Ultrastructural Study of Secondary Wall Formation in the Stem Fiber of Phyllostachys pubescens

Ultrastructural changes in secondary wall formation of Phyllostachys pubescens Mazel fiber were investigated with transmission electron microscopy. Fiber developed initially with the elongation of cells containing ribosomes, mitochondria and Golgi bodies in the dense cytoplasm. During the wall thickening, the number of rough endoplasmic reticulum and Golgi bodies increased apparently. There were two kinds of Golgi vesicles, together with the ones from endoplasmic reticulum formed transport vesicles. Many microtubules were arranged parallel to the long axis of the cell adjacent to the plasmalemma. Along with the further development of fiber, polylamellate structure of the secondary wall appeared, with concurrent agglutination of chromatin in the nucleus, swelling and disintegration of organelles, while cortical microtubules were still arranged neatly against the inner side of plasmalemma. Lomasomes could be observed between the wall and plasmalemma. The results indicated that the organelles, such as Golgi bodies together with small vesicles, rough endoplasmic reticulum and lomasomes, played the key role in the thickening and lignification of the secondary wall of bamboo fiber, though cortical microtubules were correlative with the process as well.

Measurement of Water Content in Different Organs of Phyllostachys pubescens

The height growth of bamboo in 2008 and 2009 as well as the water contents of bamboo stump,leaves,straw,and rhizome in 2009 were measured at the Tianmu Mountain Nature Reserve.The results revealed that the relationship between the height growth（Pn）and growth time（t）showed S-shaped curve in the two years;the water contents of bamboo stump,leaf,straw,rhizome and bamboo shoot were 0.50-2.31,0.46-1.8,0.50-1.38,0.56-1.58 and 0.89-8.96,respectively.Among them,the water content of bamboo shoot was the highest and noticeable changed,followed by bamboo stump,leaves,rhizome and straw in order.The water contents of the underground and aboveground parts respectively were 0.34-0.62 and 0.33-0.57.

Culm form analysis for bamboo, Phyllostachys pubescens

We investigated the culm form for one of the largest bamboo species, Phyllostachys pubescens Mazel ex Houz. in relation to the me- chanical constraint principles, i.e., elastic, stress and geometric similarity. The fine-resolution analysis of the culm taper indicated that the culm for P. pubescens consisted of three or four segments with various forms, except for the butt swell. This implied that the taper of the whole culm for P. pubescens could be expressed by neither of these principles. The regression slope between culm height and diameter at breast height on the double logarithmic coordinates was 0.629, which was significantly different from the values predicted from these principles. In conclusion, none of these mechanical constraint principles can express the culm taper and height-diameter relationship, and there may be a need for a more complicated model to express the culm form for P. pubescens.

Effects of Canopy Closure on Photosynthetic Characteristics of Ilex latifolia Thunb.in Phyllostachys pubescens Forests

Plantation under the forest is a good way of agroforestry,but the canopy closure has a great influence on understory herbs’growth.In the study,different canopy closures of Phyllostachys pubescens forests were set up to explore its influence on the growth of Ilex latifolia Thunb.The photosynthetic characteristics of Ilex latifolia leaves under different canopy closures were determined by Li-6400 portable photosynthetic system.The results showed that the net photosynthetic rate curve of Ilex latifolia leaves of T1(canopy closure of 0.56)was bimodal with an obvious"midday depression"phenomenon,while the net photosynthetic rate curves of T2(canopy closure of 0.72)and T3(canopy closure of 0.86)were unimodal.The results of light response curve showed that the photosynthetically active radiation and transpiration rate reduced with the increasing of canopy closures.The photosynthetically active radiation,transpiration rate,stomatal conductance,and net photosynthetic rate of Ilex latifolia leaves of T2 were higher than those of T3.Although the net photosynthetic rate of T2 was lower than that of T1,it had no obvious photo-inhibition which affected plant growth.Overall,the canopy closure of 0.72 was more suitable for the growth of Ilex latifolia.The herb plantation in the bamboo forest should be considered with the canopy closure for a better growth.

Effect of Management Practices on Seasonal Dynamics of Organic Carbon in Soils Under Bamboo Plantations

Soil samples for conventional management (CM) and intensive management (IM) practices were taken over a year at 2-month intervals to determine the effect of management practices on soil organic carbon (SOC) and to quantify seasonal dynamics in SOC for bamboo (Phyllostachys pubescens Mazel ex H. de Lehaie) stands. The results with IM compared to CM showed large decreases in total organic carbon (TOC), microbial biomass carbon (MBC), water-soluble organic carbon (WSOC), and the MBC/TOC ratio in the soils. With all IM plots in the 0-20 cm depth across sampling periods, average decreases compared with CM were: TOC, 12.1%; MBC, 26.1%; WSOC, 29.3%; the MBC/TOC ratio, 16.1%; and the WSOC/TOC ratio, 20.0%. Due to seasonal changes of climate, seasonal variations were observed in MBC and WSOC. Soil MBC in the 0-20 cm depth in September compared to May were 122.9% greater for CM and 57.6% greater for IM. However, due primarily to soil temperature, soil MBC was higher during the July to November period, whereas because of soil moisture, WSOC was lower in July and January. This study revealed that intensive management in bamboo plantations depleted the soil C pool; therefore, soil quality with IM should be improved through application of organic manures.

Silicon’s organic pool and biological cycle in moso bamboo community of Wuyishan Biosphere Reserve

Biomineralization of Si by plants into phytolith formation and precipitation of Si into clays during weathering are two important processes of silicon’s biogeochemical cycle. As a silicon-accumulating plant, the widely distributed and woody Phyl-lostachys heterocycla var. pubescens (moso bamboo) contributes to storing silicon by biomineralization and, thus, prevents eu-trophication of nearby waterbodies through silicon’s erosion of soil particles. A study on the organic pool and biological cycle of silicon (Si) of the moso bamboo community was conducted in Wuyishan Biosphere Reserve, China. The results showed that: (1) the standing crop of the moso bamboo community was 13355.4 g/m2, of which 53.61%, 45.82% and 0.56% are represented by the aboveground and belowground parts of moso bamboos, and the under-story plants, respectively; (2) the annual net primary production of the community was 2887.1 g/(m2·a), among which the aboveground part, belowground part, litterfalls, and other fractions, accounted for 55.86%, 35.30%, 4.50% and 4.34%, respec-tively; (3) silicon concentration in stem, branch, leaf, base of stem, root, whip of bamboos, and other plants was 0.15%, 0.79%, 3.10%, 4.40%, 7.32%, 1.52% and 1.01%, respectively; (4) the total Si accumulated in the standing crop of moso bamboo com-munity was 448.91 g/m2, with 99.83% of Si of the total community stored in moso bamboo populations; (5) within moso bamboo community, the annual uptake, retention, and return of Si were 95.75, 68.43, 27.32 g/(m2·a), respectively; (6) the turnover time of Si, which is the time an average atom of Si remains in the soil before it is recycled into the trees or shrubs, was 16.4 years; (7) the enrichment ratio of Si in the moso bamboo community, which is the ratio of the mean concentration of nutrients in the net primary production to the mean concentration of nutrients in the biomass of a community, was 0.64; and lastly, (8) moso bamboo plants stored about 1.26×1010 kg of silicon in the organic pool made up by the moso bamboo forests in the subtropical area of China.

Evaluating the Environmental Health Effect of Bamboo-Derived Volatile Organic Compounds through Analysis the Metabolic Indices of the Disorder Animal Model

Objective To identify the bamboo VOCs (volatile organic compounds) effect on animal physiological indices, which associated with human health. Methods GC/MS was used to analyze the volatile organic compounds from Moso bamboo (Phyllostachys heterocyla cv. pubescens). The effect of VOCs on environmental health was evaluated by analyzing the metabolic indices of the type 2 diabetic mouse model. Results Spectra of VOC generated by GC/MS were blasted against an in-house MS library confirming the identification of 33 major components that were manually validated. The relative constituent compounds as a percentage of total VOCs determined were alcohols (34.63%), followed by ether (22.02%), aldehyde (15.84%), ketone (11.47%), ester (4.98%), terpenoid (4.38%), and acids (3.83%). Further experimentation established that the metabolic incidence of the disease can be improved if treated with vanillin, leaf alcohol,β-ionone and methyl salicylate. The effects of these VOCs on type 2 diabetes were evident in the blood lipid and blood glucose levels. Conclusion Our model suggests that VOCs can potentially control the metabolic indices in type 2 diabetes mice. This experiment data also provides the scientific basis for the comprehensive utilization of ornamental bamboos and some reference for other similar study of environmental plants.

Surveys of harvest technology of winter bamboo shoots

Winter bamboo shoots are widely used in Asian cuisine. We surveyed growth depth （tail depth and root depth）, harvest speed, and harvest processes to provide information for developing new harvest technology. The tail depth of most winter bamboo shoots was 100 350 mm below the soil surface, and the root depth was 200 500 mm below the soil surface. Most winter bamboo shoots were difficult to locate with only the naked eye. The digging depth was 200 500 mm to cut winter bamboo shoots from the root. The highest harvest rate was 7.75 times faster than the slowest one and the average harvest speed ratio of men： women was about 1.71：1. The harvest process of winter bamboo shoots was divisible into three steps： searching, digging a hole （around the shoot） and cutting the root. The ratio of searching time to the sum of digging and cutting time was about 8：1, showing that searching required more time than digging and cutting together.

耐老化处理对毛竹竹材颜色变化的影响

采用国际照明委员会颜色系统CIE 1976 L*a*b*标准色度系统,研究耐老化处理不同竹龄、不同竹秆部位毛竹(Phyllostachys heterocycla var.pubescens)竹材对其材色的影响。结果表明,在耐老化处理过程中,竹材的颜色发生显著变化,从深红褐色变为浅黄色,颜色亮度由深至浅;随着处理时间的增加,L^(*)a^(*)b^(*)都主要呈现先增加后平缓的趋势,处理8 h后出现急剧增加,个别出现下降趋势,最后趋于平缓;不同竹龄竹材之间对耐老化处理响应出现明显差异,其中4年生毛竹的基部随耐老化处理的总体色差(ΔE*)最大达25.13,而其中部和稍部随耐老化处理总体色差(ΔE*)达到最小,分别为17.82和19.01。在立竹状态下,不同竹龄毛竹材之间黄蓝度和红绿度的主要分布范围差异不大,而颜色亮度差异较大,特别是竹材的中部和稍部;随着耐老化处理时间的增加,不同竹龄之间毛竹的材色开始出现明显差异。

Visualization of Cellulose Microfibrils of Phyllostachys pubescens Fibers with Atomic Force Microscope

Atomic force microscope(AFM) was used to investigate the arrangement of cellulose microfibrils (CMF) in Moso bamboo (Phyllostachys pubescens) fibers. Two methods of sample preparation were used here for different purposes. The first method was chemical maceration with a mixture of hydrogen peroxide and glacial acetic acid, through which the obtained fibers were suitable for observing the orientation of CMF in the primary wal1. The other method was to prepare tangential microtomed sections with a thickness of approximately 30 μm, which was used to investigate the arrangement of CMF in the inner wall of cell cavity of bamboo fibers. The results indicated that the CMF are randomly oriented in the primary wall while in the inner wall of cell cavity they are nearly vertical to the long axis of fibers , which is similar to the arrangement of CMF in the corresponding layer of wood fibers. Meanwhile, the highly oriented arrangement of CMF is also observed in a certain layer of bamboo fibers, though it is incapable of determining which layer it is in this study. The pilot investigation demonstrates that AFM is a powerful tool for the high-resolution observation of CMF in bamboo fibers, meanwhile it has the advantages of simple procedure of sample preparation and easy operation compared to the traditional transmission electron microscopy.

Study on Bamboo Treatment Technology with CuAz Preservative

In order to research the effect of preservative penetrability, CuAz (copper azole) was used for the preservative, and pieces of Moso bamboo (Phyllostachys pubescens) were used for the experimental materials in this study. The vacuum pressure process was used to treat bamboo pieces. The results showed as follows: 1) Main treatment factors were preservative concentration and applied pressure; 2) In the same technology, both the retention and the weight proportion gain of the samples without node were less than those of ones with node, due to special structure of bamboo node; 3) For the samples without node, a good result could be gotten when the preservative concentration was from 1% to 2%, treatment pressure was 0.6 MPa, and treatment time was 30 min. And for the bamboo samples with node, a good result can be gotten when the concentration was 2%, treatment pressure was 0.4 MPa, and treatment time was 30 min. This study demonstrates that the interaction between preservative and bamboo can be improved by adjusting the parameters.

Analysis on Chemical Composition of Guadua amplexifolia Planted in China

The objective of this study is to determine the properties of G. amplexifolia. In this paper; the chemical composition, including holocellulose, acid-insoluble lignin, 1% NaOH solubility, benzene-ethanol extractives and ash content, was considered for the variability with respect to positions along bamboo culm height （bottom, middle and top）, parts along radial direction （inner part and outer part）and ages （1-year and 2- year）. The test results were also compared to those of moso that is commonly planted and used in China. This study indicated that both the holocellulosecontent and the lignin content in inner part were lower than ; in outer part, but for extractives and ash content, the reverse was true. Bamboo age also had effect on chemical composition; both the holocellulose content and the ash content in the culm of 1- year were higher than those of 2-year; while the lignin content and the extractive content m the culm of 1- year were higher than those of 2-year. High holocellulose content, low lignin contentand extractive content were advantages of G. amplexifolia.

Study on Decay Resistance Performance of CuAz Preservative for Bamboo

Blocks of Moso bamboo were used as experimental materials to test the toxicity of CuAz preservative on decay fungi by the lab test in this paper. The result showed that the natural decay resistance of 4-year-old Mao bamboo is moderate, and the resistance to brown fungi is stronger than that to white fungi. The anti-fungi properties of CuAz preservative at the retention of 3.3 kg/m3 are equal to those of CCA-C and ACQ-B at the retention of about 4.0 kg/m3 , and obviously superior to those of organic acids preservatives.

Field Trial of Copper Treated Moso Bamboo in Southern China

The field trial of Moso bamboo treated with 9 copper preservatives was conducted in Guangzhou, China. The result showed that two formulations of ammonia-based copper azole (F17 and F18 ) and a formulation of amine copper added with boron (F10), as well as 2 kinds of ammonia-based ACQ, at the copper retention of 3.2 kg/m3 or over, were very resistant to decay and termites after the 5- year field test. And the durability of ACQ-B treated Moso bamboo was similar to that of treated Masson pine and slash pine at the same copper level.