豇豆四倍体的诱导及鉴定

用浓度为0.1%~0.3%的秋水仙素处理二倍体豇豆子叶期的茎尖生长点,获得同源四倍体(2n=4x=44),并对其进行形态学、细胞学、农艺学鉴定。结果表明:经0.2%秋水仙素处理4次获得同源四倍体的效果最佳,四倍体诱变率为2.809%;与二倍体相比,四倍体植株叶片、花器官、荚果等均表现巨大性,气孔密度和单个荚果种子数降低;用流式细胞仪进行倍性鉴定,豇豆二倍体DNA相对含量为250,四倍体为500,与根尖染色体鉴定结果一致。     

有机物和激素对四倍体刺槐微体快繁的影响

研究了水解乳蛋白(LH)，蔗糖，BA，NAA和IBA等物质对四倍体刺槐嫩梢增殖倍数、嫩梢长度以及根诱导的影响。结果表明，增殖时的适宜BA浓度为0．5mg／L，NAA浓度为0．05mg／L，蔗糖浓度为30g／L，增加LH有利于提高增殖倍数。根诱导用NAA为好，适宜的浓度为0．5～1．0mg／L。     

无机盐质量浓度及激素配比对四倍体刺槐组织培养苗生根的影响

在四倍体刺槐试管苗的生根培养阶段,诱导愈伤组织形成根原基,主要取决于6-BA和NAA的质量浓度配比。试验结果表明,在生根培养过程中,单加NAA0．3mg／L,可使组织培养苗发根早,根系发达,须根多,最终能形成完整的健壮植株;当培养基采用低无机盐质量浓度的Ms培养基即l／2MS时,试管苗发根早,且根多而粗壮。     

Analysis of three types of triterpenoids in tetraploid white birches (Betula platyphylla Suk.) and selection of plus trees

Betulin, oleanolic acid, and betulinic acid are naturally occurring pentacyclic triterpenoids that have significant medicinal value. Considerable amounts of these triterpenoids are available in the out...     

二倍体和四倍体泥鳅线粒体ND-5/6基因多态性的PCR-RFLP分析

采用PCR-RFLP分析方法,对洞庭湖、武汉两地的二倍体和四倍体泥鳅线粒体DNAND-5/6基因多态性及4个群体遗传变异和遗传关系进行了研究。结果表明,120尾泥鳅mtDNAND-5/6扩增片段长度均为2.2kb;从13种限制性内切核酸酶中筛选出6种多态性内切酶(HaeⅢ、DraⅠ、RsaⅠ、TaqⅠ、HinfⅠ、MspⅠ),对扩增产物进行酶切,共检测到66种单倍型。泥鳅群体内单倍型多样性和核苷酸多样性分别为0.7679～0.9385和0.01041～0.03212;其中,洞庭湖二倍体核苷酸多样性最高(0.03212),武汉二倍体其次(0.02452),二倍体群体内核苷酸多样性高于四倍体。群体间的核苷酸多样性(π)大小为0.02588～0.04144,平均值为(0.031737±0.000005)。群体间的核苷酸歧化距离(δ)大小为0.00462～0.01617,平均值为(0.010659±0.000003);其中,武汉二倍体和四倍体之间的核苷酸歧化距离最大(0.01617),武汉四倍体和洞庭湖二倍体之间的核苷酸歧化距离最小(0.00462)。MonteCarlo模拟x2检验表明,4个群体间的单倍型频率存在极...     

氟乐灵诱导甜瓜四倍体研究初探

氟乐灵是一种新型的具有染色体加倍功效的除草剂。该试验通过氟乐灵溶液处理刚刚发芽的甜瓜种子诱导四倍体,在室温条件下对甜瓜品种黄河蜜三号,以200,400,600倍浓度的氟乐灵溶液处理甜瓜种子4,6,8 h进行四倍体诱导试验,发现氟乐灵处理的根尖有明显的加粗现象。通过镜检,染色体计数法测定诱导率[1],结果表明,浓度为400倍的氟乐灵溶液处理露白的甜瓜种子8 h所获得的加倍效果最好,诱导率达到32.2%。试验结果表明,氟乐灵处理甜瓜种子可以成为获得四倍体甜瓜的有效途径之一,同时对其他作物的多倍体育种研究提供了参考依据。     

四倍体小麦矮秆基因的赤霉素敏感性及对农艺性状的影响

为明确四倍体小麦矮秆基因Rht14、Rht16和Rht18的赤霉素敏感性及其对小麦农艺性状的影响,促进这些矮秆基因的合理利用。选用分别含有Rht14、Rht16和Rht18的四倍体小麦近等基因系ANW16D(Rht14)、ANW16F(Rht16)、ANW16G(Rht18)及其高秆轮回亲本LD222以及六倍体小麦中国春(Chinese spring),测量其不同浓度GA3处理下小麦的株高,计算赤霉素敏感系数(GRI)并推断3种矮秆小麦的赤霉素反应类型。在成熟期对LD222近等基因系小麦的农艺性状如株高、穗长、主穗穗下第一茎节(P-1)节间长、节间表皮细胞、种子表皮细胞及种子体积等进行测量,分析Rht14、Rht16、Rht18这3个矮秆基因对小麦这些农艺性状的效应。结果表明,ANW16D、ANW16F和ANW16G这3个矮秆小麦株高恢复到正常LD222株高的最适GA3浓度为10-4mol/L;3个矮秆品种均为赤霉素敏感型且敏感性大小为中国春ANW16GANW16FANW16DLD222;Rht14、Rht16、Rht18均是通过降低主穗穗下第一茎节(P-1)节间长度来使小麦株高降低,降低效应为Rht18Rht16Rht14;它们降低小麦株高的根本原因均是缩短了小麦节间表皮细胞长度且缩短效应与降低株高效应一致;3个矮秆基因均在降低小麦株高的同时不影响种子的体积。     

Colchicine-induced chromosome doubling in Platanus acerifolia and its effect on plant morphology

We report the production of tetraploid plants of Platanus acerifolia, with the ultimate aim of improving the ornamental qualities of this important urban landscaping tree. Chromosome doubling was achieved by the application of colchicine to either pre-soaked seed or to the apical meristems of young seedlings. Treatment of the ungerminated seed was the more efficient method in terms of numbers of tetraploid seedlings (up to 40%, as determined by chromosome counting of the root-tip nuclei) but this method produced no mature tetraploid plants due to the deleterious effect of colchicine on subsequent root growth. When colchicine was applied directly to the apical growing tip of cotyledon-stage seedlings, leaf and stem growth was temporarily affected but the plants eventually recovered. We conducted a preliminary screen for putative tetraploids based on the observation in other plant species of a correlation of stomatal size and distribution with ploidy. Plants containing significantly larger stomata and at a lower density across the lower leaf epidermis, were selected for further analysis by flow cytometry and chromosome counting. These techniques confirmed that, of the 12 putative polyploids, four were tetraploid, five were mixoploid and three were, in fact, diploid. Morphological differences of the tetraploids included a more compact growth habit and broader, thicker leaves. These plants are being grown to full maturity in order to test their potential for use in a breeding programme aimed at producing sterile triploid lines.     

Simple sequence repeats marker polymorphism in emmer wheat (<Emphasis Type="Italic">Triticum dicoccon</Emphasis> Schrank): Analysis of genetic diversity and differentiation

Genetic diversity was investigated in 73 accessions of emmer wheat (Triticum dicoccon Schrank) from 11 geographical regions using a set of 29 simple-sequence repeat (SSR or microsatellite) markers, representing at least two markers for each chromosome. The SSR primers amplified a total of 357 different alleles with an average of 12.31 alleles per locus. The number of fragments detected by each primer ranged between 6 (Xgwm1066) and 21 (Xgwm268). Null alleles were detected in nine of the 29 primers used. A high level of gene diversity index was observed. Across the 29 primers, gene diversity ranged from 0.60 (Xgwm46) to 0.94 (Xgwm655), with a mean of 0.82. There was a highly significant correlation (r=0.882; p<0.01) between gene diversity index and the number of loci, showing the number of loci per se is a strong indicator of diversity. Analysis of genetic diversity within and among eleven geographical regions revealed most of the genetic diversity of the total sample resided within regions. The coefficient of gene differentiation (Gst = 0.27) showed that the genetic variation within and among the 11 geographical regions was 73 and 27%, respectively. High value of mean number of alleles per locus was found in Iran (4.86) followed by Morocco (4.10) and Armenia (4.03). On the contrary, lower mean number of alleles per locus was detected in Yemen (2.83). The average gene diversity index across regions ranged from 0.52 (Slovakia) to 0.67 (Morocco) with an average of 0.60. Multivariate techniques of principal component analysis and clustering were employed to examine genetic relationship among the 73 emmer wheat accessions vis-à-vis geographical regions of collections. The genetic distance coefficients for all possible 55 pairs of regional comparisons ranged from 0.63 (between Iran and Armenia, Georgia and Azerbaijan, Georgia and Slovakia) to 0.97 (between Morocco and Yemen, Spain and Georgia, and Turkey and Iran) with a mean of 0.82. From the PCA results, a two dimensional plot of PC1 versus PC2 was constructed. The scatter plot of the first two principal components which explained altogether 27% of the total variation depicted the presence of a clear pattern of geographical differentiation except in few cases like accessions from Caucasian region. Similar pattern of genetic relationships among accessions was observed in cluster analysis. The study provided genetic information of emmer wheat in relation to geographical regions of origin. The information could be utilized in crop improvement, germplasm conservation programs, and in further investigation.     

甜樱桃四倍体杂种砧木Y1高频、高效离体再生体系研究

以甜樱桃四倍体矮化砧木Y1试管苗叶片为外植体,探讨了不同基本培养基、激素组合、暗培养时间和叶片发育阶段对其不定芽再生的影响,建立甜樱桃四倍体矮化砧木的高频、高效离体再生体系,为进一步进行遗传转化研究奠定基础。结果表明,甜樱桃四倍体矮化砧木Y1采用WPM培养基再生效果最好,明显优于MS和DKW培养基;最佳激素组合为6-BA2.0 mg.L-1+IBA1.0 mg.L-1;接种后暗培养可以明显提高不定芽再生率,最适宜暗培养时间为14 d;Y1试管苗顶部完全展开的幼嫩叶片再生能力最高。通过以上条件的优化,成功建立了甜樱桃四倍体矮化砧木的高频、高效离体再生体系,离体叶片不定芽再生率达90%,每叶片平均再生不定芽数达4.1。