影响烟草根系发育的几个因素探讨

通过盆栽试验、田间试验、田间调查等形式，对影响烟草根系发育的诸多因素做了初步探讨，结果表明，在盆栽条件下，至打顶时，深栽的烟草根系总干重比浅栽的烟草根系总干重增重45．7％，表现出深栽的促根效应，而且这种促根效应主要是极大地促进了不定根的发育，不定根与主根 侧根部分的比值最大达到将近5倍，而且不定根在烟碱合成上或运输上与主根 侧根部分也有所不同，重视不定根将对调控根系及叶片烟碱含量起到积极作用。在深栽情况下，施用的氮肥总量对不定根的影响比较大，并最终表现出明显的促根效应；磷肥的施用对主根 侧根部分的发育虽有一定的促进效应，但是却减少了不定根的发育，使最终的根系总量有所减少。所以，从促进根系发育的角度来看，烟草的前期追肥应以氮肥为主。除了深栽、氮肥具有良好的促根效果外，地膜覆盖、拓展根系伸展空间、选用根系发育良好的品种对解决生产中根系发育不良的问题也能够提供一些帮助。

Effect of factors on the growth of tobacco root

Basin experiment,field experiment and the investigation of tobacco field of farmer were conducted to discuss preliminarily the effect of different factors on the growth of tobacco root.Under the condition of deep transplanting,the growth of tobacco root can be significantly promoted with45.7%,and this kind of promoting effect is mainly due to increase the growth of adventitious root.The results also showed that the adventitious root of tobacco will be different from the rest of root on function of synthesizing or transporting nicotine.So,paying more attention to adventitious root may play positive role in promoting the growth of tobacco root.Under the condition of deep transplanting,the amount of nitrogenous fertilizer of topdressing has greater influence on adventitious root,and eventually obviously promotes the growth of root.Phosphate fertilizer has certain promoting effect on taproot plus lateral root,but reduces the growth of adventitious root,resulting in the amount of roots decrease.So,Top dressing of early stage should mainly be nitrogenous fertilizer in order to promote the growth of tobacco root.Besides deep transplanting and nitrogenous fertilizer as topdressing,film mulching,expendable space and varieties with fine root would be helpful to improve the growth of tobacco root.