Hancock Jessica E, Loya Wendy M, Giardina Christian P, Li Laigeng, Chiang Vincent L, Pregitzer Kurt S
Ecosystem Science Center, School of Forest Resources and Environmental Sciences, Michigan Technological University, Houghton, MI 49931, USA.
United States Department of Agriculture-Forest Service. North Central Research Station, 410 MacInnes Drive, Houghton, MI 49931, USA.
New Phytol. 2007;173(4):732-742. doi: 10.1111/j.1469-8137.2006.01965.x.
We conducted a glasshouse mesocosm study that combined (13)C isotope techniques with wild-type and transgenic aspen (Populus tremuloides) in order to examine how altered lignin biosynthesis affects plant production and soil carbon formation. Our transgenic aspen lines expressed low stem lignin concentration but normal cellulose concentration, low lignin stem concentration with high cellulose concentration or an increased stem syringyl to guaiacyl lignin ratio. Large differences in stem lignin concentration observed across lines were not observed in leaves or fine roots. Nonetheless, low lignin lines accumulated 15-17% less root C and 33-43% less new soil C than the control line. Compared with the control line, transformed aspen expressing high syringyl lignin accumulated 30% less total plant C - a result of greatly reduced total leaf area - and 70% less new soil C. These findings suggest that altered stem lignin biosynthesis in Populus may have little effect on the chemistry of fine roots or leaves, but can still have large effects on plant growth, biomass partitioning and soil C formation.
我们进行了一项温室中型生态系统研究，该研究将¹³C同位素技术与野生型和转基因白杨（颤杨）相结合，以研究木质素生物合成的改变如何影响植物产量和土壤碳形成。我们的转基因白杨品系表现出低茎木质素浓度但纤维素浓度正常、低木质素茎浓度且高纤维素浓度或茎中紫丁香基与愈创木基木质素比例增加。各品系间茎木质素浓度存在很大差异，但在叶片或细根中未观察到这种差异。尽管如此，低木质素品系的根碳积累量比对照品系少15 - 17%，新土壤碳积累量比对照品系少33 - 43%。与对照品系相比，表达高紫丁香基木质素的转基因白杨总植物碳积累量减少30%——这是总叶面积大幅减少的结果——新土壤碳积累量减少70%。这些发现表明，杨树茎木质素生物合成变化可能对细根或叶片的化学性质影响不大，但仍可对植物生长、生物量分配和土壤碳形成产生重大影响。
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