同一氮素水平不同NO_3~-/NH_4~+对NRA和GSA的影响

为确定硝态氮和氨态氮的最佳配方,以达到氮肥的最佳调控,试验研究了不同的NO3-/NH4+对甜菜同化关键酶的影响。结果表明,在整个生育期间,同一氮素水平、不同比例的NO3-/NH4+的NRA变化趋势与单一施硝态氮、氨态氮的NRA变化趋势一致,在生育前期较高,而后下降。但不同比例的NO3-/NH4+的NR活力不同,以NO3-/NH4+为3∶1的NR活力最高,而以NO3-/NH4+为0∶4的NR活力最低。在根和叶片中,不同比例的NO3-/NH4+的GS活力变化不同,在叶片中GS活力随NO3-比例增加而增加,但在根中,GS活力则随NH4+的比例增加而增加。

Influence of the different NO-3/NH+4on NRA and GSA

The change trend of NR activity of different proportion of nitrate nitrogen and ammonium (NO3-/NH4+) was similar to that of the single nitrogen source (nitrate nitrogen or ammonium nitrogen), that was NR activity was higher in early period of sugar beet growth duration, but it was lower in later period of growth duration. NR activity of different proportionof NO3-/NH4+ was different: NR activity raised when proportion of NO3- in mixed nitrogensource raised, that was NR activity of NO3-/NH4+ - 4∶0 was highest, but NR activity of NO3-/NH4+- 3 ∶ 1 was highest in period of peak absorbed nitrogen. In roots and leaves, GS activity change of different proportion of NOr/NH4+ was different; GS activity raised when proportion of NO3- in mixed nitrogen source raised in leaves, but its activity raised when proportionof NH4+ in mixed nitrogen source raised in roots.