Effects Of Seed Size And Insect-infestation On Seedling Growth Of Quercus Tree Species

To study interannual variability dynamics of Quercus aliena and Quercusvarabilis seed rain, we carried out experiments in Tianchi Mountain National ForestPark in fall of2011and2012. At the same time, Indoor experiments were establishedto study acorn germination patterns and seedling growth of the different oak species.The main results included:1、The seed rain of Quercus varabilis lasts from the end of August to the end ofOctober in2011; while the seed rain of Quercus varabilis begins at the end of Augustand ceases at the end of early October in2012. The seed rain density of Quercusvarabilis averages at0.104±0.117nuts/m~2·d in2011and0.326±0.347nuts/m~2·d in2012, respectively. The seed rain densities of Quercus varabilis are significantlydifferent between the two years. Insect-infested rates of Quercus varabilis also showsignificant difference between the two years.2、The seed rain of Quercus aliena begins at late August and ends in earlyOctober in2011and2012. Two year investigations show that the seed rain density ofQuercus aliena is0.249±0.235nuts/m~2·d in2011and0.396±0.334nuts/m~2·d in2012,respectively. Different from Quercus varabilis, seed rain density is not differentbetween the two years. Insect infestation rates show no significant difference.3、The same pattern of the sites and quantities of the insect escape holes isobserved in infested acorns of Quercus varabilis and Quercus aliena. The insectescape holes are more likely to be found at the bottom rather than at the upper andmiddle parts of acorns. Acorns showing single insect escape hole are significantlymore than those with more than one emergence holes.4、Chi-square T tests show that germination rates vary with infestation levels andoak species: Germination rate of slightly damaged acorns is higher than those heavilydamaged by insects. It shows significant differences between acorns of differentinfestation levels of the same species, and between acorns of different species of the same infestation level. The germination rates of artificial simulated infestated acornsshare the same pattern with the infested acorns. The germination rates of large acornsof the same species are higher than the small ones, and show significant differences.5、Two-way ANOVA analyses show that dry masses of seedlings vary with acornsize and oak species: Dry masses of seedlings from large acorns are much higher thanthose from small acorns. Dry masses of seedlings of Quercus variabilis are muchhigher than those of Quercus aliena, Quercus acutissima and Quercus aliena var.acuteserrata. Dry masses of seedlings of Quercus acutissima are much higher thanthose of Quercus aliena var. acuteserrata. But seedling height and the leaf number ofseedlings don’t vary with acorn size.6、Two-way ANOVA analyses show that seedling height, leaf number and drymasses of seedlings vary with different infestation levels and oak species. Seedlingheight and leaf number show significant differences between acorns of differentinfestation levels (which has1~3insect escape holes) and sound acorns. Seedlingheight and the leaf number of Quercus variabilis and Quercus acutissima are muchhigher than those of and Quercus aliena, Quercus aliena var. acuteserrata, Quercusserrata Var. breripetislata and Quercus liaotungensis. Dry masses of seedlings fromsound acorns and infested acorns show significant differences.7、Two-way ANOVA analyses show that seedling height, leaf number, and drymasses of seedlings only vary with oak species but not with different levels ofartificial simulated infestation. Seedling height, leaf number and dry masses fromdifferent oak species show significant differences. Seedling height, the leaf numberand aboveground dry masses of different levels of artificial simulated infestation showno significant differences.