【作者】 薛艳；

【导师】 沈振国； 周东美；

【作者基本信息】 南京农业大学 ， 植物学， 2004， 硕士

【摘要】 用土培试验研究了15个品种青菜的铜锌敏感型和忍耐型；用土培和水培两种方法研究了筛选出的两个品种（分别为火青菜和四月慢）对铜的吸收及铜对两种青菜种子萌发、幼苗生长和一些其它元素吸收的影响，分析了两个品种对铜的吸收与积累过程及其铜在植物体内的分布差异，并初步探讨了其机理。结果显示： 不同品种的青菜对铜锌毒害的响应明显不同；其中四月慢对铜和锌均表现出较高的敏感性，但耐铜和耐锌的青菜品种则不同，其中火青菜和香港菜心比较耐铜，而七宝青菜和矮抗1号等比较耐锌。统计分析显示：对于自然土壤上生长的不同品种青菜地上部和地下部铜的含量表现出显著正相关；而在土壤铜胁迫条件下，则表现出显著负相关，同时铜耐性品种较敏感品种在根部积累较多的铜，而其地上部的铜含量则相对较少，说明青菜由根部向地上部运输铜的能力大小是其对铜表现出耐性与否的重要原因；而在锌胁迫条件下不同品种的青菜地上部和根部对锌的吸收表现出正相关，同时，耐锌品种的解毒能力与其将锌由根部向地上部运输能力大小有关，运输能力越大其耐性越强。 根系和下胚轴对Cu处理的反应要比萌发本身敏感。种子的萌发受铜处理的影响不大，500μmol／l Cu²⁺并不抑制青菜种子萌发，但是在种子萌发后，其根长和下胚轴的伸长受Cu的处理影响显著。与50μmol／l Cu处理相比，火青菜和四月慢下胚轴减少到显著水平（P＜0.05）的Cu处理浓度分别为100μmol／l和200μmol／l，这说明火青菜相对四月慢来说对铜更为忍耐一些。 青菜对铜有较强的运输能力，随着铜处理浓度的增加，青菜地上部的含铜量增加。就其铜浓度来说青菜体内的含铜量为：（1）对照（铜浓度0.32μmol／l）时，根＞茎＞梗＞叶；2)铜处理（铜浓度≥1μmol／l）时，根＞茎＞叶＞梗。 铜锌交互处理青菜时，火青菜和四月慢的响应不同，同时，铜、锌对青菜生长的影响不同，低锌的加入并没有影响根系对铜的吸收，但是在50mg／kg铜处理下，50mg／kg锌处理则显著降低两个品种的地上部铜含量；低铜的加入促进了植株对锌的吸收。 不同铜浓度处理时，火青菜和四月慢的根系活力、叶绿素、地上部含糖量和生物摘要量等指标的变化不同，而且这些数据显示火青菜相对四月慢对铜有较高的忍耐性，四月慢相对对铜要敏感一些;短时间的铜处理可诱导增加青菜根系中的可溶性蛋白和GSH含量.SephedaxG一50层析结果表明，铜在蛋白质提取液的洗脱液中出现的位置与蛋白质出现的位置一致，表明青菜根系中可脆存有铜结合蛋白或多肤.更多还原

【Abstract】 Copper and Zn sensitivity and tolerance of 15 cultivars of Brassica Chinensis were investigated. Two cultivars of B. Chinensis (huoqingcai and siyueman) were screened to study their Cu uptake and distribution using hydroponic cultures and pot experiments. Meanwhile, the effects of Cu on their germination and uptake of other elements were examined when different Cu concentrations were treated. The mechanisms of B. Chinensis responding to Cu toxicity were exploited in this paper. Main results are shown as following:Responses of different cultivars of B. Chinensis to Cu and Zn toxicity were different. Siyueman was sensitive to both soil Cu and Zn pollution, but the cultivars to tolerate Zn and Cu toxicity were different. Huoqingcai and Hkcaixin were relatively tolerant to Cu, and qibaoqingcai and aikanglhao were relatively tolerant to Zn. Statistic analysis results indicated that shoot Cu concentrations of B, Chinensis were positively correlated with their root Cu concentrations when the 15 cultivars of B. Chinensis grew in a clean garden soil. However, a high negative correlation coefficient between shoot Cu concentrations and root Cu concentrations; of B.Chinensis were obtained when they grew in a Cu-treated soil, which also means that Cu tolerant cultivars of B. Chinensis had a weak ability to transport Cu from their root to shoot, and stored much more Cu in root than that by Cu sensitive ones. On the contrary, shoot Zn concentrations of B. Chinensis were positively correlated with their root Zn concentrations when the 15 cultivars of B. Chinensis grew in a Zn-treated soil. Zinc tolerant cultivars of B. Chinensis had a strong ability to transport Zn from their root to shoot.In comparison to seed germination, root length and hypocotyl of B. Chinensis were more sensitive to Cu toxicity. 500 mol/1 Cu2+ in the culturing solution did not affect the germination of B. Chinensis, but heavily restrained the growth of root and hypocotyl. The Cu2+ concentrations to reduce the length of hypocotyl of huoqingcai and siyueman at a significant level (P < 0.05), compared to the case with 50 mol/1, were 100 nmol/1 and 200umol/1, respectively, which showed that huoqingcai was more tolerant to Cu than siyueman.B. Chinensis had a strong ability to transport Cu from their root to shoot. The more the increasing Cu concentration in culturing solution, the more Cu was accumulated in the shoot of B. Chinensis. The Cu distribution in the tissues of B. Chinensis varied with solution Cu concentration. When solution Cu concentration was 0.32 umol/1 (ck), the Cu content in the tissues decreased in the order of root > stem > peduncle > leaf; when solution Cu concentration was above 1.0 umol/1, the order was root > stem > leaf > peduncle.When the soil was treated with Cu and Zn simultaneously, huoqingcai and siyueman showed different responses. Low soil Zn concentration did not affect the uptake of Cu by B. Chinensis; however, when soil Zn concentration was 50 mg/kg, the Cu concentration in B. Chinensis decreased distinctly. Moreover, low soil Cu concentration promoted the Zn uptake of B. Chinensis.The responses of the root activity, ch!6rophyll and shoot sugar content of B. Chinensis to different solution Cu concentrations were different. The results showed that huoqingcai was more tolerant to copper than siyuema.The presence of Cu induced the production of GSH and dissolved proteins in the root of B. Chinensis. Through a gel filtration chromatography filled with Sephadex G-50, two Cu peaks appeared in the dilution diagram, which were consistent with the two protein peaks.更多还原