We investigated the differences of K acquisition and utilization, morphological and physiological characteristics of roots and grain yield between Elymus dahuricus H + -PPase (EdVP1) transgenic wheat and wild type wheat under low K stress. The results showed that, the grain yield and K economic utilization index (KUI-E) in wild type wheat were only 61.14% and 50.20% of those in EdVP1 transgenic wheat. EdVP1 increased the free IAA accumulations in roots, which may play a key role in the

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... nt of root system. The total root length, total root surface area, root tips and total root volume in transgenic wheat were 2.26, 2.23, 2.34 and 2.00 times as high as those in wild type wheat, respectively. Excretion H + and cation exchange capacity (CEC) of roots, which were enhanced in transgenic wheat, were positively correlated with K content.The exudate of organic acid intransgenic wheat was 2.22 times as high as that in wild type wheat, leading to the strong K activation of transgenic wheat. Therefore, we assume that well-developed rootsystem containing prosperous root morphology, high excretion H + and CEC of roots and strong excretion ability of organic acids improved K acquisition and utilization efficiency in EdVP1 transgenic wheat.