镉胁迫对菊芋生理变化及镉富集的影响

通过用耐镉性较好的徐州菊芋和耐镉性较弱的潍坊菊芋进行对比试验,设置土培CK(Cd~(2+) 0 mmol/L,即对照组)、T1(Cd~(2+) 0.1 mmol/L)、T2(Cd~(2+) 0.5 mmol/L)和T3(Cd~(2+) 1.0 mmol/L)4个处理组,探讨菊芋镉胁迫下各项生理指标和根际土壤指标以及富集能力的影响。结果表明:经过不同镉浓度胁迫21天后,2个菊芋品种的根长、株高、叶长、叶宽均受到相应程度的抑制,抗氧化酶活性随镉浓度的增加而减弱;但丙二醛(MDA)含量变化有所不同,潍坊菊芋的MDA含量伴着镉胁迫加深而增加,徐州菊芋只在T3镉浓度下才出现明显的上升变化,并在21天时达到峰值,为对照组的3.52倍。根际土壤pH大致呈现出持续下降趋势,镉处理20天时潍坊菊芋和徐州菊芋根际土壤pH均在T3处理下达到最低,降幅分别为3.85%和3.41%;有机质含量却表现出不断增加的状态,T3镉处理至第20天时,潍坊菊芋最大增幅为38.60%,徐州菊芋为36.01%;随着施加镉浓度的变大,抑制了菊芋对土壤碱解氮的吸收,总体上潍坊菊芋受抑制程度大于徐州菊芋。2个菊芋品种对镉的富集效果也不同,徐州菊芋各器官镉富集量均高于潍坊菊芋;在转运镉方面,潍坊菊芋根部的镉均等地转移到了叶、茎上,徐州菊芋则将大部分从根部转移到茎上。综上所述,菊芋在镉胁迫下体现出一定的抗性,具有较强镉富集能力,徐州菊芋镉富集能力更为明显。因此,将能源植物菊芋应用于镉污染土壤兼具经济和生态意义。

Effects of Cadmium Stress on Physiological Responses and Cadmium Enrichment in Helianthus tuberous L.

Effects of Cadmium (Cd) stress on the physiological indexes, rhizosphere soil indexes, and the bioaccumulation ability in Helianthus tuberous L. of Weifang and Xuzhou were studied by a soil culture experiment. Experimental treatments included CK (Cd²⁺ 0 mmol/L as control), T1 (Cd²⁺ 0.1 mmol/L), T2 (Cd²⁺ 0.5 mmol/L) and T3 (Cd²⁺1.0 mmol/L). The results showed that all of the root lengths, plant heights, leaf lengths, and leaf widths of two varieties of Helianthus tuberosus were inhibited to some extent under different Cd stresses after 21 days. The activities of antioxidant enzymes were decreased with the increasing of Cd concentrations. While the changes of MDA contents were different in two varieties. The MDA contents of Weifang H. tuberous were increased with Cd stress, but those of Xuzhou H. tuberous were increase only under T3 reaching the highest MDA content after 21 days, which was 3.52 times of CK. The rhizosphere soil pH decreased approximately linearly, and both values in Weifang and Xuzhou H. tuberous decreased the most after 20-day treatment of T3, with 3.85% and 3.41% respectively lower than those of CK. The organic matter contents were increased with the increasing Cd concentrations, with the largest increase of 38.60% and 36.01%, respectively in Weifang and Xuzhou H. tuberous after 20 days. As Cd concentrations became higher, it inhibited the uptake of alkali-hydrolyzable nitrogen (AN) in soil by Helianthus tuberosus. The overall inhibition was greater than that of Xuzhou H. tuberous. The destinations of Cd transfer were different in two varieties. With the increase of concentrations, Cd almost equally transferred to the leaves and stems in Weifang H. tuberous, while most of Cd in Xuzhou H. tuberous transferred from the roots to the stems. The results indicated that H. tuberous has a strong ability to accumulate Cd and a certain resistance under Cd stress, even more obvious for Xuzhou H. tuberous. Therefore, H. tuberous could be applied in Cd-polluted soils with both economic and ecological significance.