糖和氮对白榆组织培养新梢生根的影响

研究糖和无机氮源对白榆组培新梢不定根形成的影响,结果表明,含有高浓度蔗糖的培养基比低浓度蔗糖的培养基新梢生根率高.新梢对糖的这种反应与糖代谢和物理渗透都有关,用甘露作为渗透代替剂在低浓度蔗糖存在下无作用,当蔗糖浓度达到一定程度时(86.65 mmol·L-1)能影响新梢的生根率.在培养基中分别加入NO-3或NH+4作为唯一氮源,或是在MS培养基中加入NO-3/NH+4比率为标准的混合氮源,在测试范围(0 mmol·L-1～120 mmol·L-1)内均降低新梢的生根率,三者对生根的抑制作用依次为NH+4>NO-3+NH+4-N>NO-3-N.NO-3/NH+4比率与生根之间呈现直线正相关.糖/氮比值高有利于生根.插穗中碳、氮的绝对量及碳/氮比率可作为白榆新梢生根的指标.

Effect of Sugar and N to Tip Rooting of Elm Tissue Culture

The result of study on effect of sugar and inorganic nitrogen to rooting of elm tip in tissue culture showed that rooting rate of new tip was higher in higher sugar level medium than in lower sugar level medium.The response of tip to sugar content was related to sugar metabolism and physical osmosis.As a replacement of osmosis,manny hadn't effect in lower sucrose content,and when sucrose content was up to a certain degree(86.65 mmol/L),rooting rate of new tip was affected.Adding NO - 3 or NH 4 into medium as the sole N source,or adding them together under a standard NO - 3/NH 4 ratio into MS medium,in the range of measure(0 120 mmol/L),the rooting rate reduced,and the order of their inhibition function to rooting was NH 4>NO - 3 NH 4-N>NO - 3-N?There was a linear positive correlation between NO - 3/NH 4 ratio and rooting.Higher sugar/N ratio was advantageous to rooting.C and N conternt as well as C/N ratio can be taken as a rooting index of elm tip.