施氮量对烤烟根系发育和某些生理指标的影响

Effects of Nitrogen Rates on Root Growth and Some Physiological Indexes of Flue-Cured Tobacco

采用盆栽试验,研究了施氮量对烤烟根系发育和某些生理指标的影响.结果表明,氮素胁迫会严重影响根系发育和一些生理代谢,不施氮处理(CK)根干重最小,根系硝酸还原酶活性(NR)和根系活力最低.施氮过量抑制根系的早期发育,移栽后65 d以前6 g.盆-1的处理根干重小于3 g.盆-1的处理,65 d以后6 g.盆-1的处理根干重逐渐达到并超过3 g.盆-1的处理;移栽后55 d以前6 g.盆-1的处理根系活力低于3 g.盆-1的处理,55d以后6 g.盆-1的处理根系活力高于3 g.盆-1的处理;移栽后45 d以后6 g.盆-1的处理的根冠比小于3 g.盆-1的处理,6 g.盆-1的处理NR活性小于3 g.盆-1的处理.移栽后35 d以后各处理根系总氮、蛋白质氮、游离氨基酸、烟碱含量随氮用量的增加而增加.

In order to study the effects of nitrogen rates on roots growth and some physiological indexes of flue-cured tobacco, the pot-cultivation experiment was conducted. The results indicated that： nitrogen stress had serious influence on roots growth and some physiological metabolism of flue-cured tobacco, and N O（CK） root dry weights were the smallest and its root nitrate activities and root activities were the lowest. Excessive application of N-fertilizer inhibited root growth in early stage and promoted that in later stage; 6 g · plot^-1 root dry weights reached gradually and overweighed that of 3 g · plot^-1 until 65 d after transplanting, and 6 g · plot^-1 root activities became stronger than that of 3 g · plot^-1 until 55 d after transplanting ; The ratios of root/shoot and the root nitrate activities of 6 g · plot^-1 were less active than that of 3 g · plot^-1 since 45 d after transplanting. The contents of total nitrogen, protein-nitrogen, free amino acids and nicotine in roots increased with N-fertilizer rates increasing since 35 d after transplanting.