根系吸收氮的形态(NH_4~+或 NO_3~-)在很大程度上决定着离子吸收的平衡和根际的pH 值。试验是在温室条件下观察 NH_4~+对北美黄杉幼苗根系生长和根际 pH 的影响。1 试验方法将1年生黄杉幼苗栽植于含砂土的不锈钢盆钵中,每盆栽1株,重复4次。每盆均加入生产10g 干物质重所需的养分,包括每株体内所含的 N(1.5mmol NH_4~+)。4个处理 Nitrogen absorbed by roots (NH_4 ~ + or NO_3 ~ -) determines the balance of ion absorption and rhizosphere pH to a great extent. The experiment was conducted to observe the effect of NH 4 + on root growth and rhizosphere pH of Douglas fruttosa seedlings under greenhouse conditions. 1 Test Method One-year-old bonsai seedlings planted in sand-containing stainless steel pots, each pot of a plant, repeated 4 times. Nutrients required to produce 10 g of dry matter per pot, including N (1.5 mmol NH 4 ~ +) per plant, were added to each pot. 4 processing