【作者】 黄凯丰；

【导师】 曹碚生；

【作者基本信息】 扬州大学 ， 作物栽培学与耕作学， 2008， 博士

【摘要】 茭白（Zizania latifolia Turcz.）作为中国原产的特色水生蔬菜,以前主要在我国长江流域及其以南地区种植。20世纪80年代以来,随着我国种植业结构的调整和蔬菜流通体制的改革,各地纷纷引种茭白,目前茭白产品已在全国大部分地区种植并消费,成为消费量最大的22种蔬菜之一。部分加工产品已出口到日韩、北美、欧盟和澳洲等多个国家和地区。镉（Cd）、铅（Pb）是重要的污染物质,随着工业的快速发展及三废的大量排放,水体中重金属Cd²⁺、Pb²⁺的含量越来越高,而水生蔬菜栽培需要大量的灌溉用水,且大都在主要水系周边区域种植,因此受随水系扩散的重金属污染的可能性要高于其他种类的农作物。本文以江苏省特色水生蔬菜茭白的代表性品种蒋墅茭（单季茭）和葑红早（双季茭）为试验材料,研究了Cd²⁺、Pb²⁺在不同栽培介质处理下,以及Cd²⁺、Pb²⁺的单一、复合胁迫在不同肥料处理下对茭白生长发育的影响,同时测定了茭白各器官中Cd²⁺、Pb²⁺的积累量。期望为重金属胁迫对茭白伤害机理的研究提供一些科学依据,同时也为水生蔬菜的安全生产提供部分理论依据。取得如下结果:1、低浓度Cd²⁺、Pb²⁺胁迫能促进两茭白品种株高、叶面积的增加,但随处理浓度的进一步增加而显著下降;茭白的分蘖数则随Cd²⁺、Pb²⁺处理浓度的增加而呈持续下降的变化趋势。不同栽培介质处理间以苇末基质栽培下茭白的株高、叶面积、分蘖数同比高于土壤栽培。品种间以葑红早的株高、叶面积同比高于蒋墅茭,而分蘖数则低于蒋墅茭。2、不同栽培介质处理时,低浓度Cd²⁺、Pb²⁺胁迫均能促进两茭白品种的可溶性蛋白含量、脯氨酸含量、叶绿素含量和净光合速率总体的增加,但随Cd²⁺、Pb²⁺处理浓度的进一步增加而显著下降;根系活力则随Cd²⁺、Pb²⁺处理浓度的增加而呈持续下降的变化趋势;细胞膜透性随Cd²⁺、Pb²⁺处理浓度的增加而持续上升;不同栽培介质处理间以苇末基质栽培下茭白的可溶性蛋白含量、叶绿素含量、净光合速率等指标同比高于土壤栽培,而脯氨酸含量、根系活力、细胞膜透性则低于土壤栽培。不同肥料处理间相比则以有机肥处理下茭白植株受Cd²⁺、Pb²⁺胁迫伤害的程度小于无机肥处理。单一、复合胁迫处理间以复合胁迫处理时茭白受Cd²⁺、Pb²⁺的胁迫伤害大于单一胁迫。Cd²⁺、Pb²⁺胁迫能显著降低茭白的产量。品种间各指标存在差异。3、低浓度Cd²⁺、Pb²⁺胁迫能促进两茭白品种倒三片功能叶中保护酶活性的增加,但均随Cd²⁺、Pb²⁺胁迫浓度的进一步增加而下降;苇末基质栽培和有机肥处理时,茭白叶片中的保护酶活性分别高于土壤栽培和无机肥处理。复合胁迫处理时,茭白叶片保护酶活性下降的幅度显著大于单一胁迫处理。品种间以葑红早叶片中保护酶的活性高于蒋墅茭,说明葑红早对Cd²⁺、Pb²⁺胁迫的忍耐性要强于蒋墅茭。4、Cd²⁺、Pb²⁺胁迫能显著降低两茭白品种叶片中DNA提取的量以及DNA增色效应的程度。单一、复合胁迫处理间则以复合胁迫处理下茭白叶片中DNA提取的量显著低于单一胁迫处理,而复合胁迫处理下茭白叶片DNA的增色效应下降的幅度显著大于单一胁迫处理。不同肥料处理间则以无机肥处理下茭白叶片DNA提取的量显著低于有机肥处理;而无机肥处理下叶片DNA增色效应下降的幅度显著大于有机肥处理。品种间以蒋墅茭同比高于葑红早。5、Cd²⁺、Pb²⁺的单一以及复合胁迫均能促进两茭白品种根系和叶片中NPT、GSH、PCs含量的显著增加,Cd²⁺胁迫时其增加的幅度大于Pb²⁺胁迫处理,复合胁迫处理时两茭白品种根系和叶片中NPT、GSH、PCs的含量均高于单一胁迫。无机肥处理时,其含量显著高于有机肥处理。根系中NPT、GSH、PCs的含量显著高于叶片。品种间以蒋墅茭同比高于葑红早。6、Cd²⁺、Pb²⁺在茭白各亚细胞组分中的分布表现为:细胞壁>可溶性部分>细胞器,细胞壁>原生质体。有机肥处理时,茭白各亚细胞组分中Cd²⁺、Pb²⁺的积累量明显低于无机肥处理。复合胁迫处理时,茭白叶、根亚细胞组分中Cd²⁺、Pb²⁺的积累量同比均高于单一胁迫。品种间存在差异。7、随Cd²⁺、Pb²⁺胁迫处理时间的增加,其在茭白各营养器官中积累量呈显著增加的变化趋势;Cd²⁺、Pb²⁺在茭白不同营养器官间的积累量表现为:根>短缩茎>叶>产品器官;双季茭白品种葑红早在第2年采收的夏茭产品器官中Cd²⁺、Pb²⁺的残留量均显著高于当年的秋茭。苇末基质栽培和有机肥处理时茭白各器官中的残留量分别显著低于土壤栽培和无机肥处理。品种间以蒋墅茭对Pb²⁺的积累能力强于葑红早,而对Cd²⁺的积累能力则低于葑红早。8、随硫处理浓度的增加,茭白植株受Cd²⁺胁迫伤害的程度呈逐渐下降的变化趋势。当硫处理浓度达2 mmol·L^-1时茭白的产量达最大,其后随硫处理浓度的增加而持续下降,但均高于不施硫的处理;非蛋白巯基、植物络合素则在12 mmol·L^-1的硫处理时达最大,而6 mmol·L^-1处理时达最小;随硫处理浓度的增加,两茭白品种根中Cd²⁺的积累量呈明显下降的变化趋势,而短缩茎、叶、肉质茎中Cd²⁺的积累量则有所增加。有机肥处理能降低Cd²⁺对茭白的胁迫伤害,且能降低其在茭白各器官中的积累。品种间存在差异。更多还原

【Abstract】 As a kind of characteristic vegetable originated from China, Zizania latifolia Turcz. was mainly cultivated along Yangze River and the river’s south areas. Since 1980s, Zizania latifolia has been introduced to many areas of China with the adjustment of planting structure and the reformation of vegetable circulation system. It has been planted and consumed around China, and has become one of the 22 vegetables which are maximally consumed at present. Some processed products of Zizania latifolia have been exported to other countries such as Japan, Korea, North America, European Union and Australia.Cadmium (Cd²⁺) and lead (Pb²⁺) are two important contaminants in agricultural soil. With the rapid development of industry, waste and other contaminations goes to the river, content of Cd²⁺ and Pb²⁺ in water highly increasing. Aquatic Vegetable cultivation requires such a large amount of irrigating-water and this kind of vegetable needs to be cultived near the major water systems, which brings about its more possibility of being contaminated than other types of crops.In the paper, two typical cultivars of Zizania latifolia namely Jiangshu （single-harvested cultivar） and Fenghongzao （double-harvested cultivar）, characteristic hydrophytic vegetables in Jiangsu province, were used to study the influence of Cd²⁺, Pb²⁺ and their combined stress to the growth of Zizania latifolia with different cultural media and fertilizers. The Cd²⁺ and Pb²⁺ accumulation in Zizania latifolia were also determined. This paper will provid some theoretical evidences to the safety production of hydrophytic vegetables, and some scientific evidences to the study of mechanism of injury of Zizania latifolia. The main results show as follow:1. The plant height, leaf area increased under lower concentration of Cd²⁺ and Pb²⁺, but significantly decreased under higher concentration of Cd²⁺ and Pb²⁺, while tiller number descended with increased concentration of Cd²⁺ and Pb²⁺. The plant height, leaf area, tiller number in reed sediment substrate were higher than those in soil. The plant height, leaf area of Fenghongzao were higher than Jiangshu, but tiller number was lower.2. Content of soluble protein, proline, chlorophyll and net photosynthetic rate increased under lower concentration of Cd²⁺ and Pb²⁺, but significantly decreased under higher concentration of Cd²⁺ and Pb²⁺. Activities of root descended with increased concentration of Cd²⁺ and Pb²⁺, while the membrane permeability ascended. Content of soluble protein, chlorophyll and net photosynthetic rate in reed sediment substrate were higher than those in soil, but proline, activities of root and membrane permeability were lower. The harm of Cd²⁺ and Pb²⁺ to the growth of Zizania latifolia with organic fertilizer was lower than those of inorganic fertilizer. It was less harmly treated with single stress of Cd²⁺ and Pb²⁺ than combined stress. There were differences among cultivars.3. Protective enzyme activities in leaves increased under lower concentration of Cd²⁺ and Pb²⁺, but significantly decreased when increasing the concentration of Cd²⁺ and Pb²⁺. Protective enzyme activities of Zizania latifolia were higher when cultived in reed sediment substrate than when cultived in soil. Treated with organic fertilizer, the protective enzyme activities of Zizania latifolia was higher than treated with inorganic fertilizer. And it was lower when treated with single stress of Cd²⁺ and Pb²⁺ than combined stress. Protective enzyme activities of Jiangshu were lower than that of Fenghongzao in leaves. It showed that the endurance of Fenghongzao to Cd²⁺ and Pb²⁺ stress was stronger than that of Jiangshu.4. Cd²⁺ and Pb²⁺ stress could reduce the amount of extracted DNA and the hyperchromicity of DNA in the leaves of Zizania latifolia. Treated with combined stress of Cd²⁺ and Pb²⁺, the amount of extracted DNA in the leaves of Zizania latifolia was lower than single stress. The hyperchromicity of DNA had a larger descendent range when treated with combined stress than single stress. Treated with inorganic fertilizer, the amount of extracted DNA in the leaves of Zizania latifolia was lower than treated with organic fertilizer. The hyperchromicity of DNA had a larger descendent range when treated with inorganic fertilizer than organic fertilizer. The amount of extracted DNA and the hyperchromicity of DNA in leaves of Jiangshu were higher than that of Fenghongzao at the same treatment.5. Contents of NPT, GSH and PCs in functional leaves and roots of Zizania latifolia were significantly increased when treated with Cd²⁺ and Pb²⁺ stress. Under Cd²⁺ stress, contents of those had a larger increase range than Pb²⁺ stress. Contents of NPT, GSH and PCs of Zizania latifolia were higher under combined stress than under single stress. These contents of Zizania latifolia with inorganic fertilizer were higher remarkably than with organic fertilizer. Contents of NPT, GSH and PCs of Jiangshu were higher than that of Fenghongzao in leaves and roots at the same treatment.6. Distribution of Cd²⁺ and Pb²⁺ in subcellular fraction with the following sequence: cell wall>soluble fraction>organelle, and cell wall>protoplast. Accumulation of Cd²⁺ and Pb²⁺ in subcellular fraction of Zizania latifolia were lower when treated with organic fertilizer than with inorganic fertilizer. Treated with combined stress, those contents of Cd²⁺ and Pb²⁺ in leaves and roots of Zizania latifolia were lower than that of single stress. There were differences among cultivars.7. Accumulation of Cd²⁺ and Pb²⁺ in vegetative organs of Zizania latifolia was remarkably increased with the processing time of Cd²⁺ and Pb²⁺ stress. Accumulation of Cd²⁺ and Pb²⁺ in different vegetative organs of Zizania latifolia was in the order of root>culm>leaf>gall. The Cd²⁺ and Pb²⁺ acculumation in next summer-harvested galls was higher observable than those in first-autumn-harvested galls of Fenghongzao. The Cd²⁺ and Pb²⁺ acculumation of Zizania latifolia of reed sediment substrate were lower remarkably than those of soil culture at the same concentration of Cd²⁺ and Pb²⁺ stress. And it was also lower when treated with organic fertilizer than treated with inorganic fertilizer. The acculumating ability of Cd ²⁺of Fenghongzao was stronger than Jiangshu, but acculumating ability of Pb²⁺ was lower than Jiangshu. 8. Injury of Cd²⁺ stress to Zizania latifolia was decreased with increasing the concentration of SO₄^2-. At the level of 2 mmol·L^-1, the yield of Zizania latifolia reached the maximum. And it consistently descended with increasing the concentration of SO₄^2-, the yield of Zizania latifolia was still higher than the yield of Zizania latifolia which was treated without SO₄^2- . Contents of NPT and PCs in functional leaves and roots of Zizania latifolia were reached the maximum at the level of 12 mmol·L^-1 and reached the minimum at the level of 6 mmol·L^-1. It could remarkably reduce the content of Cd²⁺ in different subcellular fraction in leaves and roots of Zizania latifolia, when treated with SO₄^2-. It was concluded that supply of SO₄^2- could reduce the stress of Cd²⁺ to Zizania latifolia. It also could reduce the Cd²⁺ accumulation in roots, but improve the Cd²⁺accumulation in leaves and culms and galls. There were differences between cultivars.更多还原