Isolation and identification of pathogen of seedling blight of Platycodon grandiflorum / 中国中药杂志

<p><b>OBJECTIVE</b>To isolate and identify pathogen of the seedling blight occurred in Platycodon grandiflorum.</p><p><b>METHOD</b>The morphological observation, rDNA ITS sequence analysis, and Koch's postulates were used to identify the isolates of the causal agent.</p><p><b>RESULT</b>The isolates of the causal agent was Rhizoctonia solani.</p><p><b>CONCLUSION</b>The result confirmed that R. solani is the pathogen of seedling blight of P. grandiflorum.</p>

Study on the stigma/pollen vigor and self-compatibility of Platycodon grandiflorum / 中国中药杂志

<p><b>OBJECTIVE</b>To provide the basal data for the breeding and cultivation of Platycodon grandiflorum.</p><p><b>METHOD</b>The field investigation and pollination by bagging were carried out. TTC(2,3,5-triphenyl tetrazolium chloride) solution was used to test the pollen vigor.</p><p><b>RESULT</b>The stigma life-span of P. grandiflorum was about 9 days, however the optimal time for pollination is 4-6 days after the petals opening, with the stigma was splitting lightly or significantly. When the petals opened, the anther began scattering pollen, and finished in the same day. The pollen vigor was about 81.4% at the beginning, and decreases to 27.6% three days later. The pollen vigor still remains 64.4% three days later, when the flower was kept in the desiccant. The natural fructification rate of self-flower-pollination was 4.8%. The fructification rate and compatible index was about 62.7% and 54.6, respectively, when the self-plant-pollination performed by hand. They decreased to 12.8% and 6.5 when the pollination was implemented during the flowering period.</p><p><b>CONCLUSION</b>Low fructification percentage of self-flower-pollination attributes to the difference of maturing period of pistil and stamen, as well as the short pollen life-span of P. grandiflorum. The compatibility of self-plant-pollination is high during flowering period when pollination performed by hand. The life-span of the pollen can be prolonged significantly when keeping in the dry environment.</p>

The influence of seed maturity and seed coat on the germination of Bupleurum chinense and B. falcatum / 中国中药杂志

<p><b>OBJECTIVE</b>To investigate the factors influencing the seed germination of Bupleurum chinense and B. falcatum.</p><p><b>METHOD</b>The seeds of different maturity, and the seeds whose coat were removed or nicked before dipping in water, were germinated in a light growth chamber.</p><p><b>RESULT</b>The different inflorescence level represents different development period. Seeds harvested from cultivation have different maturity. The germination rate of the seeds in period I to III was nearly zero, and it was significant different from period IV to VII. The seed coat is not an obstacle for water absorption or gas exchange, but its removal led to significant increase of seed germination rate. However, to dip the seeds without coat into water for 48 h had no more effect on germination.</p><p><b>CONCLUSION</b>The seed maturity and germination inhibitors in seed coat are two important factor influencing seed germination in B. chinense and B. falcatum.</p>