Abstract:

The influences of silicon (Si) on the signaling systems of phosphoinositides and calmodulin (CaM) in flowering Chinese cabbage (Brassica Campestris L. ssp. Chinensis var. utilis Tsen et Lee ) was studied using the inoculation of anthracnose (Colletotrichum higginsianum) at different Si levels. Results indicated that Si played a manifest regulating role on the formation of phosphatidylinositol (PI) and phosphatidylinositol-4-monophosphate (PIP). After the infection by anthracnose, there were clearly different fluctuations of PI contents between different cultivars . At the suitable Si level, infection induced high PI content. Due to the infection, PI content increased manifestly in the susceptible cultivar at medium Si level and in the resistant cultivar at low and medium Si levels, but showed unstable trend in other treatments. The accumulation of PIP was inhibited at the early infection stage and turned to be promoted at the late infection stage in the susceptible cultivar, but the accumulation pattern of PIP was completely reverse in the resistant cultivar. At suitable Si level, the infection by anthracnose manifestly increased PIP contents in both susceptible and resistant cultivars, especially in the late infection stage with stronger induction. This is probably related to the degradation of PI in large amount and the transfer of disease-resisting signals at the late infection stage. Si also affected the CaM contents, with the extents relating to the infection by anthracnose. Low Si level clearly promoted the inducing effect of anthracnose on CaM in the susceptible cultivar, while medium Si level showed strong promoting effect on the
收稿日期：2008-01-02 ；修回日期：2008-

Key words: Brassica campestris L. ssp. Chinensis var. utilis Tsen et Lee, silicon, Colletotrichum higginsianum, phosphoinositide, calmodulin