AVENA-FATUA L SEED AND SEEDLING NUTRIENT DYNAMICS AS INFLUENCED BY MYCORRHIZAL INFECTION OF THE MATERNAL GENERATION

The objective of this study was to determine how mycorrhizal infection of one generation of plants influences the nutrient dynamics of seeds and seedlings comprising the subsequent generation. We showed that, for Avena fatua L., seeds produced by mycorrhizal (M) plants consistently contained significantly more phosphorus (particularly the phytate P and residual P fractions) than seeds produced by non-mycorrhizal (NM) plants. We also followed the development of spikelets produced by M and NM plants. The rates of increase in spikelet dry weight and nitrogen content were largely unaffected by mycorrhizal infection. However, the rate of P accumulation into spikelets was significantly increased by mycorrhizal infection. Greater endosperm P reserves in seeds produced by M plants were associated with greater rates of P accumulation in resultant seedlings. Moreover, offspring plants (all NM) produced by M mother plants had significantly higher root and rhizosphere phosphatase, ATPase and phytase activities than offspring plants produced by NM mother plants. This persistent maternal effect has never before been described. Our results suggest that mycorrhizal infection of one generation of plants may have substantial positive effects on the offspring generation, and thus, may influence plant population dynamics.