Relationship between Root Morphology and Cd/Pb Accumulation Characteristics of Nine Rape Varieties and Its Mechanism

Purpose To study the root morphology and Cd/Pb accumulation characteristics, and analyze their relationship.

Method Nine rape varieties widely cultivated in Yunnan Province were cultivated in a rhizobox filled with heavy metals-polluted soils from a farmland in a lead-zinc mining area of Yunnan Province under a greenhouse condition.

Results (1) There was a big difference between the nine varieties on the root volume and tips number, and a small difference on root length and surface area. (2) The difference is obvious on the Pb content and accumulation in the aboveground and underground part between the nine varieties, and on the Cd content in the underground part; and the difference is small on the Cd content in the aboveground part and the Cd accumulation in the aboveground and underground part. (3) A significant positive correlation between root volume and the Pb accumulation in aboveground part, and very significant positive correlations between root tip and the Cd content in aboveground and underground part were found. (4) There were very significant and significant positive correlations between the available Pb concentration in the rhizosphere with the Pb content and accumulation in the underground part of rape; and a significant positive correlation between the available Cd concentration in the rhizosphere and the Cd accumulation in the aboveground part of rape.

Conclusion There was a notable difference on root volume and tips number, which had a close relationship with Cd content and Pb accumulation in the nine rape varieties.