农艺措施对苹果幼树长期低剂量铜胁迫的影响及缓解效果分类

为探讨农艺措施对铜胁迫苹果树毒害效应的缓解效果,利用长期盆栽试验(600d),研究了棕壤上介于我国土壤环境质量二、三级标准间的低剂量铜胁迫下,钙(CaCO3)、铁(FeSO4)、钾(K2SO4)以及半腐熟鸡粪(CM)对苹果幼树生长和果实铜积累的影响。结果表明,320mg·kg-1的铜胁迫600d导致苹果树春梢萌动迟缓,生物量、果实数量下降,果实铜含量升高(P<0.05)。施加CaCO3对铜胁迫苹果树的生长(新梢萌发和果实数量)有明显的缓解效果,并降低果实铜含量(P<0.05),降低通过食物链危害人类健康的风险。K2SO4虽能够缓解铜胁迫对总生物量的抑制作用,却导致果实数量减少,果实铜含量增高(P<0.05)。FeSO4和CM对于植株生物量和果实数量没有明显的缓解作用(P>0.05),但能降低果实铜含量(P<0.05)。综合考虑对果树生长和人类食品安全的影响,将缓解效果分为安全的解毒、安全的不解毒、危险的解毒和危险的不解毒4类。K2SO4属于危险的解毒,在农用棕壤上应慎用;FeSO4和CM属安全的不解毒;CaCO3属于安全的解毒,具有较好的缓解毒害和降低食品安全风险的效果。

Effects of Agronomic Measures on Long-term Toxicity of Low-dose Copper for Apple Trees and Classification of Amelioration

To study the amelioration effects of agronomic measures for Copper(Cu) toxicity on apple trees Malus pumila Mill(OBIR-2T-47) /M.micromalus Makino]in brown soils,600d soil culture experiments were done.Cu level was 320mg·kg~(-1)(between the second and the third level of soil environmental quality standard), and calcium(CaCO_3), ion (FeSO_4), potassium (K_2SO_4), and chicken manure (CM) were applied to alleviate the toxicity. Cu treatment delayed the growth of branches, decreased plant biomass and fruit amount, and increased fruit Cu con-tent(P<0.05). Compare with Cu treatment, addition of CaCO_3 lowered the delay of branch growth, increased fiuit amount. and declined fruit Cu content significantly(P<0.05); Addition of K_2SO_4 raised plant biomass. made fruit amount decline, and increased fruit Cu concentration; FeSO_4 and CM did not show obvious amelioration on growth, just lowered fruit Cu content. Take the impact on both plant growth and food safe (fruit Cu content in the present study) into account amelioration effect can be classified into 4 groups : "safe amelioration","safe non-ame-lioration", "dangerous amelioration", and "dangerous non-amelioration". K_2SO_4 belongs to the "dangerous amelioration" class, and should be used with caution in Cu contaminated brown soils. FeSO_4 and CM belong to the "safe non-amelioration" class. And CaCO_3 belongs to "safe amelioration", alleviating plant toxicity and lowering human health risk.