Division of Tropical Crops and Pastures, Commonwealth Scientific and Industrial Research Organization, Cunningham Laboratory, St. Lucia, Queensland 4067, Australia.
Plant Physiol. 1987 Aug;84(4):1314-8. doi: 10.1104/pp.84.4.1314.
The effect of nitrogen status on phosphorous uptake and translocation was examined in 6-day-old dark-grown decapitated maize seedlings exposed to 25 micromolar phosphorous. Transfer to complete solutions containing 1 millimolar ammonium resulted in an increase in phosphorous uptake rate after 6 to 8 hours. The stimulus remained effective for at least 5.5 hours upon subsequent transfer to nitrogen-free solutions. Pretreatments for 16 hours with either nitrate or ammonium resulted in enhanced rates of subsequent phosphorous uptake and in enhanced translocation to the xylem of the exogenously supplied phosphorous. Both processes reached a plateau following pretreatment with 0.1 to 1.0 millimolar concentrations of either nitrogen ion. Further enhancement occurred with 10 millimolar nitrate, but not with 10 millimolar ammonium pretreatment. Although nitrogen pretreatments slightly increased the quantity of exogenous phosphorous retained in the root tissue, most of the extra phosphorous taken up by the nitrogen-pretreated seedlings was translocated to the xylem. The enhanced translocation, however, did not totally account for the increase in uptake implying a specific stimulation of the uptake process.
研究了氮素状况对 6 天龄暗培养去顶玉米幼苗在 25μM 磷条件下吸收和转运磷的影响。将幼苗转移到含 1mM 铵的完全溶液中，6-8 小时后磷吸收速率增加。在随后转移到无氮溶液中至少 5.5 小时，这种刺激仍然有效。用硝酸盐或铵盐预处理 16 小时，可增强随后的磷吸收和向木质部的外源性磷的转运。用 0.1-1.0mM 氮离子预处理后，这两个过程都达到了一个平台。用 10mM 硝酸盐进一步增强，但用 10mM 铵盐预处理则不会。尽管氮预处理略微增加了根组织中保留的外源性磷的数量，但氮预处理的幼苗吸收的大部分额外磷都被转运到木质部。然而，增强的转运并不能完全解释吸收的增加，这意味着对吸收过程的特异性刺激。
