提高同源四倍体粳稻花培效率的不同因素分析（英文）

通常水稻花药培养以二倍体作为材料,因此研究四倍体水稻的花培效率很有研究及应用的意义。本实验以四倍体原种零轮、02428及其二倍体做 为材料,共设计3组22种培养基配方,分别研究碳源浓度、琼脂浓度、基本培养基类型和激素对诱导率的影响。结果显示6％的蔗糖和0.75％的琼 脂浓度的组合对于四倍体水稻的诱导效率最佳;以蔗糖为碳源的N6和NB培养基更适合四倍体水稻花药培养;激素浓度为0.5 mg/L的情况下,四倍 体材料的诱导效果是二倍体材料的2倍,激动素对于零轮的效果较好,而6－苄基腺嘌呤对于02428的效果较好。总体来说在相同的培养基条件下, 二倍体和四倍体的诱导率存在明显的差异,但是同一培养基条件下不同品种之间的诱导率没有统一模式,说明基因型是花药培养中的一个关键影 响因素。 因此对于特定材料花培诱导率的提高需要考虑多种因素的影响。     

Endosperm Development in Autotetraploid Rice

By using the laser scanning confocal microscope and plastic （Leica 7022 historesin embedding kit） semi-thin sectioning technique, comparative studies on the development of endosperm were carried out between autotetraploid and diploid rices. About one third of the ovaries in the autotetraploid showed normal endosperm development as those in the diploid. In these ovaries, one of the polar nuclei would fuse with the sperm nucleus, and the primary endosperm nucleus formed and underwent the first division in 4 hours after pollination; the anticlinal wall began to grow centripetally between the free nuclei starting from the wall ingrowths of the embryo sac near the micropylar end, and some of the phragmoplasts formed transformed into periclinal walls. In addition, some of the cell wall situated in the middle of the endosperm appeared to originate from phragmoplasts, whereas others seemed to develop randomly without the obvious formation of phragmoplasts. Cellulose began to accumulate in the wall of aleurone cell layer at 6 days after pollination. The cellulose wall of the cells of the aleurone cell layer appeared to have completely formed within 7 to 8 days after pollination. On the other hand, about two thirds of the ovaries in the autotetraploid showed abnormality in endosperm development with various types, such as non-fertilization, abnormal fertilization, endosperm development-delay and non-synchronization in the development of cellulose wall of cells of the aleurone layer. These abnormalities usually resulted in decreased seed setting in autotetraploid rice.     

镉胁迫下二倍体和同源四倍体油菜DNA甲基化差异分析

二倍体与四倍体在逆境抗性上的差别可以从表观遗传学的角度予以解释。本研究以“矮脚黄”纯合二倍体和同源四倍体油菜为材料,采用DNA甲基化敏感扩增多态性分析（Methylation-sensitive amplification polymorphism,MSAP）方法和HDA-GT12TM全自动凝胶毛细管核酸电泳检测技术,在全基因组水平上研究了CdCl2胁迫下油菜二倍体和四倍体DNA序列中CCGG位点的甲基化水平及模式变化特征差异。采用56对引物在4个处理样品中共检测出9 687个基因位点。结果显示,二倍体和四倍体在镉胁迫下,其总甲基化水平、全甲基化水平和半甲基化水平较各自的对照均有一定程度的上升。由此可见,镉胁迫导致四倍体和二倍体甲基化水平的提高,但四倍体基因组在镉胁迫下拥有更高的DNA甲基化水平。DNA甲基化模式分析表明,镉胁迫导致二倍体和四倍体的过甲基化位点数均高于去甲基化位点数,二者在镉胁迫下去甲基化位点数差异不大,但四倍体发生过甲基化的位点数要明显多于二倍体。     

An improved breeding strategy for autotetraploid alfalfa (Medicago sativa L.)

Alfalfa cultivar development will be enhanced by breeding strategies whichutilize the full potential of autotetraploid population genetic structures. Thisstudy evaluates the effectiveness of an allelic selection scheme, which wasdeveloped to overcome limitations of inbreeding depression and to exploitgeneral and specific combining ability effects in autotetraploid populations.Allelic selection entails the minimization of non-additive genetic effects byselecting among full-sib families (F1) which are at uniform levels ofheterozygosity. Such F1 lines are developed by crossing individuals fromtwo unrelated random mating populations. Selected F1 lines wereintercrossed to form an improved population. Eight random matingpopulations of alfalfa were developed to study the effectiveness of allelicselection. Selection for increased dry matter yield resulted in alfalfapopulations with 38 percent greater yield than the parent populations. Twocycles of intercrossing, among selected F1 lines, did not dissipate the gainfrom selection. This result has important implications for synthetic cultivardevelopment in which a major limitation is the decline in productivity withadvancing generations of seed increase. A positively correlated response toselection for dry matter yield was observed for plant height and stemdiameter. The results of this research indicate that continued testing of theallelic selection scheme is warranted and could have a significant impact onthe breeding of autotetraploid alfalfa, particularly for synthetic cultivardevelopment.     

Enhanced productivity of tropane alkaloids and fertility in artificial autotetraploids of Hyoscyamus niger L.

Summary Genetically stable artificial autotetraploids with over 90% seed set were obtained by colchicine treatment of the solanaceous species Hyoscyamus niger L. (2n=4x=68). The tetraploids were vigorous and yielded 22.5% more tropane alkaloid per individual than the source diploids.CIMAP Publication No. 35/90     

秋水仙素诱导兰考泡桐同源四倍体

在含不同浓度秋水仙素的MS+0.1mg/L NAA+15mg/L BA(最适器官发生)双层培养基上进行兰考泡桐四倍体植株诱导试验,并通过变异植株根尖细胞染色体观察和叶片单细胞DNA含量测定进行倍性分析。结果表明,预培养12d的兰考泡桐叶片在秋水仙素浓度为10mg/L的双层培养基上预培养处理24h时,四倍体诱导率最高达到23.4%。变异植株叶片比二倍体大,叶片长宽比变小,叶片单个气孔变大,气孔密度变小。     

二倍体和同源四倍体‘辣椒枣’减数分裂的比较

 观察了‘辣椒枣’（Ziziphus jujuba Mill.‘Lajiaozao’）二倍体和四倍体花粉母细胞的减数分裂过程,并将其减数分裂的各个时期加以系统分析。结果表明,与二倍体相比,同源四倍体终变期染色体构型复杂,有单价体、二价体、三价体和四价体出现,并且此时期出现双核仁,且核仁一大一小;中期Ⅰ和中期Ⅱ有部分染色体游离于赤道板外;后期Ⅰ和后期Ⅱ出现落后染色体及染色体桥现象;四分体时期还出现了二分体、含微核的异常三分体和含微核的异常四分体;减数分裂行为异常是同源四倍体‘辣椒枣’育性降低的细胞学原因。     

离子注入后同源四倍体水稻双胚苗突变性状的表达特点

氮离子注入后在同源四倍体水稻的后代群体内筛选到1株具有双胚苗特征的突变单株.在多个世代的筛选、纯化和鉴定过程中对其多胚苗性状的表现特点进行了观察鉴定.玉米诱发的同源四倍体双胚苗材料在其性状表达特征、性状表达频率和性状表达的条件等方面均显现出一定的特异性.在试验材料的群体内双胚苗发生频率因材料种类不同或发芽温度条件不同而表现出一定的差异性.种子经过去颖壳处理后可以使其双胚苗频率提高32.4%～36.0%.在同源四倍体双胚苗材料中,其苗位特征表现出明显的多样性.     

同源四倍体水稻胚囊内反足细胞团的多态性

利用激光扫描共聚焦显微技术对6份同源四倍体水稻在生殖发育过程中胚囊内反足细胞或反足细胞团的多态性进行了研究。结果表明，在同源四倍体水稻的雌配子体发育过程中已经存在着一些不正常的发育现象。在同源四倍体水稻的胚囊内反足细胞或反足细胞团的多态性比在二倍体水稻的胚囊内表现得更明显。反足细胞或反足细胞团的多态性主要表现为胚囊内形态的多样性和位置的多样性，这是其有性生殖能力变弱和雌配子体不正常的部分形态学特征。     

Biological Effects of Low Energy N＋ Beams Implantation on Calluses of Autotetraploid Rice

Calluses of two autotetraploid rice （DPR （4） and Zijing （4）） were implanted with 30 KeV N＋beams at doses ranging from 1.0×1015 to 9.0×1015 ions cm-2. The differentiation rates of calluses, the concentration of malondialdehyde （MDA）, the activities of superoxide dismutase （SOD）, catalase （CAT） and peroxidase （POD）, and the change of esterase （EST） spectrum were measured and analyzed on the calluses stage. The results showed that differentiation rates of calluses under 3.0×1015 ions cm-2 （（46.12±2.01）%） were higher than the other treatment groups in DPR （4）, and those of Zijing （4） were similar under the doses of 1.0×1015, 3.0×1015 and 5.0×1015 ions cm-2 （（40.55±2.74）, （37.77±3.04） and （34.56±2.65）%） and were higher than that of 7.0×1015 and 9.0×1015 ions cm-2. When the doses were 3.0×1015 and 5.0×1015 ions cm-2, the activities of SOD, POD and CAT were notably enhanced, and the accumulation of MDA content was markedly alleviated in the implanted calluses of two materials, as well as the activity of EST was increased by the additional isforms DPR （4）. Whereas the anti-oxidative systems and enzymes spectrum of EST were destroyed seriously, the accumulation of MDA was signiifcantly aggravated, also the differentiation rate of calluses reduced sharply and almost closed to zero when the implantation doses were 7.0×1015 and 9.0×1015 ions cm-2. It suggested that the proper dose of ion implantation effectively maintained the normal membrane structure and metabolism, and it would be also a feasible approach for autotetraploid rice to improve its genetic characteristics at calluses stage. Additionally, the differences of the radiation resistance between DPR （4） and Zijing （4） could be related to the different genotypes.