湿地松对褐斑病抗性的研究

湿地松对褐斑病的抗性随植株年龄的增长而提高,一年生以下幼苗的病害症状以叶枯为主,二年生以上幼树则多在针叶上出现病斑。选壮苗和施用混合肥可提高一年生以下幼苗的抗病性。 用高抗、中抗和感病湿地松个体的嫩枝作接穗,一般实生苗湿地松作砧木,无性系植株的抗性和原来母株的抗性相一致,其发病程度还受到砧木感病性的影响。 针叶组织抽提液的缓冲容量与针叶病斑数显著相关。高抗植株和感病植株的抽提液对褐斑病菌的产孢影响有显著的差异。

THE RESISTANCE OF SLASH PINE TO BROWN SPOT NEEDLE BLIGHT

The resistance of slash pine to brown spot needle blight (Lecanosticta acicola) rose gradually as the age of slash pine increased.The needles became blight most frequently in the seedling stage. The resistance of seedlings could be improved by applying fertilizers and selecting vigorous seedlngs.The resistance of scion which were taken from hightly resistant, moderalely res-istant,and susceplible individual trees was identified by means of natural inoculation. The results indicated that the differential resistance of the individual trees to L. acicola was significant. This kind of resistanle was rather stable, but could be affected by the resestance of the stock.As for mechanisms of resistance, experiments showed that there was a relationship between the buffering capacity of the needle extracts and the numbers of spots on the needles of slash pine. The extracts from the susceptible plants promoted the sporulation of the pathosen more significanty than those from the hightly resistant ones.