Effects Of Different Soil Nutrients On Clonal Growth And Sexual Reproduction In Iris Japonica Thunb.

To study the influence of soil nutrient levels on clonal growth and sexual reproduction in Iris japonica Thunb, by means of investigating its effective response to heterogeneous soil nutrient and the adaptation ways in sexual reproduction, the experiment was carried out under high, medium, low levels of N, P, K. It was studied that growth character, reproductive character, reproductive allocation, the trade-off relations of clonal growth and sexual reproduction of Iris japonica Thunb under different soil nutrient levels. The results were as following:The effects of different soil nutrient levels to height of genet, ortet, second ramet and third ramet are significant. The effects of plasticity (branching tintensity, spacer length, specific spacer weight) of genet, ortet and other ramets in Iris japonica are hierarchical under different soil nutrient levels, but in terms of ramet density between them, they are not significant. The effects of different soil nutrient levels to the root/shoot ratio of genet are significant: with the increase of soil nutrient level, the root/shoot ratio has the trend of decreasing. It can reveal that the genet spend more biomass on root to strengthen the absorption potentiality to nutrient of roots. Furthermore it can also remedy the utilization nutrient reducing possibility in the environment.Floral axis height, branching intensity and biomass are not significant to the nutrient levels. With the increase of soil nutrient level, the length and width of outer petal, inner petal, the pistil and stamen length and the corolla diameter in Iris japonica increased. The difference was significant at 0.05 level. The effects of soil nutrient levels to the number of flowers per genet in Iris japonica are not significant, but the biomass per flower under the high nutrient level is more significant than that under the low nutrient level. The effects of soil nutrient level to the number of fruit per genet and the fruit set per genet in Iris japonica Thunb are not significant. The effects of soil nutrient level to the biomass per fruit and the biomass of pericarp per fruit are not significant too. Weight per 1000 seeds are not significant among different soil nutrient levels. Reproductive allocation in Iris japonica Thunb is not significant among different soil nutrient levels. There exists the negative correlation between the number of ramets per biomass and the number of fruit per genet, fruit set per genet, theheight of plant, the biomass of fruit per fruit, the number of seeds per genet in Irisjaponica Thunb, and the negative correlation is very significant between the number of ramets per biomass and the biomass of fruit per fruit, the number of seeds per genet. Resource input of Iris japonica Thunb to sexual reproduction is affected negatively by production of ramets to some extent.In general, this experiment that study the cional growth and sexual reproduction in Irisjaponica Thunb can facilitate to discover the ecological adaptation ways that cional plants can adapt to the resource heterogeneity under the natural environments. And it can reflect the evolution meaning of sexual reproduction of cional plants from side. What's more, it can also discover the trade-off relations between cional growth and sexual reproduction. Therefore, the result of the experiment can make the mechanism of cional growth more clear, and make the regulation mechanism and fitness of population understood. Maybe, it can offer reference for the theoretical research of the cional plants.