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71.
三个萝卜主产区软腐病病原菌的分离与鉴定   总被引:1,自引:0,他引:1  
为有效防治萝卜(Raphanus sativus L.)软腐病,提高萝卜产量和质量,从江苏徐州、浙江萧山和湖北利川3个萝卜主产区分别采集萝卜软腐病病样并进行病原菌的分离鉴定及致病力测定。通过结合菌落形态、生理生化指标测定和16S r DNA基因序列分析,确定3株病原菌属于胡萝卜果胶杆菌(Pectobacterium carotovorum)的2个亚种,其中2株为Pectobacterium carotovorum subsp.brasiliense,另1株为Pectobacterium carotovorum subsp.carotovorum。致病力测定分析表明,3株病原菌的致病力存在显著差异,随温度的升高均呈现出增强的趋势。  相似文献   
72.
葛姝君  赵丹  周雪  孙晴  刘林 《园艺学报》2016,43(10):2021-2028
对黄瓜不同发育阶段叶片中的脂滴进行超微观察,以期了解衰老叶内脂滴降解的场所。结果表明,衰老叶片中部分质体小球在叶绿体内降解,降解先从小球一侧开始,向另一侧推进。衰老叶片含有胞质脂滴,有些胞质脂滴紧贴叶绿体,显示其发生与叶绿体密切相关;有些胞质脂滴与液泡密切接触,并向液泡内转运,进入液泡后发生降解。显然,黄瓜叶衰老不仅引起脂滴在液泡内降解,也引起脂滴在叶绿体内原位降解,证明液泡并不是脂滴降解的唯一场所。  相似文献   
73.
β-腈基丙氨酸合成酶(CASase)是调控山黧豆(Lathyrus sativus)内源毒素β-ODAP合成的关键酶。本研究以山黧豆幼根RNA为模板,利用RT-PCR扩增了505 bp的山黧豆CASase基因序列;通过Gateway BP反应将扩增片段连接到入门载体构建pENTR-CASase。经测序验证后,将目的片段插入到植物表达载体构建pSGRNAi-CASase,并将其转化到农杆菌GV3101中;为进一步的遗传转化奠定了基础。  相似文献   
74.
A greenhouse experiment was conducted to study the effects of cadmium (Cd) on growth, biomass yield, and Cd uptake in three radish (Raphanus sativus L.) varieties at the Indian Institute of Horticultural Research, Bangalore, India, during 2008–2009. Plants were subjected to different Cd levels by application of cadmium nitrate [Cd (NO3)2] at the rates of 0, 50, 100, and 200 mg Cd kg?1 soil. Length and fresh and dry biomass yields of shoots and roots decreased because of the phytotoxic effect of Cd. Among three varieties, Japanese White Long showed the greatest sensitivity to Cd toxicity. The accumulation of Cd in shoots and roots was greatest in Japanese White Long, which had greater bioconcentration factor values. Variety Arka Nishanth recorded lower bioconcentration factor values and greater transfer coefficient values, indicating lower Cd accumulation in root tubers in this variety. Hence, variety Arka Nishanth can be preferred in Cd-contaminated soils.  相似文献   
75.
Limited information is available on biological effects of various levels of nickel (Ni) (deficiency to toxicity levels) on growth and yield of certain crops, particularly vegetables. In this sand‐culture study, we investigated the effects of four levels of Ni (0, 50, 100, and 200 μM) on growth, yield, and fruit‐quality attributes of two cucumber cultivars (Cucumis sativus L. cvs. Super Dominus and Negin) supplied with urea or NH4NO3 as nitrogen source. Addition of 50 μM Ni to the nutrient solution resulted in a significant increase of shoot and root dry‐matter yield of cv. Negin although this increase was greater in the urea‐fed plants than those fed with NH4NO3. In both cultivars, addition of 50 μM Ni increased urease activity and thereby decreased the urea concentration in the urea treatment. Addition of 100 and 200 μM Ni caused a significant decrease in root and shoot growth of cucumber although this decrease was insignificant for cv. Super Dominus in the 100 μM treatment. The highest fruit yield, total soluble solids (TSS), and fruit firmness were achieved at the 50 μM Ni treatment. Regardless of nitrogen source, Ni addition proportional to the concentration used increased leaf Ni concentration and fruit acid ascorbic concentration. The concentration of Ni required for optimum growth and yield of cucumber varied with cultivars. The level of 50 μM was sufficient for optimum growth of cv. Negin in nutrient‐solution culture while lower concentration of Ni was required for cv. Super Dominus. While the beneficial effects of sufficient levels of Ni on growth and yield of urea‐fed plants was greater than with NH4NO3‐fed plants, the toxic effects of Ni in these plants were also greater.  相似文献   
76.
黄瓜发芽期耐冷性与赖氨酸脱羧酶基因表达   总被引:5,自引:0,他引:5  
 经15℃低温诱导,采用cDNA-AFLP技术从耐冷性强的黄瓜品种长春密刺中分离到一条特异片段,该片段在耐冷性弱的北京截头中不能被诱导,命名为cctr132。将cctr132回收测序并翻译为氨基酸序列,用blastx和blsatp程序在NCBI GenBank数据库中进行同源性检索和相似性比对,结果发现cctr132与水稻推测的类赖氨酸脱羧酶蛋白同源性为88.37%,相似性为100%,并且在CCTR132中检测到了赖氨酸脱羧酶家族推测的保守结构域PGGXGTXXE,说明黄瓜发芽期耐冷性与赖氨酸脱羧酶基因表达有关。  相似文献   
77.
The detoxification of L. sativus grains by spraying of 0.5 ppm cobalt (nitrate) and 20 ppm molybdehum (ammonium molybdate) salts at the maximun flowering stage ‐ a suggestion based on preliminary findings ‐ has been confirmed in this investigation. Regulatory mechanisms of these micronutrients at the enzymatic level were also studied. On the basis of these observations, the involvement of a hitherto unknown biosynthetic pathway of BOAA cannot be ruled out.  相似文献   
78.
Iron and Zn absorption, interactions, and Cu inhibitions were characterized in cucumber (Cucumis sativus L.), watermelon (Citrullus lanatus Thunb.), and pumpkin (Cucurbita moschata Poir.) by kinetic parameters Vmax and Km. Influx and Vmax values for Fe and Zn absorption decreased in each species as plant age increased. For the Michaelis constant, Km, Fe values in cucumber and watermelon and Zn values in watermelon and pumpkin were relatively unchanged with increased plant age. Km values for Zn absorption in cucumber and Fe absorption in pumpkin decreased as plant age increased. Among species, watermelon appeared to have a particularly effective uptake mechanism for Zn at low solution concentrations. Non‐competitive inhibition of Zn absorption by Fe (20, 50 uM) was indicated in each species. Iron uptake in pumpkin was inhibited non‐competitively by Zn (5, 10 uM), however no significant effects of Zn on Fe absorption were evident in either watermelon or cucumber. Copper (0.5, 1, 5 uM) inhibited uptake of Fe non‐competitively and Zn competitively in each species.  相似文献   
79.
Abstract

A salt-sensitive cucumber cultivar “Jinchun No. 2” (Cucumis sativus L.) was used to investigate the role of proline in alleviating salt stress in cucumber. Proline was applied twice (day 0 and day 4 after salt treatment) as a foliar spray, with a volume of 25?mL per plant at each time. Plant dry weight, leaf relative water content, proline, malondialdehyde (MDA), Na+, K+ and Cl? contents, as well as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) activities in the plants were determined at day 8 after salt treatment. The results showed that 100?mmol?L–1 NaCl stress significantly decreased plant dry weight, leaf relative water and K+ contents, and increased leaf MDA, Na+ and Cl? contents and SOD, POD, CAT and APX activities. However, leaf proline accumulation was not affected by salinity. The exogenous application of proline significantly alleviated the growth inhibition of plants induced by NaCl, and was accompanied by higher leaf relative water content and POD activity, higher proline and Cl? contents, and lower MDA content and SOD activity. However, there was no significant difference in Na+ and K+ contents or in CAT and APX activities between proline-treated and untreated plants under salt stress. Taken together, these results suggested that the foliar application of proline was an effective way to improve the salt tolerance of cucumber. The enhanced salt tolerance could be partially attributed to the improved water status and peroxidase enzyme activity in the leaf.  相似文献   
80.
This work studied the behavior of different iron (Fe)-chelates as substrates of ferric chelate reductase (FCR) and their ability as Fe suppliers for mildly chlorotic plants. FCR activity and Fe concentration in xylem sap were determined in green stressed cucumber plants with different stress levels using different synthetic chelates as substrates. Both reduction and Fe concentration in the xylem sap were higher for the less-stable Fe chelates, except for Fe-EDTA, which presented a relatively low Fe concentration in sap. It was concluded that a high stability of the chelate in the nutrient solution reduces the Fe reduction, but other factors, such as the complexation of the Fe(II) by the chelating agents, should be considered when the complete process of Fe uptake is studied. The use of both indexes together, i.e., FCR determination and xylem sap concentration, is useful for understanding the Fe uptake from different Fe chelates.  相似文献   
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