Growth of Xanthomonas campestris pv. campestris populations at constant and variable temperatures

Quantitative data were collected to describe the relation between temperature and growth of the cabbage black rot pathogen,Xanthomonas campestris pv.campestris (Xcc). Relative growth rates derived from experiments at constant temperatures were used in dynamic simulation of bacterial population development. The relative growth rates were adequate to simulate growth ofXcc populations at constant temperatures but overestimated growth of populations at variable temperatures. This finding gives rise to the hypothesis, that under field conditions, disease development is slower than is expected on the basis of growth parameters obtained from studies with constant temperatures.     

双冠大白菜的选育

双冠大白菜是利用耐热大白菜Ｈｙｂｒｉｄ６２＃和中熟秋大白菜山东４号分离后代的两个自交不亲和系材料配制而成的一代杂种。生长期６０～６３天,抗病毒病和霜霉病,耐软腐病。平均每６６７ｍ２产净菜３５００ｋｇ。叶球为矮桩头球形。球叶色白,品质优良,商品性好。该品种已在江苏、浙江、安徽、四川、云南、贵州、河南等地推广种植。     

Flower formation of Chinese cabbage. I. Response to vernalization and photoperiods

The influence of temperature, vernalization duration and photoperiods on the leaf number and beginning of bolting of Chinese cabbage was tested in growth chambers. An increasing effect of vernalization was indicated by decreasing leaf number and premature bolting. Sensitiveness for vernalization started with germination and remained constant with increasing plant age. During their development on mother plants, seeds were not vernalized.Inductive temperature ranged between 0 and 20°C. The necessary vernalization duration was lowest at 5–8°C. For slight vernalization effects one week was sufficient; for complete vernalization about 3 weeks were needed. To achieve the same effect, the necessary vernalization duration increased considerably at temperatures below 5°C, but increased only slightly at temperatures above 8°C.Long days promoted bolting when the temperature rose after incomplete vernalization. In constant low or high temperature, no photoperiodic effect was perceptible.     

钙处理对白菜生长发育及货架寿命的影响

以白菜为试材,研究了不同浓度氯化钙对其生长特性及货架寿命的影响。结果表明:(1)低浓度钙处理能促进白菜的生长发育,提高其产量,其中以0.25?Cl2处理效果最好;(2)钙处理可明显降低白菜腐烂率,增加组织中钙的含量,抑制白菜的膜脂过氧化作用,降低质膜透性和呼吸强度,延长白菜的货架寿命。其中以1.0?Cl2处理延缓组织衰老腐烂效果最好。     

利用煤矸石基质进行小白菜无土栽培研究

以小白菜为材料,分析了脱硫煤矸石基质对小白菜的生长及产量品质的影响.结果表明:在脱硫煤矸石基质上,幼苗成活率在90%以上;植株的生长速率、光合速率、产量均高于土壤,与炉渣相接近.且脱硫煤矸石中的小白菜品质高于土壤中,表现为NO-3含量降低和维生素C含量的提高.脱硫处理的煤矸石作为无土栽培基质是可行的.     

紫色大白菜育种思路初探

应用大白菜与紫色小白菜亚种间杂交转育紫色性状,获得2份紫色大白菜中间材料。比较了转育获得的紫色大白菜与普通大白菜的外叶颜色、球内叶颜色以及包球的球色等。结果表明,转育紫色小白菜获得的紫色大白菜材料只在叶片的正面表现紫色,而叶片的反面依然表现绿色;剖开后的剖面表现为紫色、白色和黄色相间排列的几种颜色。研究认为,该类型的紫色材料可以在小白菜、半包球大白菜,如快菜类型和娃娃菜等紫色品种中应用,所育成的大白菜品种可以作为拼盘搭色时凉拌或做汤食用,效果会更佳。桔红心品种的VC含量在4种球色大白菜品种中最高。初步探讨了国内外紫色大白菜研究的育种思路和应用进展。     

活性炭和振荡培养对提高大白菜胚诱导率的影响

以11个大白菜品种(品系)为材料,采用NLN培养基进行游离小孢子培养,研究了活性炭和振荡培养对小孢子胚诱导和形成的影响。结果表明:11个大白菜品种有9个诱导出胚,每花蕾诱导胚数0.056～12.67个。在NLN-13培养基中添加活性炭(0.5g/L),有利于小孢子胚的诱导和形成,Y536和Y585胚诱导率分别提高了16.1和4.8倍,极难诱导出胚的材料Y516也诱导出胚;采用振荡培养方式(65r/min),Y531和Y445胚诱导率较静置培养分别提高了18.23%和30.91%,出胚时间提早2～4d。     

野生甘蓝的研究进展及展望

甘蓝近缘野生种又称野生甘蓝,与栽培甘蓝携带相同的C基因组(2n=18,CC),具有丰富的遗传变异和优良的抗逆性。野生甘蓝的挖掘与利用对于栽培甘蓝的遗传改良具有重要意义。就野生甘蓝的种类、分布、与栽培甘蓝的关系及优良性状等进行了综述。     

盈江县高山大白菜根肿菌生理小种鉴定及抗源筛选

采用Williams鉴别系统对云南省盈江县高山大白菜产区采集的根肿菌进行鉴定,4个鉴别寄主均表现为感病,病情指数分别为21、33、28、30,说明该根肿菌为4号生理小种。采用菌土法接种盈江根肿菌,对18个抗根肿病大白菜品种进行抗性鉴定,其中6个品种发病率和病情指数均为0,对盈江根肿菌表现免疫;2个品种病情指数10,表现抗病,可以作为该病区大白菜新品种选育的抗性遗传资源。