Effects Of Simulated Acid Rain And Litter On Seed Germination And Seedling Growth Of Ciyptomeria Fortunei

In order to understand the combined effects of acid rain and litter on the growth of C. fortunei, westudied the effects of the acid rain, aquatic extract and acid rain extracts from litter on the seedgermination and seedling growth of C. fortunei by using petri dishes culture method, and analyzed thechemical components of the extracts using GC-MS. Results showed that:(1) Both simulated acid rain and aquatic extracts reduced the seed germination rate and germinationpotential of C. fortune. Under the effects of acid rain extracts the seed germination rate and germinationpotential were significantly different from the controlled ones (P <0.05). It is indicated that acid rainenhanced the inhibition effect of allelochemicals from C. fortune litter on its seed germination.(2) Different levels of simulated acid rain and aquatic extracts inhibited the growth of C. fortune. Andacid rain (pH3.0) significantly reduced the bud growth and biomass (P <0.05). At50mg·mL-1theaquatic extracts significantly declined the root and bud growth, biomass and the ratios of root to bud (P<0.05). The growth indicators are significantly different from effects of acid rain extracts with thecontrolled ones (P <0.01).(3) GC-MS analysis showed that, the major compounds of different pH litter extracts were alcohols,phenolics, ketones, alkenes, aldehydes and esters. The main components of different pH extracts ofsemi-decomposed litter and topsoil are similar to litter extracts, yet the species and content decreased.Data shows that, the relative content and species of compounds in the extracts increased with thedecreasing pH of acid rain. It is indicated that acid rain has a promoting effect on the release ofallelochemicals in litter.In summary, C. fortunei forests occur in Tianmu Mountain have regeneration barriers. The possiblereason leading to regeneration failure is that, combined effect of acid rain and litter has a autotoxicity onits seed germination and seedling growth. And with the decline pH of acid rain the inhibitory effectsincreased.