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通过水培模拟试验,研究了栾树(Koelreuteria paniculata)对镉(Cd)的耐性、富集及转运特征,采用扫描透射电镜(STEM)、傅里叶红外光谱仪(FTIR)、能谱仪(EDXA)分析了栾树对Cd胁迫的响应。结果表明:栾树幼苗对浓度小于25mg·L~(-1)的Cd表现为高耐受性,高于该浓度时Cd对栾树产生明显的毒害作用,抑制栾树的生长。不同组织对Cd的富集能力为根>叶>茎,富集系数与转运系数均随Cd浓度升高而减小。低浓度Cd促进叶绿素和可溶性蛋白的合成;高浓度Cd明显抑制叶绿素和可溶性蛋白的合成,并且导致严重的膜脂过氧化和膜损伤,丙二醛(MDA)含量持续升高。超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)能对Cd胁迫做出积极有效的响应,但在高浓度Cd胁迫时失去活性。STEM分析表明,高浓度Cd胁迫使栾树根部细胞壁结构破坏,茎部导管堵塞,叶片褶皱,气孔结构受损。FTIR分析表明,Cd胁迫增加羟基自由基,加剧膜脂过氧化,连生羟基、巯基、羧基、氨基随之增加。EDXA分析表明,Cd胁迫会抑制栾树对矿质元素Ca、K、Mg的吸收,同时影响S元素的吸收与利用。
The characteristics of tolerance, accumulation and transport of Koelreuteria paniculata to cadmium (Cd) were studied by means of hydroponic simulation test. The characteristics of tolerance, accumulation and transport of Koelreuteria paniculata were investigated by scanning electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), energy dispersive spectroscopy (EDXA) The response of Lonicerae to Cd stress was analyzed. The results showed that the seedlings of Koelreuteria paniculata were highly tolerant to Cd at a concentration of less than 25 mg · L -1, above which Cd had obvious toxic effects on the Koelreuteria paniculata and inhibited the growth of Koelreuteria paniculata. Cd accumulation in different tissues was root> leaf> stem, the enrichment coefficient and transport coefficient decreased with the increase of Cd concentration. Low concentrations of Cd promoted the synthesis of chlorophyll and soluble protein. High concentrations of Cd significantly inhibited the synthesis of chlorophyll and soluble protein, and led to severe membrane lipid peroxidation and membrane damage, and the content of malondialdehyde (MDA) continued to increase. Superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) responded positively to Cd stress, but lost their activity in high Cd stress. STEM analysis showed that the Cd stress at high concentration destroyed the cell wall structure of the root of Koelreuteria paniculata, plugged the stem of the stem, leaf folds and stomatal structure were damaged. FTIR analysis showed that Cd stress increased hydroxyl radicals, aggravating membrane lipid peroxidation, with the accompanying hydroxyl, thiol, carboxyl and amino groups increased. EDXA analysis showed that Cd stress inhibited the absorption of mineral elements Ca, K, Mg and the absorption and utilization of S elements.