玉米不同抗性品种对丝黑穗病在感病年龄上的差异

ON THE DIFFERENCE OF SUSCEPTIBLE AGES AMONG CORN VARIETIES TO HEAD SMUT

选用了高感、中感和中抗3个感病程度有明显差异的玉米单交种作对丝黑穗病感病的苗龄、器官年龄和组织年龄三方面的差异比较。3年试验结果表明,品种抗病性差异不表现在感病苗龄的长短不同上,主要表现在器官和组织的感病时期长短不同上。抗病的品种表现在器官和组织的感病年龄上比感病品种上短。这种差异可能实质上反映了细胞生理老熟速度上的差异,由于其同时表现于器官和组织,因此很可能起抗侵入和抗扩展双方面的作用。不论在那种年龄中,品种均表现其固有的感病性,说明品种抗性差异除生理年龄的差异外,尚存在其他机制。研究结果同时揭示了幼器官和幼组织具最高的感病性结合侵染部位研究中已经阐明的中胚轴和胚芽鞘是主要侵染器官,对为什么出土前的幼苗是最感病的阶段作出了合理的说明。

Three hybrids with different resistance were chosed to compare the susceptible ages of seedlings,organs,and tissues.The results of threeyear's studies showed that the degree of resistance was not based on thesusceptible age of seedlings,but on the vulnerable stage of The relatedorgans and tissues.The more resistant variety had a shorter vulnerablestage than the more susceptible one,This difference might reflect the phy-siological maturity rate of their cells which might play a role in the re-sistance to penetration as well as to the extension of the fungi,of cou-rse there mightbe other mechanisms besides the physiological age.As a rule the younger organs and tissues were:the more susceptiblethese would be.This phenomanon associated with the fact that thehypocotyl and coleoptile were the main primary infected organs,wouldgive reasonable explaination for the younger seedling before emergencewas the vulnerable stage to attack.