Effects of silicon on flowering Chinese cabbage''''s anthracnose occurence, flower stalk formation, and silicon uptake and accumulation
硅对菜心炭疽病发生、菜薹形成及硅吸收沉积的影响

Different concentrations of silicon (Si) were applied to flowering Chinese cabbbage (Brassica campestris L. ssp. chinensis var. utilis Tsen et Lee) to study their effects on the flowering Chinese cabbage's anthracnose occurrence, flower stalk formation, and Si uptake and accumulation. The results indicated that Si could obviously control the occurrence of anthracnose, and the effect was genotype-dependant. The plants of susceptible cultivar applied with 2.5 mmol L(-1) Si and those of resistant cultivar applied with 0.5 mmol L(-1) Si exhibited the highest resistance to Colletotrichum higginsianum, with the lowest disease index and the higheist flower stalk yield. Si application also obviously affected the quality of flower stalk. For susceptible cultivar, Si application promoted the synthesis of chlorophyll, crude fiber and vitamin C, and induced the formation of soluble sugars. The contents of chlorophyll and crude fiber increased with increasing Si level. For resistant cultivar, the chlorophyll content increased while vitamin C content decreased with increasing Si level, but Si application had less effect on the contents of crude fiber and soluble sugars. For both cultivars, Si application did not have significant effect on the contents of crude protein and soluble protein but remarkably increased the Si accumulation in plant leaves, and the leaf Si content was significantly increased with increasing Si level. The Si granules deposited in leaf tissues were not equal in size, and distributed unevenly in epidermis tissues. It was concluded that the accumulation of Si in leaves could increase the resistance of plant to anthracnose, but there was no linear correlation between the accumulated amount of Si and the resistance.