At5g54160 gene encodes <Emphasis Type="Italic">Arabidopsis thaliana</Emphasis> 5-hydroxyconiferaldehyde <Emphasis Type="Italic">O</Emphasis>-methyltransferase

The function of an Arabidopsis thaliana gene, At5g54160 annotated as a caffeic acid O-methyltransferase CAOMT gene was characterized. The recombinant enzyme of this gene (AtOMT1) catalyzed the O-methylation of phenylpropanoid and flavonoid substrates. The specificity constants (k _cat/K _m) for 5-hydroxyconiferaldehyde (5-HCAld) and quercetin were both 0.11 μM⁻¹·min⁻¹. On the other hand, lignins of At5g54160-knockout Arabidopsis mutants lacked syringyl units. In addition, we showed that the gene silencing also resulted in significant accumulation of caffeyl alcohol (CaAlc). These results strongly suggested that At5g54160 gene is involved in syringyl lignin synthesis for the methylation of both 5-hydroxyconiferaldehyde and 3,4-dihydroxyphenyl compound(s). Part of this work was presented at the Annual Meeting of Japan Society for Bioscience, Biotechnology, and Agrochemistry, March 24–27, 2007     

木质素生物合成调控基因工程研究进展

木质素生物合成是植物体内比较复杂的生化过程,存在多基因、多条途径交互作用。基因工程调节植物木质素合成已成为国际上研究的热点。综述了转基因技术调控植物木质素生物合成的研究进展。提出创造低木质素含量和组分改变的优质新品种,对于造纸和纺织工业等的可持续发展具有重要的意义。     

水杨酸诱导辣椒抗疫病生化机制的研究

对水杨酸（SA）处理及其挑战接种辣椒疫霉菌的4个抗性不同的辣椒品系体内木质素含量和多酚氧化酶（PPO）、过氧化物酶（POD）、苯丙氨酸解氨酶（PAL）活性的测定结果表明：SA诱导的供试品系与未经诱导的相同品系相比,木质素含量增高,PPO、POD、PAL活性增强,其中木质素的含量与抗病性呈显著正相关;挑战接种后两者相比,SA处理的供试材料的木质素含量和PPO、POD、PAL活性的增强幅度更大,其中抗、耐病品系的增加早且增加幅度高于感病、高感品系。值得注意的是,经SA诱导的各供试品系接种后木质素含量与抗病性也呈显著相关。木质素含量与相关酶活性的上述变化趋势与SA对各品系的诱抗效果完全吻合。     

毛白杨木材主要组分与酸性染料的相互作用

对毛白杨木材纤维素,半纤维素和木素采用酸性染料桔黄Ⅱ进行加热浸染,观察其染色性能,并采用ＦＴＩＲ分析其染色前后的变化。结果表明：对于酸性染料桔黄Ⅱ,素和半纤维素不能上染,而木质素染色性能良好;ＦＴＩＲ分析表明,三者均未与染料反应生成新的化学官能团,而是木材组分对染料的吸附作用使木材产生颜色。     

Excellent oil absorbent kapok [Ceiba pentandra (L.) Gaertn.] fiber: fiber structure, chemical characteristics, and application

The study focused on kapok [Ceiba pentandra (L.) Gaertn.] fruit as a biomass for effective utilization. Kapok fruits were harvested just before full maturation at the campus of University of the Philippines Los Banos and in southern Vietnam. The kapok fibers are utilized locally as fiberfill in pillows, quilts, and some soft toys. Kapok fiber was isolated and analyzed microscopically, and the physicochemical properties were determined by spectroscopic methods. Some tests were done to determine the effective utilization of kapok fiber. Microscopic analysis of the higher structure of kapok fiber gave quite different results from cotton fiber, which has a significantly homogeneous hollow tube shape and is composed of cellulose (35 % dry fiber), xylan (22%), and lignin (21.5%). Kapok fiber is characterized by having a high level of acetyl groups (13.0%). Usually cell walls of plants contain about 1%–2% of acetyl groups attached to noncellulosic polysaccharides. Kapok fiber is significantly hydrophobic and does not get wet with water. Thus, the absorptivity of oil was tested. The fiber selectively absorbed significant amounts of oil (40 g/g of fiber) from an oil suspension in freshwater and seawater. It is suggested that this fiber could be used to recover oil spilled in seawater.     

Role of Tween 80 in biobleaching of unbleached hardwood kraft pulp with manganese peroxidase

The role of Tween 80 in biobleaching of unbleached hardwood kraft pulp (HWKP) with manganese peroxidase (MnP) was investigated. Among the surfactants (e.g., Tween 80, Tween 20, CHAPSO) the most significant brightness increase was obtained with Tween 80. Tween 80 and Tween 20 exhibited several effects, such as dispersion of degraded lignin and activation of MnP, that partly contributed to the brightening of HWKP during MnP treatment. However, these characteristics did not explain the most appreciable effect on the brightness increase by Tween 80. Lipid peroxidation of surfactants during MnP biobleaching was determined by measuring the peroxide value (POV). The order of the POV increase was consistent with that of the brightness increase of pulp during MnP treatment in the presence of various surfactants or linolenic acid. However, radicals and peroxides derived from lipid (linolenic acid) peroxidation by lipoxidase hardly brightened the HWKP by themselves. These results suggested that Tween 80 was peroxidized by Mn(III), and that Mn(III) and lipid peroxidation of Tween 80 synergistically brightened HWKP.This study was presented in part at the 43rd lignin symposium, Fuchu, Tokyo, Oct. 26–27, 1998 and the 49th annual meeting of the Japan Wood Research Society, Tokyo, April 2–4, 1999     

Preparation of strongly acidic cation-exchange resins from gymnosperm acid hydrolysis lignin

The chemical preparation of strongly acidic cation-exchange resin from sulfuric acid lignin (Klason lignin) (SAL), a typical acid hydrolysis lignin, was investigated. Sulfonation of resinified SAL itself gave a resin with an ion-exchange capacity of 2.3 mEq/g. After resinification with formaldehyde, the phenolized SAL with a reactivep-hydroxyphenyl group yielded a resin with an ion-exchange capacity of 3.2 mEq/g. The latter capacity is superior to that of the corresponding commercial phenol-type resins (2–3 mEq/g), but did not reach the level of the corresponding commercial styrene-type resins (4-5 mEq/g).This paper was presented at the 43th Lignin Symposium, Fuchu, October 1998     

饲草高粱茎秆特征与抗倒性关系分析

为探讨饲草高粱（Sorghum bicolor（L.）Moench）茎秆特征与抗倒性关系，本研究以2013-2017年田间选择的农艺性状一致的不同抗倒性饲草高粱为试验材料，分析了主茎鲜重、主茎重心、主茎抗折力、木质素含量等茎秆特征指标与倒伏系数的关系，以及倒伏系数与倒伏指数（田间实际倒伏情况）的相关性。结果表明，不同抗倒性饲草高粱主茎鲜重、主茎重心指标无显著差异，但主茎抗折力、木质素含量呈显著性差异（P<0.05）。相关性分析得出，饲草高粱倒伏系数与主茎抗折力呈极显著负相关（P<0.01）；木质素含量与倒伏指数、倒伏系数的相关系数分别为-0.215，-0.131，无显著相关性；倒伏系数与倒伏指数的相关系数为0.224，无显著相关性。本研究表明，倒伏系数、木质素含量作为饲草高粱抗倒性评价指标还需进一步分析。     

不同生育期橡胶树幼茎细胞壁三要素的变化动态

对巴西橡胶树热研7-33-97半年生组培苗的木质部不同发育时期的木质素、纤维素和半纤维素含量进行测定分析,用Van Soes方法计算得到木质素、纤维素和半纤维素的含量。结果表明,木质素、纤维素和半纤维素在生长发育过程中的含量随着生长发育逐渐增加。其中木质素与纤维素的含量随着生长发育趋于稳定状态,而半纤维素的含量从GX期开始迅速增加,直到SX期也没有出现趋向稳定的趋势;木质素/纤维素的比值在发育过程中变化不大,木质素/半纤维素的比值及纤维素/半纤维素的比值在GX期均达最大。木质素与纤维素的相关性显著,积累是同步的。