Growth and mineral nutrition of non-mycorrhizal and mycorrhizal Norway spruce (Picea abies) seedlings grown in semi-hydroponic sand culture .1. Growth and mineral nutrient uptake in plants supplied with different forms of nitrogen
Growth and mineral nutrition of non-mycorrhizal and mycorrhizal Norway spruce (Picea abies) seedlings grown in semi-hydroponic sand culture .1. Growth and mineral nutrient uptake in plants supplied with different forms of nitrogen
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DOI：
10.1111/j.1469-8137.1996.tb01914.x
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发表时间：
1996-07-01
期刊：
影响因子：
9.4
通讯作者：
Marschner, H
中科院分区：
文献类型：
--
作者：
Eltrop, L;Marschner, H
以挪威云杉（Piceabies（L.）喀斯特。）在以石英砂为基质和稀释营养液的半水培系统中，在受控条件下生长的幼苗。该培养系统允许测定营养吸收率的菌根根系与一个完整的extramatrical菌丝体。菌根真菌着色豆梨和漆蜡蚧的侵染率较高，而卷状桩孢菌的侵染率较低。菌根植物的根特别是枝的重量显著低于非菌根植物。尽管较低的根D。重、根尖数和根分枝比（单位根长的根尖数）在感染L.漆树和P. tinctorius比在非菌根植物。外液中铵的消耗比硝酸盐的消耗快。硝态氮的吸收率在铵浓度低于400 μ M时增加。根据Lineweaver-Burk计算的最大hi吸收率（V-max），铵态氮的吸收率显著高于硝酸盐。氮素吸收速率无显着差异之间的非菌根和菌根植物。N、P、K、Ca和Mg的浓度在较小的菌根中倾向于高于较大的非菌根植物。与非菌根植物相比，菌根植物针叶中的N含量显著增加，但以NH 4+、SO 4+为氮源时，针叶中的N含量显著增加，而以KNO 3+为氮源时，针叶中的N含量没有显著增加。wt在感染P. tinctorius的菌根植物中低于在非菌根植物中。因此，只有在NH_4 ~+-N胁迫下，才能提高菌根植物对N的吸收速率，而在NH_4 ~+-N胁迫下，菌根植物对N、P、K、Ca、Mg的吸收速率与非菌根植物的差异不显著，说明在空间养分有效性不受限制的情况下，基质外菌丝体对菌根植物吸收养分的贡献很小。这表明，菌根植物的生长下降是由于菌根真菌对光合产物的需求，即来源限制。
Growth, nitrogen uptake and mineral nutrient concentrations in the plant tissues were determined in non-mycorrhizal and mycorrhizal Norway spruce (Picea abies (L.) Karst.) seedlings grown under controlled conditions in a semi-hydroponic culture system with quartz sand as substrate and a percolating nutrient solution. The culture system allowed the determination of nutrient uptake rates in mycorrhizal root systems with an intact extramatrical mycelium. The rate of infection of the roots by the mycorrhizal fungi Pisolithus tinctorius and Laccaria laccata was high but the rate of infection by Paxillus involutus was low.When supplied with ammonium nitrate, the d. wt of the roots and particularly of the shoots was significantly lower in mycorrhizal than in non-mycorrhizal plants. Despite the lower root d. wt, the number of root tips and the root branching ratio (number of root tips per unit root length) were significantly higher in mycorrhizal plants infected with L. laccata and P. tinctorius than in non-mycorrhizal plants. The depletion of ammonium in the external solution was faster than the depletion of nitrate. Nitrate uptake rates increased at ammonium concentrations below 400 mu M. The maximal hi uptake rates (V-max), calculated after Lineweaver-Burk, were significantly higher for ammonium than for nitrate. The N uptake rates did not differ significantly between non-mycorrhizal and mycorrhizal plants. The concentrations of N, P, K, Ca and Mg tended to be higher in the smaller mycorrhizal than in the larger non-mycorrhizal plants. A significant increase in mineral nutrient concentration in mycorrhizal compared with non-mycorrhizal plants was found only for N concentrations in the needles of mycorrhizal plants infected with P. tinctorius.When they were supplied with ammonium ((NH,),SO,) as source of N, but not when they were supplied with nitrate (KNO3), the d. wt was lower in mycorrhizal plants infected with P. tinctorius than it was in non-mycorrhizal plants. Therefore, N uptake rates were increased in mycorrhizal plants with P. tinctorius only when they were supplied with ammonium but not with nitrate.The insignificant differences in uptake rates of N, P, K, Ca and Mg between non-mycorrhizal and mycorrhizal plants indicate that at unlimited spatial nutrient availability the contribution of the extramatrical mycelium to nutrient uptake by mycorrhizal plants was small. It is suggested that the decreased growth of mycorrhizal plants is due to the demand of the mycorrhizal fungus for photosynthates, i.e. source limitation.