【作者】 秦丽；

【导师】 祖艳群；

【作者基本信息】 云南农业大学 ， 环境科学， 2009， 硕士

【摘要】 通过铅锌矿区采样分析、盆栽和水培试验,研究了镉对续断菊(Sonchus asper (L.)Hill.)生长生理的影响,续断菊对镉的累积特征及续断菊对镉的吸收累积机制,结果表明:(1)低浓度的镉处理促进了植物的生长,而200 mg/kg镉处理80天时植株的株高、叶面积、根长和生物量分别比对照降低了18%、46%、42%和66%;(2)随着镉处理浓度的升高,续断菊叶片中叶绿素a、b、总叶绿素和胡萝卜素含量均下降,80天200 mg/kg镉处理时总叶绿素比对照降低了58%,MDA增加2.4倍,细胞膜透性增大2.3倍;(3)不同镉浓度处理下,续断菊地上部镉含量均大于其根部镉含量,富集系数和转移因子均大于1;续断菊不仅具有较强的耐受环境高浓度镉胁迫的能力,而且具有更强的吸收和向地上部转运镉的能力;(4)随着镉浓度增加,续断菊根际土壤pH值显著降低,成熟期200 mg/kg镉处理pH下降了0.5个单位;(5)随着镉浓度增加,续断菊根系分泌有机酸、游离氨基酸及可溶性糖含量显著增加,其中可溶性糖占绝对优势。生长初期和旺期的续断菊根系分泌物中游离氨基酸的含量可以表征植株镉的积累;而在成熟期,可溶性糖和游离氨基酸可以指示植株中镉的积累;(6)续断菊体内大部分的镉分布在细胞壁中,占40%,且随着镉浓度的升高,细胞壁中的镉含量增大,20 mg/L镉处理下,细胞壁中的镉含量达到47%,减少了代谢活跃的细胞器及以膜系统上的镉含量,而使续断菊能够耐受高镉胁迫;(7)续断菊体内的镉主要与果胶酸、蛋白质结合,从而缓解了镉的危害。更多还原

【Abstract】 Pot experiments and the solution culture were conducted in order to understand the effects of cadmium on the growth and physiology of Sonchus asper(L.)Hill., characteristics and mechanisms of cadmium uptake and accumulation in Sonchus asper (L.) Hill.. The results showed that:(1) The biomass, plant height, leaf area and root length were increased with low Cd concentration treatment. The biomass, plant height, leaf area and root length decreased 18%, 46%, 42% and 66% with 200 mg/kg Cd treatment comparing with CK in 80 days, respectively.(2) Contents of chlorophyll a and b, total chloropgyll and carotene decreased with increase in Cd concentration. Total chlorophyll decreased 58%, MDA and membrane permeability increased 2.4 times and 2.3 times with 200 mg/kg Cd treatment comparing with CK in 80 days, respectively.(3) The Cd concentrations in shoots were higher than that in roots. Enrichment coefficient and transfer factor in shoots were more than 1. Tolerate ability, transport and accumulation of Cd were observed in Sonchus asper(L.)Hill..(4) The rhizosphere pH decrased with increase in Cd concentrations. pH decreased 0.5 units in mature stage of 200 mg/kg Cd treatment.(5) The contents of organic acids, soluble sugar and dissociative amino acid in root exudates increased significantly with increase in Cd concentrations. The contents of soluble sugar were dominated. The contents of dissociative amino acid were related to Cd accumulation in early days of growth. Contents of soluble sugar and dissociative amino acid were related to Cd accumulation in mature stage.(6) The site of Cd distribution in subcelluar was mainly in cell wall, accounting for 37% (shoot) and 42% (root). The percentage of Cd contents in cell wall reached 47% with 20 mg/L Cd treatment. Cell wall which could tolerate and reserve a great deal of Cd in tissues was the main pool of Cd in Sonchus asper(L.)Hill..(7) Contents of NaCl-extractable Cd, HCl-extractable Cd were dominant in leaves and NaCl-extractable Cd was the heighest in roots. The harmful effect of Cd was relieved due to Cd bound with pectic acid and protein in leaves and roots of Sonchus asper(L.)Hill..更多还原