指数施磷模式对闽楠幼苗生长及光合生理特性的影响

Effects of exponential phosphorus application on the growth and photosynthetic physiological characteristics of Phoebe bournei seedlings

【目的】探究不同指数施磷水平对闽楠幼苗生长和光合生理特性的影响,为土壤磷背景值较低地区培育优质闽楠苗木提供理论依据。【方法】以金洞林场1年生闽楠容器苗为研究对象,设置7组指数施磷水平、1组平均施磷水平和不施磷组共9组处理,分析不同施磷处理对闽楠幼苗生长、生物量分配、根系形态和光合生理特性的影响,运用主成分分析筛选出最佳的施磷水平和施磷模式。【结果】1)施磷促进了闽楠幼苗苗高、地径的生长,随着施磷水平的提高均表现出先增加后降低的趋势。2)施磷对闽楠幼苗叶、茎、根生物量分配的影响存在差异,随着施磷水平的提高,各器官生物量表现为先增加后降低的趋势,在指数施磷2000 mg/株时达到最大,其次是指数施磷1600 mg/株,根冠比表现为先降低后升高,在CK时表现最高。3)施磷促进了根系的发育,随着施磷水平的提高,根系总根长,根表面积和根体积均表现出先增加后降低的趋势,而对根平均直径无显著影响。4)施磷促进了闽楠幼苗叶绿素的合成和光合作用的进行;随着施磷水平的提高,闽楠幼苗叶绿素a、叶绿素b、总叶绿素质量分数和表观量子效率(α)、最大净光合速率(P_(nmax))均呈先上升后降低的趋势,而光饱和点(LSP)则随着磷水平的提高而提高。【结论】合理的磷素施加可以有效促进闽楠幼苗的生长发育和光合作用;磷素过低会对幼苗生长和光合生理形成限制,而过高会造成抑制,均不利于幼苗的生长和光合作用的进行;主成分分析表明,闽楠幼苗最佳的指数施磷水平在1600~2000 mg/株;指数施磷相比平均施磷有利于闽楠幼苗苗木质量的培育和提升。

【Objective】In order to provide a theoretical basis for the cultivation of high-quality Phoebe bournei seedlings in areas with low soil phosphorus background values,this research studied the effects of different phosphorus index levels on the growth and photosynthetic physiological characteristics of Phoebe bournei seedlings.【Method】Taking Jindong annual Phoebe bournei container seedlings as the research object,we set up 9 treatments(7 groups of index phosphorus application level,1 group of average phosphorus level and no phosphorus application group)and analyzed different phosphorus application processes of Phoebe bournei seedlings including growth,biomass allocation,the influence of the root morphology and photosynthetic physiological characteristics.By using principal component analysis,the best phosphorus application level and mode were screened out.【Results】1)The application of phosphorus promoted the growth of seedling height and ground diameter of Phoebe bournei,and it showed a trend of increasing at first and then decreasing with the increase of phosphorus application level.2)There were differences in the effects of phosphorus application on the biomass distribution of leaves,stems and roots of Phoebe bournei seedlings.With the increase of phosphorus application level,the biomass of each organ showed a trend of first increasing and then decreasing,reaching the maximum at index phosphorus application of 2000 mg per plant,followed by the index phosphorus application of 1600 mg per plant.The root cap ratio first decreased and then increased,and the highest performance was at CK.3)Phosphorus application promoted root development.With the increase of phosphorus application level,the total root length,root surface area and root volume all showed a trend of first increasing and then decreasing,but there was no significant influence on the average root diameter.4)Phosphorus application promoted the synthesis of chlorophyll and photosynthesis of Phoebe bournei seedling leaves.While the light saturation point(LSP)increased with the increase of phosphorus levels,chlorophyll a,chlorophyll b,total chlorophyll mass fraction,apparent quantum efficiency(α),and maximum net photosynthetic rate(P_(nmax))of Phoebe bournei seedlings all showed a trend of increasing at first and then decreasing.【Conclusion】Reasonable application of phosphorus can effectively promote the growth and photosynthesis of Phoebe bournei seedlings.An extreme low content of phosphorus will limit the growth and photosynthetic physiology of seedlings,while a too high concentration of phosphorus will cause inhibition,which is not conducive to the growth and photosynthesis of seedlings.Principal component analysis showed that the optimum index phosphorus application level of Minnan seedling was 1600-2000 mg per plant.Compared with average phosphorus application,index phosphorus application is beneficial to the cultivation and improvement of the seedling quality of Phoebe bournei.