PEG预处理对盐及镉胁迫下黑麦草生理代谢的影响

为了探讨PEG预处理对盐胁迫和镉胁迫下多年生黑麦草幼苗生理特性的影响,将黑麦草幼苗分别用0,5%,10%,15%,20%,25%(对应水势分别为0,-0.05,-0.15,-0.30,-0.50,-0.77 MPa)的PEG-6000营养液进行预处理后,分别用含150 mmol/L NaCl和Cd~(2+)浓度为10 mg/L的胁迫液培养,然后测定黑麦草幼苗叶片的光合色素含量、MDA含量、游离脯氨酸含量、可溶性糖含量及抗氧化酶(SOD、POD、CAT、APX)活性。结果表明:盐胁迫下15%(-0.30 MPa)PEG预处理和镉胁迫下10%(-0.15 MPa)PEG预处理可以有效提高多年生黑麦草的光合色素含量,降低MDA、游离脯氨酸含量,增加可溶性糖含量,提高抗氧化酶活性。PEG预处理下多年生黑麦草在遭受逆境胁迫时,受到多种生理生化的调节,其生理指标的动态变化是黑麦草应答逆境因子胁迫的重要调节机制,体现了其对逆境胁迫的适应能力以及在多种逆境胁迫下的交叉适应能力。

Effects of PEG Pretreatment on Physiological Metabolism of Lolium perenne Under Salt and Cadmium Stress

Sand culture experiment were carried out to study the effects of PEG pretreatment on physiological characteristics of Lolium perenne seedlings under salt stress and cadmium stress. The experimental seedlings were dealt with 0%, 5%,10%,15%,20% and 25% (the corresponding water potential was 0, -0.05, -0.15, -0.30, -0.50 and -0.77 MPa, respectively) PEG-6000 pretreatment nutrient solutions, respectively, and then the seedlings were cultured separately by stress solutions containing 150 mmol/L NaCl and 10 mg/L Cd²⁺, respectively. Then the leaf chlorophyll(Chl)content, activities of antioxidant enzyme (such as catalase (CAT),superoxide dismutase (SOD), guaiacol peroxidase (POD) and ascorbate peroxidase (APX)), contents of osmoregulation substances, such as proline, soluble sugar and malondialdehyde (MDA) in leaves were determined. The test results showed that the 15% (-0.30 MPa) PEG pretreatment under the salt stress and the 10%(-0.15 MPa) PEG pretreatment under the Cd²⁺ stress could effectively increase the leaf chlorophyll contents of L. perenne seedlings, reduce the contents of MDA and proline, increase the content of soluble sugar and increase the activities of antioxidant enzymes. The above results showed that the L. perenne dealt by PEG pretreatment under stress was regulated by various physiological and biochemical factors. The dynamic changes of physiological indexes were important regulatory mechanisms for L. perenne in respons to stress, which reflected its adaptability to stress and its cross-adaptation ability under various stresses.