Root-shoot relationships in four strains of field-grown Erianthus arundinaceus at seedling stage

The production of cellulosic bioethanol from non-edible plants is a potential countermeasure against global warming. Erianthus species provide cellulosic raw material for bioethanol because they have high biomass productivity and high tolerance to environmental stress, associated with their large, deep root systems. However, it is difficult to select Erianthus species for breeding by direct observation of their root systems because the roots are widely dispersed in the soil. Instead, we examined shoot morphological traits that could be closely related to root morphology to find effective reference indices for selection. The potential to evaluate root structure and function in Erianthus according to bleeding rate was also examined. An analysis of root–shoot relationships in seedlings indicated that root number and mean length were closely related to stem number and diameter, respectively. These results suggest that root–shoot relationships may provide useful criteria for selective breeding of root systems in Erianthus.     

斑茅种质资源的表型性状及遗传多样性

为有效评价和利用斑茅种质资源,挖掘其优良性状,以162份斑茅种质资源(云南74份,福建15份,贵州19份,海南18份,四川14份,江西10份,广东4份,广西4份,浙江4份)为研究材料,对其表型性状及遗传多样性进行研究。表型性状分析结果表明:①斑茅种质资源质量性状的Shannon-Wiener多样性指数整体偏低,其中,福建斑茅的(0.762 4)最高,广西斑茅的(0.294 2)最低;②数量性状的遗传变异较丰富,其中,云南地区的变异系数(32.15%)最大,广西地区的(14.95%)最小;③海拔高度与锤度呈极显著负相关,纬度与株高呈极显著负相关。遗传分化系数和基因流结果显示,斑茅种质资源群体的遗传变异主要来自于采集地内部,群体之间存在较大的基因交流,遗传结构分化不明显。UPGMA聚类分析结果表明,各居群间的遗传距离与采集地之间有一定的相关性。     

Genetic diversity of North American and Old World Saccharum assessed by RAPD analysis

Saccharum (= Erianthus) native to North America is an untapped germplasm for genetic improvement of sugarcane (Saccharum spp. hybrids). There are five species and two varieties native to North America: S. alopecuroideum, S. baldwinii, S. brevibarbe vars. brevibarbe and contortum, S. coarctatum, and S. giganteum. There are three cytotypes of S. giganteum (2n = 30, 60, 90), and they overlap in gross morphology. Our objectives were to compare genetic diversity of North American and Old World members of Saccharum. Bulked DNA for five North American species, three Old World Erianthus spp. sect. Ripidium clones, and five sugarcane cultivars was tested by PCR with 13 RAPD primers. A total of 283 repeatable RAPD bands was scored for the nine taxa. Genetic distance coefficients ranged from 0.365 to 0.767 indicating substantial diversity among taxa. Taxa were assigned to one of three cluster groups: 1) S. baldwinii, S. brevibarbe var. contortum, S. coarctatum, and S. giganteum 2n = 90; 2) S. gig anteum 2n = 30 and 2n = 60, S. alopecuroideum, and sugarcane cultivars; and 3) Old World Erianthus spp. The RAPD analysis indicated that sugarcane was genetically more similar to North American Saccharum than it was to Old World Erianthus. This was unexpected given that North American Saccharum is geographically, cytologically, morphologically, and possibly reproductively isolated from Old World Erianthus and sugarcane. The data support the taxonomic separation of cytotypes of S. giganteum.     

甘蔗（Saccharum）与斑茅（Erianthus arundtnaceus）边缘杂交利用研究

报道了甘蔗与斑茅远缘杂交利用研究结果。本研究利用斑茅及其F1、BC1与甘蔗热带种、栽培种杂交和回交获得了一些斑茅的F1、BC1、BC2真实杂交种。结果表明：斑茅的F1、BC1的结实率低，育性低甚至不育。但通过回交可以提高斑茅杂种的结实率，且回交得到的BC1、BC2表现出了生势强，产量高、锤度高的优势，为选育具有斑茅血缘的高产高糖种质奠定了良好的基础。     

斑茅成熟种子愈伤诱导及再生体系的建立

为建立斑茅[Erianthus arundinaceum(Retz.)Jeswiet.]的组织培养再生体系,以斑茅的成熟种子为材料,对愈伤组织诱导、芽分化和根分化中的植物生长调节剂配比及浓度进行了筛选。结果表明,(1)MS中添加0.1~0.2 mg/L的6-BA与1.0~3.0 mg/L的2,4-D愈伤诱导率最高;MS中添加0.5 mg/L的2,4-D时胚性愈伤诱导率达54.29%。(2)MS中添加0.5 mg/L的6-BA与1~2 mg/L的KT更易促进芽的分化,芽分化率71.11%。(3)1/2MS中添加20 g/L的蔗糖促进生根效果最好,根分化率96.97%。     

斑茅ACO基因(aco)的克隆及其在水分胁迫下的表达

利用RT-PCR技术,首次克隆了斑茅1-氨基环丙烷-1-羧酸氧化酶基因序列.该片段长度为1123bp的片段,包括1个编码322个氨基酸的完整开放读码框,包括具有与异青霉素合成酶功能区类似的氧化功能PcbC区,和1个Fe2 和CO2活性中心。应用实时荧光PCR技术分析了1-氨基环丙烷-1-羧酸氧化酶基因在聚乙二醇胁迫下4个时段的表达。结果表明,聚乙二醇胁迫2h时,该基因在叶片明显上调表达,4h后的表达趋向平缓。本研究为1-氨基环丙烷-1-羧酸氧化酶基因进一步用于基因工程研究奠定基础,同时也初步揭示1-氨基环丙烷-1-羧酸氧化酶基因的表达与水分胁迫相互关系,为探讨乙烯对水分胁迫响应的分子机制提供了初步依据。