关键词: 供需分析, 城市绿地, 服务水平

Abstract: Influences of progressive stress of Germanium on some physiological characteristics of the indica hybrid rice Shanyou 63 grown in Yoshida nutrition solution were studied under a greenhouse condition in 1993 and 1994. There was antagonism between germanium and silica uptake. Absorption of potassium and silica was significantly depressed because of presence of the germanium in nutrition solution, whereas contents of Fe and Mn in the functional leaves were decreased significantly. Low concentration(<0.05 μg·ml^-1)of germanium slightly increased root oxidizing activities, DNA and RNA contents in the functional leaves at booting stage, and stored carbohydrates in the leaves at late tillering stage. Generally, continuous presence of germanium significantly decreased root oxidizing activity, total content of chlorophyll and soluble protein in the functional leaves, DNA and RNA synthesis, content of potassium and silica element in the leaves, but promoted the peroxidase activity and increased the content of Fe and Mn element in the functional leaves. Germanium also decreased the accumulation of phosphorus in the brown rice.

Key words: supply and demand analysis, urban green space, service level.