中文摘要：

本文利用水培试验研究了CO2浓度升高对水稻幼苗生物量、养分含量和根形态的影响,探讨了CO2浓度升高下粤杂889（YZ）和荣优398（RY）幼苗养分吸收和根系形态的差异性。结果表明,与CO2浓度正常水平（对照）相比,CO2浓度升高显著增加了2个水稻品种幼苗根系、茎叶和总生物量,YZ分别增加58.33%、27.96%、33.16%;RY分别增加45.87%、34.17%、36.07%。同时,CO2浓度升高增加了2个水稻品种的根冠比。CO2浓度升高显著降低了2个水稻品种茎叶中的N、P、K、Ca、Mg和Fe含量,这是＂稀释效应＂的结果;但YZ幼苗中S含量显著增加,2个品种幼苗Mn含量均显著增加。CO2浓度升高显著增加了2个水稻品种的幼苗根系根毛数、总根长、表面积,降低幼苗粗根比例,增加了细根比例。CO2浓度升高增加了细根在总根长中的比例,有利于水稻对养分的吸收,导致部分营养元素含量增加;但CO2浓度升高条件下水稻生物量的增加使大部分营养元素含量降低。同时,CO2浓度升高对水稻幼苗生物量、养分吸收和根形态的影响存在显著的品种差异。

英文摘要：

A hydroponic experiment was conducted to study the effects of elevated CO2 on the rice seedlings biomass,nutrient concentration and root morphology of rice Yueza-889（YZ） and Rongyou-398（RY）.The results show that compared with the control,the root,shoot and total dry weights of YZ and RY are increased significantly under the elevated CO2,the weights are increased by 58.33%,27.96% and 33.16% for YZ and increased by 45.87%,34.17%and 36.07% for RY,respectively.The roots to shoot ratios of the two rice cultivars are also increased under the elevated CO2.The shoot N,P,K,Ca,Mg and Fe contents of the two rice cultivars are decreased under the elevated CO2,while the Mn contents are increased.The shoot S concentration of YZ is increased,while the shoot S concentration of RY is decreased.The root tip numbers,length and surface area,the proportion of fine roots are also increased under the elevated.The elevated CO2 increases the proportion of fine roots,and this is a favorable change for rice to uptake more nutrition elements which could be one of the main reasons for increases of some elements concentrations,but the elevated CO2 dilutes most elements in this pot studies.There are obvious variations of biomass,nutrient concentration and root morphology between the two rice cultivars.