【摘要】 以三年生红波罗花为试验材料,比较了不同氮处理下植株的叶片性状、气体交换特性、叶氮分配、叶绿素荧光和生长参数,探讨了在高山环境中氮素对红波罗花光合特性和生长的影响。结果表明:不施氮时,虽然红波罗花减少了叶氮在捕光复合体中的分配,但还是出现了光抑制现象,并且由于叶氮含量(N)、叶绿素含量(Chl)和叶氮在光合组分中的分配量是最少的,导致光合能力最低,生长最缓。随外界施氮量的增加,红波罗花的N,Chl,叶肉厚度、叶氮在光合组分中的分配量(NR、NB、NL),光能利用效率均随之增加,光合能力相应增强。三个施氮处理中,红波罗花分配给生物力能学组分的叶氮(NB)多于分配给Rubisco的(NR),从而导致Jmax/Vcmax增加,有利于其适应高山低温和高光强。施氮量增加,植株的相对生长速率(RGR)增加,这对于红波罗花当年的开花繁殖,以及来年的生长发育都非常有利。当施氮量超过0.2g/kg基质时,植株的N,Chl,叶肉组织厚度、光合速率以及RGR都不再显著增加,因此当土壤中纯氮含量为220～230mg/kg时,即能满足红波罗花较佳光合和生长所需。更多还原

【Abstract】 To investigate the effects of nitrogen fertilization on the photosynthetic capacity and growth of three-year old potted-plants of I.delavayi,an alpine herb,the effects of nitrogen supply on the foliage traits,gas exchange response curves,leaf nitrogen partitioning,chlorophyll fluorescence parameters and growth parameters were examined.The results showed that when the nitrogen supply was 0 g/kg,severe photoinhibition occurred though the leaf nitrogen allocation to light harvesting system complex decreased in I.delavayi.In addition,the leaf nitrogen content allocated to the photosynthetic components was smallest among all treatments,which resulted in the worst photosynthetic capacity and slowest relative growth rate of whote plant(RGR).With nitrogen supply increased,the leaf nitrogen content(N),chlorophyll content(Chl),leaf nitrogen content allocated to the photosynthetic components(NR、NB and NL) and light utility efficiency increased correspondingly,and it contributed to photosynthetic capacity enhancing.Because the leaf nitrogen content allocated to bioenergetics was more than to Rubisco,after offering nitrogen fertilizer,Jmax/Vcmax increased,which helped I.delavayi adapt to the alpine environment,such as lower temperature and higher irradiance.With nitrogen supply increasing,the speed of growth of I.delavayi was accelerated,which was benefit to the reproduction and next-year growth.When nitrogen supply was more than 0.2 g/kg,N,Chl and the thickness of mesophyll tissue,photosynthetic rate and RGR did not increase statistically.In a word,the optimum amount of nitrogen needed by the I.delavayi was about 220-230 mg/kg soil.更多还原