硅氮添加对高寒草甸优势物种披针叶黄华生长及净光合速率的影响

Effects of silicon and nitrogen fertilization on the growth and net photosynthetic rate of Thermopsis lanceolata in an alpine meadow

以青藏高原高寒草甸群落中披针叶黄华(Thermopsis lanceolate)为研究对象,通过施加氮肥(60 g·m^–2)、施加不同浓度梯度硅肥(0、4、8、12 g·m^–2)、同时施加氮肥硅肥的试验,研究氮硅添加对其生长及净光合速率的影响。结果表明:1)在氮添加、硅添加以及氮硅同时添加下,披针叶黄华株高均有不同程度的增加;2)单独添加硅肥后,随着硅肥施用量的增加,其单株干重、叶片干重、比叶面积及净光合速率随着硅肥施用量的增加呈现先增加后减少的趋势;3)单独添加氮肥后,其单株干重、叶片干重、比叶面积及净光合速率显著下降(P<0.05);4)与单独添加氮肥相比,硅氮肥同时添加(NSi1、NSi2、NSi3),均可提高植物的比叶面积和净光合速率;5)披针叶黄华的净光合速率与比叶面积具有显著正相关关系。综合研究发现,氮肥添加抑制披针叶黄华的生长,引起其净光合速率的下降,而添加氮肥的同时添加硅肥,对生长及净光合速率有促进作用。

To clarify the effect of the addition of nitrogen and silicon fertilizer on the growth and net photosynthetic rate of Thermopsis lanceolate,we set up experiments in an alpine meadow.The treatments were nitrogen fertilizer(60 g·m^–2)addition,silicon fertilizer(0,4,8,and 12 g·m^–2)addition,and mixed addition of nitrogen and silicon fertilizer.The results are as follows:1)after nitrogen fertilizer,silicon fertilizer,and mixed fertilizer addition,the plant height of T.lanceolate increased to various degrees;2)after silicon fertilizer was added,with the increase in application,plant biomass,leaf biomass,specific leaf area,and net photosynthetic rate assumed a trend where it first increased and subsequently decreased;3)after nitrogen fertilizer was added,plant biomass,leaf biomass,specific leaf area,and net photosynthetic rate decreased significantly(P<0.05);4)compared with nitrogen fertilizer addition alone,addition of silicon fertilizer along with nitrogen fertilizer(NSi1、NSi2、and NSi3)enhanced the specific leaf area and net photosynthetic rate of the plant;and 5)there was a significant positive correlation between specific leaf area and net photosynthetic rate in the plant.Our studies found that nitrogen fertilizer addition inhibited the growth of T.lanceolate and decreased net photosynthetic rate;however,addition of silicon fertilizer along with nitrogen fertilizer improved both characteristics.