水稻矮化大粒突变体sdb1的鉴定与基因定位

适度矮化有利于提高水稻的抗倒伏性, 进而影响产量和品质, 是水稻育种中重要的选择性状之一, 因此研究矮秆形成的分子机制具有重要的意义。为鉴定新的矮秆资源, 探讨株高形成的分子调控机制, 我们对籼型恢复系缙恢10号的EMS (甲基磺酸乙酯)诱变体库进行了鉴定, 从中筛选到1个植株半矮化且籽粒变大的突变体sdb1。本文对其进行了形态鉴定、细胞学观察、遗传分析和基因定位等研究。田间种植条件下, 全生育期sdb1的株高都明显矮于野生型, 成熟期仅76.66 cm, 与野生型的117.43 cm相比, 下降了34.72%, 差异达极显著水平, 进一步分析发现sdb1的穗和各节间长均显著变短。在茎秆石蜡切片中发现, 纵向细胞的长度与野生型相比无显著变化, 横向细胞面积极显著变小、数量则极显著增加, 纵向细胞变少是导致sdb1植株半矮化的主要原因。除植株变矮外, sdb1的另一典型特征是籽粒变大, 千粒重由野生型的24.83 g变为突变体的29.00 g, 差异达极显著水平; 颖壳中薄壁细胞数量增加了22.05%, 致使籽粒的长、宽、厚均极显著变大, 从而提高了sdb1的粒重。此外, sdb1叶肉细胞层数增多, 导致其光合色素含量极显著高于野生型, 叶片呈现深绿色。遗传分析发现, sdb1的突变表型受单隐性核基因调控, 利用中花11/sdb1杂交组合的F₂隐性植株, 最终将调控基因定位在第4染色体SSR标记RM16632和Indel标记J50-7之间约406 kb的物理范围内。这为SDB1的克隆和功能研究奠定了基础, 也有助于水稻株高发育分子机制的进一步阐释。     

玉米多叶矮化突变体lyd1的鉴定与基因克隆

玉米株高降低通常是由节间数目减少、节间长度变短或二者共同作用所致。而本研究在基因编辑后代中发现的玉米多叶矮化突变体lyd1却表现为节间数目显著增加,株高显著降低。lyd1株高仅为93.10cm,与野生型KN5585的株高159.95 cm相比,降低了41.79%,差异达到极显著水平。然而lyd1叶片数平均达到27.8片,相较野生型平均17.8片叶,增加56.18%,差异达到极显著水平。遗传分析表明, lyd1的突变表型由1对隐性核基因控制,通过图位克隆将控制多叶矮化性状的基因定位于玉米3号染色体标记Indel10和Indel11之间,物理距离0.74 Mb。对定位区间内13个基因(不包含假基因)的序列进行测序,发现仅ZmTE1在第4外显子出现1个A碱基的替换,其他基因无差异。ZmTE1编码一个RNA结合蛋白,氨基酸的替换发生在第3个RNA结合结构域内(RRM3),导致天冬氨酸转变为缬氨酸。突变体lyd1的突变位点与已报道的te1-mum1、te1-mum2、te1-mum3、zm66不同, lyd1的发现为进一步解析玉米叶片和节间发育平衡的遗传机制提供了宝贵的材料。     

一份玉米显性矮杆突变体的遗传分析

在玉米自交系Mo17的杂交后代中,发现了一份玉米矮杆突变材料,该突变材料表现为节间缩短、植株严重矮化、簇生、花器官发育异常.该突变株与不同核背景玉米自交系(Mo17、B73、B77和W22)杂交衍生的后代群体中,出现了矮杆株与株高正常株两种类型,矮杆株数与株高正常株数的比例为1∶ 1.分离群体中株高正常的植株自交,后代株高均正常.鉴于突变表型是在F1出现,同时结合多年多点田间表型调查的数据,初步推断该矮杆性状是由显性单基因控制.利用SSR分子标记,将该基因定位于玉米第2染色体上,为该基因的克隆工作奠定了基础.     

一种水稻全包穗突变体的发现及初步分析

从恢复系T893群体中得到一全包穗突变体,通过鉴定与分析,探讨水稻全包穗性状的遗传基础与生理机制,发掘水稻新的功能基因;对全包穗突变体的农艺特性、遗传基础、幼穗分化Ⅳ-Ⅷ期茎秆激素含量及对赤霉素敏感性进行了初步分析;突变体具有全包穗特性,并表现茎秆节间缩短,植株矮化,每穗颖花数减少,花粉育性部分降低;遗传分析表明突变体包穗性状受1对隐性基因控制;突变体与T893茎秆内源激素含量比较：突变体幼穗分化Ⅵ期、Ⅷ期时的GA4含量较野生型低,ABA含量高,IAA和Z的含量无显著差异;幼穗分化末期突变体对赤霉素反应钝感;初步研究表明,突变体的产生与水稻茎秆内源激素合成及代谢途径变化有关。     

水稻茎秆壁增厚突变体的表型鉴定与基因定位

水稻的茎秆强度影响植株的抗倒伏能力。本研究通过60Coγ射线辐射籼稻‘9311’,获得了一个茎秆壁增厚的突变体st1,并对突变体进行了表型鉴定和基因定位分析。结果表明,与野生型‘9311’相比,突变体st1重心高显著降低,基部第四、五节间缩短退化,株高显著变矮。突变体基部第二节间和基部第三节间厚度分别为1.63和1.75 mm,显著高于野生型,倒伏指数显著降低。茎秆解剖结构表明,st1的基部第二节间的大维管束数目、节间表皮和基本组织厚度显著高于野生型。主要农艺性状分析表明,突变体结实率降低,粒宽显著增加,千粒重、垩白粒率和垩白度显著增大。遗传分析表明,突变体st1的突变性状受1对隐性基因控制。利用Mutmap测序定位st1基因。结果表明,st1基因位于第2染色体。本研究为水稻茎秆壁增厚基因的克隆和功能分析提供科学依据,也为水稻抗倒伏研究提供了良好的种质资源。     

水稻矮秆鞘包穗突变体茎的形态解剖学研究

以T-DNA标记的水稻矮秆、鞘包穗突变体A846及其野生型为材料,用解剖学方法对比研究茎的外部形态和显微结构。结果表明：突变体A846平均株高38.64cm,大于野生型株高的一半,为半矮秆类型;其矮生性在拔节期显著表现;主茎茎秆各节间收缩比例不一,穗下第一节间显著缩短,与sh-型突变体类似;茎秆各节间居间分生组织细胞分化正常,由居间分生组织分化的细胞延伸受到不同程度的阻碍;各节间基本组织细胞纵向长度相应缩短,穗下第一节间缩短比例最大,其平均值小于野生型的一半;主茎节间数目与旗叶的叶鞘长类似于野生型。     

彩叶草株型矮化的化学控制及其细胞学特征初探

为了探索彩叶草株型矮化的化学控制,以其扦插幼苗为材料,通过对其株高及其细胞学特性研究,发现叶面喷施15%多效唑可湿性粉剂800倍液和5%烯效唑可湿性粉剂7000倍液对彩叶草株型具有显著的矮化作用;叶面喷施50%CCC水剂400倍液,矮化效果不显著。细胞学观察表明,喷施多效唑和烯效唑,其茎秆表皮细胞长径显著变短,短径无显著变化;茎秆表皮毛显著变短,每个表皮毛的细胞数显著减少;茎秆筛管直径显著变小。多效唑和烯效唑对其细胞伸长和分裂有抑制作用,限制了筛管营养物质的运输,抑制了植株其他部位的生长,这些是使彩叶草株型矮化的主要原因。喷施CCC对彩叶草无显著控矮化作用,但有相应的细胞学变化,其原因有待进一步研究。结果表明,烯效唑对彩叶草的催衰老作用较小,细胞学性状也较稳定,植株较光滑,具有良好的观赏价值,是一种较好的彩叶草控矮化剂。     

8984×GY220F2：3家系株型相关性状的初步研究

以利用优良普通玉米自交系8984与高油玉米自交系GY220杂交构建的F2：3家系为材料,在春播环境条件下对8个植株性状进行了初步分析。结果表明：F1各植株性状介于双亲之间或高于双亲;F2：3家系间各性状均存在极显著的差异,并呈连续性正态分布,存在明显的双向超亲分离;株高与穗位高、顶高、穗上叶片数、叶面积、雄穗长,穗位高与顶高、穗上叶片数、叶面积、雄穗分枝数,顶高与顶高/株高、穗上叶片数、叶面积、雄穗长,穗上叶片数与叶面积、雄穗分枝数,叶面积与雄穗长,均呈显著或极显著的表型和遗传正相关;顶高/株高与株高、穗位高、叶面积、雄穗分枝数,穗上叶片数与雄穗长,均呈显著或极显著的表型和遗传负相关。     

水稻矮化宽叶突变体osdwl1的生理特性和基因定位

株高是影响水稻倒伏的重要因素之一,培育适度矮化水稻品种有利于提高其抗倒性,进而减少产量损失并提高稻米品质,因此研究矮秆形成的分子生理机制具有重要意义。通过辐射诱变籼稻恢复系自选1号获得一个稳定遗传的矮化宽叶突变体osdwl1,本文对其形态与生理特征、细胞结构差异、遗传分析和基因定位等方面进行了研究。大田条件下,osdwl1矮化宽叶性状始于分蘖期后,成熟期穗长和各茎节长度均极显著短于对照,最终导致株高矮化,究其原因,是由于突变体茎节细胞变短所致;而叶片石蜡切片及扫描电镜结果显示,osdwl1的叶片小维管束数及其间距显著增加,从而导致叶片变宽,且其上下表皮的小刺毛数也极显著增加。此外,osdwl1的中上部叶片还表现黄化症状,该性状始于3~4叶期幼苗。生理分析和透射电镜观察表明,与野生型对照相比,孕穗期osdwl1的叶绿体类囊体结构松散,且部分已开始降解,从而导致其倒二叶和倒三叶的叶绿素总含量、净光合速率以及Fv/Fm比值均极显著降低,而其可溶性蛋白、过氧化氢酶及超氧化物歧化酶酶活依次极显著降低,从而导致叶中H2O2及O2-累积,促使丙二醛含量急剧增加。遗传分析表明,osdwl1的矮化宽叶表型受单隐性核基因调控,利用图位克隆技术将该基因定位于6号染色体短臂的SSR标记RM19297与InDel标记ID269-2之间,物理距离为333kb,该结果为进一步克隆OsDWL1基因并研究其功能奠定了基础。     

水稻矮秆脆性突变体dbc1的鉴定与基因定位

利用EMS诱变籼型水稻恢复系缙恢10号,获得一个稳定遗传的矮化脆性突变体dbc1,苗期即表现矮化、叶片变脆,一直保持到成熟。与原始亲本相比,突变体的各节间均显著缩短,株高仅58.93 cm,略有包穗,属于dn型矮化变异,对赤霉素的敏感性显著下降,有效穗、千粒重和结实率无明显变化,穗长、穗粒数和实粒数则极显著下降。进一步分析发现,dbc1的茎秆和叶片的载荷强度极显著下降,纤维素含量无变化,木质素含量则略有下降,差异达显著水平。遗传分析表明该性状受1对隐性核基因调控,利用886株西农1A/dbc1的F₂变异单株,最终把DBC1基因定位在第2染色体SSR标记RM13943和RM13952之间,物理距离仅197 kb,含有52个注释基因。这为下一步调控基因的克隆和dbc1材料的育种应用奠定了基础。     

Location of a high-lysine gene and the DDT-resistance gene on barley chromosome 7

Summary The high-lysine gene in Risø mutant 1508 conditions an increased lysine content in the endosperm via a changed protein composition, a decreased seed size, and several other characters of the seed. The designation lys3a, lys3b, and lys3c, is proposed for the allelic high-lysine genes in three Risø mutants, nos 1508, 18, and 19. Linkage studies with translocations locate the lys3 locus in the centromere region of chromosome 7. A linkage study involving the loci lys3 and ddt (resistance to DDT) together with the marker loci fs (fragile stem), s (short rachilla hairs), and r (smooth awn) show that the order of the five loci on chromosome 7 from the long to the short chromosome arm is r, s, fs, lys3, ddt. The distance from locus r to locus ddt is about 100 centimorgans.     

Biological Activity and Quantification of Suspected Allelochemicals from Alfalfa Plant Parts

Autotoxicity restricts reseeding of alfalfa (Medicago sativa L.) after alfalfa until autotoxic chemical(s) breaks down or is dispersed into external environments. A series of aqueous extracts from leaves, stems, roots and seeds of alfalfa ‘Vernal’ were bioassayed against alfalfa seedlings of the same cultivar to determine their autotoxicity. The highest inhibition was found in the extracts from the leaves. Extracts at 40 g dry tissue l^?1 from alfalfa leaves were 15.4, 17.5 and 28.7 times more toxic to alfalfa root growth than were those from roots, stems and seeds, respectively. A high‐performance liquid chromatography (HPLC) analysis with nine standard compounds showed that the concentrations and compositions of allelopathic compounds depended on the plant parts. In leaf extracts that showed the most inhibitory effect on root growth, the highest amounts of allelochemicals were detected. Among nine phenolic compounds assayed for their phytotoxicity on root growth of alfalfa, coumarin, trans‐cinnamic acid and o‐coumaric acid at 10^?3 m were most inhibitory. The type and amount of causative allelochemicals found in alfalfa plant parts were highly correlated with the results of the bioassay, indicating that the autotoxic effects of alfalfa plant parts significantly differed.     

Simultaneous Determination of Four Phenolic Acids in Radix Salviae Miltiorrhizae Formula Granules by QAMS

[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenol...     

Changes in Seed Yield and Quality with Maturity in Onion (Allium cepa L., cv. 'Early Cream Gold')

Development of onion (Allium cepa L., cv. ‘Early Cream Gold’) seed under cool climate conditions in Tasmania, Australia occurred over a longer duration than previously reported, but similar patterns of change in yield components were recorded. In contrast to previous studies, umbel moisture content declined from 85 to 67 % over 57 days while seed moisture content decreased from 85 to 31 %. Seed yield continued to increase over the duration of crop development, with increasing seed weight compensating for seed loss resulting from capsule dehiscence in the later stages of maturation. Germination percentage was high and did not vary significantly from 53 to 77 days after full bloom (DAF), but mean germination time declined and uniformity of germination increased significantly over the same time period. The percentage abnormal seedlings declined with later harvest date, resulting in highest seed quality at 77 DAF. The results of this study suggest that the decision to harvest cool climate onion seed crops before capsule dehiscence will result in a loss of potential seed yield and quality.     

Pollen and pollination experiments. III. The viability of apple and pear pollen as affected by irradiation and storage

Summary Apple and pear pollen was irradiated with doses of 0, 50, 100, 250 and 500 krad (gamma rays) and stored at 4°C and 0–10% r.h. From the in-vitro germination percentages an average LD 50 dose of about 220 krad was estimated. For both irradiated and untreated pollen a close and corresponding lineair relationship existed between germination percentage and pollen tube growth.Irradiated pollen was much more sensitive to dry storage conditions than untreated pollen, resulting in less germination and more bursting. Apparently, irradiation caused the pollen cell membrane to lose its flexibility faster than normal. Rehydration of dry-stored, irradiated pollen in water-saturated air restored germination percentages up to their initial levels. The importance of this procedure in germination trials is stressed.     

Water Extraction Process of Chinese Herbal Compound Man Gan Ning

[Objectives]To optimize the water extraction process of Chinese Herbal Compound Man Gan Ning and establish a method for its extraction and content determination...     

Present status and future strategy in breeding faba beans (Vicia Faba L.) for resistance to biotic and abiotic stresses

Progress is being made, mainly by ICARDA but also elsewhere, in breeding for resistance to Botrytis, AScochyta, Uromyces, and Orobanche; and some lines have resistance to more than one pathogen. The strategy is to extend multiple resistance but also to seek new and durable forms of resistance. Internationally coordinated programs are needed to maintain the momentum of this work.Tolerance of abiotic stresses leads to types suited to dry or cold environments rather than broad adaptability, but in this cross-pollinated species, the more hybrid vigor expressed by a cultivar, the more it is likely to tolerate various stresses.     

Optimization of Extraction Technology and Determination of Content of Total Phenols of Leaves in Acanthopanax giraldii Harms

[Objectives] To determine the optimum extraction technology for total phenols of leaves in Acanthopanax giraldii Harms.[Methods]The single factor test and ortho...     

Cytoplasmic male sterility,resistance to gall mite and mildew,and season of leafing out in black currants

Summary Cytoplasmic male sterility (cms) is described in the F₁ hybrids Ribes × carrierei (R. glutinosum albidum × R. nigrum) and R. sanguineum × R. nigrum. In backcrosses to R. nigrum, progenies with R. glutinosum cytoplasm were either all male sterile, or segregated for full male fertility (F) and complete (S) and partial (I) male sterility. Ratios of F:I+S suggested that two linked genes controlled cms, F plants being dominant for one (Rf ₁) and recessive for the other (Rf ₂).Segregation for cms in relation to three linded genes, Ce (resistance to the gall mite, Cecidophyopsis ribes), Sph ₃(resistance to American gooseberry mildew, Sphaerotheca mors-uvae) and Lf ₁(one of two dominant additive genes controlling early season leafing out) indicated that Rf ₁and Rf ₂were in this linkage group. The gene order and approximate crossover values appeared to be: % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXafv3ySLgzGmvETj2BSbqef0uAJj3BZ9Mz0bYu% H52CGmvzYLMzaerbd9wDYLwzYbItLDharqqr1ngBPrgifHhDYfgasa% acOqpw0xe9v8qqaqFD0xXdHaVhbbf9v8qqaqFr0xc9pk0xbba9q8Wq% Ffea0-yr0RYxir-Jbba9q8aq0-yq-He9q8qqQ8frFve9Fve9Ff0dme% aabaqaciGacaGaamqadaabaeaafaaakeaacaWGdbGaamyzamaamaaa% baGaaiiiaiaacccacaGGWaGaaiOlaiaacgdacaGG0aGaaiiiaiaacc% caaaGaaiiiaiaacccacaGGGaGaamOuaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaaccdacaGGUaGaaiOmaiaacs% dacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaaaacaWGsbGaamOzaSGa% aGOmaOWaaWaaaeaacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccaaaGaamitaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccacaGGGaaaaiaadofacaWGWbGaamiAaSGa% aG4maaaa!6E4D!\[Ce\underline { 0.14 } Rf1\underline { 0.24 } Rf2\underline { } Lf1\underline { } Sph3\]. Crossover values of 0.36 for Ce-Lf ₁, and 0.15 for Lf ₁-Sph ₃were estimated from the relative mean differences in season of leafing out between seedlings dominant and recessive for Ce and Sph ₃.It is suggested that competitive disadvantage of lf ₁-carrying gametes and/or zygotes at low temperatures may be implicated in the almost invariable deficit of plants dominant for the closely linked mildew resistance allele Sph ₃. Poor performance of lf ₁- (and possibly lf ₂-) carrying gametes and young zygotes during periods of low temperature at flowering might also account for the liability of some late season cultivars and selections to premature fruit drop (running off).     

Screening techniques and sources of resistance to parasitic angiosperms

Parasitic angiosperms cause great losses in many important crops under different climatic conditions and soil types. The most widespread and important parasitic angiosperms belong to the genera Orobanche, Striga, and Cuscuta. The most important economical hosts belong to the Poaceae, Asteraceae, Solanaceae, Cucurbitaceae, and Fabaceae. Although some resistant cultivars have been identified in several crops, great gaps exist in our knowledge of the parasites and the genetic basis of the resistance, as well as the availability of in vitro screening techniques. Screening techniques are based on reactions of the host root or foliage. In vitro or greenhouse screening methods based on the reaction of root and/or foliar tissues are usually superior to field screenings and can be used with many species. To utilize them in plant breeding, it is necessary to demonstrate a strong correlation between in vitro and field data. The correlation should be calculated for every environment in which selection is practiced. Using biochemical analysis as a screening technique has had limited success. The reason seems to be the complex host-parasite interactions which lead to germination, rhizotropism, infection, and growth of the parasite. Germination results from chemicals produced by the host. Resistance is only available in a small group of crops. Resistance has been found in cultivated, primitive and wild forms, depending on the specific host-parasite system. An additional problem is the existence of pathotypes in the parasites. Inheritance of host resistance is usually polygenic and its transfer is slow and tedious. Molecular techniques have yet to be used to locate resistance to parasitic angiosperms. While intensifying the search for genes that control resistance to specific parasitic angiosperms, the best strategy to screen for resistance is to improve the already existing in vitro or greenhouse screening techniques.