2种养分水平条件下大麦幼苗对重金属铜胁迫的生长响应

Growth performance of barley seedlings in response to copper stress under two nutrient levels

以大麦(Hordeum vulgare)幼苗为研究材料,采用10%和35%浓度霍格兰营养液(Hoagland solution)2种养分水平和0、1和10 mg L^-1 3种铜胁迫水平的正交试验设计,开展为期3周的水培试验,研究养分水平对重金属铜胁迫植物生长的影响。结果表明,与10%霍格兰液相比,35%霍格兰液可提高大麦幼苗在铜胁迫时的生物量积累,增加叶片叶绿素含量以及抗氧化酶活性。但这种缓解作用受铜胁迫水平的影响。在1mg·L^-1铜胁迫水平时,提升营养液水平可显著提高植株生物量、叶片叶绿素含量和超氧化物歧化酶(SOD)活性;而在10mg·L^-1铜胁迫水平时提升营养液水平亦可显著提高叶片过氧化物酶(POD)和谷胱甘肽过氧化物酶(GPX)活性,但对叶绿素含量无影响。此外,铜胁迫对根系生长的抑制作用强于对地上部分的抑制;10%霍格兰液条件下,1 mg·L^-1铜胁迫与无胁迫处理相比可显著增加叶片叶绿素相对含量。提高养分供给是增强大麦耐受铜胁迫能力的一个重要途径。

To explore the effects of nutrients on the performance of plants in response to copper (Cu) stress, we conducted a three-week hydroponic experiment with barley (Hordeum vulgare) seedlings, using two nutrient levels (10% and 35% Hoagland solutions) and three Cu stress levels (0, 1 and 10 mg(L^-1). The results showed that 35% Hoagland solution, compared to 10% Hoagland solution, generally increased the biomass, leaf relative chlorophyll content (RCC) and activities of antioxidant enzymes of barley seedlings under Cu stress. However, the degrees of these alleviation effects varied with the levels of Cu stress. Under the level of 1 mg(L^-1 Cu stress, more nutrient supply, in terms of the use of 35% as compared to 10% Hoagland solution, significantly increased plant biomass, RCC and the activity of superoxide dismutase (SOD);while under the level of 10 mg(L^-1 Cu stress, more nutrient supply also significantly increased the activities of peroxidase (POD) and glutathione peroxidases (GPX) but had no effect on RCC. In addition, the inhibition effects of Cu stress were stronger on root growth than on aboveground growth. Under 10% Hoagland solution condition, the level of 1 mg(L^-1 Cu stress significantly increased RCC as compared to that in the control treatment. These results suggested that increasing nutrient supply can enhance the growth tolerance of barley to Cu stress.