重金属镉对玉米苗期生理特性和转运变化的研究

The Variational Study of Physiological Characteristics and Translocation Ability of Maize Seeding with Cd Stress

为了研究重金属Cd对玉米生理生化特性的影响及体内的转运规律,探索玉米应答Cd胁迫的品种差异和耐性机理。以低积累型品种郑单958和高积累型品种成单30为材料,采用室内溶液培养方法,在不同浓度（0,50,100,200,400μmol/L）胁迫不同时间后测定玉米幼苗生长,部分生理生化特性以及植株叶片和根系的Cd含量,分析Cd对玉米苗期形态特征,生理生化特性及Cd在叶片的转运能力的影响。结果表明,随着Cd浓度的增加和胁迫时间的延长,总根长、株高、整株鲜质量以及叶绿素（a＋b）含量,富集能力和转运能力均明显下降,叶片的相对电导率显著上升。相关性分析进一步证实,叶片Cd含量分别与叶片SOD、CAT活性、叶片相对电导率和叶片转运系数极显著相关,说明在耐Cd生理中,维持叶片SOD和CAT的活性能提高玉米对Cd耐性能力。此外,当生长介质的Cd浓度为50~200μmol/L,两品种的生理生化指标产生明显差异,敏感品种的生理特征和细胞膜结构均受到较强的破坏。高于200μmol/L时,成单30的叶片转运系数大于100%,将对Cd污染的生长介质具有一定的修复能力。

Studying the difference of the main physiological indexes and the relationship of accumulation of typical variety can provide some certain theoretical bases for avoiding the injury of Cd contamination. The main physiological indexes and the relationship of accumulation of typical variety responses of seedlings in different cadmium tolerant maize cultivars（ Zhengdan 958 and Chengdan 30） were investigated with a hydroponic experiment under different Cd concentration（ 0,50,100,200,400 μmol / L）. The results showed that with the increasing of the Cd concentration,total root length（ TRL）,PH fresh weight（ FW）,the content of chlorophyll（ a ＋ b）（ Chl（ a ＋ b））,enrichment coefficient（ RC） and translocation coefficient（ TC） decreased gradually. However,the relative electrolyte leakage（ REL） of leaves increased quite significantly. According to the correlation analysis,the paper had further confirmed that Cd concentration of leaves displayed most significant positive relationships with the SOD and CAT of leaves,REL and TC（ P〈 0. 01）. The study suggested that,in the resistant physiology,which played the leading role in Cd stress were sustain SOD,CAT. Furthermore,when Cd concentration was between 50 and 200 μmol / L,physiological indexes of two varieties produced difference significantly. With Cd concentration over 200 μmol / L,TC of leaves in Chengdan 30 was greater than 100%. It would be suitable for phytoremediation for Cd contaminated soil.