油菜素内酯合成基因DWF1、DET2影响毛白杨木质部形成

Influences of brassinolide synthesis gene DWF1 and DET2 on xylem formation in Populus tomentosa

油菜素内酯对植物的生长发育有重要的调控作用。以转油菜素内酯合成基因GhDWF1和GhDET2的毛白杨为材料,对其生长、木质部显微结构、细胞壁化学组成进行分析,发现油菜素内酯合成基因DWF1和DET2基因的转入影响了毛白杨的木质部形成和细胞壁组分。转基因毛白杨的木质部面积明显高于对照,且细胞较小,细胞壁较厚,可以推测毛白杨体内细胞的分裂和横向扩大受到影响;导管上的纹孔增大,可能会影响水分运输;酸性果胶升高,纤维素含量降低,可能改变了细胞壁的框架结构;转GhDET2基因的毛白杨的木质素含量较高,S型木质素含量较高,化学降解相对容易;而转GhDWF1的毛白杨的木质素含量较低,G/S比最高,S型木质素含量较小。

Brassinolides are important for plants growth and development. Transgenic poplars with brassinolides biosynthesis genes Gh DWF1 and Gh DET2 were selected and analyzed about the growth,microstructure of xylem and cell wall composition. It was found that DWF1 and DET2 had influences on xylem formation and cell wall composition in Populus tomentosa. Transgenic poplars had higher xylem area,smaller cells and thicker cell walls than the control,which may affect cell division and lateral expansion. Pits on vesselswere enlarged,which may affect water transport in poplars. Contents of acidic pectin increased,and contents of cellulose decreased in transgenic poplars, which may change frame structures of cell wall. Transgenic poplars with Gh DET2 had higher lignin content and high S-lignin ratio, which may cause chemical degradation easily,while transgenic poplars with Gh DWF1 had lower lignin content,higher G/S ratio and smaller S-lignin content .