Interaction Between Animal And Plant

To study interannual variability dynamics of Quercus aliena and Quercus varabilis seed rain, diffusion processes and disciplines of acorns with different characteristics, and seed viability of different features, we experimented in Tianchi Mountain National Forest Park in the fall of 2008 and 2009. There we collected acorns and observed the experimental phenomena directly. That numbers of seed collection boxes and seed releasing plots were set in a certain distance was to investigate seed rain characteristics and seed dispersal of Q. aliena and Q. varabilis. Meanwhile, acorns were cultivated in the farm of agricultural college of Henan University of Science and Technology. The main results included the following points.1. The seed rain density showed changes of biennial bearing: 31.75±16.65 nuts/m~2(Q. aliena 2008), 51.92±29.26 nuts/m~2 (Q. aliena 2009), annual seed density was significantly different (t = 3.432, df = 1, P = 0.007); 18.33±10.05 nuts/m~2 (Q. varabilis 2008) and 26.42±14.27 nuts/m~2(Q. varabilis 2009), the seed rain of Q. varabilis was significantly increased in 2009 (t = 3.432, df = 1, P = 0.007).2. The size of Q. aliena acorns of 2008 is obviously smaller than that of 2009 (1.94±0.61 cm~3,2.46±0.57 cm~3); insect-infested acorns were bigger than sound ones evidently (2.29±0.42cm~3, 1.59±0.32 cm~3). In addition, the number of eggs and seed size was a significant positive correlation, and insects preferred to oviposit in large-size seeds.3. The size of Q. varabilis acorns of 2008 is clearly bigger than that of 2009 (2.83±0.84 cm~3,2.49±0.84 cm~3); Moth-eaten acorns contained fewer weeils,the average number was 1.47±0.66, the egg number was also significantly correlated with seed size, and insects had a oviposition preference. Additionally, aborted and insect-infected seeds of the two oak speices falled at the early stage of seed rain.4. Seed size played a significant role in dispersal speed, post-dispersal fate and diffusion distance. Rodents preferred to remove large-size seeds quickly, and tended to spread and hoard large-size ones in a long distance, and consume small-size ones in situ. Comparing Q. aliena with Q. varabilis seeds, we found that rodents were more likely to feed Q. aliena seeds and remove and hoard Q. varabilis as a long-term food reserve.5. Acorn removal speed was influenced by insect predation, sound acorns had a quicker speed. Rodents always removed and consume sound acorns, and most moth-eaten ones remained. It showed rodents might have an ability to discriminate weevil-infested acorns. However, post-dispersal acorn fate and diffusion distance are not influenced by insect parasitism, maybe Q. aliena and Q. varabilis have formed different defense mechanismto defense the rodents and insect predations.6. Seed size and insect parasitism affected germination rate and seedling growth. Large-size seeds had higher germination rate and grew out longer seedling than small-size ones. The rate of sound ones was also higher than insect-infected ones, and there were differences in seedling length.