The Effects Of Simulated Rodent Consumption On Acorn And Seedling Vigor Of Several Oak Species

Acorn dispersal was surveyed in the field, emphasizing the special feedingbehaviors of food hoarding animals, e.g., pericarp removal, partial consumption andembryo excision. In the lab, we simulated the feeding patterns of food hoardinganimals to investigate pericarp removal, partial consumption and embryo excision onacorn germination and seedling establishment. The results were as follows:1. Rodent was the main dispersers and predators Quercus acorns in Tianchimountain, showing profound influence on the seed fate of different oaks. Our resultsshowed that the percentage of partial consumption was significantly higher than that ofpericarp removal and and embryo excision by small rodents. Seed fate was found to becorrelated with acorn size and mass. Acorn dispersal of Quercus variabili and Quercusaliena was faster and than Quercus serrata. var. brevipetiolata.2. Excluding Q. serrata var. brevipetiolata and Quercus mongolica, thegermination rate of sound acorns was much higher than that of acorns that t were cutoff1/4and1/2of the cotyledons. In addition, partial consumption significantlyreduced the seedling height, number of leaves, below and above ground dry masses.3. Time to germination of pericarp-removed acorns was much shorter than that ofsound acorns for Q. variabilis, Q. aliena, Quercus aliena var. acutiserrata and Q.acutissima, respectively. Pericarp-removed acorns showed higher germination ratethan sound acorns, however, there was no significant effect on seedling height, numberof leaves and dry masses of plant parts.4. Artificial embryo excision showed significant influences on acorn germinationrates except for Q. mongolica. Acorns that were cut off1/4of the cotyledons at theApical and end failed to germinate for all oak species except for Quercus mongolica.While, acorns that were cut off4mm of the cotyledons at the Apical and end retainedthe ability to germinate for all oak species, however, the germination rate wassignificantly reduced. We also found, although the embryo was artificially excised, acorns of Q. mongolica exhibited much higher germination rate than the other oakspecies, possibly due to the deep embryo in acorns.