Abstract: Two Pennisetum cultivars were planted in a pot experiment system to study the effects of silicon (K₂SiO₃·nH₂O) (1.0, 2.0, 3.0, 4.0 mmol·L^-1) on the physiological metabolism of seedling leaves under salt stress (100, 200, 400 mmol·L^-1). Results showed that Si relieved the salt stress-induced growth inhibition of Pennisetum seedling, and significantly decreased the malondialdehyde (MDA) contents of Pennisetum leaves under salt stress which reduced the lipid peroxidation of membrane and the electrolytic leakage of plant leaves (P<0.05). The superoxide dismutase (SOD) activities of Pennisetum leaves were increased significantly and the damage of Pennisetum seedling caused by salt stress were alleviated when Si was added to the salt solution (P<0.05). These results suggested that Si was involved in the physiological metabolisms of two Pennisetum cultivars.

Key words: Silicon, Salt stress, Pennisetum, Physiological metabolism indicators

摘要： 采用盆栽试验研究不同含量的外源硅（K₂SiO₃·nH₂O）处理（1.0，2.0，3.0，4.0 mmol·L^-1）对不同盐（NaCl）浓度（100，200，400 mmol·L^-1）胁迫下狼尾草属（Pennisetum）2个牧草生理代谢的影响。结果表明：加外源硅4.0 mmol·L^-1处理组显著降低美洲狼尾草（P. amcrieanum）叶片中丙二醛（MDA）和脯氨酸含量，显著降低杂交狼尾草（P. amcrieanum×P. purpurenm）叶片的电解质渗透率 （P<0.05）；加外源硅3.0 mmol·L^-1处理组显著降低美洲狼尾草叶片中的电解质渗透率，显著降低杂交狼尾草的脯氨酸含量（P<0.05）；加外源硅所有处理组均能显著提高盐胁迫下美洲狼尾草叶片保护酶超氧化物歧化酶（SOD）活性（P<0.05）。这说明外源硅对盐胁迫下2种狼尾草的生理代谢有缓解作用，且对美洲狼尾草的盐胁迫缓解效果比杂交狼尾草更为显著。

关键词: 硅, 盐胁迫, 狼尾草, 生理指标