An oligonucleotide primer set (PaF/PaR) was designed for polymerase chain reaction (PCR) amplification of an approximately 1. 2kb fragment DNA from Paulownia Witches’ broom(PaWB) MLO on the basis of 16S rRNA sequence...An oligonucleotide primer set (PaF/PaR) was designed for polymerase chain reaction (PCR) amplification of an approximately 1. 2kb fragment DNA from Paulownia Witches’ broom(PaWB) MLO on the basis of 16S rRNA sequence from O-MLO. Amplification of a 1. 2kb DNA fragment from PaWB-MLO-infected plants DNA in total nucleic acid extrats of the host plant Paulownlh spp., but no l. 2kb DNA fragment was observed when healthy DNA was used as a template. The study showed that the PCR method was able todetect PaWB-MLO in as little as 9. 4pg of total DNA from infected Paulernia tissue culture plantlets.展开更多
The spatial pattern of paulownia witches＇ broom was investigated using an Iwao＇s （m^＊-m） model in Shaanxi Province, China. Iwao＇s （m^＊-m） model revealed that spatial pattern of paulownia witches＇ broom exhib...The spatial pattern of paulownia witches＇ broom was investigated using an Iwao＇s （m^＊-m） model in Shaanxi Province, China. Iwao＇s （m^＊-m） model revealed that spatial pattern of paulownia witches＇ broom exhibited a uniform distribution in sample plots. In this model, characteristics of contagiousness coefficient （a） justified the probability of infection by virus-transmission vectors. For tree age less than six, susceptible individuals were aggregated as clusters in the plots and then mutually repelled over age. A preliminary survey of stand volume show that from age five to six, stand volumes of disease grade II showed excessive vegetative growth and returned to normal level between ages ten and 11. Loss rate of volume increment with disease grade II decreased, and then returned to raising trend both at grades III and IV. This phenomenon is possibly caused by an over-compensation effect and by environmental factors. The redundancy of growth hormones in branches, shoots, leaves, buds and roots increased the stem volume of entire trees.展开更多
文摘An oligonucleotide primer set (PaF/PaR) was designed for polymerase chain reaction (PCR) amplification of an approximately 1. 2kb fragment DNA from Paulownia Witches’ broom(PaWB) MLO on the basis of 16S rRNA sequence from O-MLO. Amplification of a 1. 2kb DNA fragment from PaWB-MLO-infected plants DNA in total nucleic acid extrats of the host plant Paulownlh spp., but no l. 2kb DNA fragment was observed when healthy DNA was used as a template. The study showed that the PCR method was able todetect PaWB-MLO in as little as 9. 4pg of total DNA from infected Paulernia tissue culture plantlets.
文摘The spatial pattern of paulownia witches＇ broom was investigated using an Iwao＇s （m^＊-m） model in Shaanxi Province, China. Iwao＇s （m^＊-m） model revealed that spatial pattern of paulownia witches＇ broom exhibited a uniform distribution in sample plots. In this model, characteristics of contagiousness coefficient （a） justified the probability of infection by virus-transmission vectors. For tree age less than six, susceptible individuals were aggregated as clusters in the plots and then mutually repelled over age. A preliminary survey of stand volume show that from age five to six, stand volumes of disease grade II showed excessive vegetative growth and returned to normal level between ages ten and 11. Loss rate of volume increment with disease grade II decreased, and then returned to raising trend both at grades III and IV. This phenomenon is possibly caused by an over-compensation effect and by environmental factors. The redundancy of growth hormones in branches, shoots, leaves, buds and roots increased the stem volume of entire trees.
