DHAP胁迫对天山云杉幼苗生长过程中抗氧化酶活性的影响

Effects of DHAP Stress on the Activity of Antioxigenic Enzymes during Seeding Growth of Picea schrenkiana Fisch.et Mey.

天山云杉(Picea schrenkiana)是新疆森林生态系统中的特有种,自然更新过程出现了阻碍,3,4-二羟基苯乙酮(3,4-dihydroxy-acetophenone,DHAP)已被确证是引起这一生态过程的主要自毒物质。为了揭示天山云杉天然更新障碍的内在生理机制,本文选择5个浓度梯度(0,1.0,2.0,3.0,5.0 mmol·L^(-1))DHAP处理天山云杉幼苗,以胚根长、胚芽长和鲜质量作为幼苗生长参数,测定天山云杉幼苗根尖细胞活力和6种抗氧化酶活力(SOD、POD、CAT、APX、GPX、GR)。结果显示,2.0 mmol·L^(-1) DHAP能显著促进天山云杉幼苗的胚根、胚芽和鲜质量生长,5.0 mmol·L^(-1) DHAP显著抑制天山云杉幼苗的生长;天山云杉在DHAP浓度(c≤2.0 mmol·L^(-1))处理下,抗氧化酶SOD、CAT、APX、GPX、GR的活性随着DHAP浓度的升高而升高,POD的活性随着浓度的升高而下降,6种抗氧化酶协同作用以维持抗氧化酶防御系统的稳定;DHAP浓度(2.0 mmol·L^(-1)<c≤5.0 mmol·L^(-1))处理后的前3 d,抗氧化酶SOD、CAT、APX、GPX、GR的活性随着DHAP浓度的升高而降低,POD的活性随着浓度的升高而升高,处理3 d后6种抗氧化酶活性与对照相比差异性显著但无规律,在此浓度范围内DHAP胁迫导致天山云杉生理机制紊乱,打破了正常的生长发育机制致使细胞加速死亡。DHAP通过影响天山云杉幼苗根尖细胞活力和抗氧酶活性,进而干扰天山云杉幼苗的正常生长,成为引发天山云杉天然更新障碍的一种因素。

Schrenk spruce（Picea schrenkiana） is a major tree species in the forest ecosystems of Xinjiang, China. But the natural regeneration of P. Schrenkiana has been disturbed. 3,4-dihydroxy-acetophenone（DHAP）, a major autotoxic substance which separated from P. Schrenkiana needles, has effect on the growth. This experiment was to study the physiological mechanism of antioxidant enzyme defense system and to elucidate the underling regulation on natural regeneration barrier of P. Schrenkiana. The growth radical,plumule and fresh weight of the seedings that treated with DHAP were measured, the activity of antioxidant enzyme measured too. The results showed that 2.0 mmol·L^（-1）DHAP treatment had significant effect on the growth radicle, plumule, fresh weight and root cell viability, which significantly promote the seeding growth. But 5.0 mmol·L^（-1）DHAP treatment had significant inhibition on growth of P.Schrenkiana. 1.0 mmol·L^（-1）and 3.0 mmol·L^（-1）DHAP treatment could promote or inhibit the seedings growth, but there had no significant. The other result showed that DHAP could change the activity of antioxidant enzyme, such as super oxidedismutase（SOD）, guaiacol peroxidase（POD）, glutathione reductase（GR） and so on. It seems that at higher concentration, DHAP showed significantly effects on the activity of antioxidant enzyme except for POD, however the effects were not significantly at lower concentration.