外源硅对低温胁迫下玉米和大刍草幼苗的影响

为了研究外源硅增强低温胁迫下玉米和大刍草幼苗的适应性，以普通玉米品种及野生种大刍草为材料，设置CK、LT、S1、S2、S3共5个处理，3次重复。分别测定玉米和大刍草的形态指标、叶绿素含量、丙二醛含量和SOD活性。结果表明，施加外源硅有效缓解了低温胁迫对玉米和大刍草的损害。（1）玉米和大刍草S1、S2、S3的形态指标与LT对比，均有不同程度地增加。（2）玉米和大刍草叶绿素含量分别在S2和S3增加最显著，比LT分别增加了42.08%,84.38%。（3）玉米和大刍草S1、S2、S3的丙二醛含量均低于LT，且玉米和大刍草都在S2达到最低，分别低于LT 31.44%,34.72%。（4）经S1、S2、S3处理后，玉米和大刍草的SOD活性均高于LT，玉米叶片中SOD活性在S2时最高，高于LT 14.24%；大刍草叶片中SOD活性在S3时最高，高于LT 14.96%。综上，施加外源硅可提高低温胁迫下玉米和大刍草的生物量积累和抗氧化酶活性，促进光合色素合成，减少活性氧积累，增强幼苗的耐寒性。

Exogenous Silicon: Effects on Maize and Teosinte Seedlings Under Low Temperature Stress

In order to study the adaptability of maize and teosinte seedlings enhanced by exogenous silicon under low temperature stress, five treatments, including CK, LT, S1, S2 and S3, were designed with three replicates, using common maize varieties and wild teosinte as materials. The morphological indexes, chlorophyll content, malondialdehyde content and SOD activity of maize and teosinte were determined. The results showed that exogenous silicon effectively alleviated the damage of low temperature stress on maize and teosinte. (1) The morphological indexes of maize and teosinte under S1, S2 and S3 increased by different degrees compared with those under LT. (2) The chlorophyll content of maize and teosinte increased most significantly under S2 and S3 respectively, by 42.08% and 84.38% respectively compared with that under LT. (3) The malondialdehyde content of maize and teosinte under S1, S2 and S3 were lower than that under LT, and the lowest malondialdehyde content was found under S2 for maize and teosinte, which was 31.44% and 34.72% lower than that under LT, respectively. (4) Under S1, S2 and S3 treatments, the SOD activity of maize and teosinte was higher than that of LT, and SOD activity in maize leaves was the highest under S2, which was 14.24% higher than that under LT. SOD activity in teosinte leaves was the highest under S3, which was 14.96% higher than that under LT. In conclusion, exogenous silicon could improve the biomass accumulation and the activities of antioxidant enzymes of maize and teosinte under low temperature stress, increase the synthesis of photosynthetic pigments, reduce the accumulation of reactive oxygen, and enhance the cold tolerance of the seedlings.