213份苎麻种质资源农艺性状及品质性状鉴定评价

对213份苎麻种质的农艺性状和品质性状进行了分析和评价。结果表明,农艺性状和产量以及纤维品质存在丰富的变异;8个性状间存在着不同的相关性;筛选出高产种质(单蔸产量≥110g)56份,优质种质(纤维细度≥2200m/g)38份,高产(单蔸产量≥110g)优质(纤维细度≥2200 m/g)的种质5份。     

薏苡种子形态性状多样性评价

薏苡是优质的药食兼用作物。本研究对我国36份薏苡种质的种子形态性状进行了主成分分析和聚类分析。结果表明,36份薏苡种质具有较高的形态性状多样性。不同薏苡种质的4个种子质量性状间存在差异。单因素方差分析显示11个种子数量性状在不同薏苡种质间呈极显著差异。数量性状的变异系数在8.43%~68.01%之间,种壳与外种皮重量的变异系数最大而种仁长度的变异系数最小。主成分分析将36份薏苡种质分为中部及南部栽培种质、北部栽培种质和野生种质3大类,3类种质的形态特征存在明显差异。聚类分析将36份薏苡种质分为5大类群,即中部及南部栽培种质、北部栽培种质和3个类群野生种质。初步筛选出6份可能具有较高抗肿瘤活性的薏苡种质FJNJ、TJ-BK-1、TJ-BK-2、MY-BK-1、MY-BK-2和JYSD。     

298份苎麻种质资源纤维产量性状综合评价

通过对苎麻纤维产量相关性状的评价,可为实现苎麻分子标记选择育种和有效突破高纤维产量苎麻品种的遗传改良提供科学依据.本研究以298份不同来源的苎麻种质资源为材料,基于三季大田试验调查,对苎麻纤维产量性状数据进行了频率分布直方图分析、变异系数分析、相关性分析、主成分分析和聚类分析.结果 表明,纤维产量相关的6个性状数据展现...     

24种国产金发藓科植物叶中肋细胞离析后形态学比较观察

利用强酸解离的方法对24种国产金发藓科植物的叶中肋细胞形态进行了比较观察研究.分别测量了离析后叶中肋细胞的长度、宽度和细胞壁厚度及纹孔场数目.细胞的形态特征在异蒴藓属(Lyellia)的各种种内变异程度相对小,而在金发藓属(Polytrichum)、小金发藓属(Pogonatum)和小赤藓属(Oligotrichum)等属中种内变异程度相对较大.细胞纹孔场数目较多,干燥时出现规律性卷缩,可能更适宜干燥生境.     

大豆属不同进化类型植物导管分子的演化结构研究

使用光学显微镜技术,对大豆属不同进化类型植物次生木质部导管分子进行离析。实验结果表明：野生、半野生、半栽培和栽培大豆的导管分子相对长度、粗细差异较大,导管穿孔板形态亦不同。野生大豆导管分子保留了尾端,其它大豆导管分子尾端退化消失。大豆属植物导管的管间纹孔式多样,每种导管分子的形态代表了各自的演化地位,即：野生大豆原始→半野生大豆→半栽培大豆→栽培大豆导管分子的演化规律。     

食用菌可栽培种类野生种质的评价

我国是食用菌野生种质资源丰富的国家,目前已查明自然分布可栽培野生种类93种,分布于担子菌的33个属。我国人工栽培种类近70种(变种),不同规模栽培有50种,商业规模栽培33种,分布于5目,12科,18属。与绿色植物的自养型光合作用合成有机物质相反,食用菌将植物光合作用合成的有机物分解,以体壁吸收方式摄取营养建造自身。这种生理特点的不同,导致其种质资源评价要求的不同。由于子实体形态相对于绿色植物简单,且易受环境条件的影响,常常导致以形态特征为主要依据进行分类鉴定陷入困境。另一方面,形态相似的多个可栽培近缘种在侧耳(Pleurotus)、木耳(Auricularia)、蜜环菌(Armillaria)等中广泛存在,完全靠形态特征进行分类鉴定就更加困难。因此,在食用菌可栽培种类野生种质评价中,ITS测序等成为获得菌种生物学种的常用鉴定技术。菌种的分离培养中常受到菌落形态相似真菌的污染,RAPD、ISSR或ITS测序等常用来进行菌种符合性鉴定。食用菌孢子传播的特点,使其分布地理区域广泛,地理区域的隔离产生种内的个体或群体间的差异,形成种群的多样性,常用拮抗反应进行营养亲和群(个体、菌株)的鉴定。不同区域气候和生态条件下的个体,长期的进化和对环境条件适应性的形成,导致可栽培利用的特点不同。栽培性状要通过栽培试验进行评价。栽培性状主要包括菌丝长速、温度反应、结实性、丰产性、抗性、商品形态和耐贮运性等。为了充分利用远缘优势,对于具可利用栽培性状的种质还需要与栽培菌株间的遗传距离分析,通常用生物化学和分子生物学方法进行。     

57份苎麻种质资源主要农艺性状及纤维品质鉴定评价

对57份苎麻种质的主要农艺性状和纤维品质性状进行了鉴定评价。结果筛选出高产苎麻种质10份(原麻产量≥2000 kg/hm2),纤维品质优良的种质7份(纤维细度≥2000 m/g),鲜皮出麻率≥12.5%的苎麻种质20份,炼折率超过65%的苎麻种质有10份,按照苎麻优异种质评价规范,满足高产和出麻率高2个优良指标的种质7份,满足优质和鲜皮出麻率高2个优良指标的种质1份。     

枇杷属植物4个种的花序性状多样性研究

在相同的种植和管理条件下,对普通枇杷、栎叶枇杷、大瑶山枇杷和南亚枇杷等4个种210份种质资源的8个花序性状多样性进行鉴定,旨在为进一步的分类鉴定、利用研究提供参考依据。结果表明:(1)枇杷属种质资源的花序支轴姿态、花序支轴密度、花序支轴数、花序形状、花序长度、花序宽度、花瓣颜色、花冠直径Shannon-Weaver多样性指数1.352～2.951,存在丰富的多样性。(2)不同来源地的种质资源花序性状多样性水平差异较大,多样性指数最高的为云南(2.108),其次是贵州(1.962)、四川(1.953)、福建(1.900),美国的最低(1.137)。(3)云南、贵州的枇杷种质资源花序长度、宽度显著或极显著地大于其他地区;野生资源的花序长度、花序宽度和花冠直径均极显著地大于地方品种、选育品种。     

广西野生阴生观赏植物资源及其特点

为了解广西境内蕴藏的野生阴生观赏植物资源及珍贵种质,采取野外实地考察及标本采集鉴定相结合的方法,对广西全境分布的阴生和半阴生观赏植物资源进行研究。结果表明:广西野生阴生观赏植物有5个基本特点:种类丰富(162科485属1309种)、种质资源珍贵(珍稀植物195种,广西特有植物136种)、生长基质多样(喜钙植物、喜酸植物和中间类型植物)、草本性状比值显著(草本植物约占总种数的66.1%)、野生资源贮藏量的多寡悬殊性。6个主要野生阴生观赏类群为:蕨类植物(43科240种)、兰科(37属126种)、百合科(21属82种)、苦苣苔科(17属63种)、秋海棠科(1属43种)、天南星科(12属30种)。研究结果可为合理开发利用广西野生阴生观赏植物资源提供参考。     

食用菌栽培种类野生种质的评价

我国是食用菌野生种质资源丰富的国家,目前已查明自然分布可栽培野生种类93种,分布于担子菌的33个属。我国人工栽培种类近70种（变种）,不同规模栽培有50种,商业规模栽培33种,分布于5目,12科,18属。与绿色植物的自养型光合作用合成有机物质相反,食用菌将植物光合作用合成的有机物分解,以体壁吸收方式摄取营养建造自身。这种生理特点的不同,导致其种质资源评价要求的不同。由于子实体形态相对于绿色植物简单,且易受环境条件的影响,常常导致以形态特征为主要依据进行分类鉴定陷入困境。另一方面,形态相似的多个可栽培近缘种在侧耳（Pleurotus）、木耳（Auricularia）、蜜环菌（Armillaria）等中广泛存在,完全靠形态特征进行分类鉴定就更加困难。因此,在食用菌可栽培种类野生种质评价中,ITS测序等成为获得菌种生物学种的常用鉴定技术。菌种的分离培养中常受到菌落形态相似真菌的污染,RAPD、ISSR或ITS测序等常用来进行菌种符合性鉴定。食用菌孢子传播的特点,使其分布地理区域广泛,地理区域的隔离产生种内的个体或群体间的差异,形成种群的多样性,常用拮抗反应进行营养亲和群（个体、菌株）的鉴定。不同区域气候和生态条件下的个体,长期的进化和对环境条件适应性的形成,导致可栽培利用的特点不同。栽培性状要通过栽培试验进行评价。栽培性状主要包括菌丝长速、温度反应、结实性、丰产性、抗性、商品形态和耐贮运性等。为了充分利用远缘优势,对于具可利用栽培性状的种质还需要与栽培菌株间的遗传距离分析,通常用生物化学和分子生物学方法进行。     

广西多穗柯叶片性状变异及幼苗生长量研究

多穗柯是一种珍贵天然野生药用植物,可以开发出保健食品色素和天然医用药品,广西的资源较丰富,该研究采集巴马、那坡、德保及田林等4个产地的多穗柯种子进行播种育苗,并跟踪调查测定一年生幼苗的叶片性状及幼苗生长量,并进行相关性分析。结果表明:(1)不同产地间叶片性状及幼苗生长指标均存在不同程度的差异,其中巴马与那坡、德保、田林在叶长、叶宽、叶面积、叶脉间距、叶鲜重、叶片干物质含量、叶片组织密度等叶片性状上的差异均达到显著水平,在株高、地径、单株干重、主根长、单株根干重及单株叶干重等生长指标上亦存在显著差异,且生长量是后3个产地的1~2倍;通过比较各产地的叶片保水力及植株净生长量,巴马的多穗柯植株耐旱性及生长速度优于其他三地。综合各性状表现,认为巴马的多穗柯苗期表现比较好,生长速度快,长势好,抗旱性较强,可作为多穗柯优良种源的初步选择。(2)8月份是多穗柯株高、地径的生长高峰期,建议此时应加强肥水管理,调节适宜的水肥光热条件,尽量延长幼苗的快速生长时间,以获得苗木的最大累积生长量。(3)叶片性状与幼苗生长量的相关性分析结果显示,叶面积与株高、地径、单株干重、单株根干重以及单株叶干重等呈极显著正相关,叶脉间距、叶绿素相对含量(SPAD)与株高、单株干重呈显著或极显著正相关,比叶面积与株高、地径呈显著负相关。因此,在以后的优株表型选择中,要优先考虑叶子大、叶脉间距宽、中老熟叶片叶色浓绿的植株。该研究结果为多穗柯优良种质资源的早期筛选提供了一定的依据。     

Effect of shade on plant traits,gas exchange and chlorophyll content in four ramie cultivars

The objective of this study was to investigate a response to low-light environments in hybrids and commercial cultivars of Boehmeria nivea L. Two hybrids (Chuanzhu 11 and Chuanzhu 8) and two commercial cultivars (Chuanzhu 12 and Chuanzhu 6) of ramie were subjected to a shade treatment for 6, 12, and 18 days. The shade treatment led to a significant decrease in some plant traits and fiber yield in four ramie cultivars, whereas their leaf area and plant height increased. In addition, net photosynthesis and stomatal conductance significantly declined in response to shade, while transpiration rate and intercellular CO₂ did not significantly change. Moreover, chlorophyll (Chl) and carotenoid (Car) concentration, Chl/Car, and Chl (a+b) per leaf dry mass significantly increased in the response to shade, while the Chl a/b ratio decreased. Furthermore, Chuanzhu 6 and Chuanzhu 11 were more tolerant to shade than Chuanzhu 12 and Chuanzhu 8, thus, they could be potentially used for management practices and breeding programs.     

Genomic analyses provide comprehensive insights into the domestication of bast fiber crop ramie (Boehmeria nivea)

Ramie (Boehmeria nivea) is an economically important natural fiber-producing crop that has been cultivated for thousands of years in China; however, the evolution of this crop remains largely unknown. Here, we report a ramie domestication analysis based on genome assembly and resequencing of cultivated and wild accessions. Two chromosome-level genomes representing wild and cultivated ramie were assembled de novo. Numerous structural variations between two assemblies, together with the genetic variations from population resequencing, constituted a comprehensive genomic variation map for ramie. Domestication analysis identified 71 high-confidence selective sweeps comprising 320 predicted genes, and 29 genes from sweeps were associated with fiber growth in the expression. In addition, we identified seven genetic loci associated with the fiber yield trait in the segregated population derived from the crossing of two assembled accessions, and two of which showed an overlap with the selective sweeps. These findings indicated that bast fiber traits were focused on during the domestication history of ramie. This study sheds light on the domestication of ramie and provides a valuable resource for biological and breeding studies of this important crop.     

Genetic variation for grain yield and related traits in sorghum introgression populations

Summary Each of two sorghum (Sorghum bicolor (L.) Moench) cultivars were crossed with representatives of three wild sorghum races. Backcross-derived sorghum populations containing 3.125 to 50% wild germplasm were evaluated for grain yield, 100-kernel weight, days to flower, and plant height. Population means increased linearly with backcrossing for kernel weight, increased curvilinearly for grain yield, decreased curvilinearly for plant height, and changed erratically for days to flower. For all traits, the relationship between genetic variance and level of backcrossing deviated significantly from that expected based on an additive model. Genetic variance usually reached a maximum in the BC₁ or BC₂. The BC₁ genetic variance for grain yield, averaged over matings, was twice as large as the average BC₀ genetic variance. An epistatic model involving gene regulation is proposed as a plausible explanation for the results.Joint contribution of USDA-ARS, and Journal Paper No. J-11101 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa. Project No. 2447     

Differential responses of molecular mechanisms and physiochemical characters in wild and cultivated soybeans against invasion by the pathogenic Fusarium oxysporum Schltdl

Cultivated soybean (Glycine max) was derived from the wild soybean (Glycine soja), which has genetic resources that can be critically important for improving plant stress resistance. However, little information is available pertaining to the molecular and physiochemical comparison between the cultivated and wild soybeans in response to the pathogenic Fusarium oxysporum Schltdl. In this study, we first used comparative phenotypic and paraffin section analyses to indicate that wild soybean is indeed more resistant to F. oxysporum than cultivated soybean. Genome‐wide RNA‐sequencing approach was then used to elucidate the genetic mechanisms underlying the differential physiological and biochemical responses of the cultivated soybean, and its relative, to F. oxysporum. A greater number of genes related to cell wall synthesis and hormone metabolism were significantly altered in wild soybean than in cultivated soybean under F. oxysporum infection. Accordingly, a higher accumulation of lignins was observed in wild soybean than cultivated soybean under F. oxysporum infection. Collectively, these results indicated that secondary metabolites and plant hormones may play a vital role in differentiating the response between cultivated and wild soybeans against the pathogen. These important findings may provide future direction to breeding programs to improve resistance to F. oxysporum in the elite soybean cultivars by taking advantage of the genetic resources within wild soybean germplasm.     

QTL mapping for fiber yield-related traits by constructing the first genetic linkage map in ramie (Boehmeria nivea L. Gaud)

Ramie fiber extracted from stem bast is one of the most important natural fibers. The fiber yield of ramie is a valuable trait and is decided by several components, including stem number per plant (SN), the fiber yield per stem (FYPS), stem length (SL), stem diameter (SD), and bark thickness (BT). All of these fiber yield-related traits are inherited in a quantitative manner. The genetic basis for these traits is still uncharacterized, which has hindered the improvement of yield traits through selective ramie breeding. In this study, an F₂ population derived from two ramie varieties, Zhongzhu 1 and Qingyezhuma, with striking differences in fiber yield-related traits, was used for cutting propagation and to develop an F₂ agamous line (FAL) population. A genetic linkage map with 132 DNA loci spanning 2,265.1 cM was first constructed. The analysis of quantitative trait locus (QTL) for fiber yield-related traits was performed in ramie for the first time. Finally, a total of 6, 9, 5, 7, and 6 QTLs for FYPS, SL, SN, SD, and BT, respectively, were identified in the FAL population in two environments. Among these 33 QTLs, 9 QTLs were detected in both environments and 24 QTLs exhibited overdominance. The overdominance of these QTLs possibly contributed to the heterosis of these yield-related traits in ramie. Moreover, there were 7 QTL clusters identified. The identification of the QTLs for fiber yield-related traits will be helpful for improving the fiber yield in ramie breeding programs.     

云南野生莲瓣兰形态分异与海拔的关系

莲瓣兰是中国西南地区特有的兰科濒危物种。2013年和2014年8月至10月,在云南省西北地区选取了28个野生莲瓣兰居群进行野外调查。结果表明:野生莲瓣兰在滇西北海拔为1380—2557 m的区域均有分布;莲瓣兰叶片数、花葶长、花瓣长、花瓣宽、萼片长均与海拔呈显著负相关(P0.01)。与年平均气温呈正相关的形态指标有:叶长(P0.05),株高(P0.05),花葶长(P0.01)。与空气湿度呈显著正相关的形态指标有:叶宽(P0.05),株高(P0.05),花葶长(P0.05),叶长(P0.01)。随着野生莲瓣兰分布地海拔的升高,株型矮化,形态变小;年均温越高、空气湿度越大的分布地,莲瓣兰叶片越长、越宽,植株越高,花葶越长;分布地辐射强度越大,莲瓣兰叶片越短,植株越矮,根系越发达。野生莲瓣兰居群间的叶长、叶宽、株高、根长及花葶长度的变化较大,变异系数超过了15%,表明其存在着较大的形态变异,生态适应幅度变宽,且植株矮化严重,需加强就地和迁地保护。研究结果阐明了滇西北海拔、温度等生态因子对野生莲瓣兰形态特征的影响,为进一步保护野生莲瓣兰资源提供了理论依据。     

Effects of Rht-dosage on the breaking strength of wheat seedling leaves

We report the effect of the reduced-height alleles Rht1 and Rht2 on the breaking strength and breaking stress of the first foliage leaves of wheat seedlings. Transverse size variables such as blade transverse area and blade width were positively related to the breaking strength and breaking stress of leaves, as was the total wall area of the principal fiber strands. A negative correlation was found for the Rht-dosage with respect to the breaking strength. Because Rht plants had greater transverse dimensions and equal amounts of principal fiber strands compared to wild type, we posit that Rht may affect the mechanical quality of leaf tissues per se. Rht may serve as an example of a simple genetic system that profoundly affects plant morphology, development, and biomechanics.