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针对土壤重金属污染影响作物生长和食品安全的问题,采取水培法,研究在不同种类和不同浓度重金属胁迫下,洋葱根系、根尖细胞有丝分裂、过氧化物酶(POD)和过氧化氢酶(CAT)活性等生理指标的变化,总结重金属对洋葱根系影响的机制。结果表明:铅和镉对洋葱根系的生长均有抑制作用,且随着浓度的增大而增强;在铅和镉胁迫下洋葱根尖细胞大部分处于有丝分裂的间期和前期;较高浓度的铅、镉使洋葱根尖细胞的细胞核畸变;POD酶、CAT酶活力随着镉浓度的增加而增加,随着铅浓度的增加而降低。洋葱根系能对重金属铅、镉的胁迫产生相应的生理响应机制,为重金属污染对植物影响的研究提供了理论基础和客观依据。 相似文献
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用美国产Li-6400便携式光合测定系统对峰丛山区不同地貌部位的苦丁茶的净光合速率、蒸腾速率、气孔导度等生理指标进行测定,结果表明生长于洼地和山腰不同地貌部位的苦丁茶具有不同的生理生态特性:山腰的苦丁茶的净光合速率和水分利用效率大于生长于洼地的,而蒸腾速率和气孔导度小于生长于洼地的.在一定的光强范围内,山腰的苦丁茶的净光合速率和蒸腾速率随有效光辐射强度及叶片气孔导度的增强而加快;在一定的温度范围内,蒸腾速率随叶温的升高而升高,但当叶温达到一定值(36.8℃)时,蒸腾速率则开始下降. 相似文献
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In order to improve the efficiency of bioleaching heavy metal from the contaminated soil using Penicillium chrysogenum (P chrysogenum), experiment was conducted to evaluate the influence of heavy metal stress on P. chrysogenum during bioleaching. The morphology and physiology of P chrysogenum were observed. Assuming that the heavy metals are all leached out from the experiment soil, heavy metals are added into the agar medium by simulating the heavy metal content in the soil. It is concluded that the survivable heavy metal contaminated soil mass range for P. chrysogenum is 2.5-5.0 g. As for biomass determination, the contaminated soil is added into the liquid medium directly. The soil mass that P.. chrysogenum can be survivable is in the range of 2.5-8.75 g. In this mass range, the biomass of P. chrysogenum is bigger than that of the control sample. 10 g soil mass is the threshold of the growth ofP chrysogenum. 102.2 mg/L gluconic acid, 156.4 mg/L oxalic acid, 191.6 mg/L pyruvic acid, 0.02 mg/L citric acid, 0.03 mg/L malic acid and 70.6 mg/L succinic acid are determined after 15 d bioleaching. The mycelium is broken into fragments, and heavy metals are adsorbed on the cell wall or transported into the cytoplasm during bioleaching. The GOD activity declines from 1.08 U/mL to 0.2 U/mL under 400 mg/L of multi-metal stress. The influence of Pb on GOD activity is bigger than that of Cr and Cd, and the GOD activity is not influenced apparently by Mn, Zn and Cu. 相似文献
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二本高校应用型本科人才的质量和就业能力直接决定着二本高校学生的就业率。本论文针对二本高校学生的就业形势,以应用化学专业为例,从课程体系和课程内容、师资队伍、学生主体和校企互动等四个方面论述了二本高校培养应用型人才应做的改革,试图为二本高校本科应用型人才培养模式的改革探索提供思考,实现二本高校本科应用型人才质量和就业能力的提高。 相似文献
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