Nitrogen loading of Eucalyptus globulus seedlings: nutritional dynamics and influence on morphology and root growth potential
Nitrogen loading of Eucalyptus globulus seedlings: nutritional dynamics and influence on morphology and root growth potential
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DOI：
10.1007/s11056-020-09778-2
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发表时间：
2020-02-18
期刊：
影响因子：
2.2
通讯作者：
Chassin-Trubert, Rodrigo
中科院分区：
文献类型：
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作者：
Acevedo, Manuel;Rubilar, Rafael;Chassin-Trubert, Rodrigo
在日益恶劣的地点成功移植树木是全球关注的问题。例如，在智利，新的蓝桉种植园正瞄准较贫穷、低肥力的地区，这些地区的额外压力往往会对第一个田间季节的幼苗表现产生负面影响。然而，苗圃生产后期的氮负荷可以通过增加植物生长和养分储存储备来显着改善较恶劣地点的幼苗生理性能，以供外植后后续根系生长。最大限度地发挥这些效益，并在整个作物周期中应用负荷概念，需要更好地了解氮 (N) 动态。因此，对于被认为是全球最重要的种植园物种之一的容器蓝桉，我们评估了增加氮供应（50至600 mg N L-1）对幼苗形态性状、生物量产量、根系生长潜力和叶面氮的影响。施氮15周后，幼苗的所有生长变量均有所增加，最高达到300 mg N L-1，而更高的比率允许奢侈消费。然而，对生长反应的建模显示，铵与其他大量营养素阳离子的明显拮抗作用表明，这种氮形式的高比率可能会抵消氮负载的潜在好处，或者对肥料溶液的其他修改可能会促进更高氮比率下的额外生长。叶面氮浓度可以用叶绿素计轻松准确地测量，显示出从基叶到顶端叶的梯度，表明蓝桉幼苗中氮的强烈易位。我们的结果表明，在整个生长季节提供 300 mg L-1 氮的苗圃管理可以改善幼苗的营养状况、形态属性和新根的生长，这些属性可能会改善低肥力地点的定植。
Achieving successful outplanting of trees on increasingly harsher sites is a global concern. In Chile, for example, new Eucalyptus globulus plantations are being targeted to poorer, low fertility sites where additional stresses often negatively affect seedling performance during the first field season. Nitrogen-loading during the later stages of nursery production can, however, significantly improve seedling physiological performance on harsher sites by increasing plant growth and nutrient storage reserves for subsequent root growth after outplanting. Maximizing these benefits, and applying the concept of loading throughout the entire crop cycle, requires a better understanding of nitrogen (N) dynamics. Thus, for container E. globulus, considered one of the most important plantation species worldwide, we evaluated the effects of increasing N supply (50 to 600 mg N L-1) on seedling morphological traits, biomass production, root growth potential, and foliar N. After 15 weeks of N application, seedlings showed an increase in all growth variables evaluated up to 300 mg N L-1, whereas higher rates allowed luxury consumption. Modeling growth responses revealed, however, an apparent ammonium antagonism with other macronutrient cations suggests that high rates of this N-form may negate the potential benefits of N-loading, or that other modifications to the fertilizer solution may promote additional growth at higher N rates. Foliar N concentration, which was easily and accurately measured with a leaf chlorophyll meter, showed a gradient from basal to apical leaves suggesting a strong translocation of N in E. globulus seedlings. Our results suggest nursery management that supplies 300 mg L-1 of N through the entire growing season could improve seedling nutritional status, morphological attributes, and growth of new roots, attributes that may improve establishment on low fertility sites.