氮对千日红试管苗生长和开花诱导的影响

Effects of nitrogen on growth and flowering of test-tube plantlets of Gomphrena globosa

本文以千日红组培苗为试验材料,研究培养基中氮形态及含量对千日红试管苗生长和开花诱导的影响。结果表明,1)相对于铵态氮(NH4+),硝态氮(NO3-)作为唯一氮源更有利于千日红试管苗生长和开花诱导,但千日红在NH4+和NO3-同时存在的培养基中表现最佳。2)在20mmol/L NH4+(NO3-)和5mg/L PP333存在的条件下,试管苗生长基本随着培养基中NO3-(NH4+)含量的增加而增加,并在含40mmol/L NO3-+20mmol/L NH4+(即MS培养基中氮含量)的培养基中株高达到最大值5.91cm;而叶片数和开花率则随着培养基中NH4+和NO3-含量的增加呈现先增加后下降的趋势,并在20mmol/L NO3-+5mmol/L NH4+培养基中达到最大值,分别为10.7片/株和38.89%。3)氮含量及形态配比结果表明,千日红试管苗开花率在培养基中氮总量为5mmol/L、NO3-/NH4+为4/1时达到最大值39.95%,而株高和叶片数在氮总量为35mmol/L,NO3-/NH4+为4/1时达到最大值8.52cm和13.38片/株。千日红试管苗开花率与培养基中NO3-/NH4+显著正相关,而与氮总量及株高之间显著负相关。此外,培养基中氮含量及形态配比还显著影响无菌苗根系生长。

The effects of nitrogen form and concentration on the growth and flowering induction of test-tube pla ntlets of Gomphrena globosa were investigated. The results showed： 1） Compared with the ammonium nitro gen （NH4＋）, nitrate nitrogen （NO3 ） as the sole nitrogen source was more favorable for the promotion of growth and flowering induction, while the optimum effect was observed with the presence of both NH4 ＋ and NO3 .2） In the presence of 20 mmol/L NH4 ＋ （NO3 ） and 5 mg/L PP333, the growth rate was gradually in creased with the increase of NO3 （NH4＋） level, and the plantlet height reached the maximum of 5.91 cm with 40 mmol/L NO3 @ 20 mmol/L NH~＋ （nitrogen content of MS medium）in the medium; whereas the leaf number and flowering rate increased and then decreased as total nitrogen level was increased, and reached their maximum of 10.7 per seedling and 38.89%, respectively, with 20 mmol/L NO3 @ 5 mmol/L NH4＋ （nitro gen content of MS medium） in the medium. 3） With respect to the effect of nitrogen on plant form, the maximum flowering rate of 39.95% was induced with a total nitrogen concentration of 5 mmol/L in the medium and with the ratio of ammonium to nitrate 4 ： 1; in contrast, the maximum plantlet height of 8.52 cm and leaf number of 13.38 per seedling was achieved with a total nitrogen concentration of 35 mmol/L in the medium and a 4 ： 1 ratio of ammonium to nitrate. The flowering rate of test-tube plantlets was significantly positively corre lated with the ratio of nitrate nitrogen to ammonium nitrogen, but negatively correlated with the total nitrogen content and plant height. In addition, the nitrogen content and the ratio of nitrate nitrogen to ammonium nitro gen in medium also significantly influenced the root growth of test-tube plantlets.