赖草属5个种的核型与进化

报道了国产赖草属５个种的核型,即大赖草,２ｎ＝４ｘ＝２８＝２４ｍ（２ＳＡＴ）＋４ｓｍ（２ＳＡＴ）;粗穗赖草２ｎ＝４ｘ＝２８＝２２ｍ（２ＳＡＴ）＋４ｓｍ＋２ｓｔ（２ＳＡＴ）;若羌赖草,２ｎ＝４ｘ＝２８＝２０ｍ（４ＳＡＴ）＋６ｓｍ＋２ｓｔ（２ＳＡＴ）;羊草,２ｎ＝４ｘ＝２８＝２２ｍ（４ＳＡＴ）＋２ｓｍ＋４ｓｔ（４ＳＡＴ）;窄颖赖草,２ｎ＝４ｘ＝２８＝２２ｍ（２ＳＡＴ）＋４ｓｍ（２ＳＡＴ）＋２ｓｔ（２Ｓ     

披碱草属及其近源属植物种子胚乳细胞多样性研究

披碱草属不仅是小麦、大麦等作物的重要基因库,也是优良牧草的重要组成部分。胚乳是麦类作物种子的重要组成部分,其重量占籽粒重量在90%以上。胚乳特性是一个相对稳定的遗传性状,可以将胚乳特性作为植物分类和系统关系的一个指标。胚乳细胞特征作为植物的一类微形态特征,在麦类植物系统分类与进化研究中具有一定的价值。该研究对小麦族的6个披碱草属(Elymus)物种、2个拟鹅观草属(Pseudoroegneria)物种、1个大麦属(Hordeum)物种和2个冰草属(Agropyron)物种,共4属11份材料的胚乳细胞特征进行解剖观察并测量相关指标。结果表明:(1)不同属、种的植物种子胚乳细胞之间存在丰富的多样性,属间差异大于属内种间差异;(2)同样具有P染色体组的Agropyron cristatum和A.mongolicum与同样具有St染色体组的Pseudoroegneria libanotica和P.spicata各自在细胞形状和大小上的差异很小;(3)不同物种的胚乳细胞在大小、形状和数量上均表现出差异,但不能很好地反映属以及基因组间的差异,研究结果为揭示披碱草属植物的系统关系提供了胚乳细胞方面的证据,同时也为利用该属植物改良麦类作物品质积累资料。     

新疆赖草属二新种

本文发表了我们在编写《flora of kunlun and karakorum》(禾本科)时发现的两个新种:若羌赖草Leymus ruoqiangensis S.L.Lu etY.H.Wu,sp.nov.;皮山赖草Leymus pishanica S.L.Lu et Y.H.Wu,sp.nov.     

赖草属资料

禾本科赖草属二新种及一新变种,即芒颖赖草Leymus aristiglumus L.B.Cai,伊吾赖草Leymus yiwuensis L.B.Cai ex N.R.Cui和疏节赖草Leymus secalinus var.laxinodis L.B.Cai。     

中国赖草属(禾本科)一新种——贫穗赖草

报道了中国西部赖草属一新种———贫穗赖草。该种相似于若羌赖草和广叉赖草,但它不同于前者在于穗状花序的中部或下部具孪生小穗,外稃披针形、无毛,具1.0~1.5 mm长的短尖头,内稃短于外稃1.0~1.5 mm,沿上部脊疏生小刺,叶鞘无毛,具非膜质边缘;不同于后者在于秆较高,叶片内卷,穗状花序稀疏、狭窄,小穗较短,颖较长,外稃披针形、较长,具5条不明显的脉。     

青海赖草属一新种

报道了青海赖草属植物一新种：圆稃赖草(Leymus oblongolenmatus L. Zhi et L.B. Cai)。该种的主要特征如下：多年生草本,杆直立、光滑、疏丛,高60～90 cm。叶鞘粗糙,边缘膜质,长于或短于节间,叶舌膜质;叶片边缘内卷。穗状花序直立、密集、黄绿色,长10～15 cm,宽5～15 mm,穗轴粗糙,小穗常3～4枚生于每节,含3～6小花;颖披针形,长4～7 mm,具3～5脉,边缘膜质;外稃长圆状披针形,不明显3脉,背部疏生短柔毛;花药黄色,长4～5 mm。该种与L. paboahus相似。     

11个四倍体赖草属物种的核型研究

对11个四倍体赖草属Leymus Hochst.物种的核型进行了研究,核型公式如下：沙生赖草L. arenarius (L.) Hochst., 2n=4x=28=18m+4sm+6st (4sat); 密穗赖草L. condensatus (J. Presl) A. Lve, 2n=4x=28=22m+4sm (2sat)+2st (2sat); 新生赖草L. innovatus (Beal) Pilg., 2n=4x=28=24m (4sat) +4sm (2sat);多枝赖草L. multicau     

国产赖草属的分类修订

通过标本研究和野外考察,对中国赖草属（Leymus Hochst.）进行了分类修订。结果在中国共确认了3组、33种、7变种赖草属植物,其中多穗组包含4种,少穗组包含24种、7变种,单穗组包含5种,新报道的3个种和新修订的4个类群（即3个新组合和1个新名称）皆隶于少穗组。同时对赖草属的研究简史、属的形态特征和一些类群的地理分布也分别作了简要介绍。     

新疆赖草属的新分类群

发表了禾本科赖草属的二个新种及一个新亚种:高株赖草Leymus altus D.F.Cui, sp.nov.,阿尔金山赖草L.arjinshanicus D.F.Cui, sp.nov.,大药窄颖赖草L.angustus subsp.macroantherus D.F.Cui, subsp.nov.。     

赖草属植物的遗传学研究与利用

赖草属植物具有广泛的适应性和丰富的抗逆性,作为麦类作物的重要基因资源愈来愈受到人们的重视。介绍了赖草属植物的种类及分布,分析了赖草属植物的优良特性及潜在利用价值,探讨了赖草属植物的核型、染色体带型及分子细胞遗传学研究,重点论述了赖草属植物在小麦遗传改良中的应用．阐明挖掘利用小麦近缘野生植物是未来小麦品种改良的有效途径。     

鹅观草属一些种种子胚乳细胞的特征及其分类学意义的探讨

解剖观察了鹅观草属１８个种的胚乳细胞,发现这此细胞在鹅观草属各类群间的发育是不同步的,其中胚乳细胞的大小、形状、数量以及反映丰厚程度的长宽比不仅具有类群鉴分的价值,而且还可作为推证类群演化关系的旁证。分析结果表明,胚乳细胞体积的增大。数量的增多、细胞的变圆、长宽幽会的减少皆与类群的进化趋势相顺应。据此,进一步阐述了鹅观草属组、系、种的系统发育关系。     

赖草属植物的抗逆性研究进展与应用前景

赖草属是多年生禾本科植物,在中国的分布地域较为广泛。该属内植物对逆境具有较强的抗性,尤其是对于干旱、盐碱、高寒和病虫害等有较强的抵抗能力。综述了近年来赖草属植物抗逆性方面的研究进展,从赖草的耐旱性、耐盐性、耐寒性以及抗病虫害等方面对赖草属植物的抗逆性机理进行了探讨,并对其未来应用做出了展望。     

Role of endogenous hormones,glumes, endosperm and temperature on germination of Leymus chinensis (Poaceae) seeds during development

Aims Leymus chinensis is an original dominant plant in the Songnen grassland, and it has great value for restoration of severely degraded land. However, seeds are dormant, and low germination percentage is a problem for restoring L.chinensis grassland. The mechanism of seed dormancy is not been well understood. The primary aims of the present study were to investigate the dormancy mechanism of L.chinensis seeds (caryopses) with reference to the role of embryo-covering layers, endogenous hormones and temperature.Methods Changes in concentration of the endogenous hormones GA 3, indoleacetic acid (IAA), zeatin riboside (ZR) and abscisic acid (ABA) in L.chinensis seeds from anthesis to maturity were measured by the enzyme-linked immunosorbent assay method. Germination at different stages of maturity were tested at 16/28°C, 5/28°C and 5/35°C for intact seeds with glumes (control), intact seeds with glumes removed (naked-whole seeds) and intact seeds with glumes and one-half of the endosperm removed (naked-half seeds).Important findings Of the four endogenous hormones monitored, only the concentration of ZR differed significantly between the beginning and the end of seed development (increased); the GA 3 /ABA ratio also did not differ. Rank of germination percentage of control at the three temperature regimens was 5/28°C> 16/28°C> 5/35°C. Germination percentage of the naked-half seeds reached 100% under the three temperature regimens. We concluded that dormancy of L.chinensis seeds is not mainly controlled by endogenous hormones. Germination temperature, mechanical resistance of glumes and inhibition of endosperm are the main factors controlling dormancy and germination of L.chinensis seeds.     

微生境下羊草两种生态型种群的遗传多样性及遗传分化——等位酶分析

采用水平淀粉凝胶电泳技术,应用等位酶分析方法测定了松嫩平原南部微生境条件下羊草灰绿色和黄绿色两种生态型９个种群的遗传多样性和遗传分化程度。羊草种、种群和生态型水平都维持较高的遗传多样性。两种生态型之间有明显的遗传多样性差异及遗传分化。灰绿型和黄绿型的多态位点百分率分别为６７．３％和５７．１％,等位基因平均数分别是２．２和１．９,期望杂合度分别为０．３４８和０．２９８。两种生态型种群之间平均遗传距离     

新疆阿勒泰地区5个大赖草种群的表型多样性分析

为了解大赖草种群﹝Leymus racemosus ( Lam.) Tzvel.﹞的表型变异规律及多样性特征,对分布于新疆阿勒泰地区的5个大赖草种群(分别位于阿勒泰市、福海县、布尔津县和哈巴河县)的16个表型性状进行了测定;在此基础上,对各表型性状进行了Shannon-Weaver指数( H＇)分析和主成分分析。结果表明：各种群间的16个表型性状均存在较大差异,其中分布于哈巴河县的2个种群各表型性状的平均值均较高。种群内各表型性状的变异系数为5.97%~40.05%,差异较大;其中,穗下第一节间长度的变异系数在各种群内均较大(17.16%~40.05%);总体上看,种群内与营养生长有关的性状(如穗下第一节间长度、剑叶长度和宽度等)变异较大,而与繁殖有关的性状变异较小。在种群间,穗下第一节间长度、剑叶长度和宽度的变异系数均较大,分别为31.85%、26.87%和27.85%;而小穗和外颖长度以及穗节数的变异系数均较小,分别为15.21%、16.53%和16.91%。5个种群间16个表型性状的H＇值均有较大差异,并且,种群内各表型性状的H＇平均值(1.660)明显高于种群间(0.239)。主成分分析结果显示：前5个主成分的累计贡献率为80.210%,其中,第1主成分中与营养器官相关的性状(如株高、穗下第一节间长度、剑叶长度和宽度、茎节数)载荷较大,第2至第4主成分中与繁殖器官相关的性状(如穗长度和宽度、外颖和内颖长度、小穗长度和宽度以及外稃长度)载荷较大,表明这12个性状为大赖草种群表型性状变异的主要因子。研究结果显示：大赖草种群间的表型多样性低于种群内,且营养器官的表型变异是导致大赖草种群表型多样性的主要因子。     

Endo-β-mannanases in the endosperm of germinated tomato seeds

Three forms of galactomannan-hydrolyzing enzymes (dyed galactomannan as substrate) were partially purified from germinated tomato [ Lycopersicon esculentum (L.) Mill.] seed. Two of the enzymes were of the same molecular mass, 38 kDa, as judged by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), but the points of elution from a CM-Toyopearl column by a pH-gradient were different between the two (pH 5.15 and 5.45. respectively). The molecular mass of the third form was slightly less (37.5 kDa) than that of the other two. These 3 enzymes showed no α-galactosidase (EC 3.2.1.22) or β-mannosidase (EC 3.2.1.25) activity. Thin-layer chromatography (TLC) revealed that the products of the reaction were oligosaccharides and that free galactose and mannose were not released. These results indicate that the 3 galactomannan-hydrolyzing enzymes are endo-β-mannanases (EC 3.2.1.78). Polyclonal antibodies raised against the 37.5-kDa polypeptide cross-reacted with the two 38-kDa polypeptides, indicating that the 3 endo-β-mannanases are immunologically homologous. Activity staining and immunoblotting of native PAGE of endosperm extracts revealed that only two (38-kDa. elution point pH 5.15 and 37.5-kDa proteins) of the 3 forms were major endo-β-mannanases present in the endosperm of germinated tomato seeds.