土生对齿藓逐渐干旱胁迫下耐旱性能的鉴定

Identification of the drought resistance of Didymodon vinealis under drought stress gradually

藓类结皮是生物土壤结皮的一种,在沙坡头地区广泛分布。以该区组成藓类结皮的优势物种土生对齿藓(Didymodon vinealis)为研究对象,参考拟南芥抗旱基因HDG11、CBF4、AHK1分别设计引物,以Actin2为内参设计引物,用Real-Time PCR检测土生对齿藓在干旱胁迫下的抗旱基因的表达,同时检测了土生对齿藓的可溶性糖含量、游离脯氨酸含量、丙二醛(MDA)含量和过氧化氢(H_2O_2)含量。结果表明,中度干旱胁迫下3种基因的表达量在土生对齿藓内都显著增加,可溶性糖含量、MDA和H_2O_2均有一定程度的增加。而重度干旱胁迫下,3种基因的表达量与对照没有显著性差异。可溶性糖含量、MDA含量和H_2O_2含量显著升高;而游离脯氨酸含量随着干旱胁迫程度的增加不断降低。说明土生对齿藓等藓类植物不以脯氨酸的积累来抵御干旱胁迫,中度干旱胁迫诱导土生对齿藓相关耐旱基因的表达,而重度干旱胁迫下土生对齿藓以休眠策略应对极端干旱环境。

The moss crust was a kind of biological soil crust, which was widely distributed in sandy slope area.Didymodon vinealis was researched,which was the dominant species of moss crust in this area. According to the genes of arabidopsis arabidopsis HDG11, CBF4 and AHK1 to design primers, Actin2 was used to design primers for internal reference,and real-time PCR was used to detect the expression of drought-resistant genes under drought stress. The soluble sugar contents of Pro acid,MDA and H2O2 were also examined. The results showed that the expression of three genes in Didymodon vinealis were increased significantly,the contents of soluble sugar,MDA and H2O2 were increased to a certain extent. However,under the severe drought stress,there was no significant difference in the expression levels of the three genes between the control group and the treatment group. The cortents of soluble sugar MDA and H2O2 were significantly increased. The content of free proline acid decreased with the increase of drought stress. It was indicated that Didymodon vinealis had not been able to resist the drought stress with the accumulation of propionic acid. Moderate drought stress could induce the expression of drought-tolerant genes in the mosses, while Didymodon vinealis dealed with the extreme arid environment by the dormancy under the severe drought stresses.