Response of root morphology, physiology and endogenous hormones in maize (Zea mays L.) to potassium deficiency
2016
ZHAO Xin-hua, YU Hai-qiu, WEN Jing, WANG Xiao-guang, DU Qi, WANG Jing, WANG Qiao (<sup>1</sup> Fujian Key Lab of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou 350002, P.R.China <sup>2</sup> Key Lab for Biopesticide and Chemical Biology, Ministry of Education/Fujian Agriculture and Forestry University, Fuzhou 350002, P.R.China)
Potassium (K) deficiency is one of the major abiotic stresses which has drastically influenced maize growth and yield around the world. However, the physiological mechanism of K deficiency tolerance is not yet fully understood. To identify the differences of root morphology, physiology and endogenous hormones at different growing stages, two maize inbred lines 90-21-3 (tolerance to K deficiency) and D937 (sensitive to K deficiency) were cultivated in the long-term K fertilizer experimental pool under high potassium (+K) and low potassium (–K) treatments. The results indicated that the root length, volume and surface area of 90-21-3 were significantly higher than those of D937 under –K treatment at different growing stages. It was noteworthy that the lateral roots of 90-21-3 were dramatically higher than those of D937 at tasselling and flowering stage under –K treatment. Meanwhile, the values of superoxide dismutase (SOD) and oxidizing force of 90-21-3 were apparently higher than those of D937, whereas malondialdehyde (MDA) content of D937 was obviously increased. Compared with +K treatment, the indole-3-acetic acid (IAA) content of 90-21-3 was largely increased under –K treatment, whereas it was sharply decreased in D937. On the contrary, abscisic acid (ABA) content of 90-21-3 was slightly increased, but that of D937 was significantly increased. The zeatin riboside (ZR) content of 90-21-3 was significantly decreased, while that of D937 was relatively increased. These results indicated that the endogenous hormones were stimulated in 90-21-3 to adjust lateral root development and to maintain the physiology function thereby alleviating K deficiency.
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