Cell Production and Expansion in the Primary Root of Maize in Response to Low-Nitrogen Stress

• Published in: Journal of Integrative Agriculture 2014-11, Vol.13 (11), p.2508-2517
• Main Author: GAO Kun, CHEN Fan-jun, YUAN Li-xing , MI Guo-hua (1State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an 271018, P.R.China 2Bio-Tech Research Center, Shandong Academy of Agricultural Sciences, Ji'nan 250100, P.R.China 3Shandong Rice Research Institute, Ji'nan 250100, P.R.China)
• Format: Article
• Language: English
• Subjects: cell length; cell length elemental expansion kinematic analysis root diameter root elongation Zea mays L; elemental expansion; kinematic analysis; root diameter; root elongation; Zea mays L; 主根; 低氮胁迫; 根伸长; 玉米苗; 生理机制; 电池生产; 细胞产率; 细胞分裂
• ISSN: 2095-3119; 2352-3425
• DOI: 10.1016/S2095-3119(13)60523-7

Maize plants respond to low-nitrogen stress by enhancing root elongation. The underlying physiological mechanism remains unknown. Seedlings of maize （Zea mays L., cv. Zhengdan 958） were grown in hydroponics with the control （4 mmol L-1） or low-nitrogen （40 μmol L-1） for 12 d, supplied as nitrate. Low nitrogen enhanced root elongation rate by 4.1-fold, accompanied by increases in cell production rate by 2.2-fold, maximal elemental elongation rate （by 2.5-fold）, the length of elongation zone （by 1.5-fold）, and ifnal cell length by 1.8-fold. On low nitrogen, the higher cell production rate resulted from a higher cell division rate and in fact the number of dividing cells was reduced. Consequently, the residence time of a cell in the division zone tended to be shorter under low nitrogen. In addition, low nitrogen increased root diameter, an increase that occurred speciifcally in the cortex and was accompanied by an increase in cell number. It is concluded that roots elongates in response to low-nitrogen stress by accelerating cell production and expansion.