硅对菜心炭疽病发生、菜薹形成及硅吸收沉积的影响

Effects of silicon on flowering Chinese cabbage's anthracnose occurence,flower stalk formation,and silicon uptake and accumulation

采用不同浓度硅(Si)对菜心进行处理,研究了Si对菜心炭疽病发生、菜薹形成及Si吸收沉积的影响.结果表明:Si对菜心炭疽病的发生有明显的调控作用,并存在基因型差异;感病品种2.5mmol.L-1和抗病品种0.5mmol.L-1Si处理对炭疽病菌的抗性最强,病情指数最低,菜薹产量最高.Si对菜心品质也有明显影响,不同浓度Si处理可促进感病品种的叶绿素、粗纤维、Vc的合成,并诱导可溶性糖的生成,且叶绿素、粗纤维含量随Si处理浓度的提高而增加;抗病品种的叶绿素含量随Si处理浓度的增加明显增加,而Vc含量下降,Si对抗病品种的粗纤维、可溶性糖含量影响不显著;Si对两个品种菜薹的粗蛋白和可溶性蛋白质含量影响均不显著.施Si明显提高了菜心叶片Si的积累,且叶片的Si含量随着Si处理浓度的增加而显著提高;叶片组织沉积的Si粒大小不一,Si在叶片表皮组织呈不均匀分布.表明Si在菜心叶片中的积累可提高植株的抗病能力,但其积累量与植株的抗病能力不呈直线相关关系.

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 cuhivar applied with 2.5 mmol · L^-1 Si and those of resistant cuhivar applied with 0.5 mmol · L^-1 Si exhibited the highest resistance to Colletotrichum higginsianum, with the lowest disease index and the highest flower stalk yield. Si application also obviously affected the quality of flower stalk. For susceptible cuhivar, 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 cuhivar, 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.