甘蓝类植物小孢子培养及植株再生研究

对3个甘蓝类植物(甘蓝、青花菜、羽衣甘蓝)19个品种小孢子胚胎发生和植株再生的影响因素进行了研究,结果表明,基因型不仅影响供试材料的小孢子胚状体发生频率,也影响胚状体的质量;4℃低温预处理0 ～2d结合32.5℃热激1d,能显著提高供试基因型小孢子出胚率.胚状体先在NLN-13液体培养基中培养25d,有利于胚状体分化成苗;后在B5固体分化培养基中添加1％ ～1.2％琼脂,可有效促进胚状体萌发和植株再生.小孢子再生植株先使用流式细胞仪在生长初期鉴定倍性,后对单倍体植株采用200mg·L-1秋水仙碱浸根处理20h,并用流式细胞仪鉴定,此方法可快速、有效地获得双单倍体植株.     

利用氟乐灵进行同源四倍体萝卜种质创制研究

本研究应用除草剂氟乐灵处理两叶一心幼苗生长点,进行同源四倍体萝卜种质诱导,对变异植株进行形态、细胞学鉴定和花粉母细胞染色体数目鉴定.结果表明,应用0.2 mmol/L和1.0 mmol/L氟乐灵处理,6个萝卜品种都获得同源四倍体植株,10 mmol/L处理仅在Nau-zhqh得到同源四倍体;其中0.2 mmol/L处理Nau-dy和1.0 mmol/L处理Nau-xbch获得四倍体最高诱导率（40%）;四倍体种质与二倍体种质相比,形态性状、气孔大小、保卫细胞内叶绿体数目、花器官大小、花粉粒大小及花粉萌发率都存在显著差异,将形态、气孔鉴定和染色体计数结合可以准确确定变异株的倍性.研究表明利用氟乐灵诱导是进行萝卜同源四倍体种质创新的有效途径之一.     

Ploidy polymorphism and morphological variation among reciprocal hybrids by Megalobrama amblycephala × Tinca tinca

Highly ploidy polymorphism was detected in embryos of inter-subfamily hybridization by a cross of Megalobrama amblycephala ♀ × Tinca tinca ♂. It produced an average of 23% haploids, 46.4% aneuploids, 24.6% 2n hybrid, 2.8% 3n hybrid, 3.2% hypo-4n, which are all inviable, and also a small number of viable 2n gynogens. However, different results were found in the reciprocal hybridization by T. tinca ♀ × M. amblycephala ♂. An average of 89.1% embryos were 2n hybrids with 48 chromosomes and 6% and 2.8% of embryos were aneuploids and allo-triploids, respectively. Additionally, a proper ratio of spontaneously complete tetraploidy embryos (about 2%) was able to be induced in the reciprocal hybridization. 50% of reciprocal hybrid embryos developed normally and 30% of the normal fry survived. Ploidy polymorphism (2n, 3n, 4n or 4n mosaics) and morphological variation were identified in 120-day survival of juveniles in the reciprocal hybridization.     

Biochemical and molecular differences in diploid and triploid ocean-type chinook salmon (<Emphasis Type="Italic">Oncorhynchus tshawytscha</Emphasis>) smolts

There is increasing evidence for complex dosage effects on gene expression, enzyme activity and phenotype resulting from induced ploidy change. In this study, ocean-type chinook salmon were bred using a 2 × 2 factorial mating design to create four families and test whether triploidization resulted in changes in growth performance and smolting. Eggs were pressure shocked after fertilization to create triploid fish from a subset of each family. In June, fish were sampled for size, plasma insulin-like growth factor 1 (IGF-1), gill Na⁺–K⁺-ATPase activity, and expression of two Na⁺–K⁺-ATPase α subunits in the gill. Diploids were significantly heavier than triploids, and there were significant differences due to family. Despite a significant positive correlation between plasma IGF-1 and fish size, plasma IGF-1 did not differ between diploid and triploid smolts. Diploids also had significantly greater gill Na⁺–K⁺-ATPase enzyme activities than triploids and there was a strong family effect. Gill Na⁺–K⁺-ATPase α1b isoform expression differed significantly by family, but not ploidy, and generally families with lower Na⁺–K⁺-ATPase enzyme activity had higher α1b isoform gene expression. Na⁺–K⁺-ATPase α1a isoform expression did not differ among any of the groups. Although diploids were larger and had higher specific activities of Na⁺–K⁺-ATPase in the gills, there was no difference in gene expression or circulating hormone levels. The strong family effect, however, suggests that strain selection may be useful in improving performance of triploids for aquaculture.     

45S rDNA在不同倍性沙田柚染色体上的荧光原位杂交分析

 应用荧光原位杂交技术进行45S rDNA在不同倍性沙田柚中期染色体上的定位研究。结果表明: 不同材料的NOR位点表现出明显的多态性和杂合性, 即二倍体具4个45S rDNA位点, 四倍体单株t₁和t₂ 则分别具有10个和8个位点。位点在染色体上的位置包括短臂末端、着丝粒区域、着丝粒至短臂区域、着丝粒至长臂区域、长臂末端共5种不同类型。不同材料中包含的位置类型不完全相同。不同位置类型的位点数也不相同, 以着丝粒及着丝粒至短臂区域的类型位点数最多, 其次是短臂末端。同源四倍体和相应的二倍体相比, 出现了DNA水平的变异。对用于荧光原位杂交的柑橘染色体制片方法和rDNA在染色体上的分布位置、同源四倍体和相应二倍体的遗传差异分析、重复序列的染色体原位杂交用于染色体识别和物种演化研究等进行了讨论。     

蝴蝶兰若干品种(系)的染色体数和形态分析

 采用酶解去壁法，对蝴蝶兰属（Phalaenopsis ）38个品种（系）进行了染色体观察计数和形态分析。结果表明，供试蝴蝶兰的5个品种中有3个四倍体（2n=4x=76），2个三倍体（2n=3x=57）；20个外引品系中有14个四倍体，1个三倍体和5个非整倍体；13个自育品系包括10个四倍体和3个非整倍体。均未见二倍体。不同品种（系）的染色体长度和形态相差较大，存在核型多样性；有21个品种（系）的染色体组全部由小染色体（长度2.5 μm左右）组成，17个品种或品系除了含小染色体外还含有大染色体（长度为5～9.5 μm），染色体大小组成与花色有一定相关性。本文对不同蝴蝶兰品种（系）的染色体倍性、染色体形态及其育性特点进行了分析讨论。     

澳洲指橘与粗柠檬体细胞杂种倍性FCM分析及其花粉活力检测

利用流式细胞仪对5株澳洲指橘(Microcitrus papuana Swingle,2n=2x=18)与粗柠檬(Citrus jambhiri Osbeck,2n=2x=18)属间体细胞杂种进行倍性分析,以已知倍性的二倍体粗柠檬植株的峰对应荧光值(FL)50作为对照,5棵再生植株的FL值分别为51、51、47、52、48,表明这些体细胞杂种植株均为二倍体。同时,实验结果还表明,HR(HighResolution)试剂盒中的核提取液HR-A和染色液HR-B的最佳处理时间分别是5min和2min。体细胞杂种于2002年3月首次开花,对其花粉活力进行分析,结果表明体细胞杂种的花粉活力为50％～90％。     

Ploidy screening of anthurium (Anthurium andreanum Linden ex André) regenerants derived from anther culture

Anther culture was successfully developed in Anthurium andreanum Linden ex André cv. ‘Tropical’, but resulted in variation in morphology and growth response of regenerants. Ploidy levels varied in different morphological variants. Finding a convenient, rapid, reliable, practical and indirect method to screen and determine anthurium ploidy level is important not only for anthurium, but for ornamentals in general. Regenerants derived from anther culture showing three different ploidy levels (haploids, diploids, triploids) were used in this study. Five indirect methods were used to assess chromosome number: chloroplast number in stomatal guard cells (M1), stomatal length and width ratio (M2), stomatal density (M3), ratio of length and width of leaves (M4), and microspore number per anther (M5). These were compared to chromosome counting as the direct and control method (M6). Through simple regression correlation analysis, when compared to M6, M1 was the most convenient and reliable indirect method to determine the ploidy level. This method was highly and significantly positively correlated to anthurium ploidy level (r = 0.945; p < 0.01). This method could also be applied much faster than the conventional chromosome method.     

甘蓝型油菜DH植株创建及其倍性的流式鉴定

以甘蓝型油菜大粒品系和小粒品系的小孢子为试验材料,研究取样时期、花蕾大小、培养基类型及添加成分对小孢子产胚率的影响,利用流式细胞仪对小孢子再生植株及加倍植株进行了准确、快速的倍性分析。结果表明,始花期为最佳取蕾时期,花蕾大小在2.5~3.5mm为宜,培养基以液体培养基最好。培养基中加入0.1mg/L6-BA可以促进小孢子胚的发生,而活性炭对小孢子培养没有明显的促进作用。流式细胞仪倍性检测显示小孢子再生植株加倍后的双单倍体(doubled haploid,DH)占49%,还存在少量的三倍体(11.3%)、四倍体(1.1%)及嵌合体(27.3%)植株。本研究为油菜材料的快速纯合及其DH系群体的构建等提供了新的经验。     

干旱胁迫对不同倍性小麦和八倍体小黑麦苗期光合能力与抗氧化系统的影响

为了解小麦进化过程中不同基因组及染色体倍数对小麦抗旱能力的影响,以二倍体、四倍体、六倍体小麦和八倍体小黑麦为材料,研究了聚乙二醇(PEG-6000)胁迫1d和3d后不同倍性小麦和小黑麦叶绿素荧光、气体交换参数、活性氧含量以及抗氧化酶活性的变化。结果表明,干旱胁迫3d后不同倍性小麦和八倍体小黑麦的相对水含量和叶绿素含量显著减少,气孔导度、蒸腾速率、光系统II最大光化学效率(Fv/Fm)以及光系统II实际量子产量(ΦPSII)降低,而非光化学淬灭(NPQ)、活性氧和丙二醛(MDA)含量显著上升,其中二倍体小麦变化最明显。干旱胁迫下,超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)活性呈现不同变化,SOD和POD活性先增后降,CAT活性降低,而APX活性增加,其中六倍体小麦抗氧化酶活性增加最显著。