Production efficiency of nitrogen absorbed by-potato plant at various growth stages

Accumulation of ribulose-1,5-bisphosphate carboxylase/oxygenase in potato plants and nitrogen distribution in each organ during growth in relation to productivity

“…In the previous paper (Osaki et al 1993), based on the results of the effect of nitrogen topdressing at each growth stage of potato plant on tuber yield and of the partial production efficiency of nitrogen in tuber production, it was concluded that nitrogen applied after the flowering stage was not used efficiently for the production of tubers. In the present study, therefore we attempted to determine the cause of this phenomenon.…”

“…Danshakuimo) plants (early maturing variety) were sown in vermiculite on May 15, 1987. The plants were grown under water culture conditions by the same procedures as those employed in experiment 1 reported in the previous paper (Osaki et al 1993). Nitrogen concentration in the nutrient solution was 60 mg L -1.…”

“…1B was adopted, in which nitrogen was supplied at various intervals in each plot, then nitrogen application was discontinued until harvest (Osaki et al 1993). applications of phosphorus and potassium (10 g P2Os and l0 g K20 m -2) were performed using superphosphate and potassium sulfate in both treatments.…”

“…It is, therefore, expected that the nitrogen content of leaves may remain high by topdressing of nitrogen after the flowering stage. However, it has been reported that nitrogen application after the flowering stage did not affect appreciably on tuber swelling, and that the nitrogen content of shoot rapidly decreased with growth during the tuber swelling stage (Osaki et al 1993). In this paper, in order to determine the physiological causes of the low production efficiency of nitrogen absorbed after the flowering stage in potato plants, the behavior of I~N assimilated at various growth stages and the accumulation of Rubisco in the leaves by topdressing of nitrogen were investigated.…”

15N-Allocation of15NH4-N and15NO3-N to Nitrogenous Compounds at the Vegetative Growth Stage of Potato Plants

“…Dansyakuimo) was placed at a 10 cm depth in a container with vermiculite in a greenhouse. At 21 d (August 13) after planting, seedlings were transplanted to 10 L pots containing a water culture solution under aeration according to the system reported by Osaki et al (1993). Contents of mineral elements were as follows; nitrogen applied at the rate of 60 mg N L ~ at first in the form of NH4NOs, 10 mg P L -1 (NaH2PO4"2H20), 30 mg K L -~ (K2SO4 : KCI= 1 : 1), 50 mg Ca L -1 (CaCI2-2H20), 20 mg Mg L -1 (MgSO4-H20), 2 mg Fe L -x (FeSO4"TH20), 0.5 mg Mn L -1 (MnSO4-4H20), 0.5 mg B L ~ (H3BO3), 0.2 mg Zn L -~ (ZnSO4-7H20), 0.01nagCuL -1 (CuSO4"5H20), and 0.005mgMoL -j ((NH4)6MoTO24* 4H20).…”