生物炭对镉胁迫下花生根系形态学特性及根镉含量的影响

Effects of Biochar on Root Morphology and Cadmium Content in Peanut under Cadmium Stress

试验采用盆栽方式,在3种不同镉(Cd)污染土壤中分别施用4种用量生物炭(C),探讨生物炭对镉胁迫下花生根长、根直径、根体积、侧根数、根系生物量和根镉含量影响。研究结果表明,在花生同一生长时期,相同镉处理条件下,花生的各项根系指标随着生物炭施入量的加大而逐渐增加,且这种趋势随着生育时期的延长变得更明显。在C100、C150处理下,苗期花生的根直径、侧根数和根系生物量随着Cd浓度的增加呈现Cd1>Cd10>Cd0的趋势,表明生物炭的施入,增加了花生苗期的镉耐性;而花生结荚期,不同生物炭施入处理下,花生各形态学指标均呈现Cd0>Cd1>Cd10的趋势,显示出在花生生殖后期,前期低浓度镉产生的刺激作用逐渐消失,生物炭对镉胁迫的缓解作用与花生发育时期有关。花生根镉含量与生物炭施用量之间存在极显著负相关关系,相关系数范围在-0.988至-0.922之间。灰色关联度分析显示,在花生苗期和花针期,侧根数、根系生物量是影响根镉含量的主要因素。研究未发现过多的生物炭施入对作物根系形态学指标的抑制作用。

Four rates of biochar were applied into 3 different cadmium （Cd） contaminated soils in pot experiment. We studied the effects of biochar on root length, root diameter, root volume, lateral root number, root biomass and Cd content of peanut root. In the same growth period the root index increased gradually with the increase of biochar application, and this trend was more obvious with prolonging growth period under the same Cd treatment. In CIO0 and C150 treatments, the root diameter, lateral root number and root dry weight of peanut increased at the order of Cdl 〉 Cdl0 〉 Cd0. This indicated that the application of biochar increased the Cd tolerance of peanut at the seedling. However, the morphological indices showed the decreased trend of cd0 〉 cdl 〉 cdl0 at the peanut pod period, which indicated that the low concentration of Cd had weak effect on the growth at the later stage of peanut reproduction. There was a significant negative correlation between the Cd content in root and the amount of biochar, and their correlation coefficient ranged between -0.988 and -0.922. Grey relational analysis showed that the number of lateral root and root biomass were the main factors that affected the Cd content in root at the peanut seedling stage and flower needle stage. As a result, excessive biochar application had no inhibition of plant root morphological index.