Variation in sweet potato for tolerance to some physical and biological stresses

Summary Sweet potato cultivars, breeding lines and unselected seedling clones were grown under 9 stress conditions in field and greenhouse; heavy soil, space competition, competition with maize, shading, flooding, drought, acidity, salinity, and weevil infestation. High root yield was considered to be a sign of stress tolerance. Stresses were shown to reduce the growth of shoots and roots, except flooding, which increased fibrous root production. The percentge of plants showing high stress tolerance varied from 0.35 to 30.90 for the different stress situations. Tolerances to stresses tended to occur together, as shown by low but significant correlations, significant chi-squares for numbers of plants with multiple stresses, and by low but significant correlations between yield and multiple stresses. Root flooding, space and fertility competition, and soil acidity appear to be the stress factors most closely related to production in heavy soils. Yet the magnitude of the correlations suggest that other factors or random variation also affect yield, and thus the predictive value of greenhouse stress test is presently limited.     

甘薯（Ipomoea batatas (L.) Lam.）及其近缘野生种原生质体的植株再生

对甘薯品种高系14号及其近缘野生种I.triloba L、和I.lacunosa L,进行原生质体植株再生研究。从离体培养植株的叶柄分离出原生质体,将其培养在含有0.05mg/L 2,4-D和0.5mg/L激动素(KT)的MS培养基中,从原生质体获得了高频率的愈伤组织。培养8-12周后,将直径达2—3mm的小愈伤组织转移到添加0.05mg/L 2,4-D的MS培养基上。转移3-6周后,将愈伤组织进一步转移到添加吲哚乙酸(IAA)和6-苄基嘌呤(BAP)的MS培养基上,一些愈伤组织再生出植株。未再生植株的愈伤组织进一步在MS基本培养基上培养,它们也再生出植株。本研究从I.triloba原生质体获得高频率的植株再生;首次从I.lacunosa原生质体再生出植株;从高系14号原生质体也再生出完整植株。     

Regression analysis of genotype x environment interaction in sweet potato

Summary Two experiments, each involving a set of 10 sweet potato clones, were conducted for three years at 4 sites (Ekona, Ebolowa, Nkolbisson, and Bambui Plain) in Cameroon. Data obtained were subjected to analysis of variance to determine the presence of genotype x environment (G x E) interactions, and to regression analysis to assess the performance of clones across anvironments. Environments were assessed in two ways: (i) the mean response of all clones (dependent assessment), and (ii) the average performance of a different set of clones (independent assessment).The first experiment (Expt 1) produced higher yields but had fewer stable clones than the second (Expt 2).The analysis of variance revealed that the clones interacted significantly with environments for all traits.The study has identified high yielding and stable sweet potato clones for distribution to growers in the major areas of cultivation in the tountry. Despite slight differences in numbers of clones judged stable by the various regression indices in the two methods of environmental assessments, the rankings of clones on the basis of their linear regression coefficients were similar. In a developing country like Cameroon, with limited resources and where sophisticated equipment for obtaining physical or biological measures of the environment may be lacking, the mean performance of genotypes may still be the most reliable measure of environment in evaluating the stability of performance of crop cultivars.     

Screening sweet potato for source potentials

Summary Screening sweet potato, Ipomoea batatas, L., for source potentials is more difficult than for sink capacities. Twenty clones were grafted to four tester varieties to screen them for source potentials in relation to sink capacities which are interdependent. Source potential of a clone was measured by its average scion effect when grafted on the four tester varieties. There were significant differences in source potentials among the twenty clones. Seven clones were selected for having high source potentials. Clone TIS 2498 was the best. Degrees of response of source to sink were estimated using the regression method for twenty clones showed significant differences and ranged from b–0.45 to b=2.06. Source potential showed significant relationship (r=0.62^**) with response of source to sink. Implication of this approach to sweet potato breeding is discussed.     

表达bar基因的抗除草剂转基因甘薯的获得

用农杆菌介导法将bar基因导入甘薯主栽品种徐薯18的胚性悬浮细胞中,获得了抗除草剂的转基因植株.农杆菌菌株EHA105携带的双元载体pCAMBIA3300上含有bar基因.来自于徐薯18胚性悬浮细胞的直径为0.7～1.3 min的280个胚性细胞团用于遗传转化.共培养3 d后,首先在含有2 mg/L 2,4-D、100 mg/L Carb的液体MS培养基中培养1周,然后将胚性细胞团转移到添加2 mg/L 2,4-D、100 mg/L Carb 和0.3 mg/L PPT的固体MS培养基上进行选择培养.选择8周后,将获得的37个PPT抗性愈伤组织转移到添加1 mg/L ABA、100mg/L carb和0.3 mg/L PPT的固体MS培养基上,其中的34个愈伤组织诱导得到体细胞胚并发芽形成小植株,共获得了164株拟转基因植株.PCR分析表明,其中的123株为转基因植株.Southern blot和Northern blot分析表明,bar基因稳定整合到转基因植株的基因组中并正确表达.除草剂喷洒试验结果表明,转基因植株具有高度除草剂抗性.     

白骨壤酸性多糖的分离纯化及抗补体活性研究

采用热水浸提,乙醇沉淀,超滤,三氯乙酸脱蛋白,DEAE-纤维素柱层析脱色,再经DE-AE-Sepharosefastflow和SephacrylS-400层析,从白骨壤树枝分离纯化得到多糖化合物HAM-3-Ⅱb-Ⅱ,经高效凝胶过滤色谱法和比旋光度测定法鉴定为均一性组分,其重均相对分子质量(Mw)为105200,比旋光度为 27.54°。糖组成分析表明它为酸性杂多糖,主要由半乳糖醛酸、阿拉伯糖、半乳糖和鼠李糖组成。紫外光谱表明其不含核酸和蛋白质等杂质成分;红外光谱证实它是一种酸性果胶类多糖,以α型差向异构为主;补体结合实验表明,该多糖通过经典途径和替代途径共同作用产生显著的抗补体活性,并呈一定的剂量效应关系。     

铅、镉单一及复合污染对11个空心菜品种种子萌发和幼苗生长效应的影响

以11个品种的空心菜种子为研究对象,研究了不同浓度的铅、镉及其复合污染对不同空心菜种子萌发率、幼苗根长、苗高及生物量的影响,比较了不同处理对空心菜种子萌发和幼苗生长抑制效应的品种差异,旨在为重金属中轻度污染农田土壤栽培空心菜的品种选择及农产品质量安全保障提供参考。结果发现：铅、镉单一或复合污染对幼苗生长比种子萌发的抑制作用更明显,其中幼苗根生长对铅镉污染比种子萌发等指标更为敏感,因此将幼苗根生长作为评价重金属铅镉毒害的指标更为合理。随着铅、镉单一及铅镉复合污染浓度的加大,其对空心菜各品种幼苗生长的抑制作用也逐渐增大,且同样浓度下,铅镉复合污染往往比单一重金属污染的抑制率更高,说明铅镉污染存在协同效应。其中,对空心菜各指标的综合抑制效应在铅、镉单一污染下最高达48.78％和42.84％,而在铅镉复合污染时最高达59.73％。另外,不同品种对铅、镉污染的敏感性不同,通过比较,区分了3个耐铅镉污染品种和2个铅镉污染敏感品种。     

Enhanced Stem Nematode Resistance of Transgenic Sweetpotato Plants Expressing Oryzacystatin-I Gene

Enhanced stem nematode resistance of transgenic sweetpotato (cv. Lizixiang) was achieved using Oryzacyslatin-I (OCI)gene with Agrobacterium tumefaciens-mediated transformation. A. Tumefaciens strain EHA 105 harbors a binary vector pCAMBIA1301 with OCI gene, gusA gene and hptⅡ gene. Selection culture was conducted using 25 mg L-1 hygromycin. A total of 1715 plants were produced from the inoculated 1 450 cell aggregates of Lizixiang via somatic embryogenesis. GUS assay and PCR analysis of the putative transgenic plants randomly sampled showed that 90.54% of them were transgenic plants. Transgenic plants exhibited significantly enhanced resistance to stem nematodes compared to the untransformed control plants by the field evaluation with stem nematodes. Stable integration of the OCI gene into the genome of resistant transgenic plants was confirmed by Southern blot analysis, and the copy number of integrated OCI gene ranged from 1 to 4. Transgene overexpression in stem nematode-resistant plants was demonstrated by quantitative real-time PCR analysis. This study provides a way for improving stem nematode resistance in sweetpotato.     

不同生长方式对2种入侵植物形态特征和生物量分配的影响

研究入侵植物南美蟛蜞菊(Wedelia trilobata)和五爪金龙(Ipomoea cairica)在匍匐和攀援方式下的形态、生物量和构件生物量分配特征,结果表明:1) 匍匐的南美蟛蜞菊花数明显多于攀援的植株,差异极显著(p<0.01),而平均节间长显著(p<0.05)低于攀援植株。除平均节间长外,攀援的五爪金龙分枝节数、分枝叶片数、节总数、花数和叶总数均明显高于匍匐的植株。2)攀援的南美蟛蜞菊植株叶、节和花干重均极显著低于匍匐的植株。攀援的五爪金龙植株叶极显著高于匍匐的植株,节和花干重也高于匍匐的植株。3)匍匐的南美蟛蜞菊除花干重显著高于攀援的植株外,其余均无显著性差异。攀援的五爪金龙植株叶干重比极显著高于匍匐植株、花干重比显著高于匍匐的植株,而茎干重比则极显著低于匍匐的植株。说明南美蟛蜞菊和五爪金龙表现出在不同环境条件下具有较强的形态可塑性（尤其是五爪金龙）,这也许是二者具有较强入侵性和能够成功入侵的主要原因之一。     

基于银川地区水质的空心菜营养液配方验证试验

采用深液流(DFT)无土栽培技术,在优选出空心菜水培营养液配方的基础上,于二代节能日光温室内进一步研究验证了NO3-N、P、K、Ca四种元素对空心菜生长势、产量、品质及全氮、全磷及全钾含量的影响。结果表明:采用优选的最佳配方栽培的空心菜,其生长势、根系活力、产量、品质以及全氮磷钾含量均相对高于对照。基于宁夏银川地区水质的水培空心菜NO3-N、P、K、Ca四种元素的最优配方为:9、0.5、4.54、.0 mmol/L。