On the cause of offspring superiority conferred by mycorrhizal infection of Abutilon theophrasti

In previous studies we demonstrated that for Abutilon theophrasti Medic. offspring of mycorrhizal plants grew more rapidly than did offspring of non-mycorrhizal plants. This observation was verified in the current study. We hypothesized that the faster growth of offspring of mycorrhizal plants was caused by a superior ability to absorb nutrients, since offspring of mycorrhizal plants produced faster-growing root systems with higher phosphatase activities. We tested the hypothesis by growing offspring plants in distilled water. Despite the absence of any nutrients short-term growth rates of offspring of mycorrhizal plants were still significantly greater than those of offspring of non-mycorrhizal plants. We conclude that the faster growth of offspring of mycorrhizal plants is not caused by a superior ability to acquire external resources.