NITROGEN IN WOOD AND ITS ROLE IN WOOD DETERIORATION
NITROGEN IN WOOD AND ITS ROLE IN WOOD DETERIORATION
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DOI：
10.1139/b66-167
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发表时间：
1966-01-01
期刊：
影响因子：
--
通讯作者：
MERRILL, W
中科院分区：
文献类型：
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作者：
COWLING, EB;MERRILL, W
根据目前对木材中氮(N)的来源、数量、化学形态和分布的了解，提出了以下假说：(1)木材细胞发育过程中细胞质中的N因细胞壁物质的堆积而稀释；(2)木材纤维细胞成熟后，细胞质中的N通过淋洗进入蒸腾流而被清除；(3)木质部薄壁组织细胞在边材老化和心材形成过程中死亡，同时伴随着细胞质中大量N的去除。上述假设2和3有力地表明，树木具有保存和重复利用木质细胞细胞质中的N的内部循环机制。尽管木材中的氮素供应很少，但破坏木材的真菌很容易代谢木材中富含碳的成分，并产生巨大的果实结构，在自然界中释放大量的孢子。为了解释这些能力，我们假设这些真菌使用以下三种机制中的一种或多种：(1)优先将从木材中获得的N分配给物质和途径，从而高效地利用木材成分；(2)通过动态和连续的自溶和再利用过程重新利用从木材中获得的N，而不会显著损失N：(3)利用木材本身之外的N源，例如通过固定大气N。
Based on present knowledge of the origin, amounts, chemical form, and distribution of nitrogen (N) in wood, hypotheses are proposed to explain radial gradients in N content that exist across the xylem cylinder of tree stems (1) N in the cytoplasm of developing wood cells is diluted by apposition of cell wall substances; (2) after maturation of wood fiber cells, N in their cytoplasm is removed by elution into the transpiration stream; (3) death of xylem parenchyma cells during aging of sapwood and formation of heartwood is accompanied by removal of much of the N in their cytoplasm. Hypotheses 2 and 3 above suggest strongly that trees possess an internal recycling mechanism for conservation and reuse of the N in the cytoplasm of xylary cells. Although the supply of N in wood is meager, wood-destroying fungi readily metabolize the carbon-rich constituents of wood and produce large fruiting structures that release vast numbers of spores in nature. To account for these capacities, we postulate that these fungi employ one or more of the following three mechanisms: (1) preferential allocation of N obtainable from wood to substances and pathways highly efficient in the use of wood constituents; (2) reuse of N obtainable from wood by a dynamic and continuous process of autolysis and reuse without significant loss of N: (3) utilization of N sources outside the wood itself, for example, by fixation of atmospheric N.