摘要
有关氮(N)∶磷(P)供给比例对苗木P吸收和利用影响的研地究仍存在盲点。选用长白落叶松(Larix olgensis Henry.)播种苗作为材料,对比了1∶3、1∶2、1∶1、2∶1、3∶1五个N∶P供给比例对温室条件下苗木生长、针叶和根系中P的含量以及P的吸收和利用效率的影响差异。另设试验对比了分别以NH+4-N和NO-3-N为N源情况下5个N∶P比例对P吸收的动力学特征的影响差异。结果表明:1)随着N∶P比例的增加根系有变粗和变长的趋势且根系生物量分配逐渐提高(P=0.0027);2)1∶2比例下叶片P浓度较2∶1和3∶1比例分别提高37%和45%(P=0.0187),但是P利用率却分别下降了84%和37%(P=0.0008),并且P吸收效率分别下降了48%和62%(P=0.0004);3)NH+4-N环境中,随着N浓度提高,P吸收速率呈线性上升(R2=0.908),而在NO-3-N环境中P吸收速率和N∶P比例间无相关关系(R2=0.005)。前者和后者环境中Vmax值分别为0.89和0.60 mmol/h/gFM,Km值分别为0.15和0.03 mmol/L。综上:如在N、P同时存在的情况下欲提高长白落叶松苗木对P的吸收和利用效率,可考虑适当控制N的硝化并在一定范围内提高N∶P供给比例。
The effect of supply ratio of nitrogen（N）： phosphorus（P） on P uptake and utilization in germinated Changbai larch（Larix olgensis Henry.） was analyzed in our research.The seedlings were cultivated in a greenhouse where fertilizers were supplied according to N ∶ P ratios of 1 ∶3,1 ∶2,1 ∶1,2 ∶1 and 3 ∶1.Seedling morphology and biomass accumulation,P content and concentration of needles and roots were measured.The method of vector diagnosis was used to analyze the interactions among biomass,P content and P concentration.Some seedlings were cultivated in hydroponic solutions for six hours to detect their kinetic characteristics.Two inorganic N sources,NH＋4-N and NO-3-N,were employed to create the same N ∶ P ratios in the greenhouse experiment with the P source of PO3-4,separately.The results showed that root biomass accumulation and diameter increased significantly with the increase of N ∶ P ratio（P=0.0027 and 0.10013,respectively）.Compared to the N ∶ P ratio of 1 ∶1,the N ∶ P ratio of 3 ∶1 increased the fine root length,surface area and volume by 14%（P=0.0178）,21%（P=0.0004） and 5%（P=0.0009）,respectively.Root P concentration,root P content and needle P content were not affected by N ∶ P ratios（P0.05）.However,needle P concentration was higher in N ∶ P ratio of 1 ∶2 than 2 ∶1（P=0.0270） and 3 ∶1（P=0.0014）,but it was not significantly different from that in N ∶ P ratios of 1 ∶3（P=0.0669） and 1 ∶1（P=0.0804）.In N ∶ P ratios of 2 ∶1 and 3 ∶1,P utilization index was higher than the N ∶ P ratio of 1 ∶2 by 84%（P=0.0002） and 37%（P=0.0014）,respectively.With the increase of N ∶ P ratio,P uptake efficiency increased linearly.N ∶ P ratio positively correlated with P uptake efficiency（R2=0.978）.Vector diagnosis indicated that,compared to the N ∶ P ratio of 1 ∶2,the N ∶ P ratio of 1 ∶1 resulted in a nutrient dilution while the N ∶ P ratios of 3 ∶1,2 ∶1 and 1 ∶3 resulted in a nutrient deficiency for needles;the N ∶ P ratio of 2 ∶1,1 ∶1 and 1 ∶3 resulted in a nutrient excess while the N ∶ P ratio of 3 ∶1 resulted in a nutrient dilution for roots.The activity of acid phosphatase of needles in the N ∶ P ratios of 2 ∶1 and 3 ∶1 was higher than that in the N ∶ P ratio of 1 ∶1（P=0.0026） while the activity of acid phosphatase of roots in the N ∶ P ratio of 1 ∶2 was higher than that in 1 ∶1（P=0.0003）.In solutions containing NH＋4-N or NO-3-N,the P uptake rate did not change among N ∶ P ratios（P=0.3247 and 0.0934,respectively）.However,the P uptake rate linearly and positively correlated with the ratio of NH＋4-N ∶ P（R2=0.908）,while there was no significant correlation between P uptake rate and NO-3-N ∶ P ratios（R2=0.005）.In solutions supplied with NH＋4-N and NO-3-N,Vmax and Km were regressed to be 0.89 and 0.60 mmol/h/g FM and 0.15 and 0.03 mmol/L,respectively.In conclusion,for improving the efficiencies of P uptake and utilization of larch seedlings under the circumstance of both supplied N and P,nitrification should be avoided and the N ∶ P ratio should be increased within a certain range.
出处
《生态学报》
CAS
CSCD
北大核心
2013年第2期659-667,共9页
Acta Ecologica Sinica
基金
国家林业局"十一五"科技支撑项目(2006BAD24B01)
林业公益行业科研专项资金项目(201004021)
国家林业局林业科学技术推广项目(2011-44)
