ts ofelevated atmospheric CO. concentrations on the ecophysiological responses (gas exchange, chlorophyll a fluorescence, Rubisco activity, lear area development) as well as on the growth and biomass production of two poplar clones (i.e. Populus Irichoearpa×P deltoides clone Beaupre and P. ×euramericana clone Robusta) were examined under open top chamber conditions. The elevated CO2 treatment (ambient+350μmol mol-1) stimulated above-ground biomass of clones Rohusta and Beaupr6 after the first growing season by 55 and 38%, respectively-This lncreased biomass production under elevated CO2 was associated with a significant increase in plant height. the latter beingthe result of enhancedInternode elongation ratherthan alllncreased production of leaves or internodes Both an Increased leararea index (LAI) and a stimulated net Dhotosvnthesls per unit leaf contributed to a significantly higher stem biomassperunitleararea. andthustothelncreased above-ground biomassproduction underthe elevated CO2 concentratlons 1n both clones The larger LAl was caused by a larger individuaI leaf size and lear growth rate: the number ofleaveswas not altered bythe elevatedCO2 treatment The highernetlearphotosynthesiswasthe result of an 1ncrease 1n the hotochemical fmaximal chlorophyll fluorescence Fm and photochemical efficiency Fv/Fm)as well as m the biochemical (increased Rubisco activity) process capacities No significant difierences were found in dark respiration rate, neither between dongs nor between treatments, but specific leaf area significantly decreased under elevated CO2 conditions.

灭幼脲（邻氯苯甲酰基-对氯苯基-脲）本身是一种低毒、低残留、没有致突、致癌性的农药。但是它的某些分解产物，如：氯苯、对氯苯、对氯苯基脲等有一定的毒性。邻氯苯甲酰胺（灭幼脲的主要光解产物--cBA）和未经分离的灭幼脲光解产物的混合物，在试管反应条件下能与小牛胸腺 DNA 反应形成多种 DNA 加合物，用P1加强灵敏度的22P后标记方法分析，有四种 DNA 加合物被检出（DNA-CBA），实验证明，邻氯苯甲酰胺和灭幼脲光解产物的混合物在Ames 实验中也均呈阳性结果，初步说明两者都可能具有一定的致突性。经单独碱基和邻氯苯甲酰胺试管反应的加合物鉴定，验证出其中较强的一种加合物是邻氯苯甲酰胺与2’脱氧腺嘌呤-3’-单磷酸碱基（dAMP）反应所形成的加合物（dA-cBA），且占所形成加合物总量的57%。从32P后标记方法所测的DNA加合物的自显影指纹图上二可以看出，邻氯苯甲酰胺和灭幼脲光解产物混合物的 DNA 加合物具有相同的迁移特性。初步说明，尽管灭幼脲原体化合物没有致突性，但它的主要光解产物邻氯苯甲酰胺具有一定基因突变性，所以不仅应对原体化合物进行评价。而且还必须对它的分解物和代谢物同时进行安全评价。

Lignin is a complex aromatic polymer of vascular plants that provides mechanical strength to the stem and protects cellulose fibres from chemical and biological degradation. 4-Coumarate: CoAligases (EC 6.2.1.12) are key enzymes for the biosynthetic pathway of monolignols which is an important complex aromatic polymer for lignin biosynthesis and tree growth. Recently, 4-coumarate: CoA ligase has been used as exogenous gene in transgenic plants to genetically modify the lignin biosynthesis pathway. Since most lignin is produced in the vascular cells, a tissue-specific-expressed promoter in the vascular cell would be important and useful to change and modify the content of lignin. Here we eport the existence of a promoter of GRP1.8 (the glycine-rich protein 1.8) in Sopho japonica L. (GenBank accession number AF250149) and studies on its function in transgenic tobacco. The promoter activity was analyzed in transgenic tobacco plants by histochemical staining of GUS gene expression driven by a 613-bp sjGRP1.8p promoter sequence. In sjGRP1.8p-GUS transgenic plants, intense GUS staining was detected in the xylem of the stem. To further investigate the regulation of the tissue-specific xpression of the 4CL1 gene, we analyzed the activity of the 4CL1 gene which is sense orientated with the sjGRP1.8p promoter in transgenic tobacco. The Pto4CL1 gene was expressed in the stem of ransgenic tobacco. The activity of the 4CL1 enzyme was increased 1-2-fold in the stem but not increased in the leaves of transgenic tobacco. In comparison with the control plants, the content of lignin was ncreased 25% in the stem but there was no increase in the leaves of transgenic tobacco.