不同形态锑对水稻生长及根系形态特征的影响研究

通过溶液培养试验(采用埃斯皮诺营养液),研究不同形态锑[Sb(Ⅲ)和Sb(Ⅴ)]对常规籼稻(丰美占)生长、根系形态以及不同部位Sb含量的影响。结果表明:Sb(Ⅲ)和Sb(Ⅴ)均对水稻生长有抑制作用,且Sb(Ⅲ)的毒性较Sb(Ⅴ)高。随Sb(Ⅲ)和Sb(Ⅴ)处理浓度增加,地上部分和根系Sb含量均显著增加,且大量集中在根系。水稻对Sb(Ⅲ)的转运能力较Sb(Ⅴ)强,导致Sb(Ⅲ)处理下水稻地上部分Sb含量高于Sb(Ⅴ)处理,根系Sb含量则相反。Sb(Ⅲ)的加入显著抑制大多数根系形态参数,包括根长、根面积、根体积、根尖数以及根分叉数;而仅20 mg·L~(-1)Sb(Ⅴ)能显著抑制水稻根面积、根直径、根分叉数。上述结果表明:Sb(Ⅲ)和Sb(Ⅴ)处理下,水稻能通过降低根面积和分叉数降低对Sb的吸收。随着Sb(Ⅲ)处理浓度增加,水稻细根比例从52.1%降低至41.5%,中等根比例从45.2%增加至55.2%,表明Sb(Ⅲ)处理下水稻能通过增加根系粗度来降低对Sb的吸收;而随着Sb(Ⅴ)处理浓度增加,水稻细根比例在52.1%~56.8%之间波动,中等根比例在41.7%~45.2%之间波动。

Effects of different forms of antimony on the growth and root morphology of rice plant

This study was conducted to investigate the effects of different forms of antimony(antimonite[Sb(Ⅲ)] and antimonate[Sb(V)]) on Sb concentration in different organs of rice plant(Fengmeizhan), plant growth and plant root morphology using a hydroponic culture sys-tem containing Espino nutrient solution. The results show that the additions of Sb(Ⅲ)and Sb(V)both showed a negative effect on the growth of rice plants, and the toxicity of Sb(Ⅲ)is higher than that of Sb(V)to this rice plant. The supplementation of Sb(Ⅲ)and Sb(V) to the solution significantly enhanced the Sb concentrations in all organs of this rice plant, and most uptake Sb was concentrated in the roots. This rice plants showed a weaker ability to transport Sb(V)from the roots to the shoots relative to Sb(Ⅲ), which resulted in the shoot Sb concentration of this rice plant subjected to Sb(Ⅲ)exposure being higher, but root Sb concentration being lower than that subjected to Sb(V). The addition of Sb(Ⅲ)significantly reduced most tested parameters of root morphology, including root length, root average area,root volume, root tip number and root fork number. However, only 20 mg·L-1 Sb(V)remarkably reduced the root average area, root diame-ter and root fork number. Above results suggested that the rice plant might alter the root morphology to adapt the Sb exposure, and reduce the Sb uptake via reducing the root average area and root fork number. With the increasing Sb(Ⅲ)levels in the solution, the fine root proportion decreased from 52.1%to 41.5%, and the medium root proportion increased from 45.2%to 55.2%, indicating that the rice plant could reduce the Sb uptake through enhancing the coarseness of root exposing to Sb(Ⅲ). However, the addition of Sb(V)showed a limit-ed effect on the proportions of fine roots and medium roots, which fell into the range of 52.1%~56.8%and 41.7%~45.2%, respectively.