外源硅对干旱胁迫下荞麦幼苗水分代谢的影响

Effects of Exogenous Silicon on Water Metabolism of Buckwheat Seedlings under Drought Stress

以陕北靖边苦养种子为试验材料,采用盆栽法,按土壤持水量为田间最大持水量的60％,40％,20％进行灌水处理,播种前向不同持水量的土壤中一次性分别施入浓度为0,0.025,0.050,0.075,0.1 00 mol/L的硅肥,待幼苗长到两叶一心后,分别测定叶片过氧化氢酶活性、丙二醛、脯氨酸和叶绿素含量及根系活力,以研究硅肥对荞麦幼苗抗旱性影响.结果表明,随着施水量减少,荞麦叶片中CAT明显降低,叶绿素含量及根系活力也呈逐渐下降趋势,MDA和脯氨酸含量明显升高.施硅肥后,随着硅肥浓度的增加,60％,40％,20％干旱条件下荞麦的CAT活性、根系活力、叶绿素及脯氨酸含量均先增后降,MDA含量先降后增.在同一水分胁迫下,0.050 ～ 0.075 mol/L硅肥处理下荞麦幼苗各项生理指标均显著优于对照组.因此,荞麦幼苗经适宜浓度硅肥处理有助于植物启动自身防御机制,提高荞麦幼苗叶片叶绿素的积累及根系活力,并且通过提高体内保护酶活性,将自身细胞过氧化损伤程度降到最低,促进荞麦幼苗的抗旱性.

To study on effect of silicon fertilizer on the drought resistance of buckwheat seedling, the buckwheat seeds of Jingbian in northern of Shaanxi for the material were potted in soil which water holding capacity was 60%, 40% and 20% of the maximum water holding capacity in the field, respectively 0, 0.025, 0.050, 0.075, 0.100 mol/L potassium silicate （K：SiO3） solution were applied to soil with different water holding capacity. The activity of catalase, MDA, proline and chlorophyll content and root activity of the seedlings were determined after two leaves. The results showed that increasing drought stress, CAT significantly decreased, and the chlorophyll content and root activity decreased, and the content of MDA and proline significantly increased. After pulsing silicon fertilizer, 60%, 40%, 20% arid conditions of buckwheat with silicon concentration increased, which CAT activity, root activity, chlorophyll and proline content showed a first increase and then decrease, MDA content increased after the first drop. Each treatment group with the same degree of stress compared to the control group, treatment of silicon 0.050 ～ 0.075 mol/L of various physiological indexes were significantly higher than that of the control. Therefore, by appropriate silicon concentration treatmenting buckwheat seedling could help to start their own defense mechanism and improve the buckwheat seedlings chlorophyll accumulation and root activity, and by improving the protective enzyme ac- tivity in vivo, the degree of oxidative damage to the cell was lowest drought resistance of the buckwheat seedling was promoted.