玉米在重金属污染条件下的生态分化与品种退化

通过易地栽种实验，研究了经历不同重金属污染时期的玉米种群在正常条件下的平均相对生长率、不同时间的开花百分率及其整株重、株高、穗重、５０ 粒种子重、有效穗长和无效穗长等数量性状在不同玉米种群间的差异．结果表明，经历较长时期重金属污染适应的玉米种群在正常条件下栽种，具有较低的平均相对生长率，生活史缩短，植株矮化，产量降低．可以看出，玉米对重金属污染的适应导致了生态分化和品种退化，并讨论了玉米对重金属污染适应的耐性代价．

Ecological differentiation and variety degeneration of maize under heavy metal contamination

Different populations of maize (Zea mays L.) having been exposed to heavy metal contamination in different durations were replanted on unpolluted soil,and the difference of their quantitative characters such as average relative growth rate,flowering percentage at different time, plant weight, plant height,ears weight, 50 seeds weight and lengths of effective and noneffective ears was investigated.The results show that the populations exposed to heavy metal contamination in a longer duration had a lower relative growth rate,shorter lifecycle,shorter height and lower productivity,indicating that the adaptation of maize to heavy metal contamination led to its ecological differentiation and variety degeneration. The tolerance cost of maize in adapting heavy metal contamination was also discussed.