人工倾斜火炬松3年生苗木应压木的解剖性质

Anatomical Properties of Compression Wood of Three-Year-old Loblolly Pine Induced by Artificial Inclination

以3年生火炬松苗木为研究对象,在生长季节开展人工倾斜树干试验,将苗木分成5组(每组12株),与垂直方向倾斜成不同的角度(0°,15°,30°,45°,60°),苗木生长4个月后开始测定不同倾斜角度下火炬松应压木的解剖性质,分析不同倾斜角度下火炬松应压木解剖性质的变化规律。结果表明:1)随着倾斜角度的增加,管胞壁变厚,管胞形状变圆,胞间隙逐渐增多、增大,螺纹裂隙逐渐变宽、加深,其中30°以后应压木典型特征非常明显。2)随着倾斜角度的增加,管胞长度先减小后增大,30°达最小值;管胞宽度先减小后增大,45°达最小值;双壁厚先增大后减小,45°达最大值。方差分析表明不同倾斜角度对管胞长度、宽度及双壁厚影响均极显著。3)随着倾斜角度的增加,微纤丝角度先增大后减小,30°达最大值。方差分析表明不同倾斜角度对微纤丝角度影响显著。4)随着倾斜角度的增加,管胞比量及木射线比量呈波动变化;树脂道比量先增大后减小,30°达最大值。方差分析表明不同倾斜角度对树脂道比量影响显著,而对管胞比量及木射线比量影响不显著。5)从不同倾斜角度下各种解剖性质的变化趋势来看,30°～45°为应压木解剖性质形成的重要转折点,具体原因还需进一步研究。

Three-year-old seedlings of loblolly pine （Pinus taeda） were selected as materials in this article. The seedlings were planted in spring and divided into five groups,then were artificially inclined at the angles of 0°,15°,30°,45°and 60° from the vertical. After four months,the anatomical properties and their variation patterns of compression wood changed with the different inclined angles were determined every three month （totally five times）. The following conclusions were drawn： 1） With the increase of the inclined angle,the wall thickness of tracheid increased and the outline of the tracheid became round,the intercellular spaces and helical ribs were obvious and increased gradually in all sections derived from the inclined seedlings. 2） With the increase of the inclined angle,the tracheid length decreased firstly and then increased,the minmum value reached at 30°,the tracheid width decreased firstly and then increased,the minmum value reached at 45°,the double wall thickness increased firstly and then decreased,the maximum value reached at 45°.The ANOVA results revealed that there was highly significant effect of inclined angle on the tracheid length,the tracheid width and the double wall thickness. 3） With the increase of inclined angle,MFA increased firstly and then decreased,the maximum value reached at 30°. The ANOVA results revealed that there was significant effect of inclined angle on MFA. 4） With the increase of inclined angle,the proportion of tracheid and ray varied fluctuately,the proportion of resin canal increased firstly and then decreased,the maximum value reached at 30°. The ANOVA results revealed the effect of inclined angle was significant on proportion of the resin canal,but not significant on the proportion of tracheid and ray. 5） From the variation patterns of the different wood anatomical properties at different angles,the leaning angle of 30°-45° was an important turning point for the formation of compression wood and the further study was needed to understand this mechanism.