Abstract
Northeast China produces an abundance of maize (Zea mays L.). In recent years, deficiency or relative
deficiency of potassium (K) in the soil is an important limitation to maize production. Maize inbred lines
tolerant to K deficiency (90-21-3) and sensitive to K deficiency (D937) were grown in potassium
deficiency field conditions. We investigated the root morphology, leaves stay-green, K centent, K
utilization efficiency (KUE), yield from grain filling to maturity. We found that the responses to low
potassium stress of 90-21-3 mainly embodied in root dry matter accumulation, total root length, root
volume, root surface area and average diameter changed more slightly than D937; the leaf stay-green in
90-21-3 were better than that in D937; Chlorophyll content increased to some extent in 90-21-3, while it
decreased sharply in D937; K content in root, leaf, ear increased slightly in 90-21-3, but the K content of
each organ in D937 were decreased much more; K content of each leaf and leaf sheath in 90-21-3
declined much smaller than D937, particularly where it found in three ear-leaves and sheaths; ear dry
weight and yield of 90-21-3 decreased less than D937; K use efficiency of 90-21-3 was higher than D937.
Under low potassium stress, the root system of 90-21-3 was relatively strong enough to absorb K,
moreover the K contents in three ear leaves and sheaths were maintained. The leaf stay-green could
prolong photosynthestic period. Thus, dry matter accumulation and yield were relatively higher than that
of D937.
Key words: Maize (Zea mays L.) tolerant to K deficiency, grain filling to maturity stage, root morphology, K
absorption, dry weight, leaf stay-green, yield.
