Understanding the ecological requirements of Rhododendrons; relevance to long-term conservation

摘要

Rhododendrons have always been believed to grow healthily only in acidic soil. However, some species also grow healthily in alkaline soil derived from minerals such as limestone, which is somewhat surprising, as it is well known that nutrients essential for healthy plant growth, such as iron and manganese, are normally available to these plants only in acidic soils. The factors that determine the ability of rhododendrons to survive in alkaline conditions were investigated by carrying out analyses ofsoil and leaf samples for a variety of Rhododendron plants. The pH and the organic matter content for the soil samples were measured, as well as the levels of calcium, magnesium, iron and manganese in the soil and the leaves, using ICP-AES. The analysesshowed that many rhododendrons exhibit very high manganese content hi their foliage which confirms that in limestone soils in the wild iron and manganese can be available enough for maintenance of their healthy growth.