磷对旱柳生长特性及富集重金属Cd能力的影响

The Effects of Phosphorus on the Growth Characteristics and Cd Accumulation of Salix matsudana Under Cd Stress

该研究以旱柳(Salix matsudana)为试验对象,以添加50μmol重金属Cd的去磷营养液为水培液,设计向旱柳插条不施加任何磷(No-P)、新生茎喷施磷(Shoot-P)、根系施加磷(Root-P)以及新生茎和根系均施加磷(All-P)4种磷施加方式,研究重金属Cd胁迫下,磷对旱柳新生茎和根系的数量、长度、相对生长速率、生物量和总叶面积等生长特性指标,以及重金属Cd吸收和转运能力的影响。结果显示:新生茎喷施磷会促进旱柳地上生物量的增长,抑制根系的相对生长速率,促进重金属Cd从根系向新生茎的转运,增强旱柳地下及地上部位对Cd的富集总量;水体中磷的存在会抑制Cd的毒性和有效性,提高了旱柳对Cd的耐受性,降低植物富集重金属Cd的浓度,但不会降低旱柳富集Cd的总量。研究表明,应用旱柳浮床修复重金属污染及轻度富营养化的水体是可行的,可考虑利用水体营造含磷喷雾对植物地上部分进行喷施,不但能够增强旱柳对重金属的耐受性,而且能够提高旱柳对重金属Cd的富集效率。

In order to investigate the effects of phosphorus on the number,length,relative growth rate,biomass of shoot and root,as well as Cd absorption and transport of Salix matsudana under Cd stress,Salix matsudana was chosen as experimental material,and No-P nutrient solution added with 50μmol Cd was used as the hydroponic culture solution.All cuttings were treated as follows:1)No P nutrient solution(No-P);2)No P nutrient solution with P to the shoot(Shoot-P);3)No P nutrient solution with P to the root(Root-P);and 4)No P nutrient solution with P to the shoot and root(All-P).The results indicated that supplying phosphorus to shoot promote the growth of shoot while inhibit the RGR of root,and promote the transfer of Cd from root to shoot,which resulting in strong ability of Salix matsudana to accumulate Cd.When supply Salix matsudana with Root-P,phosphorus in water could inhibit the toxicity and availability of Cd,increase Cd tolerance of plant and decrease the concentration not content of Cd in Salix matsudana.In conclusion,it is feasible to use Salix for phytoremediation in heavy metal pollution and slightly eutrophic water.Spraying water with phosphorus to the aerial parts of plants could be considered,which could not only enhance the Salix tolerance of metals,but also guarantee a strong accumulation capacity of Cd when use Salix matsudana in phytoremediation.