Study on the absorption, accumulation and distribution of copper in super-high-yielding winter wheat.

【Objective】 The objective of this study was to clarify the characteristics of copper nutrition in winter wheat cultivated under super-high-yielding (≥9 000 kg·hm-2) conditions.【Method】 A field experiment was conducted in Gaocheng County,Hebei Province during 2005-2006 winter wheat growing period.Four winter wheat cultivars,Temai 1,Shimai 12,Shixin 531 and Shixin 828,were used as experimental materials.Plant materials were collected from the plots at each growing stage and used to determinate copper concentrations in laboratory.【Result】 The main results showed that the concentration of Cu in various above-ground organs of wheat ranged from 5.5 to 18.8 mg·kg-1 at different growing stages.The concentration of Cu in leaf blade was always higher comparing with those in other organs during the growing period,but the organ with the highest Cu concentration changed with the growth center at different growing stages.The accumulation amount of Cu in leaf blades was the highest among all organs during early and middle growing period,and the distribution percentage of Cu in leaf blades was more than 55% of the total accumulation in wheat plants before booting stage,higher than those in other organs.However,the accumulation amount of Cu in grains was the highest at maturity,when the distribution percentage of Cu in grains was 33.7%-37.7%.The accumulation intensity of Cu during middle growing period (double ridge to anthesis) was the highest,and then that during late growing period (anthesis to maturity),with that during early growing period (seedling emergence to double ridge) the lowest.The total accumulation of Cu in wheat plants during its life span was 144.8-163.8 g·hm-2.The amount of Cu required for the formation of 100 kg grain yield was 1.7 g.The Cu accumulated in grains at maturity was depended more on the absorption after anthesis than on the redistribution from vegetative organs,which was only 17.1% of the total Cu in grains.【Conclusion】 According to the characteristics of Cu absorption and accumulation,Cu should mainly be applied as seed dressing or basal dressing,so as to accelerate the early growth and Cu absorption of wheat.Besides,foliar application should also be applied during mid-late growing periods to assure the supply of Cu during key absorption periods under insufficient early application.