Studies on inner wall structure of tracheids in Taxus chinensis with resin casting method

The resin casting method has been applied to studying the inner wall structure of tracheids in normal and compression wood, Taxus chinensis in gymnosperm. Not only the structures which are visible by the conventional method, but also the three-dimensional structures of pits pair in intertracheids unvisualized by the normal way have been observed. Moreover, it is found that there exist many differences in the angle, trend and occurrence of helical thickenings and distribution of warty layers on the inner walls of tracheids in normal and compression wood.

Study on tracheid variation of Picea koraiensis (nakai) in natural stand and plantation

Tracheid characteristics ofPicea koraiensis from natural stand in Liangshui area and plantation in Mao'ershan area were studied. The results of variance analysis showed that the tracheid length, diameter, and thickness of tracheid wall were significant differences between the growth rings. All those characteristics tend to increase from heart-center to bark. In natural stand, it has positive correlation between the characteristics. In plantation, the tracheid length has positive correlation with the trachied diameter, while both the trachied length and the trachied diameter has negative correlation with the thickness of trachied wall. The tracheid length and diameter have no significant difference in growth between natural stand and plantations. The thickness of tracheid wall from the plantation is a little thicker than that from the natural stand before 15 years.

Permeability and meniscus phenomenon in four Korean softwood species

The safranine impregnation differences in Pinus koraiensis, P densiflora, P. rigida, and Larix kaempferi were studied. Among them, P koraiensis conducted higher depth of safranine in radial and L. kaempferi in longitudinal direction. High magnification was used to observe the safranine penetration behavior in longitudinal direction especially in longitudinal tracheids. Safranine impregnation in longitudinal tracheids was captured in digital video mode to observe the formation of curved and flat air-safranine meniscus. Given the tracheid radius 16-20 gin, surface tension of water at 72 dynes per centimeter at 23℃ and a contact angle 30°, the capillary pressure ranges from 0.06 to 0.08 bar. The lower the lumen diameter is, the higher the capillary pressure is. It was assumed that due to the differences of total water pressure under the safranine-water interface and total air pressure above the interface, curved meniscus was formed in the cell lumen.

Anatomical and FTIR analyses of phloem and xylem of Tetracentron sinense

The fast growth of Tetracentron sinense is a potential valuable timber resource, but whether its anatomy and chemical components are suitable for timber is unknown. We used light microscopy and SEM to examine the anatomical structure and FITR to measure the chemical components of the phloem and xylem of this tree. Radial variations in growth ring width and tracheid dimensions were also evaluated. The sieve tube, phloem parenchyma cell and sclereids clusters were the main cells in phloem, and the tracheid was the fundamental cell in xylem. An unusual tracheid type, fiber-tracheids or vessel-liked elements was visible. Wood rays nonstoried, uniseriate and multiseriate, including heterogeneous II, occasionally I, and usually 3-6 cells wide. The mean growth-ring width was 2.53 +/- 0.46 mm, and the percentage of late wood was over 60%. For radial variation, growth-ring width increased at an early growth stage, and reached the largest increment during years 11-15, then decreased. The maximum growth-ring width was 5.313 mm. During late growth (60-85 years), trees also maintained a high radial growth increment. Radial variation in the percentage of late wood was uniform, about 50-70%, throughout the growth years. Growth patterns in the length and width of early and late wood were similar as the trees aged. From the FTIR results, the chemical components differed significantly between xylem and phloem, hemicellulose in particular was higher in the xylem than in the phloem, where it was apparently absent. All of these suggest that the composition of phloem in T. sinense is very similar to that of hardwood, and it has higher growth ratio and uniform wood properties.

Genetic variation of wood tracheid traits and their relationships with growth and wood density in clones of Pinus tabuliformis

To improve wood quality for pulpwood industries, it is important to examine not only wood density but also its components, especially tracheid characteristics. We studied genetic variations in the following tracheid traits by earlywood （EW） and latewood （LW）： tracheid length （TL）, double wall thickness （WT）, radial lumen diameter （R_D1）, tangential lumen diameter （T_D1）, radial central diameter （R_D2）, and tangential central diameter （T_D2）. We also studied the relationship with the following growth traits： diameter at breast height （DBH）, height （H）, crown breadth south-north axis （NSC）, crown breadth east-west axis （EWC）, ring width （RW）, latewood percentage （LWP）, and wood density （WD）. All sample materials were collected from a 33-year old clonal seed orchard of Pinus tabuliformis Carr. Genetic variation among clones was moderate for all tracheid traits, 9.49-26.03%. Clones significantly affected WT, R_D1, R_D2, T_D1, T_D2, and the two ratios WT/R_D1 and TL/T_D2 in EW but had no effects in LW. Clones significantly affected TL in LW but had no effects in EW. H2/C was higher in LW （0.50） than in EW （0.20） for TL, while H 2/C was higher in EW （0.27-0.46） for other tracheid traits and the two ratios （TL/T_D2 and WT/R_D1） than in EW （0.06-0.22）. WD and TL were significantly positively correlated, but WT and TL were negatively correlated both at individual and clone levels; all tracheid diameters and the four ratio values （EW_WT/ R_D1, LW WT/R_D1, EW_TL/T_D2 and LW_TL/ T_D2）, were strongly positively correlated with DBH, H, NSC, WEC and RW, and strongly negatively correlated with WD both at individual and clone levels. The most important variables for predicting WD were LW_TL, EW_WT and R_D1 in both EW and LW （r2= 0.22）. Selecting the top 10% of the clones by DBH would improve DBH growth by 12.19% （wood density was reduced by 0.14%） and produced similar responses between EW and LW for all tracheid traits： a reduction of 0.94 and 3.69% in tracheid length and increases in tracheid diameters （from 0.36 to 5.24%） and double wall thickness （0.07 and 0.87%）. The two ratios WT/R_D1 and TL/T_D2 across tissues （EW and LW） declined 0.59 and 4.56%, respectively. The decreased tracheid length and the ratio between tracheid length and diameter is disadvantageous for pulp production. The unfavorable relationship of tracheid traits with wood density indicate that multiple trait selection using optimal economic weights and optimal breeding strategies are recommended for the current longterm breeding program for P. tabuliformis.

Diurnal Periodicity of the Expression of Genes Involved in Monolignol Biosynthesis in Differentiating Xylem of Cryptomeria japonica

The cell wall in wood is mainly composed of three components: cellulose, hemicellulose and lignin. According to electron microscopy observations of the innermost surface of cell walls in the tracheids of Cryptomeria japonica , cellulose microfibrils are deposited during the day and a matrix containing hemicellulose is deposited at night. This indicates that the deposition of cell wall components exhibits diurnal periodicity. To gain new insights into the diurnal periodicity of lignin deposition not revealed by microscopic observations, we examined diurnal fluctuations in the expression of genes involved in monolignol biosynthesis in C. japonica saplings grown in the field and in growth chambers under a 12 h light/dark cycle. In the field experiment, two gene expression peaks were observed daily, at dusk and dawn. In the growth chamber experiment, two daily peaks were observed 0 h and 6 - 9 h after the light switched on.

Comparison of the Xylem Anatomical Traits of <i>L. gmelinii</i>and <i>P. sylvestris</i>var. <i>mongolica</i>at Three Longitudinal Sites

To find out the Xylem anatomical variations we analyzed the cell structure, lumen area early wood, lumen area late wood, ring width growth response relationship to climate factors in boreal forests. We present growth response from 3-sites KYH (Kheyihe), MEDG (Moredagha), ALH (Alihe) from central Daxing’an mountains China. Variations observed in Cell size from 2010-2016 years in Pinus sylvestris var. mongolica and Larix gmelinii. We analyzed growth response from 2010-2016. Results interoperates that significant growth of Larixgmelinii was lower at ALH-site than Pinus sylvestris var. mongolica as compared to KYH and MEDG-site. We measure the influence of temperature and precipitation which have been shown by correlations of different growing seasons. The warmest temperature from June to September at ALH-site growth of late wood show significant differences at ALH-site. It is also observed that summer temperature in late wood have a significant role in cell dimensions, while the influence of spring temperature frequently influences on tracheid size in early wood formation providing well-documented sound for anatomy and generally used for determining the relationship between maximum growth of tree ring density and effect of temperature variation.

Quantitative studies on charcoalification:Physical and chemical changes of charring wood

Charcoal is commonly preserved in both natural and artificial sediments,and is intensively used in paleontological,paleoenvironmental,and archaeological studies due to the abundant bio-information it contains.The biochemical properties of charcoal are also used for paleoclimatic reconstruction;however,the reliability of this approach has been challenged due to a lack of clarity on how physicochemical properties change during the charring process,as well as the temperatures required for charcoalification.To address this lack,in this study,Qinghai spruce and Chinese pine wood samples from the northeastern Tibetan Plateau were heated at different temperatures and for different lengths of time under restricted oxygen conditions.The reflectance;carbon,nitrogen,and oxygen content;and tracheid morphology were quantified before and after heating to assess changes related to the charring process.Archaeological charcoal remains were then evaluated to determine the charcoalification temperatures by comparing with the experimental results.The minimum temperature required for wood charcoalification was∼300℃,while temperatures recorded by archaeological charcoal were concentrated at 400-500℃.During the charring experiments,the tracheid cell walls gradually homogenized,and tracheid cell wall thickness and lumen area decreased by∼20%.On average,50%mass losses were observed;the carbon and oxygen content(%wt.)approximately changed from 47%to 60%and 48%to 35%respectively,while the nitrogen content(%wt.)fluctuated around 0.2%.The reflectance increased slightly from 0%to 0.5%.We propose that the charcoalification of wood tissue refers to charring(in restricted air)and carbonization(in the almost absence of air)when the wood is exposed to a heat source,which then finally transforms into a black,inert solid.This quantitative study provided valuable data and a thorough assessment of the process of wood charcoalification,as well as accurately estimated the feasibility of using charcoal physicochemical properties in paleoclimatic research.

The Best Width of Wood Specimen for Zero-span Tension Test

In recent years, the zero-span tension technique of paper and pulp-making industry was applied to wood industry for indirectly testing the longitudinal tensile strength of tracheids. In this paper, this technique was used to test the longitudinal tension strength of tracheids for Chinese fir specimens with different widths. The results showed that average tension strength was 357.39 MPa. The order of average tension strength of tracheids was: 3 mm > 12 mm > 6 mm > 9 mm > 7.5 mm. But, earlywood samples frequently contained a little latewood and sample-making was difficult when the width of specimen was bigger, both the testing and the putting of samples were difficult when the width of specimen was smaller. Therefore, the width of 6 mm was chosen as the best width of specimen of Chinese fir.

The Influence of S_2 Microfibril Angle on Longitudinal and Tangential Shrinkage in China-fir (Cunninghamia lanceolata) Plantation

The first objective of this study was to investigate the variation of microfibril angle (Mfa), tracheid morphology and shrinkage within China-fir (Cunninghamia lanceolata) plantation tree. The second objective was to discuss the relationship between Mfa and tracheid morphology, and the influence of Mfa on longitudinal and tangential shrinkage. The results showed that the mean value of Mfa decreased from the 2nd (30.8°) to 26th growth ring (7.7°); the radial variation of latewood tracheid length ranged f...