Characteristics Of Nitrogen Absorption And Assimilation In Strawberry And Studies On Fertilization Technology

In pot cuture and field condition,characteristics of nitrogen absorption and assimilation in strawberry and technical of rertilization were studied,the results as follow: 1. Both inorganic nitrogen (NH₄⁺-N and NO₃^--N) and organic nitrogen (Gly and L-Glu) can be absorbed by strawberry. Under water culture condition ,the sequence of ¹⁵N utilization rate was (NH₄)₂SO₄>Gly >Ca(NO₃)₂>L-Glu, besides 15N utilization rate of Gly and L-Glu was enhanced when they were mixed with NO3--N., When the leaf was labeled urea, 15N utilization rate was 39.31%,but when the leaf was labeled Gly and L-Glu, it was only19.72% and 11.07% accordingly. In the period of fruit rapid growth, the fruit had higher competition for (NH₄)₂SO₄ , Gly and L-Glu than the leaf and lower for Ca(NO₃) under water culture and leaf labeled condition. Effect of enhanced ammonium nutrition(EAN)to spring cultured strawberry and winter cultured strawberry was different,the latter got the better yield. 2. As exteral NO₃^--N concentration increased, NO₃^--N uptake rates increased and tissue NO₃^-concentration increased, but NR activity got the higest value at 7.5mM.NR activity in roots was much lower than activity in leaves. Root NR activity was significantly lower than leaf NR activity, the highest NR activity in leaf was 390nmolNO₂/Gfw/h, but in root was only 121.3nmolNO₂/Gfw/h,These date suggest NR activity was the critical facter to limitate the strawberry response to NO₃--N. 3. In greenhouse,the treatment applying N at plant time and before flower at half dose respectively got the highest nitrogen uitization rate , and it was as much as 52.5%; while the rate of the treatment applying N before flower was the lowest,it was 34.2% . The rate of N-distribution in various organs existed...