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首页> 外文期刊>Forstwissenschaftliches Centralblatt >Bacteria in radial shakes in pedunculate oak trees [German]
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Bacteria in radial shakes in pedunculate oak trees [German]

机译：有花梗的橡树上摇摇晃晃的细菌[德国]

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摘要

The occurrence and distribution of bacteria in so-called 'frost cracks' in oak trees were investigated to determine the possible role of bacteria in the formation and development of radial cracks in living trees. The bacterial samples were taken from wood cross-sections obtained at different trunk heights from freshly felled oak trees showing signs of 'frost cracks'. Inner portions of the cracks often yielded bacteria, the colonization density of which declined from the surface of the crack to the adjacent deeper wood tissues. Controls from sound wood not affected by cracks were sterile in general. The number of bacteria declined from the pith to the sapwood boundary. The sapwood was sterile for the most part. Bacteria colonization was more extensive in cross-sections from the lower parts of the tree than in cross-sections taken at heights of 1.5 or 2 meters. The pure cultures belonged mainly to Bacillaceae and to other microaerophilic or facultatively anaerobic bacteria, presumably lactic acid bacteria and Enterobacteriaccae. Degradation tests on woody cell walls and their components under aerobic and anaerobic conditions revealed a pattern typical for 'wood bacteria', i.e. degradation of parenchyma cells, pectin and cellulose derivatives as well as the lack of activity in respect to crystalline cellulose and woody cell walls. Rarely, other organisms such as a few Deuteromycetes and Ascomycetes were present in the cracks. The laboratory results may support the assumption that bacteria could be involved in the deterioration of the wood structure, especially of pectins and cellulose derivatives, and may contribute to the formation and further development of radial cracks in the wood of living trees.
机译：研究了橡树中所谓“霜裂”中细菌的发生和分布，以确定细菌在活树中径向裂痕形成和发展中的可能作用。细菌样品取自不同伐木高度的木材横断面，这些木材横断面取自刚砍伐的橡树，显示出“霜裂”的迹象。裂纹的内部经常产生细菌，细菌的定植密度从裂纹表面到邻近的更深的木质组织下降。不受裂缝影响的无害木材的对照通常是无菌的。细菌的数量从髓到边材边界减少。边材大部分是无菌的。从树的下部横截面的细菌定植要比在1.5米或2米高的横截面上的细菌定植更广泛。纯培养物主要属于杆菌科和其他微需氧或兼性厌氧菌，大概是乳酸菌和肠杆菌科。在需氧和厌氧条件下对木质细胞壁及其成分的降解测试表明，“木质细菌”具有典型的模式，即薄壁细胞，果胶和纤维素衍生物的降解，以及对结晶纤维素和木质细胞壁缺乏活性。裂缝中还存在其他生物，例如一些氘菌和子囊菌。实验室结果可以支持细菌可能参与木材结构特别是果胶和纤维素衍生物的降解的假设，并可能有助于活树木材中径向裂纹的形成和进一步发展。

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