Autotoxicity of litter extracts of leaves on seed germination and seedling growth of Larix principis-rupprechtii forest of different stages in Yanshan mountainous area

This article takes Larix principis-rupprechtii forest plantation in Yanshan mountainous area as research object to study the autotoxicity of litter extract of Larix principisrupprechtii at differentages(16a,23 a,34aand 42a)and different concentration(0.001g/mL,0.005g/mL,0.010g/ mL,0.050g/mL and 0.100g/mL)on seed germination and seedling growth.The results show that different treatments with litter extracts of leaves at different stand stages can constrain the seed germination and seedling growth,with inhibiting effect of litter extract at different concentration on germination rate,germination index,radicle length,embryo length,seedling height as well as ground diameter being 42a34a23a16a.With the increase of its concentration,the inhibiting effect increases,and the 42 a litter extract of leaves at 0.100g/mL reaches the strongest inhibitory effect,while the germination rate,germination index,radicle,embryo length,seedling height and ground diameter decrease by 64%,68%,54%,45%,55% and 78%,respectively.