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Culture of mycorrhizal tree seedlings under controlled conditions: Effects of nitrogen and aluminium

1991; Wiley; Volume: 81; Issue: 3 Linguagem: Inglês

10.1111/j.1399-3054.1991.tb08751.x

1399-3054

Georg Jentschke, Douglas L. Godbold, Aloys Hüttermann,

Mycorrhizal Fungi and Plant Interactions

A sand culture system was developed for growth of mycorrhizal seedlings under monoxenic conditions, with frequently renewed nutrient solution The composition of the nutrient solution resembled that of a forest soil solution, based on long‐term measurements from forest sites at Soiling, northern Germany. Seedlings of Picea abies (L.) Karst. inoculated with Lactarius rufus (Scop.) Fr. were grown in this culture system. Plants developed rapidly, having almost totally mycorrhizal root systems. Nitrate at 2.7 mM in the nutrient solution and applied over a 13 week period had no negative effect on mycorrhizal development. Ammonium at 2.7 mM reduced the degree of mycorrhizal infection slightly, in such a way that the degree of mycorrhizal infection was reduced to a much less extent than the total number of root lips. Hence, the impact of NH + 4 may be primarily on root development and not on mycorrhizal fungal colonization. When the concentrations of NO‐ 3 and NH + 4 used in the present study are compared to those found in forest soil solutions, NO‐ 3 and NH 4 + would not appear to influence mycorrhizal development negatively under natural conditions. Aluminium at 0.8 mM and applied over a 13 week period reduced Mg uptake into roots and needles by 52 and 64%, respectively, resulting in needle chlorosis and strongly reduced photosynthetic activity. From a comparison of this study with others, no major difference in physiological response to aluminium exposure between non‐mycorrhizal seedlings and seedlings colonized with Lactarius rufus was found.