The high IAA/ZR under P stress promote the root growth, and root /shoot ratio increased.So it can take in more P from soil in to resist unfavorable environment conditions.

• 低磷胁迫下，烟株为适应胁迫环境，IAA/ZR比值增大，促进了根系发育，使根冠比增大，以提高对磷的吸收效率，用来满足烟株对磷素的需求。