[Research of chemotaxis response of Botrytis cinerea and Alternaria panax on total ginsenosides].

In this paper, three kinds of chemotactic parameters (concentration, temperature and pH) were determined by plate assay and spore germination method to research the chemotactic response of Botrytis cinerea and Alternaria panax, and their spores on total ginsenosides. The results showed that Botrytis cinerea had strong chemotactic response at the mid-concentration of total ginsenosides (cultivation temperature was 20 degrees C and pH value was 6), and the data of chemotactic migration index (CMI) was 1.293 0, chemotactic growth rate (CGR) was 0.476 0, spore germination rate (SGR) was 53%, and dry weight of mycelial (DWM) was 0.452 6 g x L(-1); however, Alternaria panax had strong chemotactic response at the low-concentration of total ginsenosides (cultivation temperature was 25 degrees C and pH value was 6), and the data of chemotactic migration index (CMI) was 1.235 4, chemotactic growth rate (CGR) was 0.537 0, spore germination rate (SGR) was 67%, and dry weight of mycelial (DWM) was 0.494 8 g x L(-1). The results indicated that the low and middle concentration (2, 20 mg x L(-1)) of total ginsenosides had significant promoting effect on chemotactic response of these two pathogens, and the spore germination, mycelial growth rate, dry weight of mycelial of them were also significantly improved by this chemotactic response, whereas it decreased as the increase of total ginsenosides concentration.