粗秆高产小麦茎结构特性分析

以高产小麦（Ｔｒｉｔｉｃｕｍ ａｅｓｔｉｖｕｍ Ｌ．）新品种“兰考９０６－４”与北京大面积种植的小麦品种“京４１１”为实验材料,运用植物解剖学、化学和力学的理论与方法,对粗秆的高产小麦茎结构特性做了详细的比较研究。结果表明：粗秆的高产小麦品种茎秆在物理力学特性、维管束结构特征以及木质素含量等方面,均明显优于一般小麦品种。因此,在超高产小麦品种的育种中,重视外源基因的引进,改进茎秆的结构特性及提高木     

高产小麦品种茎秆的解剖和化学特性

小麦(Triticum aestivum L.)新品种"小偃81",是由抗病虫害小麦品种"小偃54"和高产小麦品种"8602"杂交筛选出的具有优良特性的后代.作者运用多种实验手段,研究了新品种茎秆组织结构以及木质素含量和分布的变化规律.结果表明:与母本"小偃54"和父本"8602"相比,"小偃81"的茎秆直径变小、横切面上维管束数目减少,而茎秆直径与壁厚比、横切面上机械组织比例却显著增大,单位面积上维管束数目增多.Klason法测定木质素结果显示:"小偃81"茎秆中木质素含量高于"小偃54"和"8602".经Maule和Wiesner的木质素显色反应,"小偃81"茎秆横切面染色明显加深.用H2O2/Hac弃除酚酸以后,新品种小麦的木质素自发荧光明显强于亲本.FTIR分析结果表明:"小偃8l"中所含的紫丁香基、愈创木酚基等木质素特征基团的吸收峰值也显著高于亲本.由此推断,新品种"小偃8l"的茎秆具有优良的组织结构和化学组成.     

高产小麦品种茎秆的解剖和化学特性

小麦(TriticumaestivumL.)新品种“小偃81”,是由抗病虫害小麦品种“小偃54”和高产小麦品种“8602”杂交筛选出的具有优良特性的后代。作者运用多种实验手段,研究了新品种茎秆组织结构以及木质素含量和分布的变化规律。结果表明:与母本“小偃54”和父本“8602”相比,“小偃81”的茎秆直径变小、横切面上维管束数目减少,而茎秆直径与壁厚比、横切面上机械组织比例却显著增大,单位面积上维管束数目增多。Klason法测定木质素结果显示:“小偃81”茎秆中木质素含量高于“小偃54”和“8602”。经Ma黮e和Wiesner的木质素显色反应,“小偃81”茎秆横切面染色明显加深。用H2O2/HAc弃除酚酸以后,新品种小麦的木质素自发荧光明显强于亲本。FTIR分析结果表明:“小偃81”中所含的紫丁香基、愈创木酚基等木质素特征基团的吸收峰值也显著高于亲本。由此推断,新品种“小偃81”的茎秆具有优良的组织结构和化学组成。     

不同小麦品种茎秆特性及其与抗倒性的关系

以黄淮麦区优良品种矮抗58、周麦18、豫麦49、百农418为研究对象,采用田间试验与实验室分析相结合的方法,对不同小麦品种在不同生育时期的抗倒伏性状进行研究.结果表明: 茎秆机械强度在开花期至花后20 d处于较高水平,在花后30 d明显下降;倒伏指数在开花期最小,花后30 d最大,其余两个时期处于中间水平.相关分析表明,开花期机械强度与重心高度呈显著负相关,与纤维素、木质素含量呈显著正相关,倒伏指数与节长、株高、重心高度呈显著正相关,与纤维素、木质素含量呈显著负相关;花后10 d和花后20 d机械强度与节长、株高、重心高度呈显著负相关,与茎粗、纤维素、半纤维素、木质素含量呈显著正相关,倒伏指数这段时期正好与之相反;花后30 d机械强度与株高、重心高度呈显著负相关,倒伏指数与株高、重心高度呈显著正相关,与木质素含量呈显著负相关.因此,明确各个生育时期与抗倒性相关的茎秆特性,可为黄淮麦区高产抗倒性品种的选育提供依据.     

小麦抗倒性研究进展

倒伏是严重影响小麦子粒产量和品质的一个重要因素。本文系统阐述了小麦茎秆形态和结构特性、茎秆化学成分与抗倒伏关系以及抗倒性的遗传和分子标记等方面的最新研究进展。株高、基部节间长度与抗倒性呈负相关;而基部节间粗度、秆壁厚、单位长度干重与抗倒性呈正相关。茎秆机械组织细胞层数、厚度,维管束数目、面积以及髓腔大小与抗倒性密切相关。茎秆化学成分中纤维素、木质素以及碳水化合物含量和硅、钾元素含量与抗倒性呈正相关。小麦抗倒性呈数量性状遗传特征,除受多对主基因控制外,可能还受微效修饰基因作用。采用分子标记技术已将抗倒性以及与抗倒性相关的茎秆形态性状进行了QTL定位。     

玉米茎秆细胞壁和组织构建对抗压强度的影响

耐密抗倒伏玉米品种是玉米育种的重要方向,探究影响玉米茎秆抗压强度的机制是培育玉米新品种的重要途径。本实验采用组织化学、显微观察的方法研究了10个玉米品种茎秆的形态结构、解剖特征和细胞壁的化学组成,并分析了这些变量之间的相关性,结果表明:茎的皮层/半径、厚壁组织比例、机械组织比例和纤维素含量、木质素含量与抗压强度呈极显著正相关关系;薄壁组织比例、茎长/茎粗、维管束个数与抗压强度呈极显著负相关关系。利用共线性诊断和逐步线性回归分析发现,影响茎秆抗压强度的主要因素为皮层/半径、机械组织比例、维管束个数、纤维素含量和木质素含量。利用通径分析进一步定量研究了这5个变量与抗压强度之间的直接作用和间接作用,明确了决定玉米茎秆抗压强度的主要因素为纤维素含量、木质素含量和单位面积维管束个数。本实验还建立了玉米茎微观结构与细胞壁化学构成的数学模型,为进一步揭示玉米茎微观力学形成机理提供了思路,进而为耐密抗倒伏玉米育种提供了研究方向。     

热碱预处理对菊芋茎秆组成和酶水解影响

为了深入了解菊芋茎秆用于生物能源转化的潜力,在对菊芋茎秆的全秆、韧皮以及髓芯的组成分析基础上,采用不同浓度的Na OH在121℃对菊芋茎秆进行预处理,并对预处理后的茎秆进行酶水解。结果表明:菊芋茎秆具有较高木质素含量(32.0%),且韧皮中木质素含量最高;茎秆中碳水化合物总含量与传统农作物秸秆相当,但纤维素含量相对较高(40.5%),半纤维含量相对较低(19.6%)。经不同浓度Na OH预处理后,相对于未处理茎秆,全秆、韧皮以及髓芯中木质素含量分别降低13.1%–13.4%、8.3%–13.5%和19.9%–27.2%,半纤维素含量分别降低了87.8%–96.9%、87.6%–95.0%和74.0%–90.2%。纤维素含量在全秆、韧皮和髓芯中相应增加了56.5%–60.2%、52.2%–55.4%和62.7%–73.2%。酶水解的结果显示,增加预处理过程中Na OH的浓度,全秆和韧皮的水解率可被提高2.3–2.6倍和10.3–18.5倍。虽然热Na OH预处理可以有效地改善髓芯水解性能,但经过高浓度的Na OH(2.0 mol/L)预处理,髓芯的水解性能下降明显。由此可见,菊芋用于生物能源转化技术中,热碱法可较好地适用于菊芋秸秆预处理。提高碱浓度,有利于半纤维素和木质素的去除,并实现酶水解糖化产率的提高。但鉴于碱浓度过高会造成髓芯糖产率降低,热碱预处理菊芋秸秆工艺条件需进一步优化。     

不同小麦品种植株地上部Cu的积累和分配规律研究

以'长5864'、'济麦20'和'中普绿麦1号'3个小麦品种为材料,研究了常规大田种植条件下植株地上部Cu的积累分配规律.结果表明:(1)随生育期推进,小麦叶片和叶鞘Cu含量在前期呈波动变化,于起身期(或拔节期)出现峰值之后逐渐降低,其茎秆、穗部和籽粒中Cu含量则持续下降.(2)小麦植株地上部Cu的积累量在三叶期-返青期增长缓慢,返青期-抽穗期急剧增长,抽穗期-灌浆末期缓慢增加,并以拔节期-抽穗期为Cu积累高峰期;叶片、叶鞘、茎秆及穗轴+颖壳中Cu的积累量在抽穗期(或灌浆初期)达到峰值,籽粒Cu积累量则持续增加.(3)灌浆末期,植株地上部各器官Cu含量以叶片最高,穗轴+颖壳最低;Cu积累量以籽粒最高,穗轴+颖壳最低;籽粒中Cu的分配比例为51.20%,其主要来自营养器官的转移,并以茎秆Cu对籽粒的贡献率最高.(4)小麦植株地上部Cu的含量和积累量存在品种间差异,其中'中普绿麦1号'植株Cu含量较高,而'长5864'植株Cu积累量较高.     

六个黄淮麦区优质小麦品种在晋中麦区晚播的产量与品质性状研究

目的：为拓宽山西优质小麦品种资源,采用田间试验,研究来自黄淮麦区的6个优质小麦品种在晋中晚熟冬麦区的籽粒产量及品质性状表现。方法：供试小麦品种分别是：来自河南省国家小麦工程中心的豫农416（编号Y-1）、豫麦34（Y-2）、豫麦70（Y-3）和豫麦18（Y-4）,来自山西省农科院棉花科学研究所的舜麦紫秆（S-1）和舜麦1718D（S-2）,以山西农业大学育成品种山农129为对照（CK）。试验于2010年10月15日在山西农业大学实验农场进行,收获后测定籽粒产量与产量结构及籽粒品质。结果：引进的6个黄淮麦区育成小麦品种在晋中晚熟冬麦区晚播种植,其籽粒品质均优于当地品种山农129,但产量不足。6个引进品种在晋中晚播种植后,其籽粒蛋白质含量、湿面筋含量等相关的籽粒品质亦明显高于原品种。相对而言,豫麦34、豫农416和舜麦紫秆均为高蛋白（〉17％）强筋（≥32％）品种,但前者高产（〉5800kg·hm-2）,后两者中产（〉4300kg·hm-2）;豫麦70和舜麦1718D均为高蛋白中筋（30％-32％）品种,但前者中产,后者低产（〈4000kg·hm-2）;豫麦18则为中等蛋白（〉16％）中筋的高产品种,当地品种山农129为低蛋白（〈16％）低湿面筋（〈30％）的高产品种。结论：豫麦34和豫麦18对改良山西小麦品种籽粒品质具有一定的意义。     

小麦抗茎腐病种质筛选及鉴定新方法的建立

为筛选针对我国黄淮麦区小麦茎腐病抗病新种质,建立可区分小麦其他茎基部病害的茎腐病抗性鉴定方法,本文采用室内苗期鉴定方法对主要来自黄淮麦区的108份小麦品种和高代品系进行茎腐病抗性评价,对其中45份小麦材料同时采用荧光定量PCR方法测定基部茎秆的禾谷镰刀菌DNA含量并与其茎腐病平均病级进行相关分析。共筛选到中抗茎腐病材料22份,未发现高抗和免疫品种(系);相关分析结果表明,小麦基部茎秆禾谷镰刀菌DNA含量与其茎腐病平均病级呈极显著正相关(r=0.73**),小麦基部茎秆禾谷镰刀菌DNA含量可以作为小麦茎腐病抗性的重要参考。抗病新种质的筛选和荧光定量PCR抗性评价方法的建立将为今后黄淮麦区小麦抗茎腐病品种的培育提供帮助。     

水稻基部伸长节间性状与茎秆机械强度的相关分析和QTL定位

分析水稻品种‘沈农265’和‘丽江新团黑谷’杂交的F2群体基部第二节间茎秆机械强度与该节间形态和茎秆解剖结构的相关性,并对基部第二节间机械强度和相关性状进行QTL定位的结果表明：机械强度与茎粗、茎壁面积、茎壁厚度、大小维管束数目、大小维管束面积、大小维管束韧皮部面积、大小维管束木质部面积呈显著或极显著的正相关,与节间长度呈极显著的负相关,而与茎秆扁平率的相关不显著。采用复合区间作图,从研究的14个目标性状中检测到18个QTL。控制基部第二节间的抗折力的QTL检测到4个,位于第4、7、9和10号染色体上,可解释遗传变异的12%～23%。在第4和第7染色体上的相同区间上还同时检测到了控制茎壁性状和维管束性状QTL,贡献率在12%～21%之间。说明这两个位点是控制基部第二节间机械强度的重要区域,也是茎壁性状、维管束性状与机械强度高度正相关的遗传学基础。     

Anatomical and Chemical Alterations but not Photosynthetic Dynamics and Apoplastic Transport Changes are Involved in the Brittleness Culm Mutation of Rice

Brittleness culm is an important agronomic trait that has a potential usefulness in agricultural activity as animal forage although the developmental mechanism is not clear yet. In the present study, the anatomical and chemical characteristics as well as some ecophysiological features in the brittleness culm mutation of rice (Oryza sativa L.) were investigated. Compared with the wild type (WT), the brittleness culm mutant (bcm) exhibited higher culm vascular bundle distance and lower culm wall thickness, leaf interveinal distance and leaf thickness. Ratio of bundle sheath cell/whole bundle and areas of whole vascular bundles and bundle sheath of leaves were reduced while ratios of xylem and phloem to whole bundles were elevated in bcm. The Fourier transform infrared (FTIR) microspectroscopy analysis and further histochemical and physiological measurements revealed that the different contents and depositions of cell wall components such as pectins, lignin, suberin and cellulose all participated in the mutation of brittleness. However, the mutant presented no significant changes in leaf photosynthetic dynamics and apoplastic transport ability. These results strongly indicate that the alterations in anatomical and chemical characteristics, rather than changes in major ecophysiological features such as photosynthesis and apoplastic transport were involved in the brittleness mutation of rice.     

Association of lignin and <Emphasis Type="Italic">FLEXIBLE CULM 1 (FC1)</Emphasis> ortholog in imparting culm strength and lodging resistance in kodo millet (<Emphasis Type="Italic">Paspalum scrobiculatum</Emphasis> L.)

To understand the lodging behavior in kodo millet (Paspalum scrobiculatum L.) at morphological, biochemical, and molecular levels, 22 germplasm accessions selected based on previous trials were characterized for culm strength-related morphological traits such as pulling force, culm weight per unit length, culm diameter, recovery angle after bending and degree of lodging, and biochemical traits such as cellulose, hemicellulose, and lignin content of the culm. Correlation among traits and path analysis with degree of lodging showed that only lignin content per unit length of the culm had a very high negative effect on degree of lodging, followed by culm diameter, which means that higher the lignin content and culm diameter, the lesser will be the degree of lodging. Hence, it was concluded that any improvement for lodging resistance in kodo millet can be achieved through improving the lignin content (mg/cm of the dry culm) and culm diameter. Gene expression studies in kodo millet for FLEXIBLE CULM 1 (FC1), a gene implicated in lignin biosynthetic pathway and lodging resistance in rice, suggests the role of FC1 gene ortholog in lignin accumulation in kodo millet as well. Accordingly, the highest gene expression was recorded in strong culm line “Adari” a land race and the lowest expression in “Aamo 10,” a weak culm line.     

Preliminary Study on Transformation of Wheat Apical Point

Apical points of young seedlings of wheat (Triticum aestivum) cultivar "Jing 411” and somatic calli of cultivar "FK8” were transformed with plasmids pBI121 and (or) pBIAH-A+ by using microprojectile bombardment. Histochemical assay of GUS activity showed positive reaction on some of the transformation processed apical points and calli. This demonstrated that foreign genes were introduced into the apical meristematic cells as well as the callus cells. The plantlets of cv. "Jing 411” survived after apical point transformation with pBIAH-A+ were transplanted into the field and the progenies were screened with kanamycin. 4 % of the screened seeds germinated into green seedlings with kanamycin resistance. Dot hybridization of total DNA from kanamycin resistant plants showed the existence of foreign DNA in some of the detected plants.     

国产嵩草属(莎草科)植物秆的解剖学研究

对嵩草属27种(亚种)植物秆的解剖学研究证明,嵩草属植物秆的解剖学性状具有系统学意义.在该属中,秆的横切面外形为三角形、圆三角形、圆形或扁圆形.在横切面上分为2个区域;外部区域包括绿色组织、外韧维管束和气腔,内部区域为薄壁组织或其碎裂形成空腔.秆表皮的横切面观和表面观均与叶的下表皮相似.以上特征与莎草科其它类群植物秆的解剖特征一致,不支持将嵩草属和其近缘属另立为嵩草科.同时,秆的解剖学特征可以做为某些在外部形态上难于区分的种之间的分类依据.     

水稻脆杆突变体bcm581-1茎杆形态结构观察、理化测定和遗传分析

在根癌农杆菌介导的Ds转座因子转化的水稻株系中,发现了脆杆突变体bcm581-1.经Basta除草剂抗性检测和PCR检测,这个脆杆突变不是由Ds转座因子插入引起;通过光学显微镜观察发现突变体的小维管束数目多于对照,小维管束之间的凹陷比对照深,而皮层纤维细胞层数少于对照;扫描电镜观察发现突变体表皮细胞外侧的硅质没有对照丰富.虽然,单位面积内的细胞数与对照相近.但是,突变体的细胞壁薄,维管束内纤维细胞壁的加厚程度也低于对照.因此,细胞腔明显比对照大.茎杆的力学测定结果表明突变体的载荷低于对照9.6倍;延伸低5.4倍;延伸率低6.9倍;应力低6倍.茎杆的相对含水量和粗纤维含量测定表明突变体的含水量高于对照3.5%,粗纤维含量则低于对照8.12%.bcm581-1与中花11号杂交试验显示,F1植株全部正常,F2群体中,正常杆和脆杆以31分离,以中花11号为回交亲本的F1B1植株,表现正常;而以脆杆为回交亲本的F1B1植株,正常茎杆和脆杆则以11分离,结果表明bcm581-1的茎杆变脆是受隐性单基因控制的突变.     

Molecular Markers of Ph1 Gene in Chinese Spring and Development of Winter Wheat New Line Harboring ph1b Gene

he genomic DNA of common wheat (Triticum aestivum L.) “Chinese Spring” (CS) and its ph1b mutant were analyzed by using 19 sequence tagged site PCR (STS-PCR) primers, which derived from RFLP probes from barley (Hordeum vulgare L.) chromosome 5H. One marker was identified on wheat chromosome 5BL, which is 5.7 cM (centiMorgan) proximal to Ph1 gene, using the CS homoeologous group 5 nullisomic-tetrasomic, ditelosomic 5BL line and an F2 population from CS×ph1b mutant. This linked PCR marker was converted into a more specific sequence characterized amplified region (SCAR) marker. To obtain a new winter wheat line containing ph1b gene, the authors used a nullisomic 5B line of “Abbodanza”as a bridge parent and crossed respectively with the CS ph1b mutant (donor) and a winter wheat variety, “Jing 411” (recipient). The meiotic chromosome pairing was checked in the progeny of each cross, as well as using the marker-assistant selection of the SCAR marker identified for ph1b gene. After three inter-crossing and one selfing, a relatively stable ph1b substitution line of winter wheat with “Jing 411” background was obtained.     

Lignification and cell wall thickening in nodes of Phyllostachys viridiglaucescens and Phyllostachys nigra

BACKGROUND AND AIMS: Bamboos are among the most important plants in the world. The anatomical structure and mechanical properties of the culm internode are well documented. Fewer details are available of the culm node. The aim of this study was a topochemical investigation on lignification and cell wall thickening in developing and maturing bamboo nodes. The deposition sequence and distribution of lignin structural units and cell wall thickening in different anatomical regions of the node of Phyllostachys viridiglaucescens and Phyllostachys nigra are discussed. METHODS: Cell wall thickening and lignification are investigated in the outer part of the nodal region and in the diaphragm of developing and maturing P. nigra culms and in maturing culms of P. viridiglaucescens of different age classes. The lignification during ageing was studied topochemically by means of cellular UV microspectrophotometry. A combination of light microscopy and image analysis techniques were used to measure cell wall thickness. KEY RESULTS: The fibre and parenchyma cell wall thickness does not significantly increase during ageing. In the diaphragm, the cell walls are thinner and the cell diameter is larger than in the outer part of the node. In shoots, the lignin content in the epidermis, hypodermis and in both fibre and parenchyma cells of the diaphragm is relatively low compared with older culms. The fibre and parenchyma cells of the diaphragm have higher values of p-coumaric and ferulic acids than fibre and parenchyma cells of the outer part of the node. CONCLUSIONS: It was hypothesized that the combination of more hydroxycinnamic acids and of thinner cell walls in combination with higher cell diameters (lower density and lower stiffness) in the diaphragm than in the outer part of the node may play an important role in the biomechanical function of the node by acting as a spring-like joint to support the culm by bending forces.