To study Ptcor8 expression related to the defoliation of Poncirus trifoliate Raf. and the temperature, 2-year-old seedlings of 60 potted Poncirus trifoliata Raf. with similar diameter, in the temperature-controlled chamber (20～25 ℃), were transferred to the field every 10 d from the 14th November, 2008 to January of next year, meanwhile, another 10 seedlings were put in the field as the control. The Poncirus trifoliate Raf. seedlings in the temperature-controlled chamber and those transferred to the field after the 14th December were non-deciduous. However, those transferred to the field before the 14th December was deciduous, and their defoliating period delayed along with the time outside the temperature-controlled chamber. In the deciduous and the non-deciduous the expression of Ptcor8 gene was both detected. Furthermore, by qPCR, the more changes of temperature and the longer duration of low temperature, the higher expression of Ptcor8. Therefore, the expression of Ptcor8 gene may not be directly related to the physiological defoliation of Poncirus trifoliate Raf., but rather closely related to low temperature induction.

Citrus is a sort of very valuably subtropical fruits which frequently suffers from the influence of cold climates. In present paper is an attempt to summarize achieves in research of citrus’ cold resistance and to introduce some latest results which in citrus still remain in vain of other plants’ cold tolerance. Then it is suggested that some work be made concerning cold-induced proteins, cold-induced genes, and gene engineering of cold resistance in citrus plants.

In order to establish a quick and reliable identification system for the main Citrus viruses,total RNA was isolated from the sampled trees showing typical symptoms of Citrus tristeza virus(CTV),Citrus exocortis viroid(CEV) and Citrus tatter leaf virus(CTLV) for RT-PCR analysis.Three pairs of primers specific for CTVt,wo for CEV and one for CTLV,were tested for the corresponding viruses’ identification.Results indicated that all of the tested primers could generate specific products at the unique anneal temperatures of 56 ℃.More samples showing CTV,CEV or CTLV symptoms from Yunnan province,Chongqing city and Hunan province were tested by the established indexing technique,and the results indicated that the RT-PCR method was reliable for the identification of these Citrus viruses.

为建立大红甜橙的再生及遗传转化体系,提高转化芽的成株率,以30 d龄的大红甜橙(Citrus sinensisOsbeck)实生苗上胚轴为材料,导入rolB基因,进行遗传转化研究.结果表明:MS+3.0 mg/L 6-BA培养基诱导不定芽的效果最好,达95%以上.遗传转化时,采用培养基Ⅱ(MS+3mg/L6-BA+200μmol/LAs)+培养基Ⅳ(MT+3 mg/L 6-BA+50 mg/L Kan+500 mg/L Cef)组合的抗性芽诱导最快,诱导率为51%.用微芽嫁接的方法,将抗性芽嫁接到卡里佐枳橙上,成苗良好,已获得19株转rolB基因植株,盆栽在温室中生长良好.