Nature and Science

Influence of Different NO3 - /NH4 + on Nitrate and Ammonium Uptake Kinetics of Sugar Beet (Beta vulgaris L.) Seedlings

Duoying Zhang 1 , Fengming Ma 1 , Yue Zhao 1 , Caifeng Li 2

Abstarc :

Solution culture experiments were carried out  to study the kinetics at cotyledon stage
(11-day-old) and the effect  of  different NO3 - /NH4 +  on NO3 -  and NH4 +  uptake at seedling  stage
(31-day-old) with two cultivars of sugar beet, including Tianyan7 and Tianyan8. NO3 -  uptake by
sugar  beet seedlings at cotyledon  stage  (11-day-old) reached equilibration after  2 hours of adaptation, and NH4 +  uptake reached equilibration after 6 hours of adaptation. Km values of NH4
+   uptake by Tianyan7 were lower than Tianyan8, and Vmax values were higher.  It was benefit for
Tianyan7  to uptake NH4 + . The kinetics  of NO3 - and NH4 + uptake  by the cultivars changed after
cultivated in nutrient solution contained different NO3 - /NH4 +   for 20 days. NO3 -  uptake by sugar
beet was stimulated by lower concentration of NH4 +  in the nutrient solution. The NH4 +  uptake by
sugar beet changed complicatedly. Even cultivated in nutrient solution contained pure NH4 + , the
uptake ability of Tianyan7 was higher. Above all, it showed that NH4 +  uptake of Tianyan7 was
higher than Tianyan8, and  when  NO3 - /NH4 +  was  1:4 it reached the  highest. This  experiment
provided a theoretical basis to realize the highly effective ammonium assimilation  for sugar beet
through the experiment. [Nature and Science. 2004;2(3):70-78]

Key Word :
sugar beet; nitrate; ammonium; uptake kinetics

Volume 2, Number 3, October 2004 , ISSN 1545-0740