior to other treatments with regards to explant necrosis percentage as such explants exhibited least activities of phenols and oxidative enzymes. Correlation studies indicated existence of high positive correlation between explant necrosis and these bio-chemicals.