【目的】了解淹水处理下不同杨树无性系苗木根系的形态变化规律,揭示杨树对淹水胁迫的根系适应策略,为筛选耐水的杨树无性系提供依据。【方法】选用3804杨、1388杨、895杨、110杨和328杨5个杨树无性系,设置对照、渍水和淹水3种处理,测定苗木根系的生物量、长度、数量、表面积、体积等指标。【结果】①渍水处理下杨树根生物量与对照无显著差异,但淹水处理下的根生物量却显著小于对照。②渍水和淹水处理下的多数杨树无性系苗木一级根数量与对照之间没有显著差异,但总根长、总根投影面积、总根表面积和总根体积却大于对照。③与对照相比,渍水和淹水处理下的杨树苗木根系平均直径有所减小,但根尖数、分叉数和交叉数却增大。④主成分分析提取出的2个主成分累积贡献率为88.58%,可较好地反映杨树苗木根系形态特征。【结论】隶属函数法分析表明,在渍水处理下5个杨树无性系根系形态表现的优劣顺序是1388杨>895杨>3804杨>110杨>328杨;在淹水处理下的优劣顺序是1388杨>895杨>110杨>328杨>3804杨。所以,从根系形态表现看,1388杨和895杨的耐水性较强。

【Objective】 In this study, the root morphology of different poplar (Populus sp.) clone seedlings under waterlogging and flooding treatment was explored, and the adaptive strategies of the poplar root system were elucidated to provide a scientific basis for the selection of poplar clones. 【Method】 Five poplar clones, i.e., 3804, 1388, 895, 110 and 328, were selected, and three treatments, i.e., control, waterlogging and flooding, were set up to determine the effects of different treatments on root characteristics such as biomass, total length, quantity, surface area and volume. 【Result】 ① There was no significant difference between the control and waterlogging groups in terms of poplar root biomass; however, in the flooding group, root biomass was significantly lower than that in the control group. ② No significant difference was found in terms of the number of first-order roots of most poplar clone stecklings between the treatment and control groups, but the total root length, projection area, surface area and volume were greater in the treatment groups than in the control group. ③ Compared with the control group, the treatment groups had decreased average root diameter but had increased number of root tips, root forks and root crossings. ④ The cumulative contribution rate of the two principal components extracted by principal component analysis was 88.58%, which may reflect the root morphological characteristics of poplar clone stecklings. 【Conclusion】 Subordinate function analysis showed that the order of the poplar clone stecklings based on root morphological performance for both treatment was as follows: waterlogging treatment, poplar 1388 > poplar 895>poplar 3804>poplar 110>poplar 328 and flooding treatment, poplar 1388>poplar 895>poplar 110>poplar 328>poplar 3804. In conclusion, based on the root morphology, we suggest that poplar 1388 and poplar 895 are more resistant to waterlogging and flooding among all studied poplar clone stecklings.