Differences in the Activation State of Ribulose-1,5-bisphosphate Carboxylase/Oxygenase in Barley,Pea, and Wheat at Two Altitudes

Activation state of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPCO) is an important parameter determining the rate of net photosynthesis (P _N) in situ for which no information is available with reference to altitude. We analyzed activation state along with P _N in three plant species and their cultivars grown at low (LA, 1 300 m) and high (HA, 4 200 m) altitudes. No significant change in P _N and the initial activity of RuBPCO was obtained with reference to altitude. However, activation state of RuBPCO was reduced significantly in the HA plants as compared to the LA ones. Hence low partial pressure of CO₂ prevailing at HA might be responsible for the lower activation state of RuBPCO.     

Effect of Pathogen Isolate, Potato Cultivar, and Antagonist Strain on Potato Scab Severity and Biological Control

Antibiotic-producing Streptomyces spp. have shown potential in biocontrol of potato scab caused by Streptomyces scabies. However, results have been inconsistent among field trials. Pathogen isolate, antagonist strain and potato cultivar were investigated as potential sources of variation in the efficacy of potato scab biocontrol. Biocontrol success varied significantly among pathogen isolates and was not correlated with in vitro sensitivity to antibiotic inhibition. Antagonists also varied in their effectiveness as biocontrol agents, and the relative effectiveness of different antagonists varied among growing seasons. Finally, biocontrol varied among potato cultivars in the field. The diverse origins of significant variation in potato scab biocontrol suggest that consistent control in the field is likely to be difficult to achieve.     

江苏省稻瘟病菌的毒性多样性及水稻品种的抗病性

在13个已知日本抗病基因品种上检测1997－1999年采集自江苏省吴江,赣榆,通州,高邮和宜兴等5个代表地区的324个稻瘟病菌株的毒性,结果可将上述菌株划分为90种毒性类型,表明江苏省稻瘟病菌存在着丰富的毒性多样性,毒性类型组成在地区间存在较大的差异,并且随着时间的推移,稻瘟病菌毒性类型组成有差异加大的趋势,在已知抗病基因品种上测定江苏省稻瘟病菌的毒力,结果显示：Pi-k^3,Pi-ta,Pi-ta^2和Pi-sh等抗病基因对江苏省的稻瘟病菌的抗谱很窄,而Pi-i,Pi-z,Pi-z^t和Pi-b等抗病基因的抗谱比较宽,可作为抗源加以利用,用6个代表性毒性类型菌株接种江苏省80筱水稻主载品种和新育成品种,品种抗性分析表明,上述水稻品种中的籼稻和杂交稻对江苏省稻瘟病菌具有较高的抗性,而粳稻品种的抗性较差,上述研究结果为利用水稻品种抗性多样性控制稻瘟病提供了依据。     

CH4 emission with differences in atmospheric CO2 enrichment and rice cultivars in a Japanese paddy soil

A pot experiment was conducted to investigate CH₄ emissions from a sandy paddy soil as influenced by rice cultivars and atmospheric CO₂ elevation. The experiment with two CO₂ levels, 370 μL L⁻¹ (ambient) and 570 μL L⁻¹ (elevated), was performed in a climatron, located at the National Institute for Agro‐Environmental Sciences, Tsukuba, Japan. Four rice cultivars were tested in this experiment, including IR65598, IR72, Dular and Koshihikari. Tiller number, root length and grain yield were clearly larger under elevated CO₂ than under ambient CO₂. IR72 and Dular showed significantly higher tiller number, root length and grain yield than Koshihikari and IR65598. Average daily CH₄ fluxes under elevated CO₂ were significantly larger by 10.9–23.8% than those under ambient CO₂, and varied with the cultivars in the sequence Dular ≧ IR72>IR65598 ≧ Koshihikari. Dissolved organic C (DOC) content in the soil was obviously higher under elevated CO₂ than under ambient CO₂ and differed among the cultivars, in the sequence IR72>Dular>Koshihikari>IR65598. The differences in average daily CH₄ fluxes between CO₂ levels and among the cultivars were related to different root exudation as DOC content, root length and tiller number. This study indicated that Koshihikari should be a potential cultivar for mitigating CH₄ emission and simultaneously keeping stable grain yield, because this cultivar emitted lowest CH₄ emission and produced medium grain yield.     

Identification of Prunus armeniaca cultivars by RAPD and SCAR markers

Nineteen cultivars of apricot (Prunus armeniaca) were distinguished using random amplified polymorphic DNA (RAPD) markers. One decamer out of 44 used was useful to differentiate cultivars of the Campania Region from those of Northern Italy, North America and Greece. A sequence characterized amplified region (SCAR) marker was obtained. The results provide a protocol to fingerprint DNA of apricots as an efficient way to quality control and fraud prevention.     

褐稻虱生物型变异动态监测及抗虫品种资源推荐

本文报道近十多年来广东省褐稻虱Nilaparvata lugens(Stal)生物型变异动态监测的研究结果,针对当前褐稻虱优势生物型及发展趋势,推荐优良的抗褐稻虱品种资源。监测结果表明;根据苗期抗性反应,分蘖期生存率测定,田间系统调查监测,广州褐稻虱田间种群对带有Bph1抗性基因的代表品种IR26的致害力不断增强,1992年以来抗性反应达生物型2的水平。1992～1994年在全省7个不同生态类型地区取样测定及验证试验结果表明,生物型 2已上升为广东褐稻虱田间主害代的优势种群。多年的抗性鉴定结果证实,外引品种IR56、IR50404同其对应亲本PTB33、Babawee一样,对褐稻虱的抗性稳定,已推荐用作进一步抗 性育种的优良抗源。粳籼89等23个品种能抗褐稻虱生物型1和2,可及时替代带即BPh1抗性 基因的品种。     

Screening for Barley yellow dwarf virus-Resistant Barley Genotypes by Assessment of Virus Content in Inoculated Seedlings

The content of Barley yellow dwarf virus (BYDV) in roots and leaves of barley seedling plants differing in their level of resistance was assessed by quantitative ELISA 1–42 days after inoculation with the strain of BYDV (PAV). High virus accumulation in roots and low concentration in leaves was characteristic of the period 9–15 days after inoculation. In leaves, the differences in virus content between resistant and susceptible genotypes became significant after 15 days and resistance to virus accumulation was better expressed 30–39 days after inoculation. Roots of resistant materials exhibited evident retardation of virus accumulation and the greatest difference in virus content between resistant and susceptible plants was detected 9 days after inoculation. By these criteria, the selected winter and spring barley cultivars and lines (in total 44 materials) fell in to five groups according to field reactions and the presence or absence of the Yd2 resistance gene. There were highly significant and positive relations between ELISA values and 5‐year field data on symptomatic reactions and grain‐yield reductions due to infection. Using the described method, resistant and moderately resistant genotypes (both Yd2 and non‐Yd2) were significantly differentiated from susceptible genotypes. The possible use of this method in screening for BYDV resistance is discussed.     

RAPD技术与桂花品种分类和鉴定

简介了随机扩增多态ＤＮＡ（ＲＡＰＤ）技术的原理,及对桂花品种分类鉴定的必要性,并建议开展ＲＡＰＤ技术在桂花品种分类鉴定的应用研究。     

光照强度及栽培基质对秋海棠新品种‘宁明银’生长的影响

秋海棠是世界著名的观赏植物,不同种类和品种对栽培基质、光照、温度和湿度等生长环境条件的要求不同。‘宁明银’秋海棠是最近培育出的新品种,具有很高的观赏价值和市场潜力,但其栽培适宜条件还不清楚。为了摸索该品种的最佳栽培基质和光照条件,该研究利用四种光强(遮光45%、60%、75%、90%)和四种无土栽培基质(泥炭∶珍珠岩=1∶1;泥炭∶珍珠岩∶松树皮=1∶1∶1;腐叶土∶珍珠岩∶松树皮=1∶1∶1;玉米秆∶珍珠岩∶松树皮=1∶1∶1)在上海辰山植物园栽培大棚中开展盆栽试验,比较分析‘宁明银’秋海棠的生长表现。结果表明:在遮光45%条件下,腐叶土、珍珠岩、松树皮同等比例混合的栽培基质中,‘宁明银’秋海棠的叶片数、最大叶面积、地上部分鲜重与干重、地下部分干重均表现出最大值,且该条件下植株的相对含水量和根冠比最小,相对叶绿素含量也最高。因此,盆栽‘宁明银’秋海棠的最佳无土栽培条件为腐叶土、珍珠岩、松树皮等比例混合栽培基质和45%遮光,利用此条件可指导‘宁明银’秋海棠的商品化盆栽生产。