超声波辅助提取紫苑总黄酮的工艺研究

[目的]探索超声波辅助提取紫苑总黄酮的最佳工艺条件,以充分合理利用紫苑资源。[方法]以紫苑提取干浸膏中总黄酮的含量为指标,采用单因素和正交试验确定超声波辅助提取紫苑总黄酮的工艺条件。[结果]最佳的工艺条件为：提取溶剂乙醇浓度为65%,超声时间为30 min,料液比为1∶25,超声次数为3次。[结论]超声波辅助提取紫苑总黄酮的工艺具有提取温度低、时间短、得率高的优点,适用于紫苑总黄酮的提取。     

吸湿-回干处理对人工老化翠菊种子活力的影响

[目的]研究人工老化及吸湿一回干处理对翠菊种子活力的影响,旨在为合理的贮存与使用翠菊种子提供科学依据。[方法]供试种子在45℃、100％RH下进行老化处理。老化后种子在20℃条件下进行吸湿,25℃下回干及发芽测定。[结果]试验结果表明,在45℃、100％RH高温高湿条件下处理翠菊种子,对翠菊种子有快速老化的作用,其主要的活力指标呈明显降低趋势,随着老化处理时间的延长,种子的发芽指数（F=1257．73〉F0.01=4.82）与活力指数（F=385614.42〉F0.01=4.82）明显下降。老化处理时间达到60h后,翠菊种子的发芽率只剩下50％。对经过人工老化后吸湿一回干处理的翠菊种子进行发芽率（F=600．06〉F0.01=4．82）和发芽势（F=543．44〉F0.01=4．82）的测定显示,经吸湿-回干处理后可以明显缓解高温对种子劣变的影响,不同程度地提高发芽率与发芽势。[结论]吸湿-回干处理可部分消除高温高湿对翠菊种子所造成的伤害,明显提高翠菊种子的活力。     

Detection and characterization of the phytoplasma associated with a phyllody disease of black pepper (Piper nigrum L.) in India

Using polymerase chain reaction (PCR), the phytoplasma was detected in black pepper (Piper nigrum) with phyllody symptoms in India. A 1.20 kb DNA fragment encoding the portion of phytoplasma 16S rDNA consistently amplified by nested PCR was cloned and sequenced. The sequenced region contained 1230 nucleotides. Sequence analyses showed that the gene was most closely related to members of aster yellows group (16Sr I) of phytoplasma. The sequence identity with members of aster yellows group (16Sr I) was >98% while that with members of other groups (16Sr II to 16Sr XV and other undesignated groups) ranged from 87 to 96%. On the basis of sequence identity and phylogenetic relationship studies, it is concluded that phytoplasma infecting black pepper in India belongs to aster yellows group. This is the first report of identification of phytoplasma in black pepper.