水稻铅积累基因型差异及其对铅胁迫的反应

对40份来源不同杂交组合的高代水稻品系进行同田种植,收获后测定其糙米的铅含量。结果表明,铅含量变异幅度为0.086~0.357 mg/kg,且不同品系存在差异。从中筛选出铅积累差异极端的6个品系,在2、4 mM 2个铅水平胁迫条件下,对其农艺性状、抽穗期超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、丙二醛(MDA)含量进行了调查测定,结果表明,2种铅胁迫条件下,株高、单株穗数、穗长、每穗实粒数、结实率、千粒重、单株产量与对照相比均受到一定的抑制,不同品系受抑制程度不一,同一品系不同胁迫条件下反应也不同,高铅水平胁迫下抑制更为明显。抗氧化酶的测定表明:胁迫条件下材料SOD、CAT、POD、MDA都发生了变化,SOD、CAT、MDA的变化与积累类型关联;低胁迫水平下低积累类型品系SOD活性升高幅度大,高胁迫水平下降低幅度小;2种胁迫条件下高积累类型品系CAT活性提高,而低积累类型品系降低;高水平胁迫时,所有品系叶片MDA含量都增加,低积累型品系增加幅度大。

Effects of Pb stress on the agronomic characters and antioxidant enzymes of different rice genotypes

The brown rice Pb contents of 40 lines from different crosses were determined.The Pb contents were significantly different among the rice genotypes varing from 0.086 to 0.357 mg/kg.The effects of Pb stress on the agronomic characters and antioxidant enzymes were studied on two Pb stress levels(2 and 4 mM) with three lower Pb accumulation lines and three higher lines.The agronomic characters(plant height,panicles per plant,panicle length,filled grains per panicle,seed setting,1000-grain wt,grain yield per plant) of most lines were significantly reduced in two Pb stress conditions compared with the Pb stress control(0 mM Pb).The reductions varied among the lines,also the response of the same line was different in different condition and the repressing was more obviously on Pb higher-level.Pb stress also affected the activities of superoxide dismutase(SOD),peroxidase(POD),catalase(CAT) and the content of malondialdehyde(MDA) in rice leaves in heading stage.The changes of SOD,CAT,and MDA were correlated to the the Pb-accumulation genotypes.The SOD activities of the lower Pb accumulation lines increased greatly on lower-Pb stress level,but declined slightly on higher level.The CAT activities of the higher Pb accumulation lines increased,but lower lines declined in two Pb stress conditions.The MDA contents of the lower Pb accumulation lines increased greatly than that of the higher Pb accumulation lines on high stress level.