中国点地梅属的修订(续)

A revision of the Chinese species of Androsace updates our knowledge of the genus by providing a brief historical survey, character analysis, discussion on gene- ric relationships and geographical distribution, and a key to species currently recogni- zed. For the sake of completeness, the key is supplemented by an enumeration, and a record of the known distribution of each species.  Furthermore, some specimen citations and additional notes on species previously very incompletly known are also included. Seven new species and two infraspecific taxa are described.     

Segregation distortion in homozygous lines obtained via anther culture and maize doubled haploid methods in comparison to single seed descent in wheat (Triticum aestivum L.)

BackgroundThe quality of wheat grain depends on several characteristics, among which the composition of high molecular weight glutenin subunits, encoded by Glu-1 loci, are the most important. Application of biotechnological tools to accelerate the attainment of homozygous lines may influence the proportion of segregated genotypes. The objective was to determine, whether the selection pressure generated by the methods based on in vitro cultures, may cause a loss of genotypes with desirable Glu-1 alleles.ResultsHomozygous lines were derived from six winter wheat crosses by pollination with maize (DH-MP), anther culture (DH-AC) and single seed descent (SSD) technique. Androgenetically-derived plants that originated from the same callus were examined before chromosome doubling using allele-specific and microsatellite markers. It was found that segregation distortion in SSD and DH-MP populations occurred only in one case, whereas in anther-derived lines they were observed in five out of six analyzed combinations.ConclusionsSegregation distortion in DH-AC populations was caused by the development of more than one plant of the same genotype from one callus. This distortion was minimized if only one plant per callus was included in the population. Selection of haploid wheat plants before chromosome doubling based on allele-specific markers allows us to choose genotypes that possess desirable Glu-1 alleles and to reduce the number of plants in the next steps of DH production. The SSD technique appeared to be the most advantageous in terms of Mendelian segregation, thus the occurrence of residual heterozygosity can be minimized by continuous selfing beyond the F₆ generation.     

稻米直链淀粉含量测定中试验材料形态调整的研究

对５０份日本粳稻品种（系）分别以糙米、精米的粒体和粉体四种形态为试验材料,作了直链淀粉含量分析。结果表明：平均直链淀粉含量分别为糙米粒体１８．４％,精米粒体１８．８％,糙米粉体１７．９％,相同形态试料的测定值非常接近,在水稻育种实践中可用糙米粒体代替精米粉体作直链淀粉含量的测定分析,提高工作效率。     

商陆小G蛋白激活蛋白基因 PaAGAP 在逆境下表达研究

利用同源克隆和RACE方法在商陆( Phytolacca acinosa )中得到一个推测的小G蛋白ArfGTPase激活蛋白 ArfGAP (ArfGTPase activating protein) 的全长cDNA序列 PaAGAP . PaAGAP 序列编码332个氨基酸.蛋白含有保守的锌指结构域(CX2CX16CX2C类)和C2结构域.实时荧光定量PCR表明在寒、旱、盐和重金属的不同时间胁迫下,PaAGAP可以被诱导,表达量有不同程度的上调.由此推测 PaAGAP 可能是通过快速启动转录和翻译,使ARF失活,抑制植物生长素极性运输,来参与植物逆境反应的.     

陇西栽培蒙古黄芪酯酶同工酶数量分析

为了对陇西栽培蒙古黄芪（Astragalus membranaceus (Fisch.) Bge. var. mongholicus (Bge.) Hsiao）的优质高产和良种选育提供一定依据，本文采用垂直板聚丙烯酰胺凝胶电泳技术，对该地区栽培蒙古黄芪种子酯酶同工酶进行了研究。结果表明：该地栽培蒙古黄芪是一个复杂的异质群体；种子酯酶同工酶电泳技术是检验蒙古黄芪种内变异的一种有效手段。     

干旱逆境对不同品种水稻生长、渗透调节物质含量及保护酶活性的影响

采用PEG-6000模拟干旱胁迫研究表明,干旱胁迫后不同水、陆稻品种茎叶所受生长抑制强于根系所受抑制,但是旱稻品种巴西陆稻对干旱逆境具有较强的生长适应能力,与常规稻品种相比,旱稻品种巴西陆稻所受的生长抑制相对较小。干旱胁迫条件下,不同水陆稻品种叶片中可溶性糖(SS)含量、游离氨基酸总量(TFA)、游离脯氨酸(Pro)含量、POD活性、CAT活性均呈一致的上升趋势,且旱稻品种巴西陆稻具有较强的有机渗透调节能力和酶促抗氧化能力,干旱胁迫后其叶片中各相应指标的变化幅度均显著高于常规稻品种。     

西林薏苡生产现状、问题与对策

薏苡为大宗常用中药材。西林县是广西薏苡的传统产区,常年栽培面积1100余hm2,产量约2000t。生产上存在品种单一、退化严重,栽培管理粗放,病虫危害严重,加工技术落后,营销环节薄弱等问题;提出了加大优良品种选育、引进力度,建立标准化种植示范基地,推动加工业发展和完善服务体系等应对措施。     

深圳地区狗牙根冬枯成因及防除技术

首次提出了深圳地区冬季气候条件下暖季型草坪草狗牙根天堂草419冬枯成因的防除技术。认为浅休眠是暖季型草坪草狗牙根渡过冬季零上低温的一种典型的生物学方式。利用冬季亚热带气候升温快，零上低温滞留较短的特殊气候，采用冬前重肥就能轻易打破这种休眠，从而维持暖季型草坪草狗牙根冬季生长和全年的绿期。