磷对植物铝毒害作用研究中两种磷铝处理方法比较

COMPARISON BETWEEN TWO P-Al TREATMENT METHODS IN STUDYING EFFECT OF PHOSPHORUS ON ALUMINIUM TOXICITY TO PLANTS

由于磷和铝在溶液中的相互作用,研究磷对植物铝毒害作用的关键是选择合适的磷铝处理方法,本研究采用两种磷铝处理方法就磷对植物铝毒害的作用进行了比较。结果表明,采用计算铝活度的方法,磷能缓解铝对小麦的毒害,而采用磷铝交替处理的方法,磷则加重铝对小麦的毒害。尽管在计算铝活度的方法中不同磷浓度处理液中铝的活度相同(用GEOCHEM软件计算),但磷浓度越高的处理液,其毒性铝的浓度越低,在该方法中,磷可能是通过降低溶液中毒性铝的浓度而缓解铝毒的,不能很好地避免溶液中磷铝相互作用。磷铝交替处理彻底避免了磷铝在溶液中的相互影响,保证相同的磷和铝处理浓度,而且长期交替处理在一定程度上也降低了磷铝不能同时处理对试验结果准确性的影响,因而,该方法是一种研究植物磷铝关系比较可行的方法。在磷铝交替处理条件下,磷加重小麦的铝毒害,可能与磷促进铝在根尖的累积有关。

Owning to interactions between phosphorus and aluminium in solution,the key to study effect of phosphorus on aluminum toxicity to plants is to select an appropriate method to treat phosphorus and aluminium. In this study comparison was made between two phosphorus and aluminium treatment methods. Results showed that adoption of the method based on calculation of aluminium activity demonstrated that phosphorus could alleviate aluminium toxicity to wheat,while the application of the P-Al alternate treatment method revealed that phosphorus aggravated aluminium toxicity to wheat. By directly determining concentration of inorganic monomeric aluminium in Al-P treatment solutions,it was found that the toxic aluminium concentrations of treatment solutions decreased with increasing phosphorus supply though the estimated aluminium activities by GEOCHEM were at the same levels,so that the alleviating effect of phosphorus on aluminium toxicity to plants in the calculating method might result from decreasing concentration of toxic aluminium in the solutions. The alternate treatment method can avoid P-Al interaction in the solution,thus can keep phosphorus and aluminium at the same concentration level. Moreover,long-term application of this alternate method may also eliminate the impact of phosphorus and aluminium not being treated at the same time on accuracy of the experiment. Therefore,this alternate method may probably be a relatively workable one. Under P-Al alternate treatment,phosphorus aggravating aluminium toxicity to wheat may be associated with phosphorus stimulating aluminium accumulation at root tips of wheat.