Effect of cross-sectional dimensions of tracheids on percentages of cell wall in Japanese larch

摘要

In order to estimate relationships between cross-sectional dimensions of tracheids and percentages of cell wall, 51 Japanese larch (Larix kaempferi) trees from 5 provenances were collected in a provenance trial stand consisting of 3 replications. Cross-sections of 15 mu m thick were prepared for image analysis to measure cross-sectional dimensions of tracheids. Measured parameters were cross-sectional area, radial and tangential diameter, cross-sectional cell wall area and percentage of cell wall.These parameters were adopted to analyze variance for determining the differences in the mean values between provenances. Significant differences of the mean values were found between the provenances in tangential diameter and cross-sectional cell wall area, while the percentage of cell wall that affects wood density showed no significant difference. Effects of the tracheid dimension on the percentage of cell wall showed different tendencies in earlywood and latewood. Whereas tracheid dimensions such asarea and diameter contributed to percentage of cell wall in earlywood, the amount of cell wall in each tracheid affected the percentage in latewood. Because the relations between cross-sectional area and cell wall area were almost the same among provenances, the dimensions had no significant effect on the percentage of cell wall, while significant differences were found in the cross-sectional dimensions of tracheids.