研究了不同浓度硒（Se）预处理（0、3、6、12、24和48 μmol·L^-1 Se）对镉（Cd）胁迫（25 μmol·L^-1 Cd）下荷花（Nelumbo nucifera Gaertn.）品种‘微山湖红莲’（‘Weishanhuhonglian’）幼苗生长和生理特性的影响。结果表明：Se0-Cd25（0 μmol·L^-1 Se-25 μmol·L^-1 Cd）处理组荷花品种‘微山湖红莲’幼苗受Cd毒害最严重，叶片黄化；随着Se浓度的提高，幼苗受Cd毒害有所缓解，但Se浓度过高时幼苗生长较弱，部分叶片出现枯萎。与CK（0 μmol·L^-1 Se-0 μmol·L^-1 Cd）组相比，Se0-Cd25处理组荷花品种‘微山湖红莲’幼苗叶片中光合色素含量和叶绿素a／b值，叶片、叶柄和根中超氧化物歧化酶（SOD）和过氧化物酶（POD）活性以及谷胱甘肽（GSH）含量总体上显著（P＜0.05）降低，丙二醛（MDA）含量显著升高。随着Se浓度的提高，荷花品种‘微山湖红莲’幼苗叶片中光合色素含量和叶绿素a／b值，叶片、叶柄和根中SOD和POD活性以及GSH含量总体呈先升高后降低的趋势；叶片和叶柄中MDA含量呈先降低后略有升高的趋势，根中MDA含量呈逐渐降低的趋势；叶片、叶柄和根中Se含量呈逐渐升高的趋势，Cd含量呈先降低后升高的趋势。6个处理组中，Se24-Cd25（24 μmol·L^-1 Se-25 μmol·L^-1 Cd）处理组荷花品种‘微山湖红莲’幼苗叶片中光合色素含量和叶绿素a／b值最高，叶片、叶柄和根中MDA含量较低，叶片中Cd含量最低；Se12-Cd25（12 μmol·L^-1 Se-25 μmol·L^-1 Cd）和Se24-Cd25处理组叶片、叶柄和根中SOD和POD活性以及GSH含量较高，叶柄和根中Cd含量最低。总体上看，各处理组SOD和POD活性以及GSH和Cd含量在叶片中最高，在叶柄中次之，在根中最低；MDA含量在根中最高，在叶柄中次之，在叶片中最低；Se含量则在叶片中最高，在根中次之，在叶柄中最低。研究结果表明：适宜浓度（12～24 μmol·L^-1）的Se预处理可以有效缓解Cd胁迫对荷花品种‘微山湖红莲’幼苗的毒害，有助于提高其对Cd的耐性。

Effects of selenium （Se） pretreatment at different concentrations （0， 3， 6， 12， 24， and 48 μmol·L^-1 Se） on growth and physiological characteristics of seedlings of cultivar ‘Weishanhuhonglian’ of Nelumbo nucifera Gaertn. under cadmium （Cd） stress （25 μmol·L^-1 Cd） were investigated. The results show that Cd toxicity to seedlings of cultivar ‘Weishanhuhonglian’ of N. nucifera in Se0-Cd25 （0 μmol·L-1 Se-25 μmol·L^-1 Cd） treatment group is the most serious， and the blades are yellowing. With enhancing of Se concentration， Cd toxicity to seedlings is alleviated， but when Se concentration is too high， the seedling growth is relatively weak， and some of blades appear withered. Compared with CK （0 μmol·L^-1 Se-0 μmol·L^-1 Cd） group， photosynthetic pigment content and chlorophyll a／b value in blade， and activities of superoxide dismutase （SOD） and peroxidase （POD） and glutathione （GSH） content in blade， petiole， and root of seedlings of cultivar ‘Weishanhuhonglian’ of N. nucifera in Se0-Cd25 treatment group decrease significantly （P＜0.05） in general， and MDA content increases significantly. With enhancing of Se concentration， photosynthetic pigment content and chlorophyll a／b value in blade， SOD and POD activities and GSH content in blade， petiole， and root of seedlings of cultivar ‘Weishanhuhonglian’ of N. nucifera generally show a tendency of first increase and then decrease； MDA content in blade and petiole shows a tendency of first decrease and then increase slightly， while that in root shows a tendency of decrease gradually； Se content in blade， petiole， and root shows a tendency of increase gradually， while Cd content shows a tendency of first decrease and then increase. Among 6 treatment groups， photosynthetic pigment content and chlorophyll a／b value in blade of seedlings of cultivar ‘Weishanhuhonglian’ of N. nucifera in Se24-Cd25（24 μmol·L^-1 Se-25 μmol·L^-1 Cd） treatment group are the highest， while MDA content in blade， petiole， and root is relatively low， and Cd content in blade is the lowest； SOD and POD activities and GSH content in blade， petiole， and root in Se12-Cd25（12 μmol·L^-1 Se-25 μmol·L^-1 Cd） and Se24-Cd25 treatment groups are relatively high in general， while Cd content in petiole and root is the lowest. Overall， SOD and POD activities and GSH and Cd contents are the highest in blade， come second in petiole， and are the lowest in root in each treatment group； MDA content is the highest in root， comes second in petiole， and is the lowest in blade； Se content is the highest in blade， comes second in root， and is the lowest in petiole. It is suggested that proper concentration （12-24 μmol·L^-1） of Se pretreatment can effectively alleviate the toxicity of Cd stress on seedlings of cultivar ‘Weishanhuhonglian’ of N. nucifera， and can help to enhance its tolerance to Cd.