提高小麦愈伤组织分化频率的因素

研究了影响小麦愈伤组织诱导、芽分化及其植株再生的一些因素。结果表明：在愈伤组织诱导和继代过程中添加ＡＢＡ（１．０ｍｇ／Ｌ）有利于小麦中晚期幼胚致密愈伤组织的诱导及再生能力的保持;外植体来源尤其是基因型对长期培养的愈伤组织再生能力有很大影响;不同的外源激素（ＫＴ、６－ＢＡ、ＩＡＡ、ＴＤＺ和玉米素等）也影响芽分化频率,其中ＴＤＺ可明显提高芽分化频率;在转入分化培养前对愈伤组织进行干燥处理可有效地提高其     

防风愈伤组织诱导及其分化研究

[目的]研究防风愈伤组织形成和分化的适宜条件,为优良品种的培育奠定基础。[方法]以防风幼苗为材料,进行愈伤组织诱导和分化研究。[结果]以茎段为外植体在黑暗下诱导愈伤组织分化最佳;在黑暗条件下继代,最佳培养基为MS+2,4-D 0.6 mg/L+6-BA 0.4 mg/L+KT 0.6 mg/L。光暗交替下MS+1.0 mg/L KT+0.4 mg/L NAA和MS+NAA 0.2 mg/L+6-BA 0.4 mg/L+KT 0.6 mg/L为最佳丛生芽诱导培养基;黑暗下MS+NAA 0.6 mg/L+6-BA0.5 mg/L和MS+NAA 1.0 mg/L+KT 0.6 mg/L为最佳不定根诱导培养基。且MS+NAA 1.0 mg/L+6-BA 0.5 mg/L和MS+NAA 0.6 mg/L+6-BA 0.4 mg/L+KT 0.2 mg/L均有利于防风丛生芽的诱导,NAA 0.2 mg/L+IAA 0.2 mg/L+IBA 0.2 mg/L有利于防风不定根的形成。[结论]成功诱导防风愈伤组织并分化出丛生芽和不定根,为再生体系建立和规模化培养提供技术支撑。     

翅果油树茎段愈伤组织和芽发生的组织的学研究

本文对翅果油树大宫灯型茎段培养在ＭＳ附加６－ＢＡ较高,ＮＡＡ较低浓度的培养基上培养０－３０ｄ的组织学变化进行了研究。创伤对其愈伤组织的形成有明显的刺激作用,培养３－４ｄ切口处的皮层细胞,形成层细胞,韧皮部薄壁细胞以及髓组织细胞,甚至表皮细胞均脱化分化开始分裂;     

提高小麦愈伤组织分化频率的因素

研究了影响小麦愈伤组织诱导、芽分化及其植株再生的一些因素。结果表明：在愈伤组织诱导和继代过程中添加ＡＢＡ（１ ．０ｍｇ／Ｌ） 有利于小麦中晚期幼胚致密愈伤组织的诱导及再生能力的保持;外植体来源尤其是基因型对长期培养的愈伤组织再生能力有很大影响; 不同的外源激素（ ＫＴ、６ＢＡ、ＩＡＡ、ＴＤＺ和玉米素等） 也影响芽分化频率,其中ＴＤＺ可明显提高芽分化频率;在转入分化培养前对愈伤组织进行干燥处理可有效地提高其芽分化频率;在生根培养基中添加适量的ＩＡＡ 或ＮＡＡ 可有效促进生根。     

油桐叶片愈伤组织诱导及植株再生

以油桐无菌苗叶片为试材,研究不同种类及浓度的植物生长调节剂对愈伤组织诱导、分化、增殖及生根的影响。结果表明：叶片愈伤组织的最佳诱导培养基为1／2MS＋2．omg·L-16-BA＋1．0mg·L～2,4-D,诱导率达100％;最佳分化培养基为1／2MS＋3．0mg·L～6-BA＋0．1mg·L-1。IBA＋0．05mg·L—IAA,分化率为86．36％;最佳继代增殖培养基MS＋3．0mg·L～6-BA＋0．05mg·L。IBA;最佳生根培养基为1／2MS＋O．1mg·L-1。IBA,生根率93．83％。炼苗后移栽到泥炭土：珍珠岩：蛭石=2：1：1的基质中,成活率达92％以上。     

小麦愈伤组织及再生植株的染色体变异

对培养在含有不同附加成分的MS培养基上的小麦愈伤组织染色体进行了跟踪研究。结果表明,在整个培养过程中各培养基上愈伤组织都有一定程度的染色体变异。在培养初期,高浓度2,4-D可增加愈伤组织中的染色体变异率,AgNO_3可降低染色体变异率。6-BA对培养初期愈伤组织染色体变异率没有显著影响。但高浓度6-BA可加大长期培养愈伤组织中的超倍体细胞频率。蔗糖浓度对最初9代愈伤组织染色体变异率无显著影响。但之后,低浓度蔗糖培养基上亚倍体细胞频率明显减小。随着培养时间的延长,各培养基上愈伤组织中正常二倍体细胞的频率都有逐渐上升的趋势。在再生植株中,大部分核型正常,只有少数植株具有染色体数目或结构变异。有些核型正常植株也有表型变异。     

小麦叶片愈伤组织及其再生植株的诱导

小麦幼苗基部外植体在补加２,４－Ｄ的ＭＳ、Ｎ６、ＢＡ１（３）培养基上均可诱导出愈伤组织,２,４－Ｄ的最适浓度为２．０ｍｇ／Ｌ;愈伤组织的增殖速度与切段部位及基本培养基有关,其中在以ＭＳ补加２．０ｍｇ／Ｌ２,４－Ｄ的培养基上诱导出的愈伤组织增长速度最快;最后讨论了小麦愈伤组织幼苗诱导率低的原因及可能解决的方法。     

崖白菜的愈伤组织诱导及植株再生

通过愈伤组织诱导不定芽发生途径,建立了崖白菜的组培再生体系,研究了崖白菜幼嫩子房和不同植物生长调节剂对其愈伤组织诱导和不定芽发生的影响。结果表明,以崖白菜的幼嫩子房作为外植体,诱导子房分化形成愈伤组织的最适培养基为MS＋6．BA1．0mg·L-1＋2,4-D0．2mg·L-1,诱导率可达82．83％;最适的不定芽分化培养基为Ms＋6-BA0．5mg·L-1＋NAA0．1mg·L-1;诱导不定芽生根的最适培养基为1／2MS＋NAA0．1mg·L-1。     

PFCA uptake and translocation in dominant wheat species (Triticum aestivum L.)

The comparative uptake of four perfluorinated carboxylic acids (PFCAs) by wheat (Triticum aestivum L.) grown in nutrient solution was investigated. Wheat is the main food crop in northern China and may become a potential pathway of human exposure to these PFCAs. The uptake of four PFCAs from water at a fixed concentration (1 μg/mL) increased over time, approaching a steady state, and except for the short-chain perfluorobutanoic acid, most of the total mass of each of the PFCAs taken up by wheat was found to be at the root. The root concentration factor (RCF) and shoot/root concentration factor (SRCF) were calculated, and with the increase in carbon chain length, the RCFs increased but SRCFs decreased, which indicated that long-chain PFCAs had stronger root uptake and weaker translocation capacities than short-chain PFCAs. In addition, pH could obviously impact the uptake of four PFCAs in the roots and shoots of wheat, and the highest concentrations were found at pH = 7 when the pH increased from 4 to 10.     

Gravitropic response growth angle and vertical distribution of roots of wheat (Triticum aestivum L.)

Recent work on root distribution, growth angles and gravitropic responses in Japanese cultivars of winter wheat are reviewed. Vertical distribution of roots, which influences the environmental stress tolerance of plants, was observed in the 12 Japanese cultivars in the field. The root depth index (RDI: the depth at which 50% of the root length has been reached) differed among the cultivars at the stem elongation stage. Since the RDI was closely related to the growth angle of seminal roots obtained in a pot experiment, it was assumed that growth angle is useful for predicting vertical root distribution among wheat genotypes. Gravitropic responses of the primary seminal root of 133 Japanese wheat cultivars assessed by measuring the growth angle in agar medium, were larger in the northern Japanese cultivars and smaller in the southern ones. It was also found that the geographical variation resulted from the wheat breeding process, i.e. genotypes with limited gravitropic responses of roots had been selected in the southern part of Japan where excessive soil moisture is one of the most serious problems.     

A new,endosperm-supported callus induction method for wheat (Triticum aestivum L.)

A new, endosperm-supported callus induetion method was developed using mesocotyls of mature wheat embryos. After seed germination under aseptic condition, most of the germ tissues were cut off and only a few mm of the mesocotyl tissue with the scutellum was used for callus induction. The seeds were placed furrow downwards in 2,4-D solution (6–8 mg l^-1). Proliferating callus tissues were already observed on the cut surface of the mesocotyls on the 2nd day after inoculation. On the MS nutrient medium, callus formation from the isolated scutella with attached mesocotyls was negligible even after 6 days. For shoot and root regeneration, the calli produced up to 10 days were removed from the seeds and transferred onto a hormone-free MS medium. As shown by histological methods, the plantlets regenerated via organogenesis.     

Silicon absorption by wheat (Triticum aestivum L.)

Although silicon (Si) is a quantitatively major inorganic constituent of higher plants the element is not considered generally essential for them. Therefore it is not included in the formulation of any of the solution cultures widely used in plant physiological research. One consequence of this state of affairs is that the absorption and transport of Si have not been investigated nearly as much as those of the elements accorded 'essential' status. In this paper we report experiments showing that Si is rapidly absorbed by wheat (Triticum aestivum L.) plants from solution cultures initially containing Si at 0.5 mM, a concentration realistic in terms of the concentrations of the element in soil solutions. Nearly mature plants (headed out) 'preloaded' with Si absorbed it at virtually the same rate as did plants grown previously in solutions to which Si had not been added. The rate of Si absorption increased by more than an order of magnitude between the 2-leaf and the 7-8 leaf stage, with little change thereafter. This revised version was published online in June 2006 with corrections to the Cover Date.     

Plant regeneration from coleoptile tissue of wheat (Triticum aestivum L.)

Plant regeneration was achieved from coleoptile tissue of wheat (Triticum aestivum L. cv. Kharachia-65). Coleoptiles (1.0 - 3.5 cm long) were excised from 2- to 5-d-old seedlings and cultured on Murashige and Skoog's (MS) medium supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D - 0.5, 2.5, and 5.0 mg dm^-3). Cream, friable callus was obtained after 6 weeks of inoculation. This callus was sub-cultured on MS medium supplemented with 2,4-D (2.5 mg dm^-3) and 5 % coconut water. After 6 weeks of sub-culturing white, cream or pale, friable, nodular callus was obtained. Plant regeneration occurred when this callus was sub-cultured on MS medium supplemented with 0.2 mg dm^-3 1-naphthalene acetic acid + 1.0 mg dm^-3 6-benzylaminopurine. For rooting, regenerated shoots or plantlets were transferred on MS medium supplemented with 0.5 mg dm^-3 indole-3-acetic acid. Rooted plantlets were directly transferred into pots and grown under field conditions. Seed setting invariably occurred in all plants. This revised version was published online in July 2006 with corrections to the Cover Date.     

The interaction of genotype and culture medium on the tissue culture responses of wheat (Triticum aestivum L. em. thell) callus

The effect of the interaction of genotype and culture medium on the initiation of callus from immature embryos and subsequent plant regeneration was investigated in eight hexaploid wheat lines. Intervarietal differences in culture response and interaction of the genotype with coconut milk are reported. The relative contributions of media and genotype effects to culture performance are assessed. The observation that primordia and shoot development was promoted by coconut milk in some lines and inhibited in others is particularly significant given that coconut milk is widely used to try to improve culture response. This report shows that this effect is dependent on the genotype of the tissues in culture.     

冬小麦生育中后期次生根特殊根毛的发生与形态结构

大田试验条件下,研究了冬小麦次生根特殊根毛的发生规律和形态结构特征.结果表明,拔节后次生根近植株基部根体上特殊根毛普遍发生,其在次生根根体上的分布可区分为集中区、适中区和稀少区.特殊根毛集中区根毛的长度、直径、密度分别均大于适中区和稀少区,其中,长度和密度的差异达极显著水平(P<0.01).随着生育期推进, 特殊根毛长度、直径和密度均呈下降趋势.大多数特殊根毛呈现出不同程度的扭曲、变形, 根毛细胞突起和分枝现象较为普遍,特殊根毛细胞次生壁出现加厚现象.     

Genetic control of in vitro response in wheat (Triticum aestivum L.)

Summary The present state of genetic control of in vitro responses of wheat and of the prospeets of its improvement and practical use are presented. The genetic factors affecting different stages of callus induction and of organogenesis in immature embryos are discussed. The dominant genotypie role in the in vitro processes and the cytoplasmic influence on the latter are shown. Genotype × environment and nucleus × cytoplasm interactions were observed. Some unsolved problems needing further investigations of cereals at the tissue culture level are pointed out.     

Zinc deficiency and the formation of white structures in immature embryo cultures of wheat (Triticum aestivum L.)

The effect of microelements on the induction of embryogenic callus from epiblast and scutellum of wheat (Triticum aestivum L.) embryos was studied by the sequential omission of each of the microelements from Murashige & Skoog medium. Omission of iron caused a marked decrease in yield and poor shoot formation from embryogenic callus. The yield of embryogenic callus on medium without added manganese was also reduced. Omission of boron, copper-cobalt, iodine, and molybdenum had little effect on the induction of embryogenic epiblast callus. By contrast there was a marked increase in the formation of white structures on the medium without any microelements or, specifically without addition of zinc. Since the formation of typical embryoids of wheat is associated with the formation of white structures, our result highlights the importance of certain microelements on somatic embryogenesis of wheat.Abbreviations 2,4-D 2,4-dichlorophenoxyacetic acid - MS medium Murashige & Skoog medium